Population viability analysis on a native Danish cattle breed

2016 ◽  
Vol 59 ◽  
pp. 105-112 ◽  
Author(s):  
Morten Hertz ◽  
Iben Ravnborg Jensen ◽  
Laura Østergaard Jensen ◽  
Iben Vejrum Nielsen ◽  
Jacob Winde ◽  
...  
Keyword(s):  
Bos Taurus ◽  
Extinction Risk ◽  
Population Viability Analysis ◽  
Cattle Breed ◽  
Population Viability ◽  
Small Population ◽  
Viability Analysis ◽  
Probability Of Survival ◽  
Population Sizes ◽  
Breeding Pool

SummaryMany domestic breeds face challenges concerning genetic variability, because of their small population sizes along with a high risk of inbreeding. Therefore, it is important to obtain knowledge on their extinction risk, along with the possible benefits of certain breeding strategies. Since many domestic breeds face the same problems, results from such studies can be applied across breeds and species. Here a Population Viability Analysis (PVA) was implemented to simulate the future probability of extinction for a population of the endangered Danish Jutland cattle (Bos taurus), based on the software Vortex. A PVA evaluates the extinction risk of a population by including threats and demographic values. According to the results from the PVA the population will go extinct after 122 years with the current management. Four scenarios were created to investigate which changes in the breeding scheme would have the largest effect on the survival probabilities, including Scenario 1: More females in the breeding pool, scenario 2: More males in the breeding pool, scenario 3: Increased carrying capacity, and scenario 4: Supplementing males to the population through artificial insemination using semen from bulls used in the populations in past generations. All scenarios showed a positive effect on the population's probability of survival, and with a combination of the different scenarios, the population size seems to be stabilized.

scholarly journals The mathematics of extinction across scales: from populations to the biosphere

2017 ◽  
Author(s):  
Colin Carlson ◽  
Kevin Burgio ◽  
Tad Dallas ◽  
Wayne Getz
Keyword(s):  
Extinction Risk ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Occupancy Models ◽  
Viability Analysis ◽  
Extinction Rates ◽  
Sixth Mass Extinction ◽  
Evolutionary Rescue ◽  
Species Area ◽  
Using Data

The sixth mass extinction poses an unparalleled quantitative challenge to conservation biologists. Mathematicians and ecologists alike face the problem of developing models that can scale predictions of extinction rates from populations to the level of a species, or even to an entire ecosystem. We review some of the most basic stochastic and analytical methods of calculating extinction risk at different scales, including population viability analysis, stochastic metapopulation occupancy models, and the species area relationship. We also consider two major extensions of theory: the possibility of evolutionary rescue from extinction in a changing environment, and the posthumous assignment of an extinction date from sighting records. In the case of the latter, we provide a new example using data on Spix's macaw (Cyanopsitta spixii), the "rarest bird in the world," to demonstrate the challenges associated with extinction date research.

scholarly journals A population viability analysis (PVA) for Cabot's Tragopan (Tragopan caboti) in Wuyanling, south-east China

2007 ◽  
Vol 17 (2) ◽  
pp. 151-161 ◽  
Author(s):  
Yanyun Zhang ◽  
Guangmei Zheng
Keyword(s):  
Population Size ◽  
Extinction Risk ◽  
Population Viability Analysis ◽  
Field Studies ◽  
Population Viability ◽  
Sensitivity Analyses ◽  
East China ◽  
Suitable Habitat ◽  
Bird Conservation ◽  
Viability Analysis

AbstractUnderstanding the status of fragmented populations and predicting their fate is an increasingly important part of bird conservation. Population viability analysis (PVA) can help in this process and is widely used for assessing the extinction risk faced by threatened species and for finding the key factors affecting population status and survival prospects. From 1982 to 2004, 14 scientists studied the population of the globally threatened Cabot's Tragopan Tragopan caboti in Wuyanling National Natural Reserve (WNNR), south-east China and collected life-history data on the population. Using VORTEX, we analysed the viability of the population in the reserve and this predicted that the population size will increase for the next 50 years and will then show a very slight decline for the next 50 years. The loss of heterozygosity is predicted to be 14%, suggesting that the population may not be viable in the long term. Sensitivity analyses showed that nest loss is the most important factor affecting population size and the survival probability of the population, which is supported by field studies. Though the new evidence shows that Cabot's Tragopan can build nests in spruce forest successfully, broad-leaf forest is still necessary for them for foraging, especially at some times of the year. The simulation also shows that the probability of survival and the size of the population will decrease markedly if the extent of suitable habitat is reduced even relatively slowly (such as 0.1% per year). Overall, we conclude that the PVA has provided very informative guidance to future management and research on Cabot's Tragopan at Wuyanling National Nature Reserve.

scholarly journals The mathematics of extinction across scales: from populations to the biosphere

2018 ◽  
Author(s):  
Colin Carlson ◽  
Kevin Burgio ◽  
Tad Dallas ◽  
Wayne Getz
Keyword(s):  
Extinction Risk ◽  
Population Viability Analysis ◽  
Population Viability ◽  
Occupancy Models ◽  
Viability Analysis ◽  
Extinction Rates ◽  
Sixth Mass Extinction ◽  
Evolutionary Rescue ◽  
Species Area ◽  
Using Data

The sixth mass extinction poses an unparalleled quantitative challenge to conservation biologists. Mathematicians and ecologists alike face the problem of developing models that can scale predictions of extinction rates from populations to the level of a species, or even to an entire ecosystem. We review some of the most basic stochastic and analytical methods of calculating extinction risk at different scales, including population viability analysis, stochastic metapopulation occupancy models, and the species area relationship. We also consider two major extensions of theory: the possibility of evolutionary rescue from extinction in a changing environment, and the posthumous assignment of an extinction date from sighting records. In the case of the latter, we provide an example using data on Spix's macaw (Cyanopsitta spixii), the "rarest bird in the world," to demonstrate the challenges associated with extinction date research.

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 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 <5% whereas ≥50-110 adults were necessary to retain >95% of existing genetic diversity over 100 yrs. These thresholds shifted upward when catastrophes were included; ≥50-200 adults were necessary for extinction risk <5% and ≥110 to more than 200 adults were necessary to retain >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.

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