Stochastic and spatially explicit population viability analyses for an endangered freshwater turtle, Clemmys guttata
Authored by J J Enneson, J D Litzgus
Date Published: 2009
DOI: 10.1139/z09-112
Sponsors:
Parks Canada
National Science and Engineering Research Council of Canada (NSERC)
Canadian Wildlife Service (WWF)
Ontario Ministry of Natural Resources
Canada-Ontario Agreement
Laurentian University
Platforms:
Scilab
Model Documentation:
Other Narrative
Mathematical description
Model Code URLs:
Model code not found
Abstract
Over two thirds of the world's turtle species are in decline as a result
of habitat destruction and harvesting. Quantitative methods for
predicting the risk of extinction of turtle populations are essential
for status assessments and recovery planning. Spotted turtles (Clemmys
guttata (Schneider, 1792)) are considered vulnerable internationally, and endangered in Canada. We used population viability analysis to
assess the risk of extirpation of a Georgian Bay, Ontario, population
that has been under study since 1977 and of nine Ontario populations for
which population size is known, and to examine the effects of dispersal
between breeding ponds on population persistence. A simple stochastic
model for the Georgian Bay population projected a 60\% probability of
extirpation in 100 years. A metapopulation model for the same study area
projected an 18\% probability of extirpation within 100 years, suggesting that dispersal between breeding ponds is important for
population persistence. Spotted turtles at this relatively pristine site
have a relatively high risk of extinction despite the absence of
anthropogenic additive mortality. Probability of quasi-extinction as a
result of stochasticity for the model simulating nine Ontario
populations was low, but the probability of six or more of the nine
known Ontario populations becoming extirpated within 100 years was 26\%, indicating that recovery action is necessary to prevent decline of
spotted turtles within the species' Canadian range, which is restricted
to Ontario.
Tags
Individual-based model
time-series
Conservation
Density-dependence
Long-lived organisms
Spotted turtles
Emydoidea-blandingii
Northern population
Sexual-maturity
Box turtle