| dc.description.abstract |
The Chinese alligator is a critically endangered species that is endemic to China,
with fewer than 200 individuals in the wild and over 13,000 in captivity. Reintroduction
is crucial to restore its wild population, and Dongtan Wetland Park (DWP) in Shanghai
is one of the reintroduction sites. However, the population size and viability were
unclear due to inconsistent post-monitoring and lack of program evaluation. No further
introduction or management plans were devised. Current literature also had little
quantitative research on Chinese alligator habitat selection.
To understand DWP population status, this study first conducted population surveys
using spotlight count. N-mixture models were employed to estimate the population size,
and an average size of 54 individuals was calculated. Then, we examined the impact
of environmental factors on Chinese alligator habitat selection in DWP by conducting
habitat surveys and applied species distribution models. Finally, this paper used
the software Vortex to identify factors influencing population growth and simulate
population development. Vortex is commonly used for population viability analysis
and has been used on crocodilian species.
We discovered that high vegetation coverage and a moderate presence of trees had a
positive impact on alligator presence, while high mortality rates, low percentage
of females breeding, and the percentage of males at birth exceeding 50% could severely
hinder population growth. The viability analysis showed that the population is viable,
and reintroduction may not be needed in the short term. Finally, we recommended that
the park should construct more proper habitat with riparian cover and elevated ground
for nesting females. Systematic and consistent monitoring should be established in
DWP to provide long-term data. If monitoring shows low recruitment rates, reintroducing
alligators from diverse genetic lineages should be considered.
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