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 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

scholarly journals Population viability analysis and potential of its application to Danube sturgeons

2009 ◽  
Vol 61 (1) ◽  
pp. 123-128 ◽  
Author(s):  
I. Jaric ◽  
Mirjana Lenhardt ◽  
G. Cvijanovic ◽  
T. Ebenhard
Keyword(s):  
Life History ◽  
River Basin ◽  
Habitat Loss ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Danube River ◽  
The Danube River ◽  
Viability Analysis ◽  
Sturgeon Species ◽  
Danube River Basin

Sturgeon species in the Danube River basin have experienced severe decline. Besides overexploitation, habitat loss, and pollution, they are further endangered by lack of efficient policy and management, as well as by serious lack of knowledge about their life history. Although population viability analysis (PVA) could represent an extremely valuable tool to cope with these problems, it has not so far been applied to Danube populations. This paper represents an assess?ment of different PVA methods and models developed for sturgeon species. It analyzes their results, main advantages, drawbacks, and problems, and discusses the possibility of applying PVA to sturgeon populations in the Danube River basin.

scholarly journals What do population viability analyses tell about the future for Baltic Dunlin Calidris alpina schinzii and Montagu’s Harrier Circus pygargus on Öland?

Ornis Svecica ◽  
2010 ◽  
Vol 20 (2) ◽  
Author(s):  
Per-Eric Betzholtz ◽  
Tobias Berger ◽  
Jan Petersson ◽  
Johan Stedt
Keyword(s):  
Extinction Risk ◽  
Bird Species ◽  
Population Viability Analysis ◽  
Field Work ◽  
Population Viability ◽  
Sensitivity Analyses ◽  
Viability Analysis ◽  
Circus Pygargus ◽  
Montagu’S Harrier ◽  
Montagu's Harrier

Population viability analysis (PVA) has become an important tool in conservation biology. Even though detailed outcomes of PVA:s are constrained by data quality, it is a useful approach when the objective is exploratory, aiming to identify important parameters for viability or to guide future field work on endangered species. In this study we perform PVA:s based on scarce data to explore viability of two endangered bird species, Baltic Dunlin and Montagu’s Harrier, on Öland. Our simulation results underline that both species are under severe threats, with a median time to extinction of 24 years in Baltic Dunlin and 63 years in Montagu’s Harrier. Sensitivity analyses show that population growth rate is the most important factor for the model outcome in both species. Since there are no apparent threats for adult birds on Öland, this suggests that conservation measures should focus on improving conditions for successful breeding on the island. In additional simulations we explore some threats in more detail. In the case of Baltic Dunlin nest predation of eggs and chicks increase the extinction risk. In Montagu’s Harrier viability increases if breeding attempts within agricultural areas are detected and safeguarded. In order to enhance the PVA model, and build a stage-structured model, we suggest that detailed data on fecundity and survival should be collected.

scholarly journals A Population Viability Analysis for Sharp-Tailed Grouse to Inform Reintroductions

2018 ◽  
Vol 9 (2) ◽  
pp. 565-581 ◽  
Author(s):  
Megan C. Milligan ◽  
Smith L. Wells ◽  
Lance B. McNew
Keyword(s):  
Habitat Management ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Average Density ◽  
Western Montana ◽  
Management Scenarios ◽  
Winter Habitat ◽  
Viability Analysis ◽  
Continental Divide ◽  
Viable Population

Abstract Sharp-tailed grouse Tympanuchus phasianellus were effectively extirpated from western Montana during the last century as a result of settlement by Euro-Americans. Recent interest in reestablishing the species west of the Continental Divide has identified information gaps related to the potential success of a restoration effort. Elsewhere, sharp-tailed grouse are widespread and exhibit plasticity in habitat use, suggesting a high potential for successful reintroduction. Using life history information from the published literature, we conducted a population viability analysis to assess the potential viability of a reintroduced population of sharp-tailed grouse in western Montana and to evaluate what management scenarios, with regard to both translocation protocols and habitat management, would be necessary to produce a viable population. Results of the population viability analysis indicated that a population parameterized with mean reported demographic rates and related environmental variation would not be viable and suggest a potential downward bias in demographic estimates in the published literature. Based on our simulation results, improvements in both fecundity and annual survival resulting from improvements in nesting and winter habitat would be necessary to produce a viable population of sharp-tailed grouse in western Montana. The minimum amount of habitat required to support a viable population of 280 individuals was 1,867–5,600 ha, assuming habitat is sufficient to support an average density of 5–15 grouse per km2. We provide a review of demographic and reintroduction information for sharp-tailed grouse and recommendations regarding reintroduction approaches based on our population viability analysis results that should increase the relative success of restoration efforts in western Montana and elsewhere. We recommend that nesting and winter habitat improvements be the focus of pre- and postrelease management and that post-translocation population studies be conducted to monitor reintroduced populations and provide site-specific demographic information to update population viability analyses.

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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