Identifying key demographic parameters for the viability of a growing population of the endangered Egyptian Vulture Neophron percnopterus

SummaryThe Egyptian Vulture Neophron percnopterus is a threatened species throughout its worldwide range. The Iberian Peninsula holds 50% of its global population, which has declined by 25% over the last 20 years. Despite this negative global trend, an increase in the number of individuals over the last 25 years has been observed in Catalonia, where it has colonised areas in which it was previously unknown. In this study, we describe the demographic evolution of an increasing population of Egyptian Vultures in central and eastern Catalonia and we apply population models and maximum likelihood procedures to investigate both the main demographic processes driving the observed trends and the viability of the population. The number of pairs in this region increased from one to 22 in the period 1988–2012. The best-supported models suggest that adult survival in this population may be higher than in other Iberian populations and that furthermore, there is a continuous influx of immigrants. Based on the most likely scenarios, Population Viability Analysis predicts that the population will continue to increase. Sensitivity analysis indicates that the adult survival rate has the greatest influence on population dynamics so conservation efforts will be more effective if concentrated on improving this rate.

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Communal roosting of Egyptian vulture Neophron percnopterus in Uttar Pradesh, India

Journal of Applied and Natural Science ◽

10.31018/jans.v12i4.2361 ◽

2020 ◽

Vol 12 (4) ◽

pp. 525-531

Author(s):

Shivangi Mishra ◽

Adesh Kumar ◽

Ankit Sinha ◽

Amita Kanaujia

Keyword(s):

Endangered Species ◽

Uttar Pradesh ◽

Total Count ◽

Conservation Strategies ◽

Egyptian Vulture ◽

Neophron Percnopterus ◽

Communal Roosting ◽

Tree Building ◽

Number Of Individuals

The behaviour of birds to settle or rest at a place at specific times of day and night is called roosting. Some birds prefer solitary roosting while others roost communally. The Communal roosting behaviour of Egyptian vulture was studied in five districts (Sambhal, Lakhimpur Kheri, Aligarh, Bareilly and Faizabad) of Uttar Pradesh, India from January 2014- December 2017. Total count was conducted at roosting sites in all the seasons (summer, winter and monsoon). The maximum number of individuals counted at the roost site was in Sambhal followed by Lakhimpur Kheri, Aligarh, Bareilly, Faizabad. Four different roost substrates were identified: Ground, tree, building, and electric pylon. A maximum (63%) of Egyptian vultures were observed roosting on the ground, followed by electric pylon (19%), tree (10%) and minimum on building (8%). The present study confirmed that Egyptian vultures are communal roosters and a number of roosting individuals most probably depended on the availability of food of the area. Egyptian vultures are globally endangered species and so far no work has been done on their roosting behaviour in India; therefore the present study will prove beneficial to plan for their conservation strategies.

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Modelling the impact of predation on reintroductions of bridled nailtail wallabies.

Wildlife Research ◽

10.1071/wr9950163 ◽

1995 ◽

Vol 22 (2) ◽

pp. 163 ◽

Cited By ~ 23

Author(s):

H McCallum ◽

P Timmers ◽

. Hoyle.S

Keyword(s):

Population Viability Analysis ◽

Population Viability ◽

Predator Prey ◽

Viability Analysis ◽

Standard Population ◽

Viable Population ◽

Almost All ◽

The Impact ◽

Number Of Individuals ◽

Simple Stochastic Model

Predation by introduced foxes and cats is generally thought to be the main reason for the poor success rate of macropod reintroductions on the Australian mainland. Predator-prey theory suggests that predation may have particularly severe impacts on very small populations, especially if a more common primary prey species is present (such as the rabbit). Thus, a sufficiently large reintroduction may overcome predation and succeed where a smaller one would fail. The minimum viable population would, however, be much larger than that predicted by standard population-viability analysis. We use a simple stochastic model based upon the bridled nailtail wallaby to explore this possibility. Even very small amounts of predation (2-4 individuals per six months) can be sufficient to cause reintroductions of up to 50 animals to fail. No clear threshold population size beyond which reintroductions will succeed is evident and, for a given mean, the probability distribution of predation has a very limited impact on the success of reintroductions. In almost all circumstances, a single reintroduction of a given size is preferable to multiple reintroductions of the same total number of individuals.

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Uncertainty in assessing the viability of the Powerful Owl Ninox strenua in Victoria, Australia

Pacific Conservation Biology ◽

10.1071/pc990144 ◽

1999 ◽

Vol 5 (2) ◽

pp. 144 ◽

Cited By ~ 10

Author(s):

Michael A. McCarthy ◽

Alan Webster ◽

Richard H. Loyn ◽

Kim W. Lowe

Keyword(s):

Management Strategies ◽

Population Viability Analysis ◽

Population Viability ◽

Large Field ◽

Adult Survival ◽

Metapopulation Dynamics ◽

Viability Analysis ◽

Term Monitoring ◽

Predicted Risk

A model of the metapopulation dynamics of Powerful Owls Ninox strenua in Victoria, Australia is described, and its parameters were derived from available data. Sensitivity analysis indicates that the survival rate of adult owls is the most important parameter in the model. Because estimates of this parameter are uncertain, the predictions of the model are uncertain and unreliable. Using the best estimates of the parameters, the predicted risk of decline across Victoria is low, and local populations larger than 100 pairs have a low risk of extinction. If the lower estimates of adult and sub-adult survival are used, the abundance of Powerful Owls across Victoria is predicted to decline exponentially and faces extinction from deterministic forces. A prohibitively large field programme involving monitoring of individuallyrecognizable owls would be required to obtain an improved estimate of adult survival, and so further use of population viability analysis to assess the adequacy of particular management strategies is unlikely to be useful for this species. An alternative is to establish a long-term monitoring programme to document changes in abundance of the species in logged and unlogged landscapes.

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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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Egyptian Vulture (Neophron percnopterus)

10.2173/bow.egyvul1.01 ◽

2020 ◽

Author(s):

Jaume Orta ◽

Guy M. Kirwan ◽

David Christie ◽

Ernest Garcia ◽

Jeffrey S. Marks

Keyword(s):

Egyptian Vulture ◽

Neophron Percnopterus

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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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