Population Viability Analysis of Yangtze Finless Porpoise in the Yangtze Main Steam Suggesting that a Total Ban on Productive Fishing could be Decisive

2021 ◽  
Author(s):  
Wu Bin ◽  
Xu Jingen ◽  
Wang Jianmin ◽  
Cao Lie ◽  
Wang Weiping ◽  
...  
Keyword(s):  
Growth Rate ◽  
Population Decline ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Initial Population ◽  
Main Stream ◽  
Baseline Scenario ◽  
Finless Porpoise ◽  
Yangtze Finless Porpoise ◽  
Main Steam

Background: China is paying more attention to ecological systems within the Yangtze River has provided great opportunities to the conservation of the Yangtze finless porpoise (YFP). The rapid population decline of YFP in the main steam appears to have slowed, but the infrequent movement of porpoises represents a considerable threat to the long-term viability of this species in this region. We studied the population viability of YFP in the Yangtze main steam, based on published ecological and genetic information.Methods: Vortex model was used to analyze the population viability of the YFP. The simulations were started from the year 2017 when the initial population size was 445 animals in baseline scenario. We examined the population viability for the species under demographic fluctuations and conservation scenarios.Result: Baseline model showed the probability of extinction was 0.245; deterministic growth rate was -0.023; stochastic growth rate was -0.036. Sensitivity analysis showed differences in population trends between the baseline and each alternative scenario and the most sensitive parameters were the percentage of females breeding and mortality rates. Under different conservation scenarios, the population of the YFP in the main stream will increase by 11.0%-181.2% in 100 years.

scholarly journals Updated population viability analysis, population trends and PBRs for Hector’s and Maui dolphin

2020 ◽  
Author(s):  
Elisabeth Slooten ◽  
Stephen Michael Dawson
Keyword(s):  
Statistical Power ◽  
East Coast ◽  
Population Decline ◽  
Population Viability Analysis ◽  
Population Viability ◽  
List Type ◽  
Population Declines ◽  
The South ◽  
Executive Summary ◽  
Viability Analysis

EXECUTIVE SUMMARYUpdated population viability analyses, incorporating the latest abundance and bycatch data indicate that: The estimated population decline for Maui dolphin is 2% per yearThere is a 68% probability that the population is continuing to declineAfter 30 years (6 more surveys) statistical power of detecting this rate of decline would be < 15%Only very large declines (37%) and recovery (45%) would be detectable with 80% statistical power after 30 years (6 more surveys)The level of conservation threat for Hector’s dolphin remains high despite a recent, larger population estimate off the east coast of the South IslandIncreased overlap between dolphins and fisheries, due to more extensive offshore distribution of dolphins off the South Island east coast, more than offsets the apparently higher population sizeThe Hector’s dolphin population has declined 70% over the last 3 generations, exceeding the 50% threshold for EndangeredPopulation declines are predicted to continue under current protection levelsThe results of this research are consistent with:◯ NOAA proposal to list Hector’s and Maui dolphins under the US Endangered Species Act◯ IWC recommendation to ban gillnets and trawling throughout Maui dolphin habitat◯ IUCN recommendation to ban gillnets and trawling throughout Hector’s and Maui dolphin habitat

Accelerating population decline of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis)

2012 ◽  
Vol 153 ◽  
pp. 192-200 ◽  
Author(s):  
Zhigang Mei ◽  
Shiang-Lin Huang ◽  
Yujiang Hao ◽  
Samuel T. Turvey ◽  
Weiming Gong ◽  
...  
Keyword(s):  
Population Decline ◽  
Finless Porpoise ◽  
Yangtze Finless Porpoise ◽  
Neophocaena Asiaeorientalis Asiaeorientalis

scholarly journals Population viability analysis of the endangered Dupont’s Lark Chersophilus duponti in Spain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander García-Antón ◽  
Juan Traba
Keyword(s):  
Habitat Loss ◽  
Habitat Restoration ◽  
Population Decline ◽  
Bird Species ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Management Scenarios ◽  
Viability Analysis ◽  
Habitat Loss And Fragmentation ◽  
Dupont’S Lark

AbstractSteppe lands in Europe are critically affected by habitat loss and fragmentation, and hold over 50% of IUCN Red List bird species in Europe. Dupont’s Lark is a threatened steppe-specialist passerine whose European geographic range is restricted to Spain, with less than 2000 pairs and an annual population decline of − 3.9%. Its strongly fragmented habitat leads to a metapopulation structure in the Iberian Peninsula that includes 24 populations and 100 subpopulations. We present an updated Population Viability Analysis based on the latest scientific knowledge regarding distribution, population trends, breeding biology and connectivity. Our results predict metapopulation extinction in 2–3 decades, through a centripetal contraction process from the periphery to the core. The probability of extinction in 20 years was 84.2%, which supports its relisting to Endangered in Spain following IUCN criteria. We carried out a sensitivity analysis showing that some parameters, especially productivity and survival of adults and juveniles, help to increase metapopulation viability. Simulation of management scenarios showed that habitat restoration in a subset of key subpopulations had a positive effect on the overall metapopulation persistence. Translocations of a limited number of individuals from source to recipient locations may help to rescue the most endangered subpopulations without reducing the global time to extinction of the metapopulation. In addition, we identified the most critical areas for action, where local populations of the species are prone to extinction. This work suggests that the viability of the Dupont’s Lark metapopulation could be improved and its risk of extinction reduced if urgent and localized conservation measures are applied. In the short-term, habitat loss and fragmentation due to ploughing, reforestation and infrastructures implementation in Dupont’s Lark habitat must be avoided. Habitat restoration and translocations could help to avoid imminent extinction of critical subpopulations. Restoration of extensive grazing is recommended as the most effective way to achieve the long-term conservation of Dupont’s Lark in Spain.

scholarly journals Blanding’s Turtle Demography and Population Viability

2021 ◽  
Author(s):  
Richard B. King ◽  
Callie K. Golba ◽  
Gary A. Glowacki ◽  
Andrew R. Kuhns
Keyword(s):  
Genetic Diversity ◽  
Extinction Risk ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Demographic Parameters ◽  
Initial Population ◽  
Blanding's Turtle ◽  
Viability Analysis ◽  
Initial Population Size ◽  
Blanding’S Turtle

In anticipation of US federal status classification (warranted, warranted but precluded, not warranted), scheduled for 2023, we provide population viability analysis of the Blanding’s turtle Emydoidea blandingii , a long-lived, late-maturing, semi-aquatic species of conservation concern throughout its range. We present demographic data from long-term study of a population in northeastern Illinois and use these data as the basis for viability and sensitivity analyses focused on parameter uncertainty and geographic parameter variation. We use population viability analysis to identify population sizes necessary to provide population resiliency to stochastic disturbance events and catastrophes and demonstrate how alternative definitions of ‘foreseeable future’ might affect status decisions. Demographic parameters within our focal population resulted in optimistic population projections (probability of extinction = 0% over 100 years) but results were less optimistic when catastrophes or uncertainty in parameter estimates were incorporated (probability of extinction = 3% and 16%, respectively). Uncertainty in estimates of age-specific mortality had the biggest impact on population viability analysis outcomes but uncertainty in other parameters (age of first reproduction, environmental variation in age-specific mortality, % females reproducing, clutch size) also contributed. Blanding’s turtle demography varies geographically and incorporating this variation resulted in both mortality- and fecundity-related parameters affecting population viability analysis outcomes. Possibly, compensatory variation among demographic parameters allows for persistence across a wide range of parameter values. We found that extinction risk decreased and retention of genetic diversity increased rapidly with increasing initial population size. In the absence of catastrophes, demographic conservation goals could be met with a smaller initial population size than could genetic conservation goals; ≥20-50 adults were necessary for extinction risk &lt;5% whereas ≥50-110 adults were necessary to retain &gt;95% of existing genetic diversity over 100 yrs. These thresholds shifted upward when catastrophes were included; ≥50-200 adults were necessary for extinction risk &lt;5% and ≥110 to more than 200 adults were necessary to retain &gt;95% of existing genetic diversity over 100 yrs. Impediments to Blanding’s turtle conservation include an incomplete understanding of geographic covariation among demographic parameters, the large amount of effort necessary to estimate and monitor abundance, and uncertainty regarding the impacts of increasingly frequent extreme weather events.

scholarly journals Population Viability Analysis of the Endangered Roan Antelope in Ruma National Park, Kenya, and Implications for Management

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Johnstone K. Kimanzi
Keyword(s):  
National Park ◽  
Habitat Management ◽  
Expert Knowledge ◽  
Population Decline ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Management Options ◽  
Viability Analysis ◽  
Management Interventions ◽  
Sustainable Conservation

Population viability analysis (PVA) was used to (1) establish causes of roan population decline for the past 30 years in Ruma National Park (RNP), the only park where wild roans remain in Kenya, and (2) predict the probability of roan persistence under existing and alternative management options. PVA was done using long-term data based on population dynamics, life history, climatic conditions, and expert knowledge. Poaching was identified as the main cause of roan decline in RNP. Several antipoaching and prioritized habitat management interventions to promote population recovery and sustainable conservation of roans are described. PVA predictions indicated that, without these interventions, the roan population cannot persist more than 3 decades. Furthermore, ensuring sustainable conservation of roans in RNP will boost tourism in Western Kenyan and thus alleviate poverty in this part of the country. Improved income from tourism will reduce the possible pressures from hunting and give greater incentives for local people to be actively engaged in roan conservation.

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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