scholarly journals Distribution range and population viability of Emys orbicularis in Slovakia: a review with conservation implications

2021 ◽  
Vol 44 ◽  
pp. 141-161
Author(s):  
Enikő Horváth ◽  
Martina Martvoňová ◽  
Stanislav Danko ◽  
Peter Havaš ◽  
Peter Kaňuch ◽  
...  
Keyword(s):  
Activity Patterns ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Freshwater Turtle ◽  
Isolated Populations ◽  
Term Survival ◽  
Emys Orbicularis ◽  
Turtle Species ◽  
Viability Analysis ◽  
Probability Of Extinction

The European pond turtle (Emys orbicularis) is the only native freshwater turtle species in Slovakia. Due to watercourse regulations in the middle of the 20th century, its range became fragmented and, currently, there are only two isolated populations. From a total of 1,236 historical records in Slovakia, most observations (782 records) came from the area of the Tajba National Nature Reserve (NNR). Three of the population viability analysis models (‘baseline’, ‘catastrophe’, ‘nest protection during a catastrophe’) indicated the extinction of the population in Tajba, with the highest probability of extinction occurring during a catastrophic event (probability of extinction 1.00). We also evaluated information about the activity patterns of seven radio-tracked individuals and about the number of destroyed nests from the area. During the period 2017–2021, we recorded only two turtles leaving the aquatic habitat of Tajba. An alarming fact is the massive number of destroyed nests found in the area during the study period (Tajba 524; Poľany 56). Our results indicate that the population in the Tajba NNR require immediate application of management steps to ensure its long-term survival.

scholarly journals Giraffe translocation population viability analysis

2020 ◽  
Vol 41 ◽  
pp. 245-252
Author(s):  
DE Lee ◽  
E Fienieg ◽  
C Van Oosterhout ◽  
Z Muller ◽  
M Strauss ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Growth ◽  
Genetic Load ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Sensitivity Analyses ◽  
Source Population ◽  
Viability Analysis ◽  
Probability Of Extinction ◽  
Founding Populations

Most populations of giraffes have declined in recent decades, leading to the recent IUCN decision to upgrade the species to Vulnerable status, and some subspecies to Endangered. Translocations have been used as a conservation tool to re-introduce giraffes to previously occupied areas or establish new populations, but guidelines for founding populations are lacking. To provide general guidelines for translocation projects regarding feasibility, we simulated various scenarios of translocated giraffe populations to identify viable age and sex distributions of founding populations using population viability analysis (PVA) implemented in Vortex software. We explored the parameter space for demography and the genetic load, examining how variation in founding numbers and sex ratios affected 100 yr probability of population extinction and genetic diversity. We found that even very small numbers of founders (N ≤ 10 females) can appear to be successful in the first decades due to transient positive population growth, but with moderate population growth rate and moderate genetic load, long-term population viability (probability of extinction <0.01) was only achieved with ≥30 females and ≥3 males released. To maintain >95% genetic diversity of the source population in an isolated population, 50 females and 5 males are recommended to compose the founding population. Sensitivity analyses revealed first-year survival and reproductive rate were the simulation parameters with the greatest proportional influence on probability of extinction and genetic diversity. These simulations highlight important considerations for translocation success and data gaps including true genetic load in wild giraffe populations.

scholarly journals Giraffe Translocation Population Viability Analysis

2019 ◽  
Author(s):  
Derek E. Lee ◽  
Elmar Fienieg ◽  
Cock Van Oosterhout ◽  
Zoe Muller ◽  
Megan Strauss ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Growth ◽  
Genetic Load ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Sensitivity Analyses ◽  
Source Population ◽  
Viability Analysis ◽  
Probability Of Extinction ◽  
Founding Populations

ABSTRACTMost populations of giraffes have declined in recent decades, leading to the recent decision to upgrade the species to vulnerable status, and some subspecies to endangered. Translocations have been used as a conservation tool to re-introduce giraffes to previously occupied areas or establish new populations, but guidelines for founding populations are lacking. To provide general guidelines for translocation projects regarding feasibility, we simulated various scenarios of translocated giraffe populations to identify viable age and sex distributions of founding populations using Population Viability Analysis (PVA) implemented in Vortex software. We explored the parameter space for demography (population growth rates: λ = 1.001, 1.010, 1.024), and the genetic load (number of lethal equivalents: LE = 2.5, 6.29, 12.6), examining how variation in founding numbers (N = 5 to 80 females) and sex ratios (M:F = 0.1 to 0.5) affected 100-year probability of extinction and genetic diversity. We found that even very small numbers of founders (N ≤10 females) can appear to be successful in the first decades due to transient positive population growth, but with moderate population growth rate and moderate genetic load, long-term population viability (probability of extinction <0.01) was only achieved with ≥30 females and ≥3 males released. To maintain >95% genetic diversity of the source population in an isolated population, 50 females and 5 males are recommended to comprise the founding population. Sensitivity analyses revealed first-year survival and reproductive rate were the simulation parameters with the greatest proportional influence on probability of extinction and genetic diversity. These simulations highlight important considerations for translocation success, and data gaps including true genetic load in wild giraffe populations.

Stochastic and spatially explicit population viability analyses for an endangered freshwater turtle, Clemmys guttata

2009 ◽  
Vol 87 (12) ◽  
pp. 1241-1254 ◽  
Author(s):  
J. J. Enneson ◽  
J. D. Litzgus
Keyword(s):  
Quantitative Methods ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Habitat Destruction ◽  
Population Persistence ◽  
Freshwater Turtle ◽  
Turtle Species ◽  
Georgian Bay ◽  
Clemmys Guttata ◽  
Risk Of Extinction

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.

Population Viability Analysis of a Long-Lived Freshwater Turtle, Hydromedusa maximiliani (Testudines: Chelidae)

2012 ◽  
Vol 11 (2) ◽  
pp. 162-169 ◽  
Author(s):  
Shirley Famelli ◽  
Sarah Cristina Piacentini Pinheiro ◽  
Franco Leandro Souza ◽  
Rafael Morais Chiaravalloti ◽  
Jaime Bertoluci
Keyword(s):  
Population Viability Analysis ◽  
Population Viability ◽  
Freshwater Turtle ◽  
Viability Analysis

Population viability analysis shows spotted-tailed quolls may be vulnerable to competition

2013 ◽  
Vol 35 (2) ◽  
pp. 180 ◽  
Author(s):  
A. S. Glen ◽  
C. R. Dickman
Keyword(s):  
Population Viability Analysis ◽  
Population Viability ◽  
Case Scenario ◽  
Worst Case ◽  
Term Survival ◽  
Exploitation Competition ◽  
Viability Analysis ◽  
Probability Of Survival ◽  
Abundance And Distribution

Competition between carnivores can strongly affect their behaviour, abundance and distribution. Recent analyses suggest a strong likelihood of competition between eutherian predators and the endangered spotted-tailed quoll (Dasyurus maculatus), although experiments are required to confirm this. If competition does occur, what are its likely effects on the long-term survival of spotted-tailed quoll populations? We used population viability analysis (PVA) to predict the fate of a hypothetical quoll population under various scenarios of competition. PVA showed that spotted-tailed quoll populations may be susceptible to extinction when faced with high densities of competitors. Model scenarios simulating exploitation competition and/or intraguild killing greatly reduced the population’s probability of survival, leading in the worst-case scenario to almost certain extinction.

scholarly journals Can we reestablish a self-sustaining population? A case study on reintroduced Crested Ibis with population viability analysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yashuai Zhang ◽  
Fang Wang ◽  
Zhenxia Cui ◽  
Min Li ◽  
Xia Li ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Population Size ◽  
Carrying Capacity ◽  
Wild Population ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Viability Analysis ◽  
Crested Ibis ◽  
Reintroduced Population

Abstract Background One of the most challenging tasks in wildlife conservation and management is clarifying which and how external and intrinsic factors influence wildlife demography and long-term viability. The wild population of the Crested Ibis (Nipponia nippon) has recovered to approximately 4400, and several reintroduction programs have been carried out in China, Japan and Korea. Population viability analysis on this endangered species has been limited to the wild population, showing that the long-term population growth is restricted by the carrying capacity and inbreeding. However, gaps in knowledge of the viability of the reintroduced population and its drivers in the release environment impede the identification of the most effective population-level priorities for aiding in species recovery. Methods The field monitoring data were collected from a reintroduced Crested Ibis population in Ningshan, China from 2007 to 2018. An individual-based VORTEX model (Version 10.3.5.0) was used to predict the future viability of the reintroduced population by incorporating adaptive patterns of ibis movement in relation to catastrophe frequency, mortality and sex ratio. Results The reintroduced population in Ningshan County is unlikely to go extinct in the next 50 years. The population size was estimated to be 367, and the population genetic diversity was estimated to be 0.97. Sensitivity analysis showed that population size and extinction probability were dependent on the carrying capacity and sex ratio. The carrying capacity is the main factor accounting for the population size and genetic diversity, while the sex ratio is the primary factor responsible for the population growth trend. Conclusions A viable population of the Crested Ibis can be established according to population viability analysis. Based on our results, conservation management should prioritize a balanced sex ratio, high-quality habitat and low mortality.

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