The Designation & Management of Threatened Species: is there any point?
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The management of threatened species is an important practical way in which conservationists can intervene with extinction process and reduce the loss of biodiversity by ensuring some (high) probability of long-term species survival (Young, 1994; Norris, 2004). Though maintaining the whole ecosystem is often the target of conservationists, if a population is severely threatened this may not be sufficient. A more direct population management may be required (Hunter, 1996). To conserve such rare species there is a critical need to assess the impacts of threats on the long term survival of an individual population. This requires detailed information about the biology of the species concerned, the habitat it prefers, and the factors that might affect both of these (Root, 1998). Natural resource agencies worldwide develop species recovery plans that specify threats, propose targets required for recovery, and evaluate the extent to which habitat alteration and restoration may influence species decline and recovery (Good et al. 2003)
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The Designation & Management of Threatened Species: is there any point?
- 1. The Designation and Management of Threatened Species ... is there any point? Mario V. Balzan 26 th March 2007 Nesoenas mayeri EN B1ab(iii) Loxodonta africana VU A2a Ursus maritimus VU A3c University of Malta Conservation & Management of Natural Resources
- 5. Small Population & Declining Population Paradigms Both paradigms are important and need to be taken into account when assessing endangerment and designing recovery plans for threatened species Strong basis in problem solving Weak link to actuality Weak theory “rooted in empiricism” Strong theory From wildlife management From genetics & population ecology Traditional Developed in 1980s Extinction due to external factors (e.g. habitat loss) Extinction due to low numbers Declining Population Paradigm Small Population Paradigm
- 12. The IUCN Red List of Threatened Species
- 18. Threatened Species Designation Some local & other illustrious examples Helichrysum melitense Common Name: Sempreviva t’Ghawdex Status: CR B1ab(i,ii,iii,iv,v) Cremnophyton lanfrancoi Common Name: Bjanka ta’ l-Irdum Status: CR B1ab(i,ii,iii,iv,v) Delphinus delphis (Mediterranean subpopulation) Common Name: Short-beaked common dolphin Status: EN A2abc Falco naumanni Common Name: Lesser Kestrel Status: VU A2bce+3bce Ursus maritimus Common Name: Polar bear Status: VU A3c Ailuropoda melanoleuca Common Name: Giant Panda Status: EN B1+2c, C2a
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Hinweis der Redaktion
- Secondary Extinctions – e.g. Hibiscadelphus – a genus of plants endemic to Hawaii. Three of the seven species of Hibiscadelphus are extinct and all of the remainder are either extinct in the wild or extremely rare. It has been suggested that this may be due to poor pollination as a result of the extinction of their honeycreeper.
- Threatened species lists have been used to: (1) set priorities for resource allocation for species recovery, (2) to inform reserve system design (3) to constrain development & exploitation, and (4) to report on the state of the environment. Each time a species goes extinct the independent evolutionary history embodied in that lineage is lost forever.
- Madsen et al. (1999) restored a severely inbred adder population by restocking from an allopatric large and genetically variable adder population.
- What is the point in managing threatened species? Aren’t these species eventually doomed? Reduced fitness due to loss of genetic diversity (genetic drift & inbreeding) & is the species able to adapt to environmental change?
- The population size at any given time is a function of both the population size at the previous time step and the values drawn at random from distributions of numbers described by the model’s parameters.
- Caro and Luarenson (1994) argue that genetic considerations are clearly important in the management of captive populations but may only be relevant to free-living populations in limited circumstances because they impact on a slower time scale than environmental or demographic stochasticities. Nevertheless if one considers only genetic stochasticities for endangered species, an effective size of at least 500 and actual numbers of adult census size of at least 5000 (Ne/N = 0.1 for wild populations) are required for maintaining long term genetic diversity and minimising inbreeding depression.
- However, this cross-fostering programme involved translocation to South East Island (12 km away) coupled with interspecific cross-fostering, then about two weeks after hatching, translocation back with further intraspecific cross-fostering to avoid imprinting in the wrong species. The robin recovery programme is an example where species-driven management has facilitated effective ecological conservation and recovery. Also it has increased support for biological conservation and appreciation of biological values, with Chatham Islanders now actively involved at all levels in local conservation issues and projects
- Besides being one of the few “extinct” animals to be rediscovered, the midwife toad is unusual because of the way it reproduces. Native only to Mallorca, A. muletensis spawns in the water, but once the female has produced her string of pearl-like eggs, the male carries around his hind legs, keeping them moist and at the correct temperature until they hatch (hence the name midwife). When they are ready to hatch, he releases the larvae into a suitable body of water where they remain as tadpoles for as long as a year.