ESM 211 Applied Population Ecology

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ESM 211 Applied Population Ecology

• Winter 2008
• Bruce Kendall
• 4514 Bren Hall
• x7539 kendall_at_bren.ucsb.edu
• INCLUDE 211 IN EMAIL SUBJECT

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Defining endangerment the US Endangered Species
Act

• A species is listed under one of two categories,
  endangered or threatened, depending on its status
  and the degree of threat it faces. An
  endangered species is one that is in danger of
  extinction throughout all or a significant
  portion of its range. A threatened species is
  one that is likely to become endangered in the
  foreseeable future. To help conserve genetic
  diversity, the ESA defines species broadly to
  include subspecies and (for vertebrates) distinct
  populations. (USFWS 2005, p. 1)

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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.

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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

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Red List Criterion A
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Red List Criterion C
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Red List Criterion D
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Red List Criterion E
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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
  
• Future status
• Threshold population size (perhaps zero)
• Trends in population size

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Logistics

• Roll
• Computer accounts
• Experiences Interests
• Syllabus

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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)

M.L. Shaffer (1981) BioScience 31131-134
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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?
• Allows triage
• 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

E.D. Forsman et al. (1996) Demography of the
Northern Spotted Owl F.W. Allendorf et al. (1997)
Conservation Biology 11140-152
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F.W. Allendorf et al. (1997) Conservation Biology
11140-152
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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

L.R. Gerber et al. (1999) Conservation Biology
131215-1219
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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

D. Crouse (1987) Ecology 681412-1423
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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

P. Armbruster R. Lande (1993) Conservation
Biology 7602-610
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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

K. Marshall G. Edward Jones (1998)
Biodiversity and Conservation 7275-296
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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)
• Bycatch
• Habitat destruction
• Particularly relevant for setting levels of
  allowable take under ESA and HCP

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Determine how many ( which) populations needed
for species persistence

• Furbishs 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

E. Menges (1990) Conservation Biology 452-62
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Approaches to PVA

• Count-based PVA
• Uses census data
• Assumes all individuals identical
• Demographic PVA
• Incorporates information about vital rates
• Can include population structure
• Spatially explicit PVA
• Incorporates migration and colonization

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Approaches to PVA
Biological realism
Data requirements
Bias
Precision
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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
• Biological Conservation
• Conservation Biology
• Ecological Applications
• Ecology and Society
• Endangered Species UPDATE
• Journal of Wildlife Management
• Natural Resource Modeling

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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.