Defining endangerment: the US Endangered Species Act.
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1. ESM 211 Applied Population Ecology Winter 2008
4514 Bren Hall
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3. Listing decision under the US ESA A species is added to the list when it is determined to be endangered or threatened because of any of the following factors:
the present or threatened destruction, modification, or curtailment of the species’ habitat or range;
overutilization for commercial, recreational, scientific, or educational purposes;
disease or predation;
the inadequacy of existing regulatory mechanisms;
other natural or manmade factors affecting the species’ survival. Listing decisions (in federal register) rarely include quantitative criteria (tho may make reference to quantitative data)
Recovery plans often have quantitative criteria for delisting, such as population size or trends.Listing decisions (in federal register) rarely include quantitative criteria (tho may make reference to quantitative data)
Recovery plans often have quantitative criteria for delisting, such as population size or trends.
4. Defining endangerment: the IUCN Red List 7 categories
Extinct (EX); Extinct in the Wild (EW)
Critically Endangered (CR); Endangered (EN); Vulnerable (VU)
Near Threatened (NT); Least Concern (LC)
Classification into CR, EN or VU based on quantitative criteria: most restrictive of 5
5. Red List Criterion A Criterion B is a complex set of rules regarding reductions in the extent or area of occurenceCriterion B is a complex set of rules regarding reductions in the extent or area of occurence
6. Red List Criterion C
7. Red List Criterion D
8. Red List Criterion E
9. Population Viability Analysis PVA is the use of quantitative methods to predict the likely future status of a population or collection of populations of conservation concern
Threshold population size (perhaps zero)
Trends in population size
10. Logistics Roll
Experiences & Interests
11. Assess extinction risk of single population Mark Shaffer (Ph.D. student at Duke): Will Yellowstone grizzlies have 95% chance of surviving to different times in the future?
100 years yes
300 years no
Influenced mgmt of GYE (less clear cutting & mining)
Forestalled premature removal from ESA “threatened” list
First quantitative PVA (1978)
12. Compare relative risks of multiple populations 10 of 11 local populations of Northern Spotted Owl are declining
Which salmon populations can be preserved with limited funding?
Some populations will be OK on their own
Some populations will be impossible to save
Focus on the rest, where conservation efforts will make a difference
14. Analyze & synthesize monitoring data Are gray whale data sufficient to merit delisting?
Species delisted in '94, after 17 surveys
Survey costs $60,000
Could have been delisted in 1978, after 11 surveys
15. Identify key life stages or demographic processes as management targets What life stage of sea turtles is most susceptible to management intervention?
Improving hatchling survival on beaches helps, but is not sufficient
Juvenile & adult survival needs to be improved
Analysis led to implementation of TEDs
16. Determine reserve size to achieve desired protection How large do parks in semi-arid Africa need to be to preserve elephants in the face of various drought projections?
Large population size is good
3.1 elephants per mile2
Need 500 mile2 for 99% chance of persisting 1000 years
17. Determine number of individuals to release to establish new pop Tradeoff between number of new populations and size of each
Latter effects probability that each succeeds
What is the value of continuing to add new individuals after initial release?
Capercaillie in Scotland; for 95% probability of surviving 50 years, need initial release of:
Without supplementation: 60 individuals
With 2 individuals added every 5 years: 10 individuals
18. Set limits on harvest or “take” How many (and what stage) individuals can be taken before pop declines?
Harvest (e.g., black bear, wild ginseng)
Particularly relevant for setting levels of allowable take under ESA and HCP
19. Determine how many (& which) populations needed for species persistence Furbish’s lousewort: grows in small populations on banks of single river in Maine
Local populations frequently go extinct through ice scouring
Protecting only extant populations will ensure eventual extinction
Must also manage other sites to enhance opportunities to colonize new populations
20. Approaches to PVA Count-based PVA
Uses census data
Assumes all individuals identical
Incorporates information about vital rates
Can include population structure
Spatially explicit PVA
Incorporates migration and colonization
21. Approaches to PVA
22. Further Reading Books
Analysis and Management of Animal Populations (2002; Williams et al.)
Population Viability Analysis (2002; Beisinger & McCullough, eds.)
Quantitative Methods for Conservation Biology (2000; Ferson & Burgman, eds.)
Species Conservation and Management: Case Studies (2004; Akcakaya et al., eds.) Journals
Biodiversity and Conservation
Ecology and Society
Endangered Species UPDATE
Journal of Wildlife Management
Natural Resource Modeling
23. References USFWS. 2005. Listing a Species as Threatened or Endangered. Online document, available at http://www.fws.gov/endangered/listing/listing.pdf. Accessed 1 Oct. 2006.