Laguna Gloria Site Assessment and Natural Area Management Guidelines by Siglo Group

Laguna Gloria Site Assessment and Natural Area Management Guidelines by Siglo Group
Site Assessment & Natural Areas Management Guidelines Laguna Gloria Produced for AMOA-Arthouse by Siglo Group, June 2013
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines Numerous individuals gave input into this report. Their help is greatly appreciated. Contributors included: Judith Sims (AMOA-Arthouse), Louis Grachos (AMOA-Arthouse), Terry Quinn (AMOA-Arthouse),Danielle Nieciag (AMOA-Arthouse), Aaron Lovell (AMOA-Arthouse), Cassandra Smith (AMOA- Arthouse), Jill Nokes (Nokes Landscape Design), Jason Singhurst (Texas Parks and Wildlife Department), Mateo Scoggins (City of Austin), Andrew Clamann (City of Austin), Mary Gilroy (City of Austin), Kathryn Murray (City of Austin), Clay Bales (Texas Forest Service), Jim Rooni (Texas Forest Service), Chris Yanez (City of Austin), Matt McCaw (City of Austin), Keith Olenick (Landmark Wildlife Management). www.siglogroup.com, info@siglogroup.com 512.699.5986 Integrating Land Use and Natural Systems: Siglo Group uses the power of geographic information to help our clients integrate land use with natural systems. We specialize in conservation planning, regional analysis, site assessment, cartography, and spatial analysis. Our work has contributed to land being set aside in perpetuity for conservation, policies and projects that work towards more sustainable land use, good development, and a greater understanding of the attributes and values of land. Project Team: Jonathan Ogren, Daniel Dietz, Johanna Arendt, Matt Fougerat, Cullen Hanks, and Juliet Whitsett
Siglo Group INTRODUCTION, 1 ECOLOGY, 5 Topography, 6 Hydrology, 6 Geology, 7 Soils, 8 Vegetation And Ecological Classification, 9 Historic Land Use Changes, 14 Trees, 16 Wildlife, 17 Potential Wildlife List, 18 Plant List, 19 NATURAL AREAS MANAGEMENT GUIDELINES, 21 Balancing Natural Resource Objectives with Visitor Needs, 22 Off-trail Recreation, 22 Invasive Plants, 23 Invasive Plant Control Methods, 24 Native Plantings, 25 Invasive Species Control Guide, 26 Poison Ivy, 31 Zonal Approach, 31 Zone A: Slope Woodland, 31 Zone B: Floodplain Forest, 34 Zone C: Path to the Point, 36 Zone D: Meadow, 37 Monitoring Progress, 39 Involving The Community, 41 Budget, 41 Schedule, 41 Monitoring Locations, 44 Photopoints, 47 SITE ASSESSMENT, 63 Water Quality Buffers & Floodplain, 64 Critical Environmental Features, 64 Zoning, 64 Historic Designation, 65 Infrastructure. 65 Stormwater Retention, 66 Boardwalk and Docks, 66 Parking, 67 Impervious Cover, 67 Concepts for Future Development, 68 Net Site Area & Allowable Impervious Cover, 69 City Contacts, 69 VISITOR EXPERIENCE, 71 Orientation, Wayfinding, & Interpretation, 72 Pathways, 73 Gathering Places & Services, 74 Scenic Views & Vegetative Buffers, 76 Accessibility, 78 Entry Sequence, 79 Programming, 80 BIRDS & BIRDING, 81 CONCLUSION, 87 SOURCES, 91 Table of Contents
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve TaylorCreek TaylorCreek LakeAustin Scenic DrScenic Dr M tBonnellRd M tBonnellRd W 35th St W 35th St LakeAustin 00 300’ Property Boundaries Sources: COA, Travis CAD Laguna Gloria & Mayfield Park Laguna Gloria & Mayfield Park Laguna Gloria & Mayfield Park Laguna Gloria & Mayfield Park AmphitheaterAmphitheater Art SchoolArt School Floodplain Forest Floodplain Forest Driscoll VillaDriscoll Villa W 35th St W 35th St Temple of LoveTemple of Love Birder’s PointBirder’s Point Boat RampBoat Ramp AmphitheaterAmphitheater Art SchoolArt School Floodplain Forest Floodplain Forest Driscoll VillaDriscoll Villa W 35th St W 35th St Temple of LoveTemple of Love Birder’s PointBirder’s Point Boat RampBoat Ramp L a g o o nL a g o o n 1
Siglo Group 2 00 4 miles Introduction Laguna Gloria ContextLaguna Gloria Context Laguna Gloria is an incredible place to experience art and nature. This report provides baseline information about the property for future designers, staff, stake- holders, and board members of AMOA- Arthouse to use as they re-envision Laguna Gloria as a renowned art experience in a natural setting. The report is broken up into five sections: Ecology, Natural Areas Management Guidelines, Site Assessment, Visitor Experience, and Birds and Birding. Each of these sections builds on and comple- ments the others. The end result is a guide that gives artists, curators, and designers a framework through which to envision the futureofthesite. This should be thought of as a dynamic document that is added to as new information comes to light. The report is grounded in concepts of ecology, restoration and sustainable land management. It incorpo- rates information from previous studies, field observations (from January to May of 2013), relevant city codes and ordinances, as well as data from federal, state, and local databases. It is not meant to be a survey or fully comprehensive, but rather provides a snapshot of various aspects of the site that need to be considered as future plans are formedandimplemented. The Laguna Gloria site comprises approximately 12 acres on the eastern bank of Lake Austin in Austin, TX. This report focuses on the natural areas of Laguna Gloria, including more than 2,900 feet of Lake Austin waterfront. Where appropriate, it also looks beyond the site's borders at interactions with the adjacent Mayfield Park and Preserve, which is approximately 23 acres, and with LakeAustinitself. The site is part of the Edwards Plateau ecosystem and is an ecological refuge, holding numerous and diverse plant and animal communities that are now hard to find in the urbanized Austin Area. Habitats range from floodplain forest and marsh to oak savanna, open meadow and sloping woodland. The site is made up of two major terraces, with the lower terrace only a few feet above the water level of Lake Austin. The upper terrace contains the historic Driscoll Villa area (approximately 2 acres), the art school area to the east, and associated parking and grounds. The terraces are joined by steep slopes, with a ridge running down to the Temple of Love. The site's ecological significance is showcased by the majestic oak woodlands in the upper areas, the floodplain forest on the shore of the lake, the marsh, and the over 210 bird species recorded at the site, which have made Laguna Gloria the third most birded site in TravisCounty. While the 2-acre historic area containing the Driscoll Villa and its grounds is of great significance to any design going forward, it is not covered in detail here. It has been well assessed by O'Connor and Levin (1999). Their compelling retelling of the site's history includes its ownership by Stephen F. Austin from 1832 to 1836, two archeological sites on the property with potential human activity as far back as 5,000 years, and the story of Clara Driscoll's vision, design, and development of the property. This report echoes Driscoll's vision of maintaining the natural elements of the site and providing a place for visitors to experi-
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines enceartandnaturetogether. In the Natural Areas Management Guide- lines section, a five year plan is outlined for improving the ecological health of the property. The management guidelines are based on the concepts of ecological restoration, which is the process of improving of the site’s natural ecological functions such as holding and creating soil, filtering water, providing habitat for native wildlife, and maintaining vibrant native plant communities that include trees, understory, forbs and grass species. The management guidelines are meant to improve ecological functions and enhance the visitor experience in majestic,healthynativeplantcommunities. The spaces created naturally by the site's plant communities can be seen as rooms of a gallery in which art pieces are displayed. As with any gallery, and perhaps especially in this case, the space itself can become integral to the exhibit. The recognition of the site's unique natural characteristics and the coordination of natural areas management with design, exhibit curation, and art creation will optimize the overall use of the site. The Natural Areas Management Guidelines section discusses potential management challenges and recommends a path forward using a zonal approach based on the property'sdistinctecologicalareas: Zone A: Sloping Woodlands, found§ aroundthehistoricarea; Zone B: Floodplain Forest, located next§ to the water's edge, and likely the area mostsensitivetohumandisturbance; Zone C: Path to the Point, the historic§ walk through the woods that connects theVillatotheTempleofLove; Zone D: Meadow, a highly modified§ component of the lower terrace that offers the most opportunity for change inthefuture. For each of these areas, treatments are recommended throughout a five year period including invasive species control, restoration, and adaptive management techniques such as regular monitoring. Information is provided in both narrative and tabular formats, and is accompanied by a summary AerialimageoftheLagunaGloria. Source:Bing 3
Siglo Group of treatments and a work schedule. For this plan to be successful, it will require the ongoing involvement of professional consultants, AMOA-Arthouse staff, resource allocation, and ongoing management. Moving forward, numerous regulatory and physical issues will need to be considered as well. In the Site Assessment section, this report looks at water quality buffers and floodplains, critical environmental features, zoning, historic designation, infrastructure, boardwalks and docks, impervious cover, net site area, and concepts for future development. There are various challenges including required building setbacks (because Lake Austin supplies drinking water to the city), environmental features, substantial slopes, the site's single-family residential zoning, its State Archeological Landmark, its partial historic designation, the risk of flooding, and the fact that no new impervious cover is allowed. However, there are new technolo- gies to reduce impervious cover, and this site assessment also confirmed that there is substantial opportunity to increase visitors' accesstoLakeAustin. Inallcases,becauseof the uniqueness of the site within the regulatory framework, developing and imple- menting a new design will likely entail detailed dialogue and cooperation with the CityofAustinregulatorydepartments. The integration of the site's ecology, management, and design will define the visitor experience into the future. In the Visitor Experience section, the four management zones are assessed to understand the movement of individuals through the site, their potential impacts, and general opportunities for design into the future. This assessment should not limit design ideas, but rather support them by providing information about the existing and future needs of the site and its visitors. This section looks at the site's entry sequence, visitor orientation, wayfinding system, pathways through the site, gathering places, scenic views and vegetative buffers, mobility issues, connec- tivity, water access, and potential programming. Analyzing the natural area management needs and the visitor experience together allows the two to inform each other and to illuminate mutually beneficial opportunities that might not have been evidentotherwise. This report touches on key elements to consider while re-envisioning and designing the future of the site. The natural structure of the site offers a framework in which to integrate land management, design, and the visitor experience. It is the goal of this report to support the creation of a place-based art museum showcasing nationally and interna- tionally acclaimed artists with a robust visitor experience that seamlessly combines artandnature. 4
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & PreserveDriscoll Villa Driscoll Villa Art School Art School TaylorCreek TaylorCreek LakeAustin Scenic DrScenic Dr M tBonnellRd M tBonnellRd W 35th St W 35th St LakeAustin TopographyTopography 00 300’ Property Boundaries Slopes 15 to 25% Slopes 25 to 35% Slopes Greater than 35% 2’ Contours Sources: COA, Travis CAD 5
Siglo Group 6 The ecological characteristics and history of Laguna Gloria add up to make the site we see today. From the creation of the Hill Country limestone over 200 million years ago and the rise of the Balcones Escarpment over 12 million years ago to the initial damming of Lake Austin in the 1890s, events have woven together to make the literal bedrock, soils, vegetation communities, and wildlife of Laguna Gloria. Understanding the elements mentioned here provides us with the background to make informed decisions about natural areas management, design, andthevisitor'sexperience. TOPOGRAPHY The Laguna Gloria site consists of two relatively flat terraces connected by steep slopes. The highest part of the site is the historic area, which has an approximate elevation of 524 feet above mean sea level (msl). The property slopes from there down to the west to the lower terrace, which includes the meadow and floodplain forest, which has an approximate elevation of 495 feet above msl. A single ridge, ranging from 502 to 506 feet above msl, extends down the eastern side of the peninsula to the Temple of Love. The lowest elevation on the site is Ecology approximately 492 feet at the edge of Lake Austin. While much of the site is flat, the slopes that do exist are very steep. Significant slope percentages include: a 37% rise at the stairs west of the Driscoll House, 25% near the amphitheater, and 20% to the west of the Temple of Love and slopes over 60% behind the art school. These slopes are significant when thinking about the risk of erosion and about human accessibility, especially if new improvements areadded. Elements of interest within the topography include the rock outcrops found from the eastern edge of the property's waterfront to the Temple of Love area as well as the rim rock found behind the art school. The floodplain forest features microtopography, small undulations of the forest floor created through natural forest processes and historic manipulation of the environment. In addition, the slopes bordering the southern and western sides of the historic area that have been historically altered provide opportunities for views to the lake and throughtheproperty. The topography at Mayfield Park is surpris- ing and dramatic. Similar to Laguna Gloria, the historic homestead is on a flat terrace with a high elevation of 546 feet. Moving deeper into the site, sheer cliffs drop down to Taylor Slough in the interior of the property. In addition to these cliffs, there is undulating topography that can comfortably bring a hiker down to the water's edge. The connec- tion between Laguna Gloria and Mayfield Park is part of the upper terrace and is relatively flat until it gets to the water's edge where there are substantial slopes and rock outcrops that drop steeply 27 feet to Lake Austin. HYDROLOGY Laguna Gloria is located north of the lagoon formed by the juncture of Taylor Slough and Lake Austin. The entire property drains into Lake Austin and is part of the Lake Austin watershed. It is important to note that Lake Austin is the drinking water source for Austin and the two water treatment plants currently providing the city with water are very close to Laguna Gloria. The intake for the Albert R. Davis plant is only 840 feet upstream and the intake for the Albert H. Ulrichplantislessthanamiledownstream.
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines Based on soils found in the Floodplain Forest, it is likely that the peninsula and lower slopes of Laguna Gloria experienced flooding prior to the initial damming of Lake Austin in 1890, but the soils were not perpetually inundated by water as they are today. Tom Miller Dam, built in 1940 after two previous dams failed, has created a constant level lake that does not rise above 492.8 feet and is typically kept at 491.7 feet (LCRA 2013). The raised water table has increased the possibilities of what can grow and sustain itself at the Laguna Gloria site, from open water, to marsh, to floodplain forest. GEOLOGY The signature “stair-step” topography of the Balcones Canyonlands lent this region its name when early Spanish explorers described the bluffs as looking like a series of balconies rising up through the hills. This regional character can be seen in even relatively small sites such as Laguna Gloria where the museum and buildings sit atop a flat “balcony,” which then descends sharply tothe floodplainforestbelow. The underlying geologic layer causing this terracing at Laguna Gloria is the Fredericksburg group (Kfr). This complex group includes Edwards Limestone, Bee Cave Marl, and Comanche Limestone. This is the same layer that is found at the surface of the Barton Springs Aquifer recharge zone and that tops the aquifer on the Jollyville plateau(Barnes1974). The Fredericksburg group is famous for having numerous karst features (caves or sinkholes), although no such features are known to occur on the property. While one may assume that the limestone underneath Laguna Gloria has fractures that make the rock permeable, it is not connected to an aquifer system, being cut off from the Barton springs segment by the Colorado River. It is likely that any water that enters the limestone underneath Laguna Gloria flows directly into Lake Austin, which makes water quality protection measures on the site especially important. This is discussed in moredetailintheSiteAssessmentsection. Laguna Gloria sits at the heart of geologic activity in the area where the Balcones Faulting occurred somewhere between 12 and 27 million years ago. This uplift, GeologyGeology Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve TaylorSlough TaylorSlough LakeAustin Scenic DrScenic Dr M tBonnellRd M tBonnellRd W 35th St W 35th St LakeAustin 00 600’ Kfr-Fredericksburg Limestone Kgr(u)-Glen Rose Limestone Kdr-Del Rio Clay Sources: TNRIS Kgr (u)Kgr (u) KfrKfr KfrKfr KfrKfr KdgKdg 7
Siglo Group 8 running northeast and southwest through Austin, raised what is now the Hill Country to the west and lowered what is now the Blackland Prairies to the east for a net difference in elevation of over 1,000 feet. It is believed that the faulting occurred over a geologically short period of time. The Mt. Bonnell fault is the most dramatic of these faults with movement of more than 700 feet (McGlameryandDietz2008). SOIL According to map and soil data obtained from the United States Department of Agriculture's Natural Resources Conserva- tion Service, three soil map units containing three different soil series occur within the site'sboundaries. Lu (Less than 1% slope, occasionally flooded). Approximately 46% of the property is within this map unit, which includes all low areas on the peninsula. Lu is composed primarily of Gaddy soils. This excessively drained sandy alluvium has been deposited by the Colorado River in the last 10,000 years. It typically consists of loamy fine sand up to 17 inches deep, which is underlain by fine sand. This soil is characteristic of floodplains and is in fact found in the floodplain forest at Laguna Gloria. It is notfoundanywhereatMayfieldPark. Tef (18-40% slopes). Approximately 27% of the property is part of this map unit. It is found on the steep south facing slopes in the eastern portion of the property. Tef is composed primarily of the Tarrant soils series, which was formed from the residuals of weathered limestone. This well-drained soil has very low water holding capacity and a basic ph. A typical soil profile will consist of very stony clay as deep as 6 inches, with bedrock often found within the first foot. At both Laguna Gloria and Mayfield Park, the Sloping WoodlandisfoundinTef. UuE (1-12% slopes). Approximately 27% of the property is part of this map unit. This area includes the higher portions of the property where the buildings are located, as well as the land directly adjacent to the trail that leads to the Temple of Love. 40% of this map unit is classified as urban land with miscellaneous soils, and 35% of UuE is classified as Brackett soils, with minor components making up the remaining 25%. The Brackett soil series is well drained with very low water holding capacity and a basic SoilsSoils Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve TaylorSlough TaylorSlough LakeAustin Scenic DrScenic Dr M tBonnellRd M tBonnellRd W 35th St W 35th St LakeAustin TeF-Tarrant Lu-Gaddy UuE-Brackett VuD-Volente BrF-Brackett Sources: USDA-NRCS 00 600’ UuEUuE TeFTeF LuLu TeFTeF UuEUuE VuDVuD VuDVuDBrFBrF
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines ph. It is a clay loam until bedrock is reached. Because of the Laguna Gloria infrastructure, much of the UuE map unit has been manipulated over time, but it is the primary upland soil at Mayfield Park, and its natural expres- sioncanbeobservedthere. VuD (1- 8% slopes). This map unit is found at Mayfield Park in the valley floor formed by Taylor Slough. It consists of about 45% Volente soils, about 20% Urban land, about 25% other soils, and about 10% Rock outcrop and Mixed alluvial land. The Volente soil has a surface layer of dark grayish-brown calcareous clay loam about 22 inches thick. The next layer is brown calcareous silty clay that extends to a depth of about 46 inches. The underlying material isreddish-yellowcalcareousclayloam. VEGETATION AND ECOLOGICAL CLASSIFICATION Laguna Gloria resides within the Balcones FaultZone,whichisatthefareasternedgeof the Edwards Plateau ecoregion, less than 1 mile from the Blackland Prairie ecoregion to the east. The Edwards Plateau is one of four areas in the United States recognized as a center of plant diversity for both richness and rarity (Davis 1997). The Edwards Plateau is characterized by Cretaceous era limestone bedrock that supports a mosaic of vegetation ranging from live oak/ashe juniper savannas to mixed juniper oak woodlands and deciduous riparian areas. The vegetation in the region has been modified extensively by livestockgrazingandurbanization. Ecological communities have been mapped on the property based on the Texas Parks and Wildlife Department's Ecological System Classification database, and were refined based on field observations. The ecological systems and vegetation types below represent the current expression of vegetation on the property. They are subject to change over time due to management practices, changes in site conditions (such as climate change), or the passage of time since the last major disturbance (succession). Vegetation communities found at Laguna Gloria and Mayfield Park include: floodplain forest, limestone savanna and woodland, dry-mesic slope woodland, disturbed vegetation, and riparianmixedusedeciduousforest. In addition to this broad scale examination of vegetation, a list of individual plant species was created based on site visits during the Plant CommunitiesPlant Communities Laguna Gloria Floodplain Forest Limestone Savanna & Woodland Dry-Mesic Slope Woodland Disturbed Vegetation Riparian Mixed Deciduous Forest Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve TaylorSlough TaylorSlough LakeAustin Scenic DrScenic Dr M tBonnellRd M tBonnellRd W 35th St W 35th St LakeAustin 00 600’ Sources: TPWD, Field Observation 9
Siglo Group late winter and spring of 2013 and a mid- spring site visit by Noreen Damude in May 2011 as seen on pages 19 and 20. This list is not exhaustive, especially concerning plants that are dormant or out of season during late winterandspringmonths. Vegetation communities are not just associations of plant species, but also include the disturbance patterns with which they evolved and that help maintain them. In the floodplain forest, floods would have played a significant role in depositing sediment and selecting against plants that are not water tolerant. In the upland woodlands, wind and ice storms promote diversity by creating light gaps and depositing woody debris when trees are uprooted or large branches break. Understoryfiresreduceleaflitterand allow more light to penetrate to the ground, which increases Spanish oak recruitment, but reduces ashe juniper seedling abundance. Drought impacts all of the plant communities. Finally, human management, mostly in the form of selective species removal and the planting of non-native species, has played a substantial role in LagunaGloria'slandscape. Floodplain Forest: This vegetation type is found in the broad valley bottoms of large rivers in Texas. It is characterized by deep alluvial soils and a rich variety of deciduous hardwood species that are not found in upland areas. At Laguna Gloria, this system is found on the shore of Lake Austin and along the entire peninsula except for the ridgewheretheTempleofLoveislocated. Laguna Gloria has a rich diversity of overstory trees in the floodplain forest including bald cypress (Taxodium distichum) and cottonwood (Populus deltoids). However, pecan (Carya illinoinensis), green ash (Fraxinus Pennsylvania), and box elder (Acer negundo) are also common, as are the non- Floodplain ForestFloodplain Forest 10
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines native invasive Chinese tallow (Triadica sebifera) and chinaberry (Melia azedarach). The sub-canopy woody plant assemblage is equally diverse with dwarf palmetto (Sabal minor), cherry laurel (Prunus caroliniana), roughleaf dogwood (Cornus drummondii), possumhaw holly (Ilex decidua), Carolina buckthorn (Frangula caroliniana), and Mexican plum (Prunus mexicana) all present. Unfortunately, the non-native glossy privet (Ligustrum lucidum) is becom- ing the dominant small tree/large shrub in much of the area. The herbaceous layer is relatively sparse, with some patches of wood oats (Chasmanthium latifolium), Canada wildrye (Elymus canadensis), spiderwort (Tradescantia sp.), and horseherb (Calyptocarpus vialis) found on the peninsula. More often, the groundcover consists of vines with poison ivy (Toxicodendron radicans) being the dominant native in shaded areas and mustang grape (Vitis mustangensis) and trumpet creeper (Campsis radicans) found in sunny openings. Non-native vines are abundant too, with the principal ones being catclaw (Macfadyena unguis-cati), Japanese honeysuckle (Lonicera japonica), English ivy (Hedera helix),andbigleafperiwinkle(Vincamajor). Portions of the floodplain forest have been transformed through clearing and filling to become the meadow area later discussed in the Natural Area Management Guidelines section. In this area, extending north to Dry-Mesic Slope WoodlandDry-Mesic Slope Woodland Previous floodplain forest that has been filled and mowedPrevious floodplain forest that has been filled and mowed 11
Siglo Group 12 south from the lower entrance from 35th street to the end of the peninsula, a lawn has been maintained in Bermuda grass (Cynodon dactylon), although Texas wintergrass (Nassella leucotricha), rescue grass (Bromus catharticus), and an unidentified paspalum are also present, along with some native wildflowers. Johnson grass (Sorghum halepense), and giant reed (Arundo donax) are two large invasive grasses found in sunny areas near pathways andopeningsthatprovidelight. Limestone Savanna and Woodland: This ecological system is found throughout central Texas on Cretaceous limestone soils in level to rolling topography. At Laguna Gloria, this ecological site is found chiefly on the path from the main building to the (Styphnolobium affine), Mexican buckeye (Ungnadia speciosa), coralberry (Symphoricarpos orbiculatus), and hackberry (Celtis laevigata) are also present. Like in the floodplain forest, the herbaceous layer is sparse in many areas, having been overtaken by English ivy and catclaw vines. Where not overtaken, native species in the herbaceous layer such as dewberry (Rubus trivialis), Turk's cap (Malvaviscus arboreus), snailseed (Cocculus carolinus), frostweed (Verbesina virginica), woodoats, and Canada wildrye are good food sources for birds and butterflies. Dry-Mesic Slope Woodland: This system is found on steep limestone slopes throughout the Hill Country and in larger patches in western Travis County, and it provides habitat for the endangered golden-cheeked warbler. Laguna Gloria does not have the correct structure or patch size to support this endangered species, but this ecosystem does provide further habitat diversity for the property. It is found on the steep hill just below the developed area. It is principally found on the slopes to the east of the amphitheater and below the art school. The dominant trees in this area include live oak, cedar elm (Ulmus crassifolia), ashe juniper, Spanish oak, and some extremely large glossy privet. In some areas, the sub-canopy is almost exclusively Japanese honeysuckle, but in the more eastern areas, mountain laurel, Texas persimmon, wax myrtle Temple of Love, and the area above the amphitheater that is not part of the formal historicarea. At Laguna Gloria, this ecosystem is dominated by large live oaks (Quercus virginiana), although Spanish oak (Quercus buckleyi), ashe juniper (Juniperus ashei), and glossy privet also are common. The sub- canopy contains a large number of non- native species such as Carolina jasmine (Gelsemium sempervirens), heavenly bamboo (Nandina domestica), golden bamboo (Phyllostachys sp.), and bridal wreath spirea (Spiraea prunifolia), although natives such as Texas persimmon (Diospyros texana), possumhaw holly, cherry laurel, Texas mountain laurel (Sophora s e c u n d i f l o r a ) , E v e ' s n e c k l a c e Limestone Savanna & WoodlandLimestone Savanna & Woodland
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines13 Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve LakeAustin Scenic Dr Scenic Dr W 35th St W 35th St LakeAustin LakeAustin 19401940 Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve LakeAustin Scenic Dr Scenic Dr W 35th St W 35th St LakeAustin LakeAustin 19581958 Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve LakeAustin Scenic Dr Scenic Dr W 35th St W 35th St LakeAustin LakeAustin 19751975 Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve LakeAustin Scenic Dr Scenic Dr W 35th St W 35th St LakeAustin LakeAustin 19801980 00 250’ 00 250’00 250’ 00 250’
(Morella cerifera), and Mexican buckeye are the principal shrubs. In the herbaceous layer, Turk's cap, frostweed,boneset (Ageratina havanensis) and cedar sedge (Carexsp.)arefound. Riparian Mixed Deciduous Forest: This ecological system is common along creeks in western Travis County and all along the Balcones Fault Zone on the eastern end of the Hill Country. Ashe juniper (Juniperus ashei) and plateau live oak (Quercus fusiformis) are the frequent dominant trees of this mixed forest. Cedar elm (Ulmus crassifolia), American sycamore (Platanus occidentalis), green ash (Fraxinus pennsylvanica), and sugar hackberry (Celtis laevigata)arealsocommon. This system is found along Taylor Slough in Mayfield Park, but is not found on the LagunaGloriasite. HISTORIC LAND USE CHANGES Historic records and aerial photos can show us some of the major events that shaped the ecology of the site we see today. Here we have images looking over seventy years into thepast. 1940: The completion of Tom Miller Dam in 1940 and consequent creation of Lake Austin had a substantial impact on the land. In this photo, the shoreline as we know it today is not defined, the southern portions of the peninsula are in marsh, and much of the lower terrace appears to have little woodland. While it is not clear, it does appear that layout of the formal grounds around the DriscollVillahasbeencompleted. 1958: Water-loving vegetation has adapted to the lake levels, defining a visible shoreline on the property and the island to the south. One can see that the boat ramp has been installed, along with a road leading to 35th street. The lower terrace seems to be covered generally in woody species, with the areas to the southwest of the Temple of Love remaininginmarsh. 1975: Major development has occurred in the area, with the subdivision being built across the lagoon and a parking lot added to Mayfield Park and Preserve. We also see Siglo Group 14 Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve LakeAustin Scenic Dr Scenic Dr W 35th St W 35th St LakeAustin 20092009 00 250’
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines 00 250’ American Elm Cedar Elm Elm Box Elder Hackberry Cedar Sources: Bury, Field Observation Mulberry Live Oak Oak White Oak Palm Cypress Green Ash Pecan Cottonwood Willow TreesTrees Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve Driscoll Villa Driscoll Villa Art School Art School LakeAustin Scenic Dr Scenic Dr W 35th St W 35th St LakeAustin 15
Siglo Group dbh. Bringing together all of the resulting data, Siglo was able to define the size and species of a majority of the trees on the property. It is important to note that some of the trees in the 2000 and 2006 surveys have died, and that was not taken into account in this study. However, the Bury surveys and the additional data collected by Siglo will provide that the lower terrace of Laguna Gloria has been substantially altered. In the center of the peninsula from north to south, the marshy areas have been filled in and woody speciesremoved. 1980: Infrastructure improvements can be seen on the property including the paved road in the lower terrace (built in 1979) and thecomponentsoftheschoolcomplex. 2009: This aerial is used throughout this study to represent existing conditions. In it we can see the completed school complex on the upper terrace and the further reduction of woody species in the northern portions of the lower terrace. In addition, the marshy area at the southern end of the peninsula appears to be expanding further into the lagoonandLakeAustin. These snapshots of the past allow us to see some of the major issues that have helped to shape the site's existing vegetation. They show a dynamic system that can change substantiallygivenenoughtime. TREES The diverse trees of Laguna Gloria are a significant part of the visitor's experience, from the majestic cypresses by the water's edge to the heritage live oaks around the historic buildings. In 2000 and 2006, tree surveys were completed by Bury+Partners on the upper grounds, the Temple of Love ridge, and on a small portion of the lower grounds. In 2013, Siglo Group used general evaluation methods to look at “significant” trees on the lower grounds that were not captured in the Bury surveys. The goal of this evaluation was to record the type and size of native trees in that area. Siglo's evaluation included 144 trees ranging from a cedar elm that was 8” in diameter at breast height (dbh) to a bald cypress that was 55” Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve Driscoll Villa Driscoll Villa Art School Art School LakeAustin Scenic Dr Scenic Dr W 35th St W 35th St LakeAustin Heritage TreesHeritage Trees 00 250’ 16
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines some guidance for property management andimprovementprojectsintothefuture. Looking at trees throughout the entire site as shown in the map on, one can see the importance of live oaks and cedar elms within the historic and art school areas. At the bottom of slopes, pecan trees become more significant, and moving out into the floodplain forest, there is a bald cypress canopy with ash, elm, box elder, willow, and cottonwood. There are a total of 526 native trees recorded on the site over 8” dbh. Of those, 147 are considered to be heritage trees. These trees are over 19” dbh and have special protections fromtheCityofAustin. Inorder to cut one down, a City permit is required, along with the approval of a licensed arbor- ist. Of note are some of the gaps of native tree cover in the floodplain forest. These areas are predominately invasive species with Chinese tallow dominating much of the area. In the southern portions of the floodplain forest, there are also numerous ligustrum and chinaberry trees. Using the natural area guidelines here and in other professional resources, Laguna Gloria can cautiously move forward on a multi-year plan to reduce non-natives and increase the recruitment of young native species. It should also be noted that the oaks within the historic area are aging. While the Natural Areas Manage- ment Guidelines within this report do not deal specifically with the formal areas, the propagation of young trees should be considered with the understanding that this site will outlast many of the beautiful trees foundtherenow. WILDIFE A formal wildlife survey was not performed during the site visits. Wildlife characteristic of the Edwards Plateau ecoregion is expected to be on the property, although larger predators such as bobcats and coyote are unlikely to be present. Even evidence of common large omnivores and herbivores such as feral hog and white-tailed deer were not observed on the site. Neighborhoods near Mt. Bonnell have high deer densities and this species is likely to visit Laguna Gloria, even if they are not found there in daylight hours. Other species that are common to Central Texas and may be on the property are listed on the following page. BirdspeciesarelistedintheBirdandBirding Section. 17
Siglo Group Potential Wildlife of Laguna Gloria Potential Wildlife of Laguna Gloria white-tailed deer, Odocoileus virginianus Virginia opossum, Didelphis virginiana eastern cottontail, Sylviagus floridanus eastern fox squirrel, Sciurus niger hispid pocket mouse, Chaetodipus hispidus fulvous harvest mouse, Reithrodontomys fulvescens plains harvest mouse, Reithrodontomys montanus Texas mouse, Peromyscus attwateri deer mouse, Peromyscus maniculatus white-ankled mouse, Peromyscus pectoralis hispid cotton rat, Sigmodon hispidus common gray fox, Urocyon cinereoargenteus common raccoon, Procyon lotor striped skunk, Mephitis mephitis couch's spadefoot, Scaphiopus couchii Blanchard's cricket frog, Acris crepitans Cope's gray treefrog, Hyla chrysocelis green treefrog, Hyla cinerea gray treefrog, Hyla versicolor spotted chorus frog, Pseudacris clarkia Stecker's chorus frog, Pseudacris feriarum feriarum eastern green toad, Bufo debilis debilis red-spotted toad, Bufo punctatus Texas toad, Bufo speciosus Gulf coast toad, Bufo valliceps valliceps Rio Grande frog, Rana berlandieri great plains narrowmouth toad, Gastrophryne olivacea common snapping turtle, Chleydra serpentina serpentina yellow mud turtle, Kinosternon flavescens flavescens ornate box turtle, Terrapene ornata ornata green anole, Anolis carolinensiseastern collared lizard, Crotaphytus collaris collaris Texas earless lizard, Cophosaurus texanus texanus Texas spiny lizard, Sceloporus olivaceus southern prairie lizard, Sceloporus undulates consobrinus eastern tree lizard, Urosaurus ornatus ornatus short-lined skink, Eumeces tetragrammus ground skink, Scincella lateralis Texas spotted whiptail, Cnemidophorus gularis gulariss six-lined racerunner, Cnemidophorus gularis gularis plains blind snake, Leptotyphlops dulcis dulcise eastern yellowbelly racer, Coluber constrictor flaviventris great plains rat snake, Elaphe guttata emoryi Texas rat snake, Elaphe obsoleta lindheimerii eastern hognose snake, Heterodon platirhinos Texas night snake, Hypsiglena torquata jani western coachwhip, Masticophis flagellum testaceus broad-banded water snake, Nerodia fasciata confluens diamondback water snake, Nerodia rhombifera rhombifera rough green snake, Opheodrys aestivus bullsnake, Pituophis catenifer sayi Taylor's ground snake, Sonora semiannulata taylori Texas brown snake, Storeria dekayi texanaflathead snake, Tantilla gracillis eastern blackneck garter snake, Thamnophis cyrtopsis ocellatus checkered garter snake, Thamnophis marcianus marcianus redstripe ribbon snake, Thamnophis proximus rubrilineatus Texas garter snake, Thamnophis sirtalis annectens lined snake, Tropidoclonion lineatum rough earth snake, Virginia striatula Texas coral snake, Micrurus fulvius tener broad-banded copperhead, Agkistrodon contortrix laticinctus western cottonmouth, Agkistrodon piscivorus leucostoma western diamondback rattlesnake, Crotalus atrox 18
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines Plants of Laguna GloriaPlants of Laguna Gloria Aquatic chaff-flower, Alternanthera caracasana water hyacinth, Eichhornia crassipes,*,++ Forb boneset, Ageratina havanensis Canada wild onion, Allium canadense var. canadense wild garlic, Allium drummondii elephant ears, Alocasia macrorrhizos,*,++ giant ragweed, Ambrosia trifida horseherb, Calyptocarpus vialis shepherd's purse, Capsella bursa-pastoris,* chile pequin, Capsicum annuum chervil, Chaerophyllum tainturieri water hemlock, Cicuta maculata dayflower, Commelina erecta rainlilly, Cooperia drummondii bearded swallowwort, Cynanchum barbigerum bedstraw, Galium aparine wild geranium, Geranium carolinianum water-pennywort, Hydrocotyle yellow flag iris, Iris pseudacorus,*,++ water willow, Justicia americana wild lettuce , Lactuca ludoviciana lantana, Lantana horrida smooth pepperweed, Lepidium virginicum Texas bluebonnet, Lupinus texensis turk's cap, Malvaviscus arboreus var. drummondii least burclover, Medicago minima,* Roemer's sensitive briar, Mimosa roemeriana banana, Musa sp.,* yellow wood sorrel, Oxalis dillenii Drummond's wood sorrel, Oxalis drummondii rock pellitory, Parietaria pensylvanica marsh fleabane, Pluchea sp. smartweed, Polygonum sp. Mexican hat, Ratibida columnifera pigeonberry, Rivina humilis wild petunia, Ruellia sp. silverleaf nightshade, Solanum elaeagnifolium sow thistle, Sonchus sp. ,chickweed, Stellaria media,* dandelion, Taraxacum officinale,* ballmoss, Tillandsia recurvata sockbane, Torilis arvensis,* spiderwort, Tradescantia sp. southern cattail, Typha domingensis broad-leaf cattail, Typha latifolia frostweed, Verbesina virginica plateau goldeneye, Viguiera dentata common primrose, Vinca minor,*,++ Grass purple threeawn, Aristida purpurea giant reed, Arundo donax,*,++ King ranch bluestem, Bothriochloa ischaemum var. songarica,* silver bluestem, Bothriochloa laguroides ssp. torreyana Japanese brome, Bromus arvensis,* rescuegrass, Bromus catharticus,* cedar sedge, Carex planostachys wood oats, Chasmanthium latifolium Bermuda grass, Cynodon dactylon,* Scribner panicgrass, Dichanthelium oligosanthes var. scribnerianum crabgrass, Digitaria sp.,* Canada wildrye, Elymus canadensis Virginia Wildrye, Elymus virginicus inland rush, Juncus interior Texas wintergrass, Nassella leucotricha switchgrass, Panicum virgatum hairyseed paspalum, Paspalum pubiflorum bamboo, Phyllostachys aurea,*,++ ornamental bamboo, Phyllostachys nigra,*,++ little bluestem, Schizachyrium scoparium three square bulrush, Schoenoplectus americanus southwestern bristlegrass, Setaria scheelei johnsongrass, Sorghum halepense,*,++ St. Augustine grass, Stenotaphrum secundatum,* Shrub/ Small Tree prairie acacia, Acacia angustissima huisache, Acacia farnesiana roughleaf dogwood, Cornus drummondii Texas persimmon, Diospyros texana oleaster, Eleagnus sp. loquat, Eriobotrya japonica,* kidneywood, Eysenhardtia texana elbow bush, Forestiera pubescens Carolina buckthorn, Frangula caroliniana Lindheimer's silktassel, Garrya ovata ssp. 19
Siglo Group lindheimeri Gelsemium sempervirens possum haw , Ilex decidua yaupon holly, Ilex vomitoria waxleaf ligustum, Ligustrum japonicum,*,++ glossy privet, Ligustrum lucidum,*,++ Chinese ligusturm, Ligustrum sinense,*,++ agarita, Mahonia trifoliolata wax myrtle, Morella cerifera heavenly bamboo, Nandina domestica,*,++ prickly pear, Opuntia engelmannii Chinese photinia, Photinia serratifolia,* pittasporum, Pittosporum sp.,* cherry laurel, Prunus caroliniana pomegranite, Punica granatum,* firethorn, Pyracantha sp.,*,++ evergreen sumac, Rhus virens rose, Rosa sp. ,* dwark palmetto, Sabal minor Texas mountain laurel, Sophora secundiflora bridal wreath spirea, Spiraea prunifolia,* eve's necklace, Styphnolobium affine coralberry, Symphoricarpos orbiculatus Mexican buckeye, Ungnadia speciosa chaste tree, Vitex agnus-castus Tree boxelder, Acer negundo pecan, Carya illinoinensis sugar hackberry, Celtis laevigata var. laevigata netleaf hackberry, Celtis laevigata var. reticulata redbud, Cercis canadensis sandpaper tree, Ehretia anacua green ash, Fraxinus pennsylvanica Texas ash, Fraxinus texensis Arizona walnut, Juglans major black walnut, Juglans nigra Ashe juniper, Juniperus ashei crapemyrtle, Lagerstroemia indica,* Chinaberry, Melia azedarach,*,++ mulberry, Morus alba ,* retama, Parkinsonia aculeata cottonwood, Populus deltoides Mexican Plum, Prunus mexicana escarpment black cherry, Prunus serotina var. eximia Spanish oak, Quercus buckleyi plateau live oak, Quercus fusiformis shin oak, Quercus sinuata var. breviloba live oak, Quercus virginiana Mexican palm, Sabal mexicana,* black willow, Salix nigra western soapberry, Sapindus saponaria L. var. drummondii gum bumelia, Sideroxylon lanuginosum bald cypress, Taxodium distichum Chinese tallow, Triadica sebifera,*,++ American elm, Ulmus americana cedar elm, Ulmus crassifolia Vines peppervine, Ampelopsis arborea trumpet creeper, Campsis radicans unidentified leatherflower, Clematis sp. Carolina snailseed, Cocculus carolinus English Ivy, Hedera helix,*,++ Japanese honeysuckle, Lonicera japonica,*,++ catclaw vine, Macfadyena unguis-cati,*,++ green milkweed vine, Matelea reticulata snapdragon vine, Maurandella antirrhiniflora Virginia creeper, Parthenocissus quinquefolia yellow passionflower, Passiflora affinis yellow passionflower, Passiflora lutea dewberry, Rubus trivialis greenbrier, Smilax bona-nox eastern Poison Ivy, Toxicodendron radicans ssp. eximium eastern Poison Ivy, Toxicodendron radicans ssp. radicans Spanish grape, Vitis cinerea var. helleri mustang grape, Vitis mustangensis * non-native ++ invasive 20
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines ZONE B FLOODPLAIN FOREST ZONE B FLOODPLAIN FOREST ZONE A SLOPING WOODLAND ZONE A SLOPING WOODLAND ZONE C PATH TO THE POINT ZONE C PATH TO THE POINT ZONE D MEADOW ZONE D MEADOW ZONE B FLOODPLAIN FOREST ZONE B FLOODPLAIN FOREST ZONE A SLOPING WOODLAND ZONE A SLOPING WOODLAND ZONE C PATH TO THE POINT ZONE C PATH TO THE POINT ZONE D MEADOW ZONE D MEADOW Management Areas Management Areas Laguna Gloria Mayfield Park & Preserve Laguna GloriaLaguna Gloria Mayfield Park & Preserve Mayfield Park & Preserve Driscoll Villa Driscoll Villa Art School Art School LakeAustin Scenic Dr Scenic Dr W 35th St W 35th St LakeAustin Management Areas Management Areas Sources: Field Observation 00 250’ Zone A: Sloping Woodland Zone B: Floodplain Forest Zone C: Path to the Point Zone D: Floodplain Forest 21
Siglo Group Natural Areas Management Guidelines When Clara Driscoll donated her property to become a museum for the people of Austin, in addition to the historic buildings and gardens, she also donated the beautiful natural areas that surround them. AMOA- Arthouse is the steward of this rich natural heritage. The guidelines given below, grounded in ecological restoration princi- ples, recommend management techniques that will further support ecological processes on the site, increase the native vegetation, reduce invasive species, improve bird and wildlife habitat, and enhance the visitor's experience. In addition to these many stewardship issues, this section also discusses the need for ongoing staff, capital, professional, and community resources to main- tainthenaturalareas. As described in the Ecology section, Laguna Gloria has incredible ecological value, with numerous habitat types that result in a diversity of flora and fauna. This diversity is threatened by substantial invasive species as well as informal off-trail hiking. This section breaks the property into zones and recommends management practices for each area, providing a five year restoration and maintenance schedule and looking at potentialcosts. It is important to remember that natural areas are not static communities. They are ever changing and will respond differently at different times to the same treatment. For that reason, all information here should be looked at through an adaptive management lens—if a technique is not working, first adjust it to see if it can be made more effective, and then try something different if it is still not working. The recommenda- tions here are based on established best practices, but each site is unique. Adaptive management is an iterative process, which allows the land manager to learn about the particular site over time, and to be aware of changes as they happen, adjusting his or her methodsaccordingly. BALANCING NATURAL RESOURCE OBJECTIVESWITHVISITORNEEDS It is important to balance the desire for a healthy ecosystem with the needs of the site's principal users and AMOA-Arthouse's missiontostimulateappreciationforart. It may be desirable to not remove all the invasive plants at once as the control work will be highly disruptive. The trampling and cutting required may not be aestheti- cally pleasing to hikers who are seeking a natural experience. In areas with a high density of invasive plants, removing them all may simplify the vegetation structure, potentially resulting in a temporary loss of bird diversity until native shrubs grow in to provide habitat (Wiens and Rotenberry 1981). In addition, the existing vegetation serves to segment the site into different areas, each with its own character. For example, a visitor can walk down the Path to the Point, through the Meadow, and into the Floodplain Forest and have unique experi- ences in each, partly because the vegetative barriers between them have remained intact. Removing all the invasive species from some of these areas would reduce AMOA- Arthouse's ability to create a robust experience throughout the site. To insure that there is not too great an impact to the visitor experience, and to allow for focused atten- tion on specific areas, the schedule recommended here staggers work over multiple years. OFF-TRAILRECREATION Off-trail hiking is occurring throughout the property, but is most prevalent in the Floodplain Forest. While other areas have formal trails of crushed granite, concrete, asphalt, or mown footpaths, the Floodplain Forest trails are narrow, soft-surfaced footpaths. Many appear to have been created through repeated foot traffic rather than from an intentional trail design. Where obstacles are currently present or 22
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines have occurred in the past, side trails have been created—this can be seen around the two-trunked bald cypress in the Floodplain Forest. Even informal trails can impact their surroundings through disturbance of vegetation and soil compaction. These primary disturbances may lead to other issues including erosion, a decrease in native species and an increase in exotics. A note of caution, the potential for new informal trails mayrisewiththecommencementofinvasive control, restoration activities, and increased visitorship. The disturbance associated with management may make the current trails difficult to find and lead to the establishment of new one. For the purposes of land management as well as the enhancement of the visitor experience, as discussed later in this report, it is important to formalize trails throughout the site, particularly in the FloodplainForest. INVASIVEPLANTS Invasive plants are the primary threat to the natural areas of Laguna Gloria. In order to restore the landscape and prevent further damage, invasive plants will need to be removed and replaced with native plant communities. The official definition of an invasive plant is one that did not evolve within the native ecosystem, and whose presence is likely to cause economic and/or ecological harm. Their aggressive growth and spread may cause them to crowd out and replace native plants, or may lead to a disruption of natural processes. The impact of invasive species can be very dramatic, and alien species rank second only to direct habitat destruction as the principal threat to rare species, with 49% of imperiled species being negatively impacted (Wilcove 1998). Some of the ways that invasive plants threatennativecommunitiesinclude: Alteringsoilorwaterchemistry;§ Altering natural processes such as fire§ andflooding; Direct displacement through competi-§ tion(“crowdingout”ofnativeplants); Changing the amount of light in or§ belowthecanopyorsub-canopy. Invasive plants also impact native animals and insects. Invasive plants tend to crowd out natives, which many birds and other wildlife rely on for protection and food. A 2006 study in Austin found that sites with intact native plant communities had higher species richness and abundance than sites that were dominated by non-natives (Kalmbach2006). There are sixteen invasive plant species found at Laguna Gloria that are negatively impacting the property. The table above Species Common name COA rank AMOA rank Impacts Arundo donax Giant reed High Moderate 1,5 Colocasia esculenta Elephant ears Moderate Low 1 Cynodon dactylon Bermuda grass Moderate Low 1, 4 Eichhornia crassipes Common water hyacinth High Low 1, 6 Hedera helix English ivy not listed Moderate 1, 7 Iris pseudacorus Yellow flag iris not listed Low 1 Ligustrum lucidum Glossy privet High High 1 Lonicera japonica Japanese honeysuckle Moderate High 1, 3, 7, 8 Macfadyena unguis-cati Catclaw vine Moderate High 1 Melia azedarach Chinaberry tree High Moderate 1, 2 Nandina domestica Heavenly bamboo Moderate Moderate 1 Phyllostachys aurea Golden bamboo High Moderate 1 Pyracantha cocciniea Scarlet firethorn Moderate Low 1 Sorghum halapense Johnson grass High Low 1 Triadica sebifera Chinese tallow Moderate High 1,2 Vinca minor Common periwinkle not listed Low 1 Impacts: 1) Crowds out native plants, forms monocultures; 2) Alters soil chemistry, changing system; 3) Can girdle overstory trees by wrapping tightly around the trunks; 4) Alleopatic - releases toxins that inhibit growth of nearby plants; 5) May use large volume of water relative to native plants, reducing downstream flow in riparian areas; 6) Reduces dissolved oxygen and light levels in aquatic environments; 7) Grows on other plants and weight may cause stemdamage;8)Aggressiverootgrowthcompeteswithnativeplants,slowsgrowthofoverstorytrees. Invasive Species of Laguna Gloria 23
Siglo Group lists each species and shows whether it is considered a Low, Moderate or High level threat by the City of Austin, as described in their Invasive Species Management Plan. In the next column, “AMOA rank," each species was rated according to how great a threat it is at Laguna Gloria specifically, basedonfieldobservationsatthesite. The invasive plant species that have the greatest potential to negatively impact Laguna Gloria are ligustrum, Japanese honeysuckle, catclaw vine, and Chinese tallow. INVASIVEPLANT CONTROLMETHODS Invasive plant control will consist of a mix of mechanical and chemical methods. In some cases, such as in the Floodplain Forest and much of the Sloping Woodland, removal may be all that is required. This relatively passive approach to restoration is less likely to work in areas where invasive plants dominate. Removal may need to be coupled with seeding and in some cases native plantings. Finally, a monitoring protocol is recommended to ensure that improvements in the natural area do not deteriorate over time. MechanicalControl Mechanical control is any method that directly removes the invasive plant without the use of chemicals. Examples includehand pulling, pulling with weed wrenches or other devices that provide leverage, and repeated mowing that does not allow a plant togotoseedorreproduce. While mechanical control is often preferred in order to reduce the amount of herbicide placed on a property, it also has significant drawbacks. Mechanical control methods usuallyresultingreater soildisturbance than chemical controls, thereby increasing the chance of erosion and/or re-invasion. When mechanical control methods are recommended, care should be taken to minimize soil disturbance. In some areas, erosion control measures will be necessary to slow down storm runoff, and/or to reduce the amountofexposedsoil. ChemicalControls Chemical controls (herbicide) are recommended for most of the invasive species discussed below. Please note that all herbicide application must be conducted under the supervision of a licensed herbicide applicator and must follow the EPA's Worker Protection Standards. Applicators should also follow the herbicide label directions and maintain pesticide use records. ApplicationMethods: Foliar spray: the spraying of an herbicide solution on the leaves of plants. Because of the potential for non-target kill through overspray, this method will be recommended primarily in dense monocultures where other methods are uneffective, with arundo orcatclawvine. Wick applications: wiping a highly concen- trated herbicide solution onto the leaves. Generally not as effective as a foliar spray, but reduces the danger of overspray and non-target kill. Recommended only in areas where highly desirable plants would be negativelyaffectedbyafoliarspray. Cut stump: the cutting of a woody plant and applying an herbicide solution to its stump. This targeted approach is highly effective, but often requires considerable labor if the cut portion of the plant must be removed fromthesiteorchipped. Basal bark: the spraying of an herbicide/oil solution on the lower portions of a tree's or shrub's bark. This method may not be Evaluation of the Floodplain Forest for bird habitatandinvasivespecies. 24
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines preserves with similar vegetation types, such as Wild Basin Preserve and the BalconesCanyonlandsPreserve. Special consideration was given to species that are commercially available, but even the ones that are not can still be considered for planting. AMOA-Arthouse can reach out to local chapters of the Native Plant Society of Texas, many of whose members are willing to grow small amounts of unusual plants. Also, commercial growers can often be contracted togrowplantsforspecificcustomers. Species not recommended in this section do not need to be ruled out if offered by volunteers, but it is best if the plant is native to this areaofTexas. When live planting is necessary, it should take place in the fall to early winter, preferably between late October and late January so that saplings have an opportunity to become established before the heat of summer. For lakeside plantings where water is not a constraint, timing is less important, and planting dates will need to be opportunistic to take advantage of Lake Austin drawdowns. A mix of fast and slow growing trees is preferred, even if some species are considered less desirable, in order to promote diversity and to quickly provide shade for visitors and reduce the potential of invasive re-establishment. Sowing of native grass and wildflower seeds should take place between late October and early March. In general, cool season grasses effective for large trees with thick bark, and should not be used on the water's edge where the oil (which serves to penetrate the bark) may be harmful to amphibians or fish eggs. This method results in a standing dead tree or shrub, which may be beneficial to many forms of wildlife, and does not require the labor of plant disposal, but is unsafe if near a trail or area with human use. Basal bark applications are more effective in late summer and fall. In the spring, large amounts of water moves up the stem to support leaf flush, flowering, and fruit production, making it more difficult for the chemicaltoreachtheroots. Basal frill or “hack and squirt”: cutting into the bark of a tree, usually along the entire circumference, and applying an herbicide solution. This has similar pros and cons to basal bark method, but is safer in wet areas sinceanoilsurfactantisnotusuallyrequired. Integrating Mechanical and Chemical Controls Recommended control strategies for each species are shown in the table on pages 26 through 30. For many of the species, a combination of mechanical and chemical control measures will be necessary, and control methods will vary based on site conditions and the time of year in which the opportunityforcontrolarises. NATIVEPLANTINGS In some areas, removal of invasive plant species will likely result in regeneration of native species, but in other areas a mixture of live plantings (container grown plants) and seed sowing is recommended. Many ecological restoration projects require that plant materials come from local sources, often within an adjacent county. Laguna Gloria's natural areas have been manipulated for decades, and so this plan does not require local genotypes. It is likely that seeds procured within the state of Texas, however, will perform better than seeds from out of state, as the parent material will be better adapted to the local climate. The plants recommended in this section were chosen for one or more of the following reasons: They are listed in the Texas Parks and§ Wildlife Department's descriptions of the vegetation types found on the property; They are found at Mayfield Preserve,§ which serves as a reference site for this project; They are found on other nearby§ Dense bamboo just beyond the bridge railing blocks viewsofthewaterandhillsidebelow. 25
Siglo Group Bermuda grass, Cynodon dactylon, High Priority in Zone D, Low Priority in other areas Foliarspray Foliar spray with glyphosate solution during growing season months. It will not be effective if applied during drought conditions. Repeated application willbenecessary. Zone D (Meadow) April-June/ Sep-Oct Low No High Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Combination of cutting andfoliarspray Step 1: In areas where English ivy is climbing into a tree, cut at ground level. Allow the top to die; do not attempt to pull it from the tree or shrub. English ivy latches onto plants and bark so damage may result from pulling it off. Step 2: Where English ivy is growing as a groundcover, use foliar spray with triclopyr and a surfactant that is specifically designed to break down the waxy coating of the leaf surface. Avoid contact with both the bark and foliage of desirable vegetation. Dead surface stems will act to hold soil, and should not beremovedexceptforaestheticreasonsinselectareas. AllAreas Winter– It’s Evergreen Moderate to High Yes Moderate Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: English Ivy, Hedera helix, High Prioirity in Zone A; Moderate Zone B and C, Low in Zone D Yellow flag iris, Iris pseudacorus, Low Prioirity Mechanicalremoval Control of these waterside species should wait until one of the periodic drawdowns of Lake Austin. Attempting to remove them when the lake is full may create significant soil compaction and disturbance. The rhizomes of these plants need to be carefully dug from the ground and disposed of. Leaving even a small fragment may result in them re-rooting. Plant replacement species immediately. Because it is difficult to remove all of the underground rhizomes, it is important to introduce native competition while the plant is weakened. Some people are sensitive to the plant's juices, so long sleeves and pants are preferred. Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Shoreline Low Lake Levels Low No High (Planting) Glossy privet, Ligustrum lucidum, High Prioirity Mechanical removal with weedwrench Remove plants that are 2 inches or less in basal diameter using weed wrenches or other mechanical devices. This is a highly effective method for this plant. Hand pulling of new seedlings is required in multiple years until the seed bed is diminished and other plants can fill the niches. Provide for erosion control if workinginZonesAorC. Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: All Areas Any Yes No High For plants greater than 2 inches in diameter, cut down the tree and use a cutstump herbicide application containing triclopyr. Provide for erosion control if inZonesAorC. CuttingandPainting Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: All Areas Fall Yes Yes High Invasive Species Control Guide 26
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines Foliarspray,Imazamox Giant reed, Arundo donax, Moderate Priority Step 1: Foliar spray with Imazamox solution no earlier than mid-June. Step 2: If arundo is not mixed with desirable vegetation, then spray it with an Imazamox and glyphosate solution. Step 3: Wait until the stems have completely died before cutting and removing the vegetation, which may be severalweeks. Step4: Repeat asnecessary. Note:donotcutarundo foratleast ayearpriortousingthismethod,oreffectivenesswillbegreatlyreduced. All Areas Summer Moderate Yes Low to Moderate Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Frequentmowing Frequent mowing may eventually cause roots to lose enough reserves that nearby Bermuda grass and other turf plants are able to take over the area. The first mowing should take place when the giant reed is in flower so that as much of its energy reserve is aboveground as possible. The area must be mown at least several times a month, because arundo grows very aggressively. The area ontheshorelinewilllikelybetoomuddyandsofttousethismethod. Areas to Turf Growing Season Low No Moderate Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Digging and root removal Step 1: Cut and remove tops of plants. Step 2: Dig and remove as much of the roots as possible. Even the smallest stolon left in the ground may take root and grow. Step 3: Wait for new sprouts to show and dig a second time. Digging will cause massive soil disturbance and open the area to erosion. Step 4: Install restorationplantingsassoonaspossible. Immediate Need Any Low No High Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Wick or drip chemical application Step 1: Using a wick applicator, wipe a glyphosate-based herbicide mixed with surfactant that aids herbicide penetration of leaves. This will allow for application on the giant cane without any herbicide touching the restoration plantings. OR, cut individual stems and squirt a glyphosate solution into the stem cavity. If near a shoreline, the product should be labeled for use in wetlandoraquaticenvironments. After Digging/Mowing Summer Uncertain Yes High Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Elephant ears, Low PriorityColocasia esculenta, Mechanicalremoval Control of these waterside species should wait until one of the periodic drawdowns of Lake Austin. Attempting to remove them when the lake is full may create significant soil compaction and disturbance. The tubers of these plants need to be carefully dug from the ground and disposed of. Leaving even a small fragment may result in them re-rooting. Plant replacement species immediately. Because it is difficult to remove all of the underground tubers, it isimportanttointroducenativecompetitionwhiletheplantisweakened. Shoreline Low Lake Levels Low No High Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Foliarspray During growing season months, spray foliage with an aquatic approved glyphosate solution. Repeat several times throughout growing season as the herbicide label dictates. Plant replacement species in late fall. Planting is essentialtopreventshorelineerosionduetowaveaction. Shoreline April to October Low Yes High (Planting) Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Invasive Species Control Methods (continued) 27
Siglo Group Japanese honeysuckle, Lonicera japonica, High Priority in Zone B; Moderate to Low elsewhere Step 1: Cut Japanese honeysuckle that is growing into trees at head height. Step 2: Spray with glyphosate solution. Take care to avoid herbicide contact or driftontodesirablevegetation. Foliarspray Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: When Monoculute Late Fall to Winter High Yes Low to Moderate Cut Japanese honeysuckle at ground level, and remove aboveground biomass from the site. Where the vine is tangled in overstory trees and cannot be pulled down without damaging native tree branches, cut it at head height and allow the vine in the upper branches to desiccate and fall. Step 2: Allow Japanese honeysuckle to re-sprout from roots. Step 3: When it is 2 feet in height/spread, use foliar spray with herbicide solution that contains glyphosate. Cutting followed by foliar spray Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Non-monoculture Cut Spring/Spray Winter Moderate Yes Moderate Step 1: Where catclaw is tangled in overstory trees and cannot be pulled down without damaging native tree branches, cut it at head height and allow the vine in the upper branches to desiccate and fall on its own. Step 2: Use a foliar spray withanherbicidesolutionthatcontainsglyphosateandtriclopyr. Combination of cutting andfoliarspray Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: When Monoculture Non-Drought Unclear Yes Moderate Catclaw vine, Macfadyena unguis-cati, High Priority Step1:Cutcatclawatgroundlevel,andremovetheabovegroundbiomassfrom the site. Step 2: Where catclaw is tangled in overstory trees and cannot be pulled down without damaging native tree branches, cut it at head height and allow the vine in the upper branches to desiccate and fall on its own. Step 3: Allow catclaw to re-sprout from underground tubers. When it reaches 2 feet in height/spread, use foliar spray with an herbicide solution that contains glyphosateandtriclopyr. Cutting followed by foliar spray Non-Monoculture Non-Drought Unclear Yes Moderate to High Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Cut tree down, providing for safety first. Paint the top of the stump with a triclopyr-basedsolutionimmediately,takingcaretocoveredges. Cutstump Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: All Areas Fall Preferrable Moderate Yes Moderate Chinaberry tree, Melia azedarach, Moderate Priority Spraythebaseofthetreewithatriclopyrandoilsolution.Basalspray Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: No Trail Danger Small Fall Preference Moderate Yes Low 28
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines Cut tree down, providing for safety first. Paint the top of the stump with a triclopyr-basedsolutionimmediately,takingcaretocoveredges. Cutstump Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: All Areas Fall Preferrable Moderate Yes Moderate Chinaberry tree, Melia azedarach, Moderate Priority Spraythebaseofthetreewithatriclopyrandoilsolution.Basalspray Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: No Trail Danger Small Fall Preference Moderate Yes Low Nandina domestica, Heavenly bamboo, Moderate Priority Step 1: Foliar spray with a solution containing both glyphosate and triclopyr. Step 2: Once completely brown, cut and remove the vegetation. This is an aestheticconsiderationratherandanecologicalone. Foliarspray Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Lack of Labor Growing Season Moderate Yes Step 1: Cut all the stems of the shrub clump. Step 2: Drip or paint a triclopyr solution OR a glyphosate solution on the cut stump. Step 3: Remove cut stems. Cutstump Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: With Abundant Labor Small Fall Preference Moderate Yes Moderate Golden bamboo, Phyllostachys aurea, Moderate in Zones A and C. Low in Zones B and D Step 1: Cut bamboo near ground level and remove the biomass. Step 2: Allow bamboo to sprout from its base and reach a height of approximately 2-3 feet. Step 3: Apply a foliar spray of glyphosate. Step 4: Allow bamboo to become completelybrownbeforeremovingthedeadfoliage. Foliarspray Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: All Areas Cut Winter/Spray Late Spring or Early Fall Moderate Yes Moderate Pyracantha coccinea, Scarlet firethorn, Low Priority Pullbyhandorwithweedwrench. Onlyafewsites.Mechanicalremoval Where Appropriate: Optimal Time of year: Effectiveness: Applicator Required: Labor Intensity: All Areas Anytime High No Low Invasive Species Control Methods (continued) 29
Siglo Group In areas with desirable groundcover underneath Johnsongrass, apply glyphosate based herbicide with a wick applicator. This method tends to actuallyusemoreherbicideproduct,butavoidsnon-targetkill. Wickapplication Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Anytime Spring or Fall Moderate Yes Moderate Use a basal bark herbicide application using a triclopyr based herbicide or Imazamox (Clearcast) mixed with mineral oil (not diesel). The standing dead snag will be excellent habitat for many insects and birds. Preferred when tree heightisshorterthanthe distancetothenearesttrail. Basalbark Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Away from Trails Slight Fall Preference High Yes Low Step 1: Cut stem. Step 2: Paint entire cut of the stump with a triclopyr based solutionorClearcast. Cutstump Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Near Trails Slight Fall Preference High Yes Moderate Chinese tallow, Triadica sebifera, High Priority in Zone B, Moderate in Zone D, Low in other Zones Foliar spray of Imazamox solution. This herbicide is very specific to Chinese tallow and should not harm bald cypress, green ash, hackberry or American elm if some of the chemical should drift onto their leaves. Be patient. It may takeseveralmonthsforChinesetallowtoshowdamage. Foliarspray Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Trees under 10’ Growing Season High Yes Low Foliar spray on small patches growing in Zone A and Zone B. Spray at the same time that English ivy is being treated (it requires the same surfactant that Englishivyrequires). Notenoughof athreatonitsown. Foliarspray Where Appropriate: Optimal time of year: Effectiveness: Applicator required: Labor Intensity: Any Any Low Yes Low Common periwinkle, Vinca minor, Low Priority Foliar spray with glyphosate based herbicide prior to adding plants into the wildflowermeadow. Foliarspray Where Appropriate: Optimal Time of Year: Effectiveness: Applicator Required: Labor Intensity: Anytime Spring or Fall High Yes Low Johnson grass, Sorghum halapense, Moderate Priority in Zone D, Low all other Zones 30
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines and spring wildflowers will do better if sown in the fall, while warm season grasses and fall wildflowers may be planted in late winter. Planting rates are usually measured in pounds per acre, and this may be appropriate for the wildflower meadow, but in general a more creative approach is necessary at Laguna Gloria. Pockets of bare ground will be apparent upon the removal of invasive vines and groundcover, and areas between a few square feet and thousands of square feet willneedtobehand-seeded. Achieving good seed-to-soil contact is the most important aspect of seed planting. In general, it is recommended that an area be lightly raked, hand-seeded, and then lightly raked a second time. However, if volunteer groups offer to provide seed balls or other more labor intensive planting methods, they shouldnotbedissuaded. POISONIVY Poison ivy is common throughout the property and is abundant in the Floodplain Forest. While it is not acceptable in areas with high amounts of human use such as trail edges and should be cut back or removed in these locations, Laguna Gloria should avoid large scale eradication. Poison ivy is common in riparian areas and floodplains throughout eastern and central Texas, and removing it will open areas to non-nativeplants. Poison ivy benefits the site in many ways. It is a beautiful native plant with bright red foliage in fall. The berries are a good food source for birds, and it provides erosion control when it grows as a groundcover. It is also the primary competition on the site for Japanese honeysuckle and catclaw vine. Its removalwouldbenefittheseinvasivevines. If possible, simply cut the vine aggressively away from the trail and avoid using herbi- cides, which may kill the whole plant. If necessary, a glyphosate foliar spray will usuallybeeffectivefortemporarycontrol. All workers need to know how to identify the plant, wear long sleeves and pants, wash with Technu or another poison ivy removing soap directly upon finishing work, and wash clothing separately if acutely sensitive. These precautions are especially important whenworkingintheFloodplainForest. ZONALAPPROACH The natural areas at Laguna Gloria have been divided into four zones to help priori- tize and guide land management. This approach recognizes the differences between the zones in regards to natural communities, restoration plantings, site use, user needs, and invasive plant density. Initially, control and restoration efforts could focus on highly visible areas in order to engage the public, build support for the project and recruit volunteers. Next, areas with high ecological integrity or unusual ecological systems should be worked on to prevent their further degradation. Both the prioritizations and the schedules listed at the end of the chapter should be viewed as flexible. The important thing to remember is that each of these zones has its own attributes that will determine the approach taken. This plan calls for a portion of at least one zone to be addressed each year, but if financial capacity is higher, multiple zones can be tackled in one year. A zonal approach, however, should prevent staff from overextending themselves by providing a way to strategically focus efforts and resources. Restoration is not an event, but Aquatic invasive plants in the lagoon area in Zone A. Above: elephant ear. Below: yellow flag iris. 31
Siglo Group ExamplesignfromMayfieldParkinformingvisitorsoftherestorationworkbeingdone. anongoingprocess. ZONEA:SLOPINGWOODLAND Zone A is the area that is primarily dry-mesic slope woodland between the developed area and the shoreline in the eastern section of LagunaGloria. Zone A is a highly visible area, moving from the formal historic area to the naturalistic Path to the Point and lower terrace. Depending on the final design, this area may have more formal native plantings that transition into the more natural portions of the property. As invasive species control begins, it will be important to consider erosion prevention on the steep slopes, including temporary erosion mats or long term stabilization. Because this area is highly visible, could have erosion issues, and has a substantial amount of invasive species, it will likely be appropriate if not necessary to use native plantings in Zone A rather than relying on native regeneration or seeding. This may also result in the need for tempo- raryirrigationinsomeareas. InvasivePlantManagement The main invasive threats in this zone are ligustrum and catclaw vine, with the heaviest infestation being near the amphitheater. Additional invasive species on the slopes include English ivy, bamboo, and chinaberry. Along the shore, elephant ears, yellow iris and water hyacinth are all present. Removal work in this zone should be accompanied with signs, whether perma- nent or temporary, explaining the work that is being done and listing contact information so that the public knows how they may become further involved. An example of such a sign from the City of Austin is shown above. Invasive control work should begin to the west of the amphitheater. Catclaw vine control will be the number one priority followed by English ivy and ligustrum. Bamboo, nandina, and other invasive species are having less of an impact currently, but should be controlled as well. Control work along the shores of the lagoon should be attempted last as both elephant ears and yellow flag iris are difficult to control and successwillbelesslikely. CutMaterialandPreventionofErosion Zone A is relatively close to the museum parking lot. Material should be hauled and stacked in this area. Woody material such as ligustrum should be chipped on site, preferably into a rented dumpster or into a pickup truck so it can be hauled to Zone D. Vines and bamboo may be thrown directly 32
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines33 intothedumpster. ErosioncontrolisessentialinZoneA: Option 1: On steep slopes where extensive ligustrum and other woody species removal is necessary, dead branches should be stacked along contour lines to slow storm runoff and reduce erosion. Branches should be 2 feet in length or longer and all berries and seeds should be removed. The mounds of branches do not need to be more than a foot in height, but it is essential that they be compactedontotheground. Option 2: Use a natural fiber erosion control blanket that is rolled along the contours of the land and stapled to the ground with metal staples. These must be accompanied with restoration plantings. The fibers decompose over time, so it is essential that a robust herbaceous cover is established before thisoccurs. RestorationPlantingsandSeeding Zone A may require more intense restoration plantings than any other zone due to aesthetic concerns and its adjacency to the historic site, as well as the need to reduce the probability of erosion on the steep slopes. Plantings are made more feasible in this area bythecloseproximitytoirrigationwater. Restoration plantings should be a mix of live plantings and seed dispersal. Planting will be more necessary where large areas have been cleared of invasive species. Where plantings occur, a drip irrigation system is recommended. Grass and wildflower seed planting is necessary between the planted trees and shrubs in the Sloping Woodland and in areas where catclaw and English ivy removalhastakenplace. Live planting is also recommended along the edge of Lake Austin where elephant ears and yellow flag iris have been removed, although this planting should consist of large herba- ceousspeciesandshrubsratherthantrees. The windrows of plant materials in the Sloping Woodland should slow rain runoff enough to prevent seeds from being washed away. However, if this assumption proves to be false, Laguna Gloria can consider using erosion control blankets. The seeds get placed upon the bare dirt and are then covered with an erosion blanket that is stapled to the earth with metal brackets. Holes may be cut into the blanket to allow for the planting of live trees and saplings. Some erosion blankets are sold with seeds already enmeshed in them, but these should not be used, as the seeds are generally non- nativeandsomeareinvasive. AchievingBalance Laguna Gloria should consider not removing some of the larger ligustrum trees to the east of the amphitheater for several years. They dominate the over-story and their removal would denude the area of shade trees. While conventional wisdom says that the removal of large seed-producing invasive plants is a top priority, their removal may drastically reduce the area's enjoyment by the public. Instead, the ligustrum should be thinned so that more light reaches the ground, and native trees should be planted in the newly Sloping Woodlands south of the Driscoll Villa, overlooking the lagoon, with substantial catclaw invasion thathasbeenpartiallycutbackfromthetrees. Thisisalsothesiteofvegetationplot3.
Siglo Group 34 created openings. Once the natives reach a height of 10 to 15 feet, then the larger ligustrumcanberemoved. RecommendedSpecies-LivePlantingsinUplands: Trees: The following trees will eventually grow to provide some shade and can be planted in either sun or shade. Live oak and Spanish oak are the most natural choices as they are already abundant on the site, but they are susceptible to oak wilt. It is important to increase the number of trees that are notsusceptibletooakwilt,suchas: shinoak,Quercussinuatavar.breviloba Texasash,Fraxinustexensis cedarelm,Ulmuscrassifolia escarpment black cherry, Prunus serotina var. eximia hackberry,Celtislaevigata Shrubstosmalltrees: elbowbush,Forestierapubescens Lindheimer's silktassel, Garrya ovata ssp. Lindheimeri, Carolinabuckthorn,Frangulacaroliniana evergreensumac,Rhusvirens aromaticsumac,Rhusaromatic Mexicanplum,Prunusmexicana Texasredbud,Cerciscanadensis Eve'snecklace,Styphnolobiumaffine Mexicanbuckeye,Ungnadiaspeciosa Texaspersimmon,Diospyrostexana rusty blackhaw viburnum, Viburnum rufidulum waferash,Pteleatrifoliata Most of the grasses should be planted by seed, especially if an erosion control mat is used. However, interspersing a few live plantswillhastentheirestablishment. Grassesinsun: littlebluestem,Schizachyriumscoparium greensprangletop,Leptochloadubia sideoatsgrama,Boutelouacurtipendula tallgrama,Boutelouahirsuta var.pectinata Lindheimer's muhly, Muhlenbergia lindheimeri Grassesintheshade: Canadawildrye,Elymuscanadensis Virginiawildrye,Elymusvirginicus woodoats,Chasmanthiumlatifolium ZONEB:FLOODPLAINFOREST Zone B contains the Floodplain Forest in the western part of the peninsula. It is bounded by Lake Austin to the west and the road and Meadowareatotheeast. Zone B is a complex forest environment with bald cypress, ash, willow and cottonwood, which has been heavily invaded by Chinese tallow and Japanese honeysuckle. This area should be managed in a manner that has the lightest touch possible, while still allowing for a robust visitor experience. Invasive control in this Zone is daunting, but possible, and native trees will be planted to speed the replacement of the Chinese tallow. Finally, the informal trail should be formalized and informal spur trails decommis- sioned. The Floodplain Forest in this area has tremendous woody plant diversity in spite of the high number of invasive plant species. Large river floodplain forest examples are rare in the Austin area where the shores of Lady Bird Lake and Lake Austin are highly developed. Maintaining and improving this community is a high priority, even though invasiveplantcontrolwilllikelybedifficult. InvasiveSpeciesManagement Invasive plant species that are highly problematic in this zone include: Chinese tallow, Japanese honeysuckle, catclaw vine, Two bald cypresses in the Floodplain Forest with youngChinesetallowandpalmettos.
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines and ligustrum. English ivy and giant reed are also present in this area or around its border. The removal of Chinese tallow should be the highest priority, since research suggests that its presence has the ability to alter soil chemistry. The invasive vines are thenexthighestpriority. Not all the invasive plants should be removed at once due to both ecological and aesthetic concerns. From an aesthetic perspective, opening up too much of the Floodplain Forest to the Meadow (Zone D) would affect the intimate experience currently found in the Floodplain Forest. This would also happen if too much vegetation was removed internally from the forested area. Chinese tallow’s abundance in Zone B means that total removal would result in substantially more sun reaching the forest floor. That could cause an explosion of growth in the shrub and herbaceous layer, which is predominantly made up of invasives. It is essential that removal of individual Chinese tallow trees be accompanied with control of Japanese honeysuckle, arundo, and any other invasive plants underneath the cleared tallow. Because of the intensity of the invasive species control needed, it is recommended that initial controls be limited to 1 acre of the 2.5 acre zone, and that the results be assessed before control work continues. The initial area shouldincludevegetationplot2. Control work may initially make the area appear to be in worse condition, and special accommodations for visitors may be helpful. The site will be trampled during the invasive plant removal, but it should grow back quickly. Unless a formal trail has been established, AMOA-Arthouse may want to close down portions of the forest trail during portions of the control work to reduce furtherinformaltrailcreation. DisposalofCutMaterial Cut vegetation in Zone B may be left on the ground to rot, used to block unwanted trails, or chipped on site. Downed woody debris is common in a healthy, functioning forest. It provides excellent habitat for insects, reptiles, and soil fungus. Large stems, roughly greater than 6 inches in diameter, can be left where they have fallen when they are not blocking the main trail. Some stems may be stacked to block access along informal trails that staff would like to decommission. Smaller stems and vines can be hauled away for disposal and, in the case of stems, chipping. Chipped material can be used to create a more formalized trail with the understanding that it will wash away withfuturerains. RestorationPlanting Zone B's woody plant assemblage is rich, so restoration plantings will focus not on increasing diversity, but on increasing abundance and replacing the Chinese tallows as quickly as possible. Increasing the herbaceous cover and the number of native trees per acre will help prevent the return of invasive plants by shading the soil and providing competition. While it is possible that numerous native tree species will establish themselves without live planting, because of the intensity of the invasive problem in this area, Chinese tallow’s known ability to rapidly colonize an area, and the effort required to remove invasives, it is recommended that live plantings be used as soon as possible after invasives have been removed. It is recommended that restoration plantings be done without the aid of irrigation. The installation of an irrigation system would create a large disturbance and possibly cause more harm than benefit. Instead, tree and shrub plantings will be denser due to the expectationofhighertreemortality. The USDA's Natural Resources Conserva- tion Service recommends a tree density of Informal path through the Floodplain Forest in ZoneB. 35
Siglo Group 200 stems per acre when restoring riparian woodlands, and this tree density is also required by the Army Corps of Engineers for the restoration of bottomland hardwood forests in wetland mitigation banks. Based on vegetation plot data from Laguna Gloria, the Floodplain Forest currently has a density of 70 large (>5” dbh) native trees per acre. Allowing for a 20 foot buffer with Zone D where control work will not be undertaken in order to leave a screen of plants to block the road's view, this leaves approximately 2.5 acres to be planted at some point, requiring a totalof325trees. Trees can be contract-grown in tree tubes, and planted only after initial invasive control has taken place. Since only one acre of invasive control work is recommended at present, only 130 trees should be ordered. Once the success of the restoration is determined, both control work and tree plantingcanbeexpanded. Seeding of herbaceous cover is also important. Zone D lacks many of the floodplain grasses that one would normally find there, suchaswoodoatsandCanadawildrye. Both live plantings and seeding will be opportunistic. Areas with dense native vines and trees will be avoided, while areas formerly covered with Japanese honeysuckle orChinesetallowwillbeheavilyplanted. RecommendedSpecies Herbaceous layer seeding: seed in great quantity will be difficult to find. The following are available from Native Ameri- C should focus on retaining its historic, natural feel while removing invasive plants andestablishingmorenativeflora. InvasivePlantManagement The principal invasive plant threats in this area include catclaw vine, nandina, and ligustrum. While the slopes in Zone C are shorter than in Zone A, they are just as steep, and invasive control work will need to take this into account. In a few areas, it may be necessary to create small berms or windrows with cut invasiveplantbranchestopreventerosion. As in Zone B, invasive species serve an important role by helping to create a vegetative buffer between the Path to the Point and the Meadow area, as discussed in the Visitor Experience section. Mindfulness will be necessary when controlling invasive plants to the west of the granite path so that the maximum number of invasive plants can canSeed. Canadawildrye,Elymuscanadensis Virginiawildrye,Elymusvirginicus woodoats,Chasmanthiumlatifolium easterngamagrass,Tripsacumdactyloides switchgrass,Panicumvirgatum pigeonberry,Rivinahumilis goldeneyedaisy,Viguieradentata Americanbeautyberry,Callicarpaamericana bluecurls,Phaceliacongesta goldengroundsel,Packeraobovata whiteavens,Geumcanadense frostweed,Verbesinavirginica Tree Saplings: live plantings contract-grown intreetubes. pecan,Caryaillinoinensis baldcypress,Taxodiumdistichum Americanelm,Ulmusamericana buroak,Quercusmicrocarpa sycamore,Platanusoccidentalus greenash,Fraxinuspennsylvanica cottonwood,Populusdeltoides willow,Salixnigra ZONEC:PATHTOTHEPOINT Zone C, referred to here as the Path to the Point, contains the limestone savanna and woodland that is on the eastern portion of the peninsula on the small ridge between the road and the water. There are a number of large live oaks and a fair amount of native shrub diversity. Zone C has is well used and has the most formal visitor experience in the natural areas. The historic Path to the Point Trail winds through Zone C, ending at the Temple of Love. Land management in Zone Invasive catclaw and nandina dominate the understoryatPhotopoint11inZoneC. 36
Laguna Gloria: Site Assessment and Natural Areas Management Guidelines be removed without compromising the visitorexperience. DisposalofCutMaterial Material cut in Zone C can be dragged or hauled to the asphalt road that runs down the center of the peninsula, where it can be chipped and either used as trail base or removed from the site. It may be desirable to leave some large stems on the ground to make foot travel more difficult in order to dissuade off-trail use. Much like in Zone A, branches can be stacked in small rows along the contours in steep areas to slow down waterrunoffandpreventerosion. RestorationPlanting The restoration planting for Zone C can likely focus entirely on planting seeds to increase diversity and coverage in the herbaceous layer. With the herbaceous layer the northwest shoreline. Large turf grass areas are found at the northern and southern ends of the Zone and an asphalt road runs most of its length. The road forms a loop in the central portion of the Zone and there is a vegetated island with native and exotic trees atthecenteroftheloop. Because of the highly manipulated characteristics of Zone D and the challenge of restoring a native meadow, land management practices in this area should focus on programmatic needs and future design ideas while including the preservation of specimen trees throughout the Zone. Invasive species control in this area can result in niche or large scale gallery spaces for displaying art and increasing views. As discussed previously and in more detail in the Visitor Experience section, caution should be used when clearing invasive species between the Meadow area and the Floodplain Forest as well as at the Path to the Point. If too much clearing is done, the individual integrity of these three zones may be lost, thereby decreasing the complexity of the visitor experience. InvasivePlantManagement Ligustrum is common in the edge of the meadow, along with chinaberry and Chinese tallow. Giant reed is found in four areas including two stands in the northern portion, one partially cleared in April 2013, one in the road island, and one near Birder’s Point. Bermuda grass is the main turf grass. Johnsongrassissporadicinsunnyareas. Temple of Love at the southern end of the Path to the Point in Zone C. currently dominated by catclaw in many areas, it will be important to introduce native plants that will fill that niche once the catclaw is managed. In a few areas where catclaw is dense, live planting could be an option. Inthecaseofliveplanting,irrigation maybeaconcern. RecommendedSpecies(seedsonly) Canadawildrye,Elymuscanadensis Virginiawildrye,Elymusvirginicus woodoats,Chasmanthiumlatifolium cedarsage,Salviaroemeriana Americanbeautyberry,Callicarpaamericana pigeonberry,Rivinahumilis bluecurls,Phaceliacongesta goldengroundsel,Packeraobovata ZONED:MEADOW Zone D is the highly modified area in the central portion of the peninsula and along 37

Laguna Gloria Site Assessment and Natural Area Management Guidelines by Siglo Group

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