The document compares two methodologies for assessing native vegetation condition: the Habitat Hectares methodology and the NCSSA methodology. For each indicator (e.g. large trees, tree canopy cover), it outlines how the indicator is measured in each methodology and whether the relevant data can be extracted from biological survey databases. While there is broad alignment between many of the indicators, some data like log length are not captured by biological surveys.
2. www.environment.sa.gov.au
Site Condition
1. Large Trees
2. Tree Canopy Cover
3. Understorey
4. Lack of Weeds
5. Recruitment
6. Organic Litter
7. Logs
Landscape Context
8. Patch size
9. Neighbourhood
10. Distance to Core Area
Habitat Hectares Indicators
(based on Parkes, Newell and Cheal (2003))
Indicators
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• Each indicator is recorded relative to a benchmark value for a particular
vegetation type.
Example: Large Trees indicator
Habitat Hectares MethodologyIndicators
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• Each indicator is recorded as a raw value.
• These values are compared to a benchmark value for a particular
vegetation type at the end of the assessment process.
Example: Large Tree Habitat indicator
NCSSA MethodologyIndicators
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1. Large
Trees • Number of large trees and canopy health
a) the number of large trees per hectare (dead or alive)
b) canopy health is determined from the average projective foliage
cover of the large trees
Habitat Hectares Methodology
Relevant Biological Survey data
• Large trees are defined
by a minimum diameter
at breast height for each
vegetation community
benchmark
a) Number of large trees per hectare is not measured as a part of the
Biological Survey
b) Canopy health can be derived from the projective foliage cover
recorded for the overstorey within the Biological Survey
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1. Large
Trees • Tree Habitat Features
a) the diameter at breast height is recorded for ten adult trees from the
tallest or dominant stratum (can be converted to ‘large trees’)
b) canopy health is determined by the canopy cover of ten adult trees
from the tallest or dominant stratum (percent dieback is converted to
percent remaining)
Equivalent NCSSA Indicator
Relevant Biological Survey data
a) Number of large trees is not measured as a part of the Biological Survey
b) Canopy health can be derived from the projective foliage cover
recorded for the overstorey within the Biological Survey
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X ~
• Number of large trees
X
• Number of large trees
• Tree health
Summary1. Large
Trees HABITAT HECTARES
Large Trees
NCSSA METHODOLOGY
Tree Habitat Features
Biological Survey
Database
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2. Tree
Canopy
Cover
• Projective foliage cover of tree canopy and canopy health
a) the projective foliage cover of trees at least 80% of the benchmark
mature height
b) canopy health is determined from the average projective foliage
cover of the large trees
Habitat Hectares Methodology
Relevant Biological Survey data
• Tree canopy cover is only
assessed for those trees
that are at least 80% of
the benchmark mature
height
a) Projective foliage cover is calculated for the overstorey within the
Biological Survey
b) Canopy health can be derived from the projective foliage cover
recorded for the overstorey within the Biological Survey
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2. Tree
Canopy
Cover
• Tree Habitat Features
a) the canopy cover is recorded for ten adult trees from the tallest or
dominant stratum (percent dieback is converted to percent
remaining)
b) canopy health is derived from the canopy cover recorded above
Equivalent NCSSA Indicator
Relevant Biological Survey data
a) Projective foliage cover is calculated for the overstorey within the
Biological Survey
b) Canopy health can be derived from the projective foliage cover
recorded for the overstorey within the Biological Survey
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• Projective foliage cover
Summary2. Tree
Canopy
Cover
HABITAT HECTARES
Tree Canopy
Cover
NCSSA METHODOLOGY
Tree Habitat Features
Biological Survey
Database
• Tree health
• Projective foliage cover
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• Number of understorey life forms present and their degree of modification
a) the number of understorey life forms present
b) the degree of modification to life forms
Habitat Hectares Methodology
3.
Understorey
Relevant Biological Survey data
a) Number of understorey life forms can be extracted from the Biological
Survey database
b) Species diversity and percent cover of life forms can be extracted from
the Biological Survey database.
• Degree of modification is
determined by:
- species diversity, or
- percent cover,
depending on the
benchmark cover value
for each life form
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3.
Understorey • Structural Diversity B: Plant Life Forms
a) the number of life forms present
b) the percent cover of each life form
Equivalent NCSSA Indicator
Relevant Biological Survey data
a) Number of life forms can be extracted from the Biological Survey
database
b) Percent cover of each life form can be extracted from the Biological
Survey database.
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• Number of understorey life forms
~
• Degree of modification
• Number of understorey life forms
3.
Understorey
Summary
HABITAT HECTARES
Understorey
NCSSA METHODOLOGY
Structural Diversity B:
Plant Life Forms
Biological Survey
Database
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• Percentage weed cover and proportion of high threat weeds
a) the average projective foliage cover of all weeds
b) the proportion of weed cover due to high threat weeds
Habitat Hectares Methodology4. Lack of
weeds
Relevant Biological Survey data
a) Cover abundance of weed species can be extracted from the
Biological Survey database.
b) Weed species names can be extracted from Biological Survey data to
determine the proportion of high threat weeds.
• Weed cover is expressed
as an actual value rather
than as a percentage of
the benchmark weed
cover
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• Weeds Abundance and Threat
a) the five most abundant weed species
b) the cover abundance of each weed species
c) the invasive threat category of each weed species
Equivalent NCSSA Indicator
Relevant Biological Survey data
a) The five most abundant weed species can be extracted from the
Biological Survey database using the cover abundance rating.
b) Cover abundance of weed species can be extracted from the
Biological Survey database.
c) Weed species names can be extracted from Biological Survey data to
determine the invasive threat category of each weed.
4. Lack of
weeds
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~ ~
• Projective foliage cover of weeds
Summary
HABITAT HECTARES
Lack of Weeds
NCSSA METHODOLOGY
Weed Abundance and
Threat
Biological Survey
Database
4. Lack of
weeds
~
• Proportion of weed cover due to high threat weeds
• Projective foliage cover of weeds
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• Presence of recruitment and its adequacy and diversity
a) evidence of a recruitment cohort
b) adequacy of recruitment for each woody species in the canopy and
the understorey
c) the number of native woody species that have adequate recruitment
d) the total number of woody species (to determine diversity)
Habitat Hectares Methodology
5.
Recruitment
Relevant Biological Survey data
a) The life stage of individual species can be extracted from the Biological
Survey data to determine recruitment evidence.
b) The life stage of individual species can be extracted from the Biological
Survey data to determine adequacy of recruitment.
c) The number of woody species with adequate recruitment can be
extracted from the Biological Survey data.
d) The total number of woody species can be extracted from the
Biological Survey data.
• “…‘adequate’ is
considered to be
sufficient recruitment to
replenish natural attrition
of individual plants and
species within the various
life forms found in the
habitat zone” (DSE, 2004)
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• Regeneration
a) the number of regenerating tree species
Equivalent NCSSA Indicator
Relevant Biological Survey data
a) The number of regenerating tree species can be extracted from the
Biological Survey database.
5.
Recruitment
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X
• Evidence of a recruitment cohort
• Evidence of a recruitment cohort
X
• Adequacy of recruitment for each woody species in the canopy and the understorey• Adequacy of recruitment for each woody species in the canopy and the understorey
• Number of native woody species that have adequate recruitment
~
X
• Number of native woody species that have adequate recruitment
• Total number of woody species
Summary
HABITAT HECTARES
Recruitment
NCSSA METHODOLOGY
Regeneration
Biological Survey
Database
5.
Recruitment
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• Percentage cover of native and non-native organic litter
a) the percentage cover of organic litter
b) the proportion of organic litter comprising native and non-native
ground cover species
Habitat Hectares Methodology6. Organic
Litter
Relevant Biological Survey data
a) The plant litter attribute can be extracted from the Biological Survey
database to represent cover of organic litter.
b) The proportion of organic litter comprising native and non-native
species can not be determined from the Biological Survey database.
• Litter is defined as
“organic material
detached from the
parent plant, including
both coarse and fine
plant debris, and material
such as fallen leaves,
twigs and small branches
less than 10cm diameter
present at ground level”
(DSE, 2004).
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• Structural Diversity A: Ground Cover
a) the percentage of bare ground
b) the percentage of total ground cover
Equivalent NCSSA Indicator
Relevant Biological Survey data
a) The bare ground attribute can be extracted from the Biological Survey
database.
b) The total ground cover figure can be derived from the bare ground
figure, assuming the remaining area represents total ground cover.
6. Organic
Litter
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• Percentage cover of organic litter
Summary
HABITAT HECTARES
Organic Litter
NCSSA METHODOLOGY
Structural Diversity A:
Ground Cover
Biological Survey
Database
6. Organic
Litter
XX
• Proportion of organic litter comprising native and non-native ground cover species
• Percentage cover of organic litter
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• Estimation of log length and presence of large logs
a) the total length of logs greater than 10cm diameter
b) the presence of large logs that are > 25% of the benchmark log length
Habitat Hectares Methodology7. Logs
Relevant Biological Survey data
a) Log length is not recorded in the Biological Survey database.
b) The presence of large logs can not be determined from the Biological
Survey database.
• Logs are defined as
“dead timber fallen to
the ground with a
diameter > 10cm” (DSE,
2004).
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• Tree Habitat Features
a) the number of fallen trees or logs > 30cm diameter
Equivalent NCSSA Indicator
Relevant Biological Survey data
a) The number of fallen logs is not recorded in the Biological Survey
database
7. Logs
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• Total length of logs greater than 10cm diameter
XX
X
Summary
HABITAT HECTARES
Logs
NCSSA METHODOLOGY
Tree Habitat Features
Biological Survey
Database
7. Logs
• Total length of logs greater than 10cm diameter
X X
X
• Presence of large logs that are > 25% of the benchmark log length
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• Estimation of log length and presence of large logs
a) the total length of logs greater than 10cm diameter
b) the presence of large logs that are > 25% of the benchmark log length
Habitat Hectares Methodology8. Logs
Relevant Biological Survey data
a) Log length is not recorded in the Biological Survey database.
b) The presence of large logs can not be determined from the Biological
Survey database.
• Logs are defined as
“dead timber fallen to
the ground with a
diameter > 10cm” (DSE,
2004).
29. www.environment.sa.gov.au
• Tree Habitat Features
a) the number of fallen trees or logs > 30cm diameter
Equivalent NCSSA Indicator
Relevant Biological Survey data
a) The number of fallen logs is not recorded in the Biological Survey
database
7. Logs
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• Total length of logs greater than 10cm diameter
XX
X
Summary
HABITAT HECTARES
Logs
NCSSA METHODOLOGY
Tree Habitat Features
Biological Survey
Database
7. Logs
• Total length of logs greater than 10cm diameter
X X
X
• Presence of large logs that are > 25% of the benchmark log length
Hinweis der Redaktion
Recorded as a percentage of the benchmark value rather than an actual number of trees.
present = i.e. not missing to due tree death, decline, insect attack or mistletoe infestation
BS Can life form height categories be used to define a minimum height for ‘Large Trees’ rather than a DBH?
(defined as > 190cm diameter at breast height)
HH states trees must be 80% of benchmark height – can we assume the overstorey as defined in BS are > 80% benchmark height?
Cohort – a group of woody plants established in a single episode
Point 3 - Number of woody species: NCSSA only records regenerating TREE species