Annual Survival Probability Research Articles

A novel prediction model for survival in individual patients with cardiac resynchronization therapy with a defibrillator: Analysis of the new Japan cardiac device treatment registry database.

Accurate prediction for survival in individualized patients with cardiac resynchronization therapy with a defibrillator (CRT-D) is difficult. We analyzed the New Japan cardiac device treatment registry (JCDTR) database to develop a survival prediction model for CRT-D recipients. Four hundred and eighty-two CRT-D recipients, at the implantation year 2018-2021, with a QRS width ≥120 ms and left ventricular ejection fraction (LVEF) ≤35% at baseline, were analyzed. During an average follow-up of 21 ± 10 months, death occurred in 66 of 482 CRT-D patients (14%). A prediction model estimating annual survival probability was developed using Cox regression with internal validation. With seven explanation predictors (age >75 years, serum creatinine >1.4 mg/dL, blood hemoglobin <12 g/dL, heart rate ≥90/min, LVEF, prior NSVT, and QRS width <150 ms), the model distinguished patients with and without all-cause death, with an optimism-corrected C-statistics of 0.766, 0.764, and 0.768, and calibration slope of 1.01, 1.00, and 1.00 at 1 year, 2 years, and 3 years. Additionally, we have devised the calculator of survival probability for individual CRT-D recipients. Using routine available variables, we have developed a survival prediction model for individual CRT-D recipients.

Using mark–recapture techniques to evaluate catch and release, recycling, and associated survival probabilities of stocked Muskellunge at two Ohio reservoirs

AbstractObjectiveMuskellunge Esox masquinongy fisheries in Ohio are almost exclusively catch and release. Catch and release is expected to benefit anglers via recaptures of previously caught fish (i.e., recycling). We used mark–recapture techniques to evaluate catch‐and‐release dynamics over multiple years in two stocked Muskellunge fisheries in Ohio.MethodsMuskellunge were collected and tagged each spring by the Ohio Department of Natural Resources, Division of Wildlife (ODNR‐DOW) at Clearfork Reservoir (1991–2006) and Leesville Lake (2016–2022). A total of 4139 Muskellunge were tagged, of which 38% (n = 1575) were recaptured at least once by either the ODNR‐DOW or anglers. A total of 252 anglers reported 1339 catches of tagged fish. Multistate modeling was used to estimate survival and transition probabilities across years for the following marked fish states: at large (L, ODNR‐DOW marked fish not reported caught by anglers); catch and release (C, those fish reported caught and released by anglers); and recycled (R, catch‐and‐release fish caught and reported by anglers again). Transition probabilities between states L to C and C to R estimated Muskellunge catch and release and recycling, respectively.ResultRaw angler catch reports indicated that intra‐annual recycling was rare, with the median time between recapture events exceeding a year. Modeled annual survival probability of L fish at Clearfork Reservoir and Leesville Lake was 0.67 and 0.87, respectively. About a quarter of these fish were caught and released by anglers at both reservoirs. Survival of C fish was lower than L fish at both reservoirs (Clearfork Reservoir = 0.58; Leesville Lake = 0.67), suggesting a “catch‐and‐release effect” on survival. Joint probability of catch‐and‐release fish surviving and being recycled annually was 0.24 and 0.23 for Clearfork Reservoir and Leesville Lake, respectively.ConclusionIntegration of survival and catch probabilities over the long‐term provides a comprehensive evaluation of catch‐and‐release dynamics. Estimates suggest that post‐catch‐and‐release survival and probability of recycling may be lower than anticipated, which may have implications for managing Muskellunge fisheries and angler expectations.

Habitat and density effects on the demography of an expanding wolf population in Central Europe

Demographic parameters are key to understanding population dynamics. Here, we analyse the survival and reproduction of the German wolf population in the 20 years following recolonization. Specifically, we analysed the effects of environmental, ecological and individual characteristics on 1) survival probability of the population; 2) annual survival rates of age classes; 3) reproduction probability; and 4) reproductive output, measured as the number of detected pups/juveniles. Using Cox proportional hazards model, we estimated a median survival time of circa three years for wolves. Annual survival probabilities were found to be 0.75 for juveniles, 0.75 for subadults and 0.88 for adults. Survival was lower for juveniles in winter and for subadult males in summer, probably associated with dispersal events. Low habitat suitability was clearly associated with lower survival in juveniles and subadults, but not in adults. Local territory density was related to increased survival. Reproduction probability within a territory was 0.88, but explanatory variables had no effect. Reproductive output was four pups/juveniles on average, positively related to habitat suitability and female experience, but negatively related to territory density. Survival values were very high for the species when compared to other regions. We hypothesize that carrying capacity has not been reached in the study area, thus the survival may decrease in the future if the landscape becomes saturated. Furthermore, our results highlight a spatial pattern in survival and reproduction, with area of better habitat suitability favouring faster population growth. Thus, targeting conservation measures to low habitat suitability areas will have a strong population effect on the short term by boosting survival and reproduction of the individuals, while long‐term viability should be carefully planned with high suitability areas in mind, as those contain the territories with higher survival and reproduction potential.

Florida sandhill crane survival along a wildland‐to‐urban land use gradient

AbstractThe Florida sandhill crane (Antigone canadensis pratensis) is a state‐threatened non‐migratory subspecies. Our understanding of adult crane survival in Florida, USA, is unclear, as it relies on decades‐old unpublished data of birds residing in natural areas. Since that time, the loss of natural habitat precipitated cranes using urbanized areas such as suburban lawns and roadside verges for foraging and loafing. Contemporary studies are needed to properly guide crane management and conservation efforts. We addressed this knowledge gap by estimating the annual survival rate for sandhill cranes in 12 central Florida counties. We used a live‐dead capture‐recapture multistate model, monitoring 118 adult cranes from June 2017 to May 2023; 76 were color‐banded and 42 were tagged with Global System for Mobile Communications (GSM) transmitters. Fifteen cranes died during the study, with vehicle strikes (n = 9) being the most prevalent identified source of mortality. Overall, the annual survival probability was estimated at 0.79 (95% credibility interval = 0.75–0.84). Using the subset of GSM‐tagged cranes, we observed no influence of urbanization on annual survival rate (βurbanization gradient = 0.007, 95% credibility interval = −0.008, 0.022). The adult survival rates we observed are lower than reported for other populations of sandhill cranes in North America that are considered stable or growing.

Post-release survival of loggerhead sea turtles (Caretta caretta) incidentally hooked in a North Atlantic pelagic longline fishery

Estimating mortality of sea turtles incidentally captured in fishing gear is essential to understanding fishery impacts on sea turtle populations. Loggerhead turtles (Caretta caretta) are a component of bycatch in pelagic longline fisheries, including those operating in Atlantic Canada. In this study, we used pop-up satellite archival tags (PSATs) attached to 62 loggerhead turtles incidentally hooked in Atlantic Canadian shallow-set pelagic longline gear (2012–2018) to estimate associated post-release survival. Consistent with conventional fishing practices, hooks were not removed from turtles prior to release. Analysis of diving behaviour, ocean temperature, and ambient light level was used to assign fates to turtles. Post-release survival was calculated using the Kaplan-Meier estimator with right censoring. Based on this method, the annual survival probability of an individual loggerhead post-release is 0.877 ± SE 0.052. While it is commonly assumed that hook location is an important variable in predicting fates of turtles after release, there was no difference in survival of deep-hooked (swallowed hook) versus shallow-hooked turtles. These results indicate higher survivorship among hooked loggerheads captured in shallow-set pelagic longline gear than prevailing wisdom and suggest that at least some of the population impacts on loggerhead turtles conventionally attributed to pelagic longline interactions may be linked to other threats.

Age truncation due to disease shrinks metapopulation viability for amphibians.

Metapopulations often exist in a fragile balance between local extinctions and (re)colonisations, in which case emerging threats that alter species vital rates may drastically increase metapopulation extinction risk. We combined empirical data with metapopulation simulations to examine how demographic shifts associated with amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) have altered metapopulation viability for threatened amphibians in Australia. Comparing the ages of museum specimens collected before Bd emerged in Australia with individuals from geographically matched remnant populations revealed significant truncation of age structures post-Bd, with a halving of annual adult survival probabilities. Spatially realistic metapopulation modelling demonstrated that reduced adult survival led to major reductions in the parameter space over which persistence was possible for the focal species, with contractions to landscapes with higher landscape connectivity, lower environmental stochasticity and considerably higher recruitment rates. Metapopulation persistence post-Bd required greater landscape connectivity than pre-Bd. This arises from a landscape-level analogue of compensatory recruitment at the population level, in which higher (re)colonisation rates can offset more frequent local extinctions, enabling persistence of amphibians susceptible to Bd. Interactions between recruitment rate, environmental stochasticity and landscape connectivity were also more important for metapopulation persistence post-Bd. Higher recruitment was required to mitigate the impacts of environmental stochasticity, and higher landscape connectivity was required to mitigate the impacts of environmental stochasticity and poor recruitment. Increased reliance on these interdependencies shrunk the parameter space over which metapopulations could persist post-Bd. Our study demonstrates that emerging threats that alter species vital rates can drastically reduce the capacity of certain environments to support metapopulations. For our focal species, reductions in adult survival rates due to Bd produced major reductions in the conditions under which persistence was possible, providing a mechanistic insight into the processes underpinning observed range and niche contractions of amphibians impacted by this pathogen. More broadly, our study illustrates how environmentally mediated host resilience can enable persistence following the emergence of novel pathogens. This pathway to persistence is worthy of greater attention on both conceptual and applied grounds.

Moderate evidence for the sex‐dependent effect of poisoning on adult survival in a long‐lived raptor species

AbstractSurvival rate is usually the greatest contributor to population growth in long‐lived species, and its accurate estimation along with the evaluation of the factors influencing it is therefore essential for effective conservation. Here, we studied the survival of breeding eastern imperial eagles Aquila heliaca in Hungary between 2011 and 2022 and investigated the effect of poisoning, the leading known anthropogenic cause of mortality. We used the Cormack‐Jolly‐Seber mark‐recapture model to estimate annual apparent survival and encounter probabilities based on the capture histories of 208 males and 411 females. We obtained encounter data from the DNA profiles of shed feathers collected at the nest sites, which we also supplemented with presences inferred from parentage analysis. The most supported model estimated a constant 91.6% annual survival over the study period, but models including the effect of sex and poisoning rate on survival had similar support. Sex difference in survival was less than 1% on average, but the survival of males decreased more with poisoning rate than the survival of females. However, due to smaller encounter probabilities, the estimates for males were less precise compared to females. Males may be more at risk from poisoning than females not only due to their more active foraging behaviour during incubation and chick‐rearing but also due to their smaller body size. Apart from providing direct practical information for the conservation management of imperial eagles, our results also highlight the importance of long‐term studies for estimating population parameters of birds of prey.

Mortality in patients receiving renal replacement therapy in South Korea.

This study analyzed data from the end-stage renal disease patient registry collected by the Korean Society of Nephrology to explore trends in mortality among dialysis patients from 2001 to 2022. Mortality was analyzed in two ways: firstly, using the annual mortality rate; and secondly, by assessing survivability after a certain period of time since the initiation of dialysis. Additionally, we categorized the causes of death by disease group annually to observe how the proportions changed. Since 2001, annual mortality for dialysis patients generally declined, except for a rise in 2020 and 2021 among hemodialysis patients. Overall mortality rates for all dialysis patients dropped from 74.2/1,000 person-years in 2001 to 42.3/1,000 person-years in 2022, with a more pronounced decrease in peritoneal dialysis. While survival probability over the 5 years following initiation of dialysis has shown a steady increase, short-term mortality from 2018 to 2020 affected by coronavirus disease 2019 (COVID-19) has shown a yearly increase by age group, with a greater effect in those aged 75 years and older. The leading causes of death for all dialysis patients have changed little, in the order of heart disease, infection, and vascular problems. While annual mortality and survival probability after dialysis initiation have generally improved in dialysis patients, there has been a temporary deterioration during the COVID-19 pandemic, most pronounced in the elderly.

Survival and population size of the Indo‐Pacific humpback dolphins off the eastern Leizhou Peninsula

AbstractIndo‐Pacific humpback dolphins form a resident population off the east coast of Leizhou Peninsula (LZP) in South China. The most recent study suggested ~1,500 individuals in this area, making this population one of only two populations of this species exceeding 1,000 individuals. However, demographic information regarding this population has been lacking since 2012. Using a 5‐year (2019–2023) photo‐identification data set, we examined two key demographic parameters of the LZP population, namely the apparent survival and population size, using multistate capture‐recapture analyses. Annual survival probabilities (φ) changed over time, fluctuating between 0.942 and 0.961 for adults, and between 0.787 and 0.837 for juveniles. Jolly‐Seber multistate model analyses resulted in highly comparable noncalf population size estimates from 2020 to 2023 (2020 = 479, SE = 28; 2021 = 458, SE = 29; 2022 = 481, SE = 27; 2023 = 446, SE = 31). By reviewing the available demographic information, we conclude that the population size of LZP humpback dolphins has been previously overestimated. The time‐dependent survivals seemingly reflect a dynamic development of anthropogenic disturbance during the pandemic period. We propose that the population status should be re‐evaluated, especially in the postpandemic era when the human activities came back to “normal” levels.

Mule deer mortality in the northern Great Plains in a landscape altered by oil and natural gas extraction

AbstractA worldwide increasing demand for renewable and non‐renewable energy resources has been ongoing since the mid‐1970s and is projected to increase for the next 2 decades. The effects of oil and natural gas development on wildlife mortality risk may play an important role in mule deer (Odocoileus hemionus) population dynamics. We evaluated the potential effects of oil and natural gas development on mortality risk of mule deer in western North Dakota and eastern Montana, USA. We assessed adult and juvenile female mule deer mortality risk with Poisson point process models using 265 deer fitted with global positioning system (GPS) radio‐collars that were deployed from 2013–2016. Mortality covariates included proportion of area disturbed by oil and natural gas development, distance to oil and natural gas development, distance to roads, temperature, snow depth, normalized difference vegetation index (NDVI), and age of deer. During the study there was no effect of oil and natural gas development or roads on mule deer mortality, though &lt;1% of all deer locations were within 500 m of active drilling rigs. Mule deer mortality was greatest in winter and spring, and positively related to temperature during these seasons. Estimated annual adult survival probability was 0.79 (95% CI = 0.71–0.85). Given the strong influence of season and temperature variables on mortality risk, weather had the strongest influence on mule deer mortality during this study. Although we did not detect an effect of energy development on mule deer mortality, effects on space use resulting from development could influence deer dynamics in the region through displacement and could occur over longer time scales than we evaluated. This study can be used in pre‐development planning in a risk assessment framework to minimize effects of development on mule deer.

Juvenile survival of little owls decreases with snow cover.

Global environmental changes are associated with warmer average temperatures and more extreme weather events, potentially affecting wildlife population dynamics by altering demographic processes. Extreme weather events can reduce food resources and survival in all seasons of the year. Estimates of season-specific survival probabilities are therefore crucial to understand the moderating effect of extreme events on annual mortality. Here, we analysed survival probabilities of 307 radio-tracked juvenile little owls (Athene noctua) over two-week periods from fledging to their first breeding attempt in the following spring to assess the contribution of extreme weather events. Survival probabilities were typically lowest during the first weeks after fledging in summer but were moderated by seasonal extremes in winter. The duration of snow cover in winter had a strong negative effect on survival probability, while being food supplemented during the nestling stage increased survival during the first weeks after fledging in summer and ultimately led to a larger proportion of birds surviving the first year. Overall annual survival probability over the first year varied by 34.3% between 0.117 (95% credible interval 0.052-0.223) and 0.178 (0.097-0.293) depending on the severity of the winter, and was as high as 0.233 (0.127-0.373) for food-supplemented fledglings. In years with mild winters, the season with the lowest survival was the summer post-fledging period (0.508; 0.428-0.594), but in years with extensive snow cover the winter was the season with the lowest survival (0.481; 0.337-0.626). We therefore show that extreme weather events occurring in a particular season reduced the proportion of first-year survivors. Increasing extreme weather events can moderate seasonal survival probability through altering food supply of juvenile little owls either during the nestling period or in winter, with similarly large effects on annual survival and the viability of populations.

Bigger is better: age class‐specific survival rates in long‐lived turtles increase with size

AbstractVital rates for small, non‐breeding individuals are important components of population dynamics for many species, but often individuals of these sizes are difficult to locate, capture, and track. As such, biologists frequently lack reliable estimates of juvenile survival because sample sizes and recapture rates for this life stage are low. Long‐lived animals often take many years to reach sexual maturity and spend much of this time in the smaller size classes, making them sensitive to changes in survival rates. We estimated the survival rates of all size classes for the northern map turtle (Graptemys geographica) using a mark‐recapture dataset with &gt;3,500 captures from 2019–2021 and 210 nests from 2018–2021. As turtle size increased, annual survival probability increased regardless of sex. Estimated annual survival probability for turtles &gt;18 cm long (i.e., adult females &gt;15 years) was about 0.95, over 4 times higher than turtles that were 3 cm long (i.e., hatchlings &lt;1 year; 0.22 annual survival probability). Although we did not observe a difference in survival probability between sexes of any size class, adult females are nearly twice the size of adult males, leading to an increased annual survival probability for females of 0.95, compared to 0.80 for males. Changes in adult survival had the greatest influence on population estimates over time, with temporary decreases, such as those due to poaching or an environmental disaster, potentially leading to unrecoverable decreases in the overall population size. Our study provides detailed survival rates for all size classes in a long‐lived turtle, which are necessary to assess population stability and can be used to determine the most effective conservation or management practices.

Population status of the endemic Pitcairn Reed Warbler Acrocephalus vaughani on Pitcairn Island, South Pacific

Summary Reed warblers are widespread throughout Eurasia, Africa, and Australasia, and many species undertake long seasonal migrations. By contrast, other species of the genus Acrocephalus are sedentary and endemic to single oceanic islands. The Pitcairn Reed Warbler Acrocephalus vaughani is confined to the small volcanic island of Pitcairn in the South Pacific Ocean, and no population assessments have ever been conducted for this species. Due to its restricted range, the presence of invasive species, and the loss of natural habitat, the species is considered as globally “Endangered”, but its actual conservation status is entirely speculative. We conducted transect surveys and nest monitoring in the austral summer of 2022/23 and present abundance estimates for the species. We counted between 51 and 158 reed warblers along 54 transects that were each 100 m long and covered all habitats and roughly 13% of the vegetated island area. Using binomial mixture models accounting for imperfect detection and habitat variation in abundance, we estimated that Pitcairn may hold 1,568 (95% confidence interval 812–3,237) Pitcairn Reed Warblers, and that the species appeared to be most abundant in introduced Rose Apple Syzygium jambos stands. Based on the monitoring of 49 nests, of which only four failed to fledge any young, we estimated that Mayfield nest survival rate was 0.69 and estimated productivity was 1.07 (± 0.39 standard deviation) fledglings per nest. Assuming that Pitcairn Reed Warblers have similar annual survival probabilities as other island reed warblers, the productivity appears sufficient to maintain the population and there is no indication that the species has decreased significantly over the past three generations. Given the limited extent of occurrence, and the stable current population size between 442 and 2,774 mature individuals, we recommend that the global conservation status of the Pitcairn Reed Warbler be classified as “Vulnerable”.

Long‐term conservation efforts at flyway scale can halt the population decline in a globally endangered migratory raptor

AbstractMany threatened species require ongoing management, which is often funded through short project cycles. Evaluating whether the management is effective in protecting a species is important to inform future management investments. For migratory species, management may affect only part of a species' annual cycle, and reversing a population decline is challenging to achieve and demonstrate. Here, we evaluate whether conservation management projects funded by the European LIFE programme to safeguard a migratory vulture population achieved their major objective of stabilizing the target breeding population. Between 2012 and 2022, an international alliance of conservation organizations implemented multiple actions to reduce poisoning, direct persecution, and electrocution and collision with power lines along the Eastern Mediterranean flyway. We monitored breeding territories of the Balkan population of the globally endangered Egyptian Vulture Neophron percnopterus between 2006 and 2022, and tracked 60 young birds with GPS transmitters since 2010. We used these data to examine whether population growth rate and survival probability had increased since project implementation. The mean annual survival probability of adult territorial birds increased by 1.9% since 2014 from 0.937 to 0.955, and the monthly survival probability of wild juvenile birds increased by 9.7% from 0.833 to 0.914 since 2018. The population growth rate across the Balkans increased by 6.9% from 0.939 before 2018 to 1.005 since 2018. This indicates that the Egyptian Vulture population has remained stable for the past 5 years (2018–2022), but at a population size that is only half (105 adult territorial birds in 2022) than at the beginning of the time series (204 in 2006). We caution that ongoing management along the flyway and reinforcement are required to ensure that the Egyptian Vulture population on the Balkans can recover, but we show that flyway‐scale collaboration of direct conservation actions can have lasting benefits for migratory species.

Estimating survival in continuous space from mark-dead-recovery data — Towards a continuous version of the multinomial dead recovery model

Understanding spatially varying survival is crucial for understanding the ecology and evolution of migratory animals, which may ultimately help to conserve such species. We develop an approach to estimate an annual survival probability function varying continuously in geographic space, if the recovery probability is constant over space. This estimate is based on a density function over continuous geographic space and the discrete age at death obtained from dead recovery data. From the same density function, we obtain an estimate for animal distribution in space corrected for survival, i.e., migratory connectivity. This is possible, when migratory connectivity can be separated from recovery probability. In this article, we present the method how spatially and continuously varying survival and the migratory connectivity corrected for survival can be obtained, if a constant recovery probability can be assumed reasonably. The model is a stepping stone in developing a model allowing for disentangling spatially heterogeneous survival and migratory connectivity corrected for survival from a spatially heterogeneous recovery probability. We implement the method using kernel density estimates in the R-package CONSURE. Any other density estimation technique can be used as an alternative. In a simulation study, the estimators are unbiased but show edge effects in survival and migratory connectivity. Applying the method to a real-world data set of European robins Erithacus rubecula results in biologically reasonable continuous heat-maps for survival and migratory connectivity.

Turkey Vulture survival is reduced in areas of greater road density

Abstract The demography of, and factors that influence these metrics, are largely unknown for most vultures in the Americas. Survivorship of Turkey Vultures (Cathartes aura) may be influenced by landscape heterogeneity and human disturbance. We quantified the effects of landscape composition (Shannon’s diversity index) and configuration (contagion, edge density, and largest patch index), and human disturbance (road density) on the annual and seasonal survival probabilities of the three North American breeding populations (western, central, and eastern) of Turkey Vultures that spend the nonbreeding season in the southeastern portion of the Nearctic and the northern Neotropics during a 17-year period. We used Cox’s proportional hazards models with time-varying covariates to estimate spatial and temporal changes in survival rates of adult Turkey Vultures. Road density, but not landscape composition or configuration, influenced survival rates in space and time. Overall annual survival averaged 0.87 (95% confidence interval [CI]: 0.74–0.98). Mortality risk was low in western and central populations (hazard ratio &amp;lt; 1) but was 3.7 times greater for vultures in the eastern population. Survival during the breeding (0.97, 95% CI: 0.96–0.98) and outbound migration (1.0, 95% CI: 1–1) seasons was significantly higher than the other seasons. Average survival tended to be higher for nonbreeding (0.81, 95% CI: 0.71–0.88) compared to return migration (0.69, 95% CI: 0.56–0.81) seasons. The risk of mortality for all vulture populations increased with road density, and this was greater during the nonbreeding and return migration seasons. The spatial variation in road density across the Americas may generate a network of ecological traps for Turkey Vultures induced to stop in areas of greater road-kill abundance. Road-killed animals acting as an attractant for vultures can increase the occurrence of vulture–vehicle collisions and potentially aggravate human–wildlife conflicts. Further analyses are needed to address survivorship and mortality factors for young birds. Our results may help the implementation of specific mitigation efforts to reduce human–vulture conflicts and vulture mortality. For instance, concentrating efforts to remove road-killed animals in areas where road density is highest can likely reduce vulture–vehicle collisions and associated mortalities of these birds.

Drought Influences Annual Survival of Painted Turtles in Western Nebraska

Aquatic habitats in the Great Plains of North America have increased risk of droughts under climate forecasts. Droughts have the potential to influence the population dynamics of pond turtles, and long-term studies are useful to assess the impact of climatic variation on turtles. We compiled twelve years of mark-recapture data for painted turtles (Chrysemys picta) captured in a pond in Keith County, Nebraska during 2005–2016 that included two periods of drought. We used a robust design analysis to investigate influences on population size, annual survival, temporary immigration, and capture probability. Estimates of the annual population size ranged from 92 (CI: 90–94) to 180 (CI: 175–186) but did not vary with drought conditions. Despite a relatively stable depth of water in our study pond, the probability of annual survival was reduced by 0.07 in females and 0.10 in males during drought years. Approximately one-fifth (temporary emigration probability: 0.19, CI = 0.16–0.23) of the population was outside the study pond at any given time. Our long-term research provides insights into the potential challenges to turtles in aquatic habitats undergoing prolonged changes in long-term climate conditions.

Survival and cause-specific mortality of coyotes in Wisconsin

Abstract Understanding the drivers of population dynamics informs management actions and assures the public that harvest activities are not detrimental to the long-term stability of wildlife populations. We examined the survival and cause-specific mortality of 66 adult coyotes (34 males, 32 females) using GPS radiotelemetry in southwestern Wisconsin during October 2016 to March 2020. We paired our study with a literature review of coyote survival and mortality across the United States and Canada, focusing on the geographical distribution of studies, demographic aspects of survival, and the level of exploitation by humans on coyote populations. In Wisconsin, annual survival did not differ between sexes or across years but did vary among seasons and social statuses. The relative risk for a coyote dying was higher during the winter compared to the summer. A transient coyote had a higher relative risk of mortality compared to a resident coyote. Mean annual survival probability (sexes combined) was higher for a year-long resident compared to a year-long transient. The predominant sources of known mortality (n = 37) were harvest (83.8%) and vehicle collisions (13.5%). For our literature review, we identified 56 studies estimating coyote survival or mortality from 1971 to 2021 spanning the geographic range of coyotes. We found no distinct temporal or regional patterns in survival probability or the proportion of human-induced mortality, although fewer studies originated from the northeast region of the United States. Additionally, we detected weak correlation between survival probability and proportion of human-induced mortality, suggesting coyote harvest may be compensatory. Although our findings indicate that the Wisconsin coyote population had relatively higher human-induced mortality than populations in other regions, these mortality rates appear to be sustainable for this population under current landscape and habitat conditions.

Population dynamics of killer whales (Orcinus orca) in the Crozet Archipelago, southern Indian Ocean: a mark-recapture study from 1977 to 2002

Population size and annual survival probabilities for the killer whales (Orcinus orca) inhabiting the inshore waters of Possession Island, Crozet Archipelago, southern Indian Ocean, were estimated through mark-recapture modelling. Capture histories were generated from a set of photographs taken under a photo-identification protocol and a set of photographs taken opportunistically, between 1964 and 2002. Photographs were selected according to their intrinsic quality and the degree of natural marking of individuals. Under those conditions, only well-marked individuals were considered as ‘marked’ from a capture-recapture perspective. The purpose of this double selection was to minimise identification errors and reduce the heterogeneity of capture probabilities. Abundance estimates were derived from the Mth sequential model for closed populations and adjusted for the proportion of well-marked individuals in the study population and for the number of photo-identified individuals. Under this framework, estimates of 98 (95% CI 70-156) individuals in 1988-89, and 37 (95% CI 32-62) individuals in 1998-2000 are proposed. After a weighted model averaging, the Cormack-Jolly-Seber models with the strongest support from the data produced low survival probability estimates, decreasing from 0.935 (95% CI 0.817-0.979) to 0.895 (95% CI 0.746-0.961) for males, and from 0.942 (95% CI 0.844-0.980) to 0.901 (95% CI 0.742-0.966) for females over the period 1977-2002. A Jolly-Seber model was used as a ‘second opinion’ model. It confirmed the worrying status of the population with a constant survival probability estimated at 0.89 (95% CI 0.84-0.93) and a constant rate of increase (applying to the well-marked fraction of the population) estimated at 0.94 (95% CI 0.90-0.99) for the period 1987-2000. This rate of increase is consistent with the abundance estimates presented here. Possible violations of the underlying model assumptions were investigated and it was concluded that the abundance estimates for the period 1988-89 and the CJS survival estimates should be the most reliable results. It is feared that the killer whales around Possession Island are in sharp decline, as may be true for the whole Crozet Archipelago. The effect of low prey stocks and lethal interactions with fisheries as the most likely causes of this decline are discussed.

Post-weaning survival in kangaroos is high and constant until senescence: Implications for population dynamics.

Large herbivores typically have consistently high prime-aged adult survival and lower, more variable, juvenile, and senescent survival. Many kangaroo populations undergo greater fluctuations in density compared with other large herbivores, but age- and sex-specific survival of kangaroos and their response to environmental variation remain poorly estimated. We used long-term capture-mark-recapture data on 920 individuals to investigate the survival component of eastern grey kangaroo (Macropus giganteus) population dynamics. Forage availability and population density were monitored quarterly and included as predictors of survival in Bayesian Cormack-Jolly-Seber models. Annual survival probabilities were estimated for five age classes: 0 years (juveniles), 1-2 years (subadults), 3-6 years (prime-aged adults), 7-9 years (presenescent adults), and ≥10 years (senescent adults). Survival of juveniles varied widely during our 12-year study, ranging from 0.07 to 0.90 for females and 0.05-0.92 for males. Subadult survival was 0.80-0.93 for females and 0.75-0.85 for males, while that of prime-aged adults was ≥0.94 for females and ≥0.83 for males, despite large fluctuations in forage and density. The survival of presenescent adults spanned 0.86-0.93 for females and 0.60-0.86 for males. Senescent survival was variable, at 0.49-0.90 for females and 0.49-0.80 for males. Male survival was significantly lower than female survival in prime-aged and presenescent adults, but not in other age classes. Although most of the models supported by Watanabe-Akaike Information Criterion selection included at least one environmental covariate, none of these covariates individually had a discernible effect on survival. Temporal variability in overall survival appeared mostly due to changes in the survival of juvenile and senescent kangaroos. Kangaroo survival patterns are similar to those of ungulates, suggesting a strong role of sex-age structure on population dynamics.