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The current extinction crisis requires effective assessment and monitoring tools. Genetic approaches are appealing given the relative ease of field sampling required to estimate genetic diversity characteristics assumed related to population size, evolutionary potential, and extinction risk, and to evaluate hybridization with non-native species simultaneously. However, linkages between population genetic metrics of diversity from survey-style field collections and demographic estimates of population size and extinction risk are still in need of empirical examples, especially for remotely distributed species of conservation concern where the approach might be most beneficial. We capitalized on an exceptional opportunity to evaluate congruence between genetic diversity metrics and demographic-based estimates of abundance and extinction risk from a comprehensive Multiple Population Viability Analysis (MPVA) in a threatened fish, the Lahontan cutthroat trout (LCT). We sequenced non-native trout reference samples and recently collected and archived tissue samples of most remaining populations of LCT (N=60) and estimated common genetic assessment metrics, predicting minimal hybridization with non-native trout, low diversity, and declining diversity over time. We further hypothesized genetic metrics would correlate positively with MPVA-estimated abundance and negatively with extinction probability. We uncovered several instances of hybridization that pointed to immediate management needs. After removing hybridized individuals, cautious interpretation of low effective population sizes (2-63) suggested reduced evolutionary potential for many LCT populations. Other genetic metrics did not decline over time nor correlate with MPVA-based estimates of harmonic mean abundance or 30-year extinction probability. Our results demonstrate benefits of genetic monitoring for efficiently detecting hybridization and, though genetic results were disconnected from demographic assessment of conservation status, they suggest reduced evolutionary potential and likely a higher conservation risk than currently recognized for this threatened fish. We emphasize that genetic information provides essential complementary insight, in addition to demographic information, for evaluating species status.

Ongoing environmental changes may reduce the population size and geographic distribution of many ecologically sensitive species. Predicting where populations will (or will not) be likely to resist these changes is crucial for planning their protection. The blond titi monkey (Callicebus barbarabrownae) is listed as Critically Endangered by the International Union for Conservation of Nature because of its small and declining population due to deforestation and hunting. The species is endemic to the Brazilian Caatinga dry forest, which has undergone extensive deforestation and climate-induced desertification. We address the extinction risk of this species in a spatially explicit context by predicting the geographic distribution of suitable areas that may permit the persistence of potentially viable populations over the next 50 years. We combined species distribution modeling with population viability analysis under more optimistic and pessimistic climate change scenarios and simulated forest loss, assessing how different populations will likely cope with these changes during the coming decades. Future models did not differ between the scenarios, but changes in the climatic suitability of the species’ habitat predicted a reduction of one-third of the currently suitable area. Viable populations in large forest remnants represent only a quarter of all known populations, and they also face a decline in climatic suitability. Smaller populations may be extirpated, regardless of the level of forest recovery. This species’ long-term persistence entails improving habitat quality and the connectivity of the large remnants to neighbor areas. Finally, the integration of spatial and temporal models is feasible and helpful to address threats and aid the conservation of primates.

Conceptual and methodological advances in population and evolutionary ecology are often pursued with the ambition that they will help identify demographic, ecological and genetic constraints on population growth rate (λ), and ultimately facilitate evidence-based conservation. However, such advances are often decoupled from conservation practice, impeding translation of scientific understanding into effective conservation, and of conservation-motivated research into wider conceptual understanding. We summarise key outcomes from long-term studies of a red-billed chough (Pyrrhorcorax pyrrhocorax) population of conservation concern, where we pro-actively aimed to achieve the dual and interacting objectives of advancing population and evolutionary ecology and advancing effective conservation. Estimation of means, variances and covariances in key vital rates from individual-based demographic data identified temporal and spatial variation in sub-adult survival as key constraints on λ, and simultaneously provided new insights into how vital rates can vary as functions of demographic structure, natal conditions and parental life-history. Targeted analyses showed that first-year survival increased with prey abundance, implying that food limitation may constrain λ. First-year survival then decreased dramatically, threatening population viability and prompting emergency supplementary feeding interventions. Detailed evaluations suggested that the interventions successfully increased first-year survival in some years, and additionally increased adult survival and successful reproduction, thereby feeding back to inform intervention refinements and understanding of complex ecological constraints on λ. Genetic analyses revealed novel evidence of expression of a lethal recessive allele, and demonstrated how critically small effective population size can arise, thereby increasing inbreeding and loss of genetic variation. Population viability analyses parameterised with all available demographic and genetic data showed how ecological and genetic constraints can interact to limit population viability, and identified ecological management as of primacy over genetic management to ensure short-term persistence of the focal population. This case study demonstrates a full iteration through the sequence of primary science, evidence-based intervention, quantitative evaluation and feedback that is advocated in conservation science but still infrequently achieved. It thereby illustrates how pure science advances informed conservation actions to ensure (short-term) stability of the target population, and how conservation-motivated analyses fed back to advance fundamental understanding of population processes.

This study of Astragalus holmgreniorum examines its adaptations to the warm desert environment and whether these adaptations will enable it to persist. Its spring ephemeral hemicryptophyte life‐history strategy is unusual in warm deserts. We used data from a 22‐year demographic study supplemented with reproductive output, seed bank, and germinant survival studies to examine the population dynamics of this species using discrete‐time stochastic matrix modeling. The model showed that A. holmgreniorum is likely to persist in the warm desert in spite of high dormant‐season mortality. It relies on a stochastically varying environment with high inter‐annual variation in precipitation for persistence, but without a long‐lived seed bank, environmental stochasticity confers no advantage. Episodic high reproductive output and frequent seedling recruitment along with a persistent seed bank are adaptations that facilitate its survival. These adaptations place its life‐history strategy further along the spectrum from “slower” to “faster” relative to other perennial spring ephemerals. The extinction risk for small populations is relatively high even though mean λ s > 1 because of the high variance in year quality. This risk is also strongly dependent on seed bank starting values, creating a moving window of extinction risk that varies with population size through time. Astragalus holmgreniorum life‐history strategy combines the perennial spring ephemeral life form with features more characteristic of desert annuals. These adaptations permit persistence in the warm desert environment. A promising conclusion is that new populations of this endangered species can likely be established through direct seeding., We used a 22‐year demographic dataset to produce a matrix population model for Astragalus holmgreniorum, an endangered Mojave Desert perennial with an unusual life‐history strategy. We demonstrated that the species depends on a stochastic environment for persistence. Favorable years permit high seed production and high recruitment success, while unfavorable years are tolerated through the existence of a long‐lived seed bank. This perennial spring ephemeral is short‐lived and has many life‐history features in common with desert annuals, increasing its probability of survival in the warm desert environment.

In long‐lived species, although adult survival typically has the highest elasticity, temporal variations in less canalized demographic parameters are the main drivers of population dynamics. Targeting recruitment rates may thus be the most effective strategy to manage these species. We analyzed 1,136 capture–recapture histories collected over 9 years in an isolated population of the critically endangered Lesser Antillean iguana, using a robust design Pradel model to estimate adult survival and recruitment rates. From an adult population size estimated at 928 in 2013, we found a yearly decline of 4% over the 8‐year period. As expected under the canalization hypothesis for a long‐lived species, adult survival was high and constant, with little possibility for improvement, whereas the recruitment rate varied over time and likely drove the observed population decline. We then used a prospective perturbation analysis to explore whether managing the species’ immature cohorts would at least slow the population decline. The prospective perturbation analysis suggested that a significant and sustained conservation effort would be needed to achieve a recruitment rate high enough to slow the population decline. We posit that the high recruitment rate achieved in 2014—likely due to the maintenance in 2012 of the main nesting sites used by this population—would be sufficient to slow this population's decline if it was sustained each year. Based on the results of diverse pilot studies we conducted, we identified the most likely threats targeting the eggs and immature cohorts, stressing the need to improve reproductive success and survival of immature iguanas. The threats we identified are also involved in the decline of several reptile species, and species from other taxa such as ground‐nesting birds. These findings on a little‐studied taxon provide further evidence that focusing on the immature life stages of long‐lived species can be key to their conservation., In long‐lived species, under normal conditions, adult survival is fairly high and constant, whereas less canalized demographic traits (e.g. the recruitment rate) vary over time and drive population trajectories. We used a long‐term set of capture–recapture data collected on a population of the critically endangered Lesser Antillean iguana, and show that the current demographic parameters will lead that population to quasi‐extinction. We also predicted population trajectories under different scenarios to forecast the magnitude of conservation effort that could halt the population decline. We finally review the threats to preadult stages and proposed actions to improve recruitment rates. Our study provides further evidence, in an understudied taxon, that managing immature stages can be key to the conservation of long‐lived species.

Accurate status assessments of long-lived, widely distributed taxa depend on the availability of long-term monitoring data from multiple populations. However, monitoring populations across large temporal and spatial scales is often beyond the scope of any one researcher or research group. Consequently, wildlife managers may be tasked with utilizing limited information from different sources to detect range-wide evidence of population declines and their causes. When assessments need to be made under such constraints, the research and management communities must determine how to extrapolate from variable population data to species-level inferences. Here, using three different approaches, we integrate and analyze data from the peer-reviewed literature and government agency reports to inform conservation for northwestern pond turtles (NPT) Actinemys marmorata and southwestern pond turtles (SPT) Actinemys pallida. Both NPT and SPT are long-lived freshwater turtles distributed along the west coast of the United States and Mexico. Conservation concerns exist for both species; however, SPT may face more severe threats and are thought to exist at lower densities throughout their range than NPT. For each species, we ranked the impacts of 13 potential threats, estimated population sizes, and modeled population viability with and without long-term droughts. Our results suggest that predation of hatchlings by invasive predators, such as American bullfrogs Lithobates catesbeianus and Largemouth Bass Micropterus salmoides, is a high-ranking threat for NPT and SPT. Southwestern pond turtles may also face more severe impacts associated with natural disasters (droughts, wildfires, and floods) than do NPT. Population size estimates from trapping surveys indicate that SPT have smaller population sizes on average than do NPT (P = 0.0003), suggesting they may be at greater risk of local extirpation. Population viability analysis models revealed that long-term droughts are a key environmental parameter; as the frequency of severe droughts increases with climate change, the likelihood of population recovery decreases, especially when census sizes are low. Given current population trends and vulnerability to natural disasters throughout their range, we suggest that conservation and recovery actions first focus on SPT to prevent further population declines.

As an endemic bird to the Fynbos biome, prominently featured in literature and marketing material for the avifauna of the continent, the Cape Rockjumper Chaetops frenatus is an iconic species of So...

OBJECTIVES Infanticide in white-faced capuchins (Cebus capucinus imitator) typically occurs in association with alpha male replacements (AMRs). Although infanticide is likely adaptive for males, it imposes costs on females that are difficult to quantify without long-term demographic data. Here we investigate effects of AMRs and infanticide on female reproductive success and how these costs affect capuchin groups. We investigate (1) effects of AMR frequency on the production of surviving infants; (2) energetic and (3) temporal "opportunity costs" of infant loss; and (4) how AMR frequency impacts capuchin group sizes. MATERIALS AND METHODS We censused six groups (7-33 years/group, 74 adult females). We modeled surviving infant production in relation to AMR. We estimated a female's energy requirements for lost infants and the temporal cost relative to the median reproductive window. We simulated how varying AMR rates would affect future capuchin group sizes. RESULTS Females exposed to more frequent AMR tended to produce fewer surviving offspring. We estimate the average lost infant requires approximately 33% additional energy intake for its mother and represents 10% of the average reproductive opportunity window available to females. Simulated populations remain viable at the observed rate of AMR occurrence but decrease in size at even slightly higher rates. DISCUSSION While infanticide is adaptive for males, for females it affects lifetime reproductive success and imposes energetic and opportunity costs. Although capuchin populations have evolved with AMRs and infanticide, small increases in AMR frequency may lead to population decline/extinction. Infanticide likely plays a large role in population maintenance for capuchins.

This study was made possible with financial support from Earthwatch Institute, Atlantis Blue Project Foundation, with permission to conduct research granted by the Bahamas Department of Marine Resources. Little Bahama Bank in the northern Bahamas supports several populations of bottlenose dolphins (Tursiops truncatus). We provide the first estimates of birth rate and age-class-specific apparent survival rates for the local South Abaco population using data from a long-term (1997–2014) photo-identification (photo-ID) study and use the estimated life history parameters in a population viability analysis (PVA) to predict future population trends. Hurricane events are predicted to become more intense due to climate change but knowledge of how hurricanes may impact cetacean populations is limited. Little Bahama Bank is subject to hurricane activity, so we also investigate the potential impact of hurricanes on calf, juvenile and adult survival. Photo-ID data confirmed the existence of a core adult population with relatively high site fidelity in South Abaco, but also evidence of transient animals. Estimated annual birth rate was 0.278 (95% CI: 0.241–0.337). We found strong support for a decline in apparent survival for all age-classes. Estimated survival declined by 9% in adults (0.941 in 1998, to 0.855 in 2013), 5% in juveniles (0.820 in 2000, to 0.767 in 2013) and 36% in calves (0.970 in 1997, to 0.606 in 2013). Evidence that survival was influenced by repeated hurricane activity leading to increased mortality and/or emigration was stronger for calves and juveniles than for adults. PVA simulations of an assumed isolated South Abaco population showed that declines would lead to extinction within decades, even under the most optimistic scenario. Future work should focus on establishing if South Abaco is part of natural source–sink metapopulation dynamics on Little Bahama Bank by assessing trends in abundance in local populations and establishing how they interact; this will be important for assessing their conservation status in a potentially increasingly changing environment. Publisher PDF

These R scripts contain the code to replicate the analyses performed in Demographic consequences of changing environmental periodicity, Ecology. Vital-rate estimation We used the demographic data of each species to model periodic differences in vital rates for each life-cycle stage using generalized linear models and mixed models (GLMs for the deterministic vital rates in dewy pines and GLMMs for all other vital rates). More specifically, we tested for the effect of season on marmot and meerkat vital rates and of post-fire habitat states (time since fire, TSF) on dewy pine vital rates. For all three species, we estimated stage-specific survival and probability of transition to another stage using a binomial distribution, and reproductive output using a Poisson distribution. In addition, we estimated meerkat helper emigration probability and dewy-pine flowering probability using a binomial distribution. In addition to fixed effects, we incorporated year random effects in all appropriate models to model year-specific differences among season-specific average vital-rates (for marmots and meerkats) or among vital-rate averages (for dewy pines). For the meerkats and dewy pines, we also incorporated the fixed effect of density on vital rates. For each modeled vital rate, we first selected the best random-effect structure where appropriate (i.e., testing whether a random effect on the average vital rate and the slope between seasons outperformed a random effect on the average vital rate only). We then selected the best fixed-effect variables using the Akaike Information Criterion corrected for small sample size (AICc). When the difference in AICc values was not significant (dAICcPopulation projections We used the predictions of the vital-rate models described above to parameterize periodic matrix population models (MPMs) and project the population dynamics for 100 years according to two scenarios—control and perturbed—to assess the effect of changes in vital-rate periodicity on the stochastic growth rate (log λS), the variance of 100 annual growth rates (var(log λ)), and the probability of quasi-extinction (pqext, i.e., the ratio of simulations leading to quasi-extinction out of 500 simulations, with a threshold set at 15% of the minimum observed abundance or number of reproductive individuals for the marmot and meerkat populations, and at 50% of the minimum observed aboveground or seed bank abundance for the dewy pines). Yellow-bellied marmot and meerkat (seasonal dynamics) For the meerkats and marmots, we projected population dynamics under changing patterns of vital rates for which the year random effect in the GLMM was applied both on the mean vital-rate estimate (i.e., the model intercept) and the difference between seasons. That is, for the marmots, we assessed the population responses to changes in the seasonal patterns of yearling and non-reproductive and reproductive adult survival. For the meerkats, we did so for subadult, helper, and dominant survival, helper emigration, transition from helper to dominant, and helper and dominant recruitment. We used the above models to predict season- and year-specific vital rates and parameterize periodic matrix population models (MPMs) for each season. We then simulated population dynamics by projecting MPMs representing low- (LS) and high-seasonality (HS) years for each of the vital rates. Half of all years in which a vital rate was estimated were considered as LS and the other half as HS. That is, for a given vital rate, we defined the threshold between LS and HS years as the 50th percentile of all year-specific absolute differences between seasons. In addition, we used a control scenario, where we projected the population dynamics using MPMs representing both high- and low-seasonality years indistinctly. We performed 500 simulations, each starting with the same population vector, and projected the population dynamics for 100 years. For each simulation, we randomly selected 100 years corresponding to each scenario (LS, HS, or control). In each step of the simulation, all vital rates were predicted based on the same randomly selected year. This allowed us to maintain within-year vital-rate correlation. The predicted vital rates were then used to build the corresponding period-specific MPM. Dewy pine (Multi-year habitat succession and periodicity in fire regimes) For dewy pines, we simulated two distinct types of fire regimes, each with two frequencies: (1) periodic burning occurring systematically every 15 or 30 years, and (2) stochastic fires occurring on average every 15 or 30 years. In all simulations, dewy pines transition deterministically through the first four post-fire states, TSF0 to TSF3. Under periodic fires, once in the fifth state, TSF>3, the population remains in that state until the next fire (15 or 30 years after the previous fire) and then transitions to TSF0. Under stochastic fires, the population can transition from TSF>3 to TSF0 conditional on fire frequency (p). This is done using a Markov-chain approach. In addition to the different periodic patterns in fire regimes, we perturbed periodic patterns in habitat succession in natural heathlands by introducing an additional human disturbance (i.e., using vital rates from populations under a browsing-induced disturbance) first only in the years of the last post-fire state (TSF>3), and then increasingly in the previous states (i.e., in TSF3 and >3, in TSF2, 3, and >3, etc.) until all post-fire states of a natural population were perturbed. We used TSF-specific vital-rate predictions from our models and rates on seed-bank dynamics to build MPMs for each TSF. We used these MPMs to project population dynamics for 100 years using 500 simulations, in each iteration randomly sampling among MPMs describing one of the two natural populations. In addition, for each iteration in the stochastic post-fire state TSF>3, we randomly sampled a year-specific MPM. We increased browsing pressure by replacing MPMs associated with natural habitat conditions by MPMs parameterized with vital rates estimated from human-disturbed populations, for any given TSF. We then compared scenarios of increasing anthropogenic pressures to the control scenario (i.e., natural populations with no browsing perturbation) in each fire regime. Population responses to vital-rate periodic patterns under density dependence For the meerkats and dewy pines, projections of population dynamics incorporated density dependence. That is, at each iteration of the simulations, population density was estimated and used to predict vital rates and parameterize an MPM from these predictions at the next iteration. We then compared density-dependent projections to ones where the density input during parameter estimation was fixed at constant average values obtained from the observed data. Analysis of the simulations results For all three systems and for each simulation, we recorded the stochastic growth rate log λS. We also investigated the effect of changes in vital-rate patterns on the variance in 100 annual log λ, var(log λ), and the quasi-extinction probability pqext. We checked the overlap of the distributions of each metric (i.e., the mean and the 2.5th and 97.5th percentiles) across the 500 simulations between two scenarios. We considered a metric to differ between scenarios when 95% of the distributions (i.e., between the 2.5th and 97.5th percentiles) did not overlap. Comparing population sensitivity to changes in periodic environmental patterns vs. stochastic environmental variation We compared our results from periodic population models to “classic” assessments of population fitness sensitivity to stochastic environmental variation. To do so, for marmots and meerkats, we computed the stochastic elasticities of the population growth rate to changes in the mean and standard deviation of vital rates. We then calculated the relative importance of the stochastic elasticity of the growth rate due to changes in the variability of vital rates compared to changes in their mean. For dewy pines, as the effects of periodic patterns consisted of changing the sequences of post-fire habitat states, we explored the link between the effects of human-induced disturbances in various post-fire habitat states and the role of these states in shaping population dynamics. We thus used the megamatrix approach to calculate the elasticity of the population growth rate to each post-fire habitat state., Additional funding acknowledgment: University of Pretoria MAVA Foundation Ministerio de Economía y Competitividad (CGL2011-28759/BOS) Ministerio de Economía y Competitividad (CGL2015-64007-P) National Geographic Society (8140-06) National Science Foundation (DBI-1226713) National Science Foundation (DEB-1557130)

The Endangered Macadamia jansenii (C.L. Gross & P.H. Western, 1992) was known only from one small populationand a reintroduction program was implemented from 2009 to increase the number of populations. Recently, new subpopulations were discovered. However, in 2019, fire directly affected M. jansenii and the surrounding habitat. This study aimed to examine the abundance and distribution of M. jansenii in the wild pre- and post-fire, as well as to assess the success of the reintroduction program and species population viability. We undertook genetic analysis, population viability analysis (PVA) and updated the existing habitat models. The known wild M. jansenii population increased in abundance from 59 in a single population to 200 individuals (including seedlings), across three subpopulations. Results from the post-fire survey suggest that 83% of the wild plants have survived, with many plants resprouting. The newly discovered subpopulations were within predicted suitable habitat in the Bulburin National Park. These subpopulations are genetically similar to the original known population. Novel alleles suggest the potential for more plants to be located. The reintroduction program successfully established 20 individuals. PVA results indicate that even with the effects of fire, the species is unlikely to become extinct in the next 150 years.

Age‐based demography is fundamental to management of wild fish populations. Age estimates for individuals can determine rates of change in key life‐history parameters such as length, maturity, mortality and fecundity. These age‐based characteristics are critical for population viability analysis in endangered species and for developing sustainable harvest strategies. For teleost fish, age has traditionally been determined by counting increments formed in calcified structures such as otoliths. However, the collection of otoliths is lethal and therefore undesirable for threatened species. At a molecular level, age can be predicted by measuring DNA methylation. Here, we use previously identified age‐associated sites of DNA methylation in zebrafish (Danio rerio) to develop two epigenetic clocks for three threatened freshwater fish species. One epigenetic clock was developed for the Australian lungfish (Neoceratodus forsteri) and the second for the Murray cod (Maccullochella peelii) and Mary River cod (Maccullochella mariensis). Age estimation models were calibrated using either known‐age individuals, ages derived from otoliths or bomb radiocarbon dating of scales. We demonstrate a high Pearson's correlation between the chronological and predicted age in both the Lungfish clock (cor = .98) and Maccullochella clock (cor = .92). The median absolute error rate for both epigenetic clocks was also low (Lungfish = 0.86 years; Maccullochella = 0.34 years). This study demonstrates the transferability of DNA methylation sites for age prediction between highly phylogenetically divergent fish species. Given the method is nonlethal and suited to automation, age prediction by DNA methylation has the potential to improve fisheries and other wildlife management settings.

Across the Global South, wildlife is an important source of nutrition and income, particularly for rural communities. While wildlife consumption provides a valuable source of nutrition, high levels of hunting can endanger wildlife species. In the Makira region of north-eastern Madagascar, human health is threatened by food insecurity and malnutrition, and spiny tenrecs are a crucial source of subsistence bushmeat with 91% of households consuming tenrecs at least once per year. Moreover, Makira’s human populations are increasing, resulting in forest decline and degradation. In order to inform conservation and public health efforts, we investigated the influence of hunting, habitat loss and forest degradation on spiny tenrec population dynamics in the Makira region. We collected data on tenrec population densities as well as hunting and consumption by humans in 51 communities. We used these data to conduct a population viability analysis for the two most commonly hunted spiny tenrecs (Tenrec ecaudatus and Setifer setosus). We found that current harvest rates for these species are generally sustainable in the Makira region, largely due to tenrecs’ extraordinary fecundity. However, even assuming no change in current hunting rates, tenrec populations could become threatened if fecundity were to decline or background mortality to increase, both possible scenarios under future trajectories of habitat loss and degradation. We find that any future increase in hunting-induced mortality rates for tenrecs are similarly unsustainable – and likely to occur as human populations expand and hunting areas decline. We conclude that there is a vanishing window of opportunity to sustainably manage tenrec hunting in northeastern Madagascar in order to avoid negative conservation and human health outcomes.

The endangered Moorish tortoise Testudo graeca is the unique terrestrial chelonian species in Northwest Africa. In west-central Morocco, the endemic subspecies, the Souss valley tortoise T. g. soussensis, occupies semi-arid to arid low-quality habitats, and is subject to serious threats. A long-term mark-recapture programme from 2001 to 2012 allowed estimating population size and structure, sex ratio, and survivorship in one of the well-known populations in a degraded and overgrazed arid steppe-land of west-central Morocco. Spring population size considerably decreased to more than half in less than 10 years, with a mean density lower than 3 ind.ha-1 in 2012 compared to its last known density estimated in 2003. In spring 2012, the population structure exhibited an unbalanced male-biased sex ratio (61:39) and a scarcity of juveniles (

Context Species translocations are used in conservation globally. Although harvest for translocation may have negative impacts on source populations, translocation programs rarely explore ways of minimising those impacts. In fluctuating source populations, harvest timing may affect its impact because population size and trajectory vary among years. Aims We explored whether the timing and scale of harvest can be altered to reduce its impact on a fluctuating source population of Mallee Emu-wrens, Stipiturus mallee; an endangered passerine in south-eastern Australia. Mallee Emu-wren populations fluctuate with ~5–10-year drought–rain cycles. Methods We used population viability analysis (PVA) to compare the impact of five harvest scales (no harvest, 100, 200, 300 or 500 individuals) under three population trajectories (increasing, stable or decreasing) and two initial population sizes (our model-based estimate of the population size and the lower 95% confidence interval of that estimate). To generate a model-based estimate of the population size, we surveyed 540 sites (9 ha), stratified according to environmental variables known to affect Mallee Emu-wren occurrence. We used an information-theoretic approach with N-mixture models to estimate Mallee Emu-wren density, and extrapolated results over all potential habitat. Key Results We estimate that in spring 2019, the source population consisted of 6449 individuals, with a minimum of 1923 individuals (lower 95% confidence interval). Of 48 harvest scenarios, only seven showed no impact of harvest within 5 years (15%). Those seven all had increasing population trajectories and carrying capacity set to equal initial population size. Twenty-six populations showed no impact of harvest within 25 years (54%). These were either increasing populations that had reached carrying capacity or decreasing populations nearing extinction. Conclusions Initial population size, carrying capacity, harvest scale and population trajectory were all determinants of harvest impact. Given the importance of carrying capacity, further research is required to determine its role in the Mallee Emu-wren source population. Implications Harvesting Mallee Emu-wrens after high-rainfall years will have the least impact because source populations are likely to be large with increasing trajectories. For fluctuating source populations, flexibility in the timing of harvest can reduce its impact and should be considered during translocation planning.

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.

Although population viability analysis (PVA) is widely used in setting conservation policy, there is disagreement about the usefulness of this method. Objections have been raised concerning the precision of predictions in view of the short time series of data available and the sensitivity of estimates of extinction risk to estimated parameters (Hamilton & Moller 1995; Taylor 1995; Groom & Pascual 1998; Ludwig 1999). Beissinger and Westphal (1998) reviewed the use of demographic models for endangered-species management. They pointed out that poor data cause difficulties in parameter estimation, which in turn lead to unreliable estimates of extinction risk. There are additional

Europe has set ambitious green energy targets, to which offshore renewable developments (ORDs) will make a significant contribution. Governments are legally required to deliver ORDs sustainably; however, they may have detrimental impacts on wildlife, especially those already experiencing declines due to climate change. Population viability analysis (PVA) is the standard method for forecasting population change in ORD assessments, but PVAs do not currently account for climate effects. We quantified climate effects on seabird breeding success for 8 UK species breeding in the North Sea. We assessed the potential for seabirds to mitigate climate-driven changes in breeding success by accessing wider resources through increased foraging ranges around colonies. We demonstrate strong links between breeding success and climate in 5 species. In 4 of these species, future climate projections indicated large declines in breeding success relative to current rates. Only one species was predicted to increase breeding success under future climate. In all 5 species, there was limited opportunity for species to increase breeding success by expanding foraging ranges to access more suitable future climatic conditions. Climate change will have significant ramifications for future breeding success of seabirds breeding in the North Sea, an area undergoing extensive and rapid offshore renewable energy development. We recommend 3 methods for including climate-driven changes to seabird breeding success within ORD assessments: development of predictive climate-driven habitat use models to estimate ORD-wildlife interactions; delivery of a new ORD assessment framework that includes dynamic predictions of climate-driven habitat use and demography of wildlife populations; and consideration of climate-driven changes in the implementation of compensatory measures.

Variation in individual demographic rates can have large consequences for populations. Female reproductive skew is an example of structured demographic heterogeneity where females have intrinsic qualities that make them more or less likely to breed. The consequences of reproductive skew for population dynamics are poorly understood in non-cooperatively breeding mammals, especially when coupled with other drivers such as poaching. We address this knowledge gap with population viability analyses using an age-specific, female-only, individual-based, stochastic population model built with long-term data for three Kenyan populations of the Critically Endangered eastern black rhino ( Diceros bicornis michaeli). There was substantial reproductive skew, with a high proportion of females not breeding or doing so at very low rates. This had a large impact on the projected population growth rate for the smaller population on Ol Jogi. Moreover, including female reproductive skew exacerbates the effects of poaching, increasing the probability of extinction by approximately 70% under a simulated poaching pressure of 5% offtake per year. Tackling the effects of reproductive skew depends on whether it is mediated by habitat or social factors, with potential strategies including habitat and biological management respectively. Investigating and tackling reproductive skew in other species requires long-term, individual-level data collection.

Several methods of measuring biodiversity in development-offset trades exist. However, there is little consensus on which biodiversity metrics should be used for quantifying development impacts and assigning offsets. We simulated development impacts in a virtual landscape and offset these impacts using six biodiversity metrics: vegetation area, vegetation condition, habitat suitability, species abundance, metapopulation connectivity and rarity-weighted richness. We tested long-term impacts of metric choice during offsetting by combining simulated landscapes with population viability analyses. No net loss or net gains in habitat were achieved using all metrics except vegetation area and condition. Limited habitat and like-for-like requirements resulted in offsets exhausting available habitat in each vegetation class before offset requirements were met when using vegetation-based metrics. We also found that impact avoidance was an important driver in how much compensation offsets could deliver. When impacts avoided high-suitability habitats, all six metrics achieved no net loss or net gains for most species. However, when core habitats were developed, none of the metrics were able to consistently prevent population declines. Synthesis and application. When impacts on high-quality habitat were avoided, and assuming the protection and restoration benefits can occur in practice, vegetation-based metrics may produce offsets which deliver gains in species abundance equivalent to species-specific metrics. However, species-specific metrics outperformed vegetation-based metrics when core habitats were lost. Applying avoidance measures as a first step to minimise biodiversity impacts during development will significantly improve offset outcomes for species and result in greater long-term population benefits delivered through offsetting.

Together climate and land-use change play a crucial role in determining species distribution and abundance, but measuring the simultaneous impacts of these processes on current and future population trajectories is challenging due to time lags, interactive effects and data limitations. Most approaches that relate multiple global change drivers to population changes have been based on occurrence or count data alone. We leveraged three long-term (1995-2019) datasets to develop a coupled integrated population model-Bayesian population viability analysis (IPM-BPVA) to project future survival and reproductive success for common loons Gavia immer in northern Wisconsin, USA, by explicitly linking vital rates to changes in climate and land use. The winter North Atlantic Oscillation (NAO), a broad-scale climate index, immediately preceding the breeding season and annual changes in developed land cover within breeding areas both had strongly negative influences on adult survival. Local summer rainfall was negatively related to fecundity, though this relationship was mediated by a lagged interaction with the winter NAO, suggesting a compensatory population-level response to climate variability. We compared population viability under 12 future scenarios of annual land-use change, precipitation and NAO conditions. Under all scenarios, the loon population was expected to decline, yet the steepest declines were projected under positive NAO trends, as anticipated with ongoing climate change. Thus, loons breeding in the northern United States are likely to remain affected by climatic processes occurring thousands of miles away in the North Atlantic during the non-breeding period of the annual cycle. Our results reveal that climate and land-use changes are differentially contributing to loon population declines along the southern edge of their breeding range and will continue to do so despite natural compensatory responses. We also demonstrate that concurrent analysis of multiple data types facilitates deeper understanding of the ecological implications of anthropogenic-induced change occurring at multiple spatial scales. Our modelling approach can be used to project demographic responses of populations to varying environmental conditions while accounting for multiple sources of uncertainty, an increasingly pressing need in the face of unprecedented global change.

The South China tiger (SCT) is close to extinction in the wild and the captive population may be the only hope of saving this species. Based on the international studbook of the SCT from 1956 to 2019, the life history and population parameters were summarized, and lethal equivalents (B) were estimated. Population viability analysis (PVA) was carried out to simulate the population dynamics and the effects of key factors influencing population dynamics were assessed on the basis of sensitivity analysis, including lethal equivalent, sex ratio, percentage of females breeding and percentage of males breeding. The average B value for the captive SCT population was estimated to be 4.24 at the population level. The captive population of SCT is currently growing up, with a positive growth rate of 0.093 (SD = 0.088) and a probability of extinction of 1% within the next 100 years. The current SCT population is sensitive to lethal equivalents (S = 2.30) and the percentage of females breeding (S = 1.94). We suggest a feasible breeding plan that can practically reduce the effect of inbreeding, and better husbandry practices to improve the percentage of females breeding.

Global wildlife trade is a multibillion-dollar industry and a significant driver of vertebrate extinction risk. Yet, few studies have quantified the impact of wild harvesting for the illicit pet trade on populations. Long-lived species, by virtue of their slow life history characteristics, may be unable to sustain even low levels of collecting. Here, we assessed the impact of illegal collecting on populations of endangered broad-headed snakes (Hoplocephalus bungaroides) at gated (protected) and ungated (unprotected) sites. Because broad-headed snakes are long-lived, grow slowly and reproduce infrequently, populations are likely vulnerable to increases in adult mortality. Long-term data revealed that annual survival rates of snakes were significantly lower in the ungated population than the gated population, consistent with the hypothesis of human removal of snakes for the pet trade. Population viability analysis showed that the ungated population has a strongly negative population growth rate and is only prevented from ultimate extinction by dispersal of small numbers of individuals from the gated population. Sensitivity analyses showed that the removal of a small number of adult females was sufficient to impose negative population growth and suggests that threatened species with slow life histories are likely to be especially vulnerable to illegal collecting.

Captive breeding is important for ex-situ conservation and the future reintroduction of bovids that become extinct in the wild. The age structure, development, and viability of captive-bred bantengs (Bos javanicus) are important to sustain the long-term reintroduction program in Salakphra Wildlife Sanctuary (SWF) and other areas. This research conducted a long-term population viability analysis (PVA) using height, weight, body condition scores (BSC), age structure, and development in captivity for a sustainable reintroduction program of bantengs in Thailand. Monthly development photographs of 23 founder individuals (12 males and 11 females) were assessed by three banteng experts, two researchers, and three members of the general public. The assessments of weight and BCS were not significantly different among the three groups, while height was underestimated by the general public. The PVA showed that the time to reach the maximum population in a captive banteng program is dependent on the carrying capacity of the habitat. The reduction of a small banteng founder group by the reintroduction of animals into the wild can negatively affect the population growth of the captive group. This information can be used to maintain the population viability of bantengs and sustain ex-situ conservation and the reintroduction program in Thailand and elsewhere.

Predicting changes in the abundance of species over time is a central goal of conservation ecology. Typically, demographic data are used to parameterise models which describe population dynamics. Vital rates of plants vary across a species’ distribution, yet most demographic estimates are spatially constrained. Banksia ornata (Proteaceae), a widespread serotinous obligate-seeding shrub in southern Australia, has previously had a fire management model developed based on demographic data derived from a chronosequence in one part of the species’ range. We asked: are demographic data collected from a limited geographic range robust for developing population dynamic models that are applied across the broader species’ range? How much variation exists in the demography of species across their range and does this matter for estimating fire return intervals necessary for species persistence? We examine site-to-site variation in the pyrodemography of six populations of B. ornata encompassing its geographic range. We documented changes in population density, time to first reproduction and canopy seed bank accumulation in stands varying in age from 0.5 to 55 years. We model year of maximum seed production on demographic parameters such as population starting density and survival rate. Density, primary juvenile period, rates of mortality and seed bank accumulation varied across populations. Primary juvenile period varied across populations (from 6 to

The US Fish and Wildlife Service (USFWS) has initiated a re-envisioned approach for providing decision makers with the best available science and synthesis of that information, called the Species Status Assessment (SSA), for endangered species decision making. The SSA report is a descriptive document that provides decision makers with an assessment of the current and predicted future status of a species. These analyses support all manner of decisions under the US Endangered Species Act, such as listing, reclassification, and recovery planning. Novel scientific analysis and predictive modeling in SSAs could be an important part of rooting conservation decisions in current data and cutting edge analytical and modeling techniques. Here, we describe a novel analysis of available data to assess the current condition of eastern black rail Laterallus jamaicensis jamaicensis across its range in a dynamic occupancy analysis. We used the results of the analysis to develop a site occupancy projection model where the model parameters (initial occupancy, site persistence, colonization) were linked to environmental covariates, such as land management and land cover change (sea-level rise, development, etc.). We used the projection model to predict future status under multiple sea-level rise and habitat management scenarios. Occupancy probability and site colonization were low in all analysis units, and site persistence was also low, suggesting low resiliency and redundancy currently. Extinction probability was high for all analysis units in all simulated scenarios except one with significant effort to preserve existing habitat, suggesting low future resiliency and redundancy. With the results of these data analyses and predictive models, the USFWS concluded that protections of the Endangered Species Act were warranted for this subspecies.

Developers are often required by law to offset environmental impacts through targeted conservation actions. Most offset policies specify metrics for calculating offset requirements, usually by assessing vegetation condition. Despite widespread use, there is little evidence to support the effectiveness of vegetation-based metrics for ensuring biodiversity persistence. We compared long-term impacts of biodiversity offsetting based on area only; vegetation condition only; area × habitat suitability; and condition × habitat suitability in development and restoration simulations for the Hunter Region of New South Wales, Australia. We simulated development and subsequent offsetting through restoration within a virtual landscape, linking simulations to population viability models for 3 species. Habitat gains did not ensure species persistence. No net loss was achieved when performance of offsetting was assessed in terms of amount of habitat restored, but not when outcomes were assessed in terms of persistence. Maintenance of persistence occurred more often when impacts were avoided, giving further support to better enforce the avoidance stage of the mitigation hierarchy. When development affected areas of high habitat quality for species, persistence could not be guaranteed. Therefore, species must be more explicitly accounted for in offsets, rather than just vegetation or habitat alone. Declines due to a failure to account directly for species population dynamics and connectivity overshadowed the benefits delivered by producing large areas of high-quality habitat. Our modeling framework showed that the benefits delivered by offsets are species specific and that simple vegetation-based metrics can give misguided impressions on how well biodiversity offsets achieve no net loss.Cuantificación del Impacto de las Medidas Basadas en la Vegetación sobre la Persistencia de las Especies cuando se Eligen las Compensaciones por la Destrucción del Hábitat Resumen Con frecuencia se requiere por ley que los desarrolladores compensen los impactos ambientales por medio de acciones de conservación. La mayoría de las políticas de compensación especifican medidas para calcular los requerimientos de cada compensación, generalmente mediante la evaluación de las condiciones de la vegetación. A pesar del uso extenso de estas medidas basadas en la vegetación, existe muy poca evidencia que respalde su efectividad para asegurar la persistencia de la biodiversidad. Comparamos los impactos a largo plazo de las compensaciones de biodiversidad basadas solamente en el área; solamente en la condición de la vegetación; la idoneidad del área x hábitat; y la idoneidad condición x hábitat en las simulaciones de desarrollo y restauración para la Región Hunter de Nueva Gales del Sur, Australia. Simulamos el desarrollo y las compensaciones subsecuentes mediante la restauración dentro de un paisaje virtual, conectando las simulaciones con los modelos de viabilidad poblacional para tres especies. Las ganancias del hábitat no aseguraron la persistencia de las especies. No hubo pérdida neta cuando el desempeño de las compensaciones se evaluó en relación con la persistencia. El mantenimiento de la persistencia ocurrió más seguido cuando se evitaron los impactos, lo que proporciona un mayor respaldo para mejorar la aplicación de la fase de prevención de la jerarquía de mitigación. Cuando el desarrollo afectó a las áreas con una alta calidad de hábitat para las especies, no se pudo garantizar la persistencia. Por lo tanto, las especies deben considerarse más explícitamente en las compensaciones, en lugar de sólo considerar a la vegetación o al hábitat. Las declinaciones causadas por la falta de consideración directa de las dinámicas poblacionales de las especies y de la conectividad opacaron los beneficios producidos por las grandes áreas de hábitat de alta calidad. Nuestro marco de trabajo para el modelado demostró que los beneficios producidos por las compensaciones son específicos para cada especie y que las medidas simples basadas en la vegetación pueden brindar impresiones mal informadas sobre qué tanto influyen las compensaciones de biodiversidad en la no pérdida neta.法律经常要求开发商通过有针对性的保护行动来抵消对环境的影响。大多数生物多样补偿政策明确规定了计算补偿量需求的指标, 通常都是基于对植被条件的评估。这类基于植被的指标虽然已经得到广泛使用, 但其在确保生物多样性续存方面的有效性却几乎没有证据支持。本研究模拟了澳大利亚新南威尔士州猎人区的开发和恢复情况, 并分别从面积、植被条件、地区及生境的适宜性、植被条件及生境的适应性这几个方面比较了生物多样性补偿措施的长期影响。我们在一个虚拟景观中模拟了开发及随后通过恢复得到的补偿, 并将模拟情况与 3 个物种的种群生存模型进行整合。结果显示, 如果以恢复生境的数量来评价补偿效果, 则可以实现无净损失; 但如果以物种续存来进行评价, 则不能实现。在避免影响的情况下, 物种更有可能续存, 这一结果为更好地执行减缓影响层级结构中的避免影响阶段提供了进一步支持。当发展影响到物种高质量生境的区域时, 不能保证物种续存。因此, 必须更明确地将物种纳入补偿机制中, 而不仅仅是考虑植被或生境。因未能直接考虑物种种群动态和连接度而导致的种群数量下降的影响, 会超出制造大面积高质量生境带来的好处。我们的模型框架表明, 生物多样性补偿带来的好处是物种特异的, 而简单的基于植被的指标可能会误导人们, 使其对生物多样性补偿在多大程度上实现了无净损失产生错误印象。【翻译: 胡怡思; 审校: 聂永刚】.

Fisheries bycatch is recognised as the dominant anthropogenic threat facing many protected species globally. Estimates of total bycatch are often associated with wide confidence intervals as a result of limited coverage by on-board observers. This makes it difficult for managers to assess risk and design effective management plans. Here, we present a case study of grey seal (Halichoerus grypus) bycatch in static net fisheries across Irish waters, where potentially unsustainable bycatch levels have been reported with typically wide confidence intervals. We used Population Viability Analysis (PVA) to explore potential bycatch scenarios at a national level in order to inform future monitoring and management efforts; including (i) a baseline scenario where the probability of seals becoming bycaught was independent of age and sex; (ii) probability was biased towards juvenile, male, or female seals; (iii) there was net immigration of seals from outside of the national population; and (iv) colony-specific bycatch rates were applied to assess the relative vulnerability of the major grey seal breeding colonies to bycatch mortality. Results demonstrated that (i) higher levels of bycatch reduced population growth, with bycatch of 800 seals per year reducing the national population by 99% over 100 years; (ii) population viability was most sensitive to bycatch mortality of female seals, and more robust to juvenile or male mortality; (iii) recruitment of 500 seals per year prevented population decline despite a worst-case bycatch scenario of 800 seals bycaught per year; (iv) colonies in the south and southwest were the first to show signs of decline under increasing bycatch pressure. PVA provides a clear justification for improved monitoring of seal bycatch to obtain more precise bycatch estimates, and highlights the need for future studies to identify appropriate grey seal management units.

Rats are among the worst invasive alien predators. They prey upon eggs, chicks, and sometimes adults of seabirds, leading to the decline of many populations. Rats have invaded 93% of the islands in the western Indian Ocean, which is an avian biodiversity hotspot. Europa Island, Mozambique Channel, is a major seabird breeding site, where at least 1,000,000 pairs bred at the end of 20th century, including the endemic white-tailed tropicbirds (Phaethon lepturus europae). This species and the red-tailed tropicbird (Phaethon rubricauda) are vulnerable to predation by black rat (Rattus rattus), barn owl (Tyto alba), and pied-crow (Corvus albus) on Europa Island. In this study, we estimate the current population sizes of these tropicbird species and their breeding success. The impact of predators on tropicbird nests was quantified with camera traps. Finally, we model the dynamics of these populations under three management scenarios (no action, complete rat eradication, and targeted control of rats around nests). In 2019, 1,027 pairs of redtailed and 100 pairs of white-tailed tropicbirds bred on Europa Island, which indicates an annual decline of 5% and 17% since 2009, respectively. Breeding success of red-tailed tropicbirds and white-tailed tropicbirds was extremely low (0.08 ± 0.07 and 0.06 ± 0.03 respectively). Rats were detected at most surveyed nests and were the main predators of eggs and chicks. Pied-crows and barn owls also depredated nests occasionally. Population viability analysis projected a local extinction in 32–85 years for the red-tailed tropicbird, and in 11–50 years for white-tailed tropicbirds without conservation intervention. The complete eradication of rats would result in a rapid recovery of both populations. Rat control around nests only would result in population recovery only if 74% of the nests of white-tailed and 63% of the nests of red-tailed tropicbirds are free of rats., Les rats font partie des prédateurs étrangers les plus invasifs. Ils se nourrissent d’oeufs, d’oisillons et parfois d'oiseaux de mer adultes, ce qui provoque le déclin de nombreuses populations. Les rats ont envahi 93 % des îles de l'ouest de l’océan Indien, qui est un haut lieu de biodiversité aviaire. L’île Europa, dans le canal du Mozambique, est un site majeur de reproduction des oiseaux, puisqu’au moins un million de couples s’y reproduisaient à la fin du XXe siècle, notamment le phaéton à bec jaune (Phaethon lepturus europae). Cette espèce, ainsi que le phaéton à brins rouges (Phaethon rubricauda) est vulnérable à la prédation par le rat noir (Rattus rattus), la chouette effraie(Tyto alba) et le corbeau-pie (Corvus albus) sur l’île Europa. Dans cette étude, nous estimons la taille des populations de ces espèces d'oiseaux tropicaux et le succès de leur reproduction. L’impact des prédateurs sur les nids de phaétons a été quantifié à l’aide de pièges photographiques. Enfin, nous modélisons la dynamique de ces populations dans trois scénarios de gestion (aucune action, éradication complète des rats et contrôle ciblé des rats autour des nids). En 2019, 1 027 couples de phaétons à brin rouge et 100 couples de phaétons à bec jaune se sont reproduits sur l’île Europa, ce qui correspond respectivement à un déclin annuel de 5 % et de 17 % depuis 2009. Le succès de la reproduction des phaétons à brin rouge et des phaétons à bec jaune était extrêmement faible (0,08 ± 0,07 et 0,06 ± 0,03 respectivement). Des rats ont été détectés autour de la plupart des nids surveillés et étaient les principaux prédateurs d’oeufs et d'oisillons. Les corbeaux-pie et les chouettes effraie détérioraient parfois également les nids. L’analyse de viabilité de la population projetait une extinction locale d'ici 32 à 85 ans pour le phaéton à brin rouge et d'ici 11 à 50 ans pour le phaéton à bec jaune sans intervention de conservation. L’éradication complète des rats entraînerait le rétablissement rapide des deux populations. Pour que le contrôle des rats à proximité des nids permette le rétablissement de la population, il faudrait que 74 % des nids de phaétons à bec jaune et 63 % des nids de phaétons à brin rouge soient débarrassés des rats.

Climate change affects population cycles of several species, threatening biodiversity. However, there are few long-term studies on species with conservation issues and restricted distributions. Huemul is a deer endemic to the southern Andes in South America and it is considered endangered mostly due to a 50% reduction of its distribution over the last 500 years. To assess environmental variables potentially affecting huemul population viability and the impact of climate change, we developed population dynamics models. We used a 14-year survey data from Bernardo O’Higgins National Park, coastal Chilean Patagonia. We used Ricker models considering winter and spring temperatures and precipitation as variables influencing huemul population dynamics. We used the Bayesian information criterion (BIC) to select models with the greatest predictive power. The two best models (ΔBIC

Small populations are at risk of extinction from deterministic and stochastic factors. Less than 250 Asian elephants (Elephas maximus) remain in China, and are distributed in a few isolated areas; yet, population viability analyses of this endangered population have not been conducted. Here, the current genetic status of the Pu'Er-Mengyang Asian elephant populations in China was analyzed, and the risk of extinction was predicted over the next 500 years. Factors affecting the viability of this population were determined through simulations. The genetic diversity of the population was very low (mean allele number: 3.1; expected heterozygosity: 0.463), even though a recent population bottleneck was not detected. The effective population size was approximately 24.1 adult elephants. Enough adult breeding individuals exist to maintain population viability. VORTEX simulation model showed that this population would not go extinct in the next 500 years. However, illegal poaching and harvesting could negatively affect population size. A sensitivity analysis showed that the mean stochastic growth rate of the study population is sensitive to sex ratio, number of breeding females, mortality of females of different age classes, carrying capacity, and lethal equivalents. Based on our results, we suggest that action should be taken to alleviate inbreeding and any further loss of genetic diversity, by connecting fragmented elephant habitat or by translocating individual elephants. In addition, human-elephant conflict should be mitigated using various modern approaches, including crop guarding techniques, and by encouraging farmers to switch to crops and income sources not vulnerable to elephant raids.

SummaryAfrican White-backed Vultures were recently uplisted to ‘Critically Endangered’ by IUCN due to declines across their range. Poisoning is widely accepted as the major reason for these declines. Botswana supports a high number of this species (breeding pairs > c.1,200), but as yet no published information exists on their breeding success in the country. However, mass poisonings within Botswana and neighbouring countries have killed thousands of White-backed Vultures in recent years. We therefore expected that nesting numbers may have declined in this region if these poisoning events killed local breeding birds. We used information from aerial surveys conducted between 2006 and 2017 in Khwai and Linyanti, two important breeding areas for this species in north-central Botswana, to determine if there was any change in nesting numbers and breeding success of White-backed Vultures. Results showed an overall 53.5% decline in nesting numbers, with a greater decline in Linyanti than in Khwai. In both areas, breeding success was significantly lower in 2017 than it was 10 ten years earlier. We recommend that similar repeat surveys are continued to provide greater confidence in the trends of both nesting numbers and breeding performance. Population viability analysis suggested that if the productivity levels detected in 2017 were a true indication of current productivity levels for this population, and if recent high poisoning rates continue, this population could be extirpated from the area in the next 13 years.

The southern African population of Bearded Vultures Gypaetus barbatus has declined rapidly and it is threatened with extinction. In response to this decline and the additional threats of wind farm ...

The Arabian Leopard Panthera pardus nimr, classified by IUCN as “Critically Endangered”, is Saudi Arabia’s flagship predator. The population of this species has declined to approximately 50 individ...

Giant anteaters (Myrmecophaga tridactyla) are one of the most charismatic Neotropical mammals; however, the overall population trend for the species is decreasing due to numerous threats, including road kill. Population viability analysis (PVA) is an important tool to assess the viability of populations, rank alternative management scenarios and determine research priorities. A detailed baseline model for giant anteaters was developed using data from the literature, fieldwork, researcher expertise and captive populations. A sensitivity analysis was performed to evaluate the relative impact of each parameter on model results to prioritize potential threats and future research efforts. A case study based on three years of research in the Brazilian Cerrado on the impact of vehicle collisions on giant anteaters was tested. Model results showed a potential stochastic growth rate of 5% in the absence of significant threats, and sensitivity testing revealed that mortality rates and the percentage of females breeding are the most sensitive parameters of the model. Using real data for model inputs on road kill as well as sex ratio and age class showed that deaths of giant anteaters due to vehicle collisions decreases the stochastic growth rate of that population by half. Knowledge on the sex ratio of animals killed by vehicles is key to understanding the impact of roads in this polygynous species. This baseline model for giant anteaters can be adapted to populations throughout the species range and is valuable for use in conservation planning for the species.

SummaryAlthough the population of Griffon VultureGyps fulvusis significantly increasing in Europe, in Italy the species is still on the Red List as ‘Critically Endangered’, with the last natural population persisting on the island of Sardinia. Several episodes of poisoning hampered the success of conservation actions implemented in the years 1987–1995. In 2005 there were estimated to be only 31–32 territorial pairs, with the population occupying the territories of Alghero and Bosa. We used a long-term dataset of reproductive records from the Sardinian Griffon Vulture populations to run a population viability analysis (PVA) to evaluate the extinction risk using the Vortex simulation software. The model estimated the probability of extinction over the next five generations (estimated generation time: 11 years, simulation time used: 55 years) as 96.4% for the Alghero population, and near-zero for the Bosa population. We used sensitivity analyses to understand how uncertainty about parameter values affect model outcomes. Population projections were evaluated under different management scenarios tackling the main threats (poisoning and human disturbance) and implementing conservation actions (supplementary feeding and restocking). Our results showed that population size is a critical factor in affecting the projections of population dynamics of Griffon Vultures. Sensitivity analyses highlighted the importance of poisoning events to population persistence and showed that juvenile and adult mortality rates had a secondary impact on population viability. The only conservation measure effective in significantly increasing stochastic growth rates in the Alghero population, whose initial population was set at five individuals, was the complete removal of poisoning events. When targeting the Bosa population (initial population size 94 individuals), supplementary feeding, mitigation of the risk of poisoning episodes, restocking, and mitigation of human disturbance in the reproductive sites significantly increased stochastic growth rate. A cost-effectiveness analysis should be performed to prioritise interventions.

Madagascar is home to 208 indigenous palm species, almost all of them endemic and >80% of which are endangered. We undertook complete population census and sampling for genetic analysis of a relatively recently discovered giant fan palm, the Critically Endangered Tahina spectablis in 2008 and 2016. Our 2016 study included newly discovered populations and added to our genetic study. We incorporated these new populations into species distribution niche model (SDM) and projected these onto maps of the region. We developed population matrix models based on observed demographic data to model population change and predict the species vulnerability to extinction by undertaking population viability analysis (PVA). We investigated the potential conservation value of reintroduced planted populations within the species potential suitable habitat. We found that the population studied in 2008 had grown in size due to seedling regeneration but had declined in the number of reproductively mature plants, and we were able to estimate that the species reproduces and dies after approximately 70 years. Our models suggest that if the habitat where it resides continues to be protected the species is unlikely to go extinct due to inherent population decline and that it will likely experience significant population growth after approximately 80 years due to the reproductive and life cycle attributes of the species. The newly discovered populations contain more genetic diversity than the first discovered southern population which is genetically depauperate. The species appears to demonstrate a pattern of dispersal leading to isolated founder plants which may eventually lead to population development depending on local establishment opportunities. The conservation efforts currently put in place including the reintroduction of plants within the species potential suitable habitat if maintained are thought likely to enable the species to sustain itself but it remains vulnerable to anthropogenic impacts., We studied the genetics, population ecology and suitable habitat for Tahina spectabilis a critically endangered palm from Madagascar to assess its long term viability. We found that current conservation measures may enable the species to persist. Its endangerment is not due to intrinsic population decline.