The Last-Surviving Moroccan Dorcas Gazelle (Gazella dorcas massaesyla) Viability Analysis [M’Sabih Talaa Reserve, Morocco]

The single remnant Moroccan dorcas gazelle (Gazella dorcas massaesyla) has been isolated for more than five decades in the M’Sabih Talaa reserve, an arid area of west-central Morocco. This population has been subject to different disturbances, especially poaching and depredation by feral dogs. A five-season line transect survey revealed that the population size has been halved in less than 15 years with a lower apparent fecundity rate. In the present work, we carried out a population viability analysis simulating different scenarios using VORTEX software based on available demographic and life-history data from captive populations,. A sensitivity analysis revealed that inbreeding depression and possible catastrophic events could have a considerable impact on the population’s prospects. Scenarios of splitting population into two subpopulations with different management measures reducing/deleting mortality sources, is proposed. Such scenarios resulted in reducing the consequences of catastrophic events would significantly mitigate the harmful effects of both inbreeding and environmental stochasticity. These results may be of a general interest to conservationists dealing with this unique and imperiled population.

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Using stationary vital rates in impact assessments may underestimate potential threat

10.1101/2021.07.01.450685 ◽

2021 ◽

Author(s):

Cat Horswill ◽

Julie Miller ◽

Matt J Wood

Keyword(s):

Predictive Accuracy ◽

Temporal Trends ◽

Population Viability Analysis ◽

Environmental Stochasticity ◽

Leslie Matrix ◽

Management Decision ◽

Vital Rates ◽

Potential Threat ◽

Viability Analysis ◽

Management Decision Making

Population viability analysis (PVA) is commonly used to assess future potential risks to threatened species. These models are typically based on mean vital rates, such as survival and fecundity, with some level of environmental stochasticity. However, the vital rates of wild populations, especially those already exhibiting declining trajectories, may be nonstationary, such that the mean or variance changes over time. In this study, we examined whether including observed temporal trends in vital rates affects the predictive accuracy of PVA, as well as the projected impact associated with a hypothetical threat. To achieve this, we ran a series of simulations using Leslie matrix PVA models that included different combinations of environmental stochasticity, temporal trends in vital rates, and threat. We found that including observed temporal trends in vital rates was (i) crucial for the accurate reconstruction of observed population dynamics and (ii) had a dramatic effect on the projected impact from the hypothetical threat. In an era when many animal and plant populations are declining due to long-term trends in their vital rates, we conclude that this demographic structure is essential for robustly evaluating potential threats using PVA models. Omitting observed temporal trends in vital rates from impact assessments is highly likely to yield unreliable results that could misinform conservation and management decision making.

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PROFIL KERAGAMAN VEGETASI EKOSISTEM MANGROVE DI DESA TAMUKU KABUPATEN LUWU UTARA

Jurnal Pendidikan Teknologi Pertanian ◽

10.26858/jptp.v5i0.8564 ◽

2019 ◽

Vol 5 ◽

pp. 104

Author(s):

Suhendra Purnawan ◽

Subari Yanto ◽

Ernawati S.Kaseng

Keyword(s):

Survey Methods ◽

Mangrove Ecosystem ◽

Line Transect ◽

Mangrove Forests ◽

Vegetation Diversity ◽

Line Transect Survey ◽

Analysis Technique ◽

Mangrove Vegetation ◽

Data Collection Technique ◽

The Impact

This study aims to describe the profile of vegetation diversity in the mangrove ecosystem in Tamuku Village, Bone-Bone-Bone District, North Luwu Regency. This research is a qualitative research using survey methods. The data collection technique uses the Quadrant Line Transect Survey technique. The data analysis technique uses the thinking flow which is divided into three stages, namely describing phenomena, classifying them, and seeing how the concepts that emerge are related to each other. The results of this study are the profile of mangrove vegetation in Tamuku Village, which is still found 16 varieties of true mangrove vegetation and 7 varieties of mangrove vegetation joined in the coastal area of Tamuku Village, Bone-Bone District, North Luwu Regency, South Sulawesi. The condition of mangrove vegetation in Tamuku Village is currently very worrying due to human activities that cause damage such as the project of normalization of flow, opening of new farms, disposal of garbage, water pollution due to chemicals, and exploitation of mangrove forests for living needs. The impact is ecosystem damage and reduced vegetation area as a place to grow and develop mangroves.

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Faculty Opinions recommendation of Incorporating ecological drivers and uncertainty into a demographic population viability analysis for the island fox.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1158627.618836 ◽

2009 ◽

Author(s):

Nigel Yoccoz

Keyword(s):

Population Viability Analysis ◽

Population Viability ◽

Viability Analysis ◽

Island Fox

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

Avian Research ◽

10.1186/s40657-021-00250-z ◽

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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