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The conservation of pollinators, such as bees, is important because they provide criticalpollination services in urban, natural, and agricultural ecosystems. While pollinators and theirservices are better studied in agricultural systems, less is known about the pollinators and theirfloral visitation patterns in urban/suburban areas. This includes the knowledge of bee speciespresent on the University of California, Riverside campus, located in an urban setting. Urbanareas, including college campuses, have been known to provide floral resources to pollinatorswith the integration of urban greenspaces. In this study, we aimed to: (1) characterize pollinatorvisitation to landscaping plantings on the University of California, Riverside campus, and (2)describe their foraging behaviors. Six plots throughout the campus were selected, with mostmeasuring at least 1 ha and each at least 100 meters apart. In these plots, we observed andrecorded any pollinators visiting floral species. We used mark-recapture methods to assesswhether the bee species stayed loyal to a specific floral species or whether they visited a widevariety of plants. Overall, we detected a total of 12 pollinator species marked that had visited 36flowering plant species in our plots in the UC Riverside campus. Of these 12 pollinator species,three were recaptured, Bombus melanopygus, Melissodes spp., and Apis mellifera. Recaptureprobability varied by the plant species visited and the pollinator’s identity but was consistentacross plots. Overall, our findings suggest that floral resources provided in urban greenspaces atthe University of California, Riverside have the potential to support native pollinatorcommunities.

Understanding storm impacts on marine vertebrate demography requires detailed meteorological data in tandem with long‐term population monitoring. Yet most studies use storm proxies such as the North Atlantic Oscillation Index (NAOI), potentially obfuscating a mechanistic understanding of current and future risk. Here, we investigate the impact of extratropical cyclones by extracting north Atlantic winter storm characteristics (storm number, intensity, clustering and wave conditions) and relating these with long‐term overwinter adult survival of three long‐lived sympatric seabirds which winter at sea—common guillemot Uria aalge, Atlantic puffin Fratercula arctica and razorbill Alca torda. We used multidecadal mark‐recapture analysis (1970s–2020s) to estimate survival while correcting for resighting probability, combined with spatially explicit environmental data from geolocation‐derived wintering areas, to determine the impact of different storm characteristics (i.e., number, intensity, duration, gap between storms, wave height and wind speed), as well as broad‐scale climatic conditions (NAOI and sea surface temperature [SST]). All three species experienced rapid population growth over the study period. Guillemot and razorbill survival was lower during stormier winters, with an additive effect of summer SST for guillemots, and a negative interaction with population size for razorbills. Puffin survival was negatively correlated with winter SST, and the lowest puffin survival coincided with intense winter storms and a large seabird wreck in 2013/14. The number of days with wind speed >30 and 35 ms−1 negatively impacted razorbill and guillemot survival, respectively, and puffin survival was higher when gaps between storms were longer. Our results suggest negative but divergent storm impacts on these closely related sympatric breeders, which may be compounded by warmer seas and density‐dependence as these populations return to their previously much larger sizes. We tentatively suggest that frequent, long‐lasting storms with strong winds are likely to have the greatest negative impact on auk survival. Moreover, we highlight the possibility of tipping points, where only the most extreme storms, that may become more frequent in the future, have measurable impacts on seabird survival, and no effect of NAOI. [ABSTRACT FROM AUTHOR]

In the face of global warming and frequent catastrophe, monitoring wild populations of stream salmonids is increasingly important. However, with declining human birthrates and aging populations predicted for developed countries, conventional monitoring surveys conducted solely by fisheries researchers may not be sustainable owing to labor shortages. Local anglers sometimes form communities, such as fishing clubs or cooperatives. Community-based fishing reports can ensure monitoring accuracy similar to conventional population estimates. In this study, a mark–recapture survey using the Petersen method was performed on white-spotted charr Salvelinus leucomaenis and red-spotted masu salmon Oncorhynchus masou ishikawae in a mountain stream of the Fuji River basin, central Japan, from 2018 to 2023. The marking survey was conducted for age-1 and older fish by electrofishing with the participation of local anglers. For the recapture surveys, anglers fished and reported on the number of total and marked individuals in their catch for each species. The total catch by anglers was 1.5–2.9 times higher than the number of fish captured for marking by electrofishing. The reporting method of fishing results varied widely: direct reporting to the lodge staff including the third author, social networking sites, e-mail, telephone, and fax. The estimated population density of both species combined was at least 0.18 individuals m-2, indicating a high abundance in the stream when compared with literature reports for similar mountain streams. Significant positive correlation was shown between the population densities and the number of fish caught per angler per day, suggesting that the estimation accuracy was reasonably robust. The results of the mark–recapture survey were fed back to the anglers every October. [ABSTRACT FROM AUTHOR]

Context: Non-invasive identification of individual animals in wild populations can occur in species with unique coat patterns (e.g. zebras, giraffes, jaguars). However, identification in other species often relies on capture-mark–recapture techniques, involving physical handling of animals. Identification of individual koalas (Phascolarctos cinereus) is difficult and has so far relied mostly on invasive methods such as ear tagging, microchipping and/or collaring, which require capture. The validation of a non-invasive method to identify koalas could improve monitoring of individuals in the wild, allowing targeting of specific koalas in disease and survival studies, reducing the need to capture individuals. Aims: This study describes a novel effective method to identify koalas from their nose markings, specifically using the unpigmented pattern of the nose to determine unique features of individuals. Methods: Photographs of koalas from different populations in Victoria and New South Wales (NSW), Australia, were examined in the study. Nose patterns were traced from photographs and matched through visual assessment if they were thought to belong to the same individual. Differences in identification success between datasets from different populations and the effect of sex on match success were evaluated statistically. For the NSW koalas, the effect of lighting conditions and photographic angle were also assessed. Key results: Overall identification success was 89.7% (range 87.1–91.8%) and was not affected by any of the variables tested, demonstrating that nose patterns can be used reliably to identify individual koalas. Conclusions: The proposed non-invasive method is simple, yet accurate and stable over time, hence it offers a vital tool for monitoring endangered koalas whilst minimising human interference. Implications: Pattern-based recognition of koalas is cost-effective, reduces stress on the animals, has the potential to improve data collection and allows involvement of citizen scientists in monitoring of populations or individuals. Identification of individual koalas is difficult and relies mostly on invasive methods requiring capture. This study describes and validates a novel non-invasive method to identify koalas from their nose markings, using the unpigmented pattern of the nose to determine unique features of individuals. This new method offers a vital tool for monitoring endangered koalas whilst minimising human interference. Photograph by Koala Clancy Foundation. [ABSTRACT FROM AUTHOR]

The Charnov‐Bull hypothesis is the leading explanation for the evolution of environmental sex determination (ESD), which includes temperature‐dependent sex determination (TSD), the most common form of ESD. Charnov‐Bull predicts a sex‐by‐incubation temperature interaction for fitness, matching offspring sex with thermal conditions that increase parental fitness. However, there is no general explanation for how the sex‐by‐temperature interaction arises. Two competing explanations for the interaction lie in the survival to maturity hypothesis (SM) and the Trivers–Willard extension (TW). Under SM, the sex that matures later is produced under optimal incubation regimes as the late‐maturing sex accrues more mortality by maturation, while TW suggests that males are always produced under optimal incubation regimes as male mating success is more sensitive to condition (general health, vigor) than female fecundity. In a system where females mature later than males, as in the painted turtle Chrysemys picta, SM and TW generate opposite predictions for the effect of incubation temperature on juvenile survival. We incubated C. picta eggs under either female‐promoting temperatures (28 ± 3 °C) or male‐promoting temperatures (25 ± 3 °C), then released the hatchlings into their natal pond. We used a Bayesian capture–mark–recapture approach to follow their survival over two growing seasons. We found a 2% depression of biweekly survival in individuals incubated under the cooler temperature, providing subtle support for SM. Incubation treatments did not influence growth. Large‐scale field experiments such as this one will be necessary for understanding TSD evolution, and we underline general principles to execute such experiments successfully. [ABSTRACT FROM AUTHOR]

Understanding the drivers of population abundance and distribution is fundamental to ecology and key to informing conservation actions, particularly in endangered species like blue whales (Balaenoptera musculus). Historically, some Eastern North Pacific blue whales have aggregated in the Gulf of California (GoC) each winter. Using photo‐identification data collected around Loreto Bay from 1984 to 2020, we analyzed 453 sightings histories using mark‐recapture models. Estimated apparent survival (including permanent emigration) decreased from 0.991, 95% CI [0.977, 0.997] in 1985 to 0.889, 95% CI [0.807, 0.939] in 2019. The estimated number of whales using the study area declined from 96 whales, 95% CI [50, 254] in 2012 to 13 whales, 95% CIs [12, 23 and 12, 28] in 2018 and 2019. Abundance of the whole Eastern North Pacific population is slowly increasing, so our results likely reflect declining usage of the GoC. Linear models found a relationship between the number of whales in the GoC and the difference in sea surface temperature between the study area and the Costa Rica Dome wintering area, suggesting that environmental variation could explain variation in blue whale numbers in the GoC. These results highlight the importance of tracking population dynamics as changing environmental conditions affect the range and distribution of populations. [ABSTRACT FROM AUTHOR]

Context. The population of introduced fallow deer (Dama dama) is thought to have increased exponentially across much of the island of Tasmania, Australia, since 2000. Historically, deer management decisions have relied on population trend data from vehicular spotlight surveys. Renewed focus on the contemporary management of the species requires development of more robust and precise population estimation methodology. Aims. This study demonstrates two aerial survey methods – conventional counts by trained human observers, and thermal imaging footage recorded during the same flights – to inform future survey practices. Methods. Conventional counts were carried out by three observers, two seated on the left side of the helicopter, and one on the right. A high-resolution thermal camera was fitted to the helicopter and was orientated to meet the assumptions of distance sampling methodologies. Both survey methods were used to generate deer population density estimates. Spatial distribution of deer was also analysed in relation to patches of remnant native vegetation across an agricultural landscape. Mark–recapture distance sampling was used to estimate density from human observer counts and provide a comparison to the distance sampling estimates derived from the thermal camera. Key results. Human observer counts gave a density estimate of 2.7 deer per km2, while thermal camera counts provided an estimate of 2.8 deer per km2. Deer population density estimates calculated via both methods were similar, but variability of the thermal camera estimate (coefficient of variation (CV) of 36%) was unacceptably high. Human observer data was within acceptable bounds of variability (CV, 19%). The estimated population size in central and north-eastern Tasmania for 2019 approximated 53,000 deer. Deer were primarily congregated within 200 metres of the interface between canopy cover and open pasture. Conclusions. The population density estimate provides a baseline for monitoring and managing the Tasmanian deer population. Human observer data was more precise than thermal camera data in this study, but thermal counts could be improved by reducing sources of variability. Implications. Improvements for the collection of thermal imagery are recommended. Future control efforts may be more efficient if they preferentially target habitat edges at this time of year, paired with random or grid-based searches where population density is lower. [ABSTRACT FROM AUTHOR]

Conservation monitoring is paramount for the gathering of information on species and populations in need of conservation actions. However, monitoring of the mountain bongo Tragelaphus eurycerus isaaci, a Critically Endangered antelope endemic to Kenya, has hitherto been limited to surveillance (i.e. focused on persistence of the species in particular areas), thus limiting the information that could be retrieved on the status and trends of these populations. Using a newly developed identification system, we implemented robust design mark–recapture using existing camera-trap records of four wild subpopulations of the bongo. We provide data on sex and age structure and the first estimates of population size in the wild. Males and calves seem to be suffering higher mortality than females, and only two of the four monitored populations include adults of both sexes and calves. The combined size of these two breeding populations is estimated to be 29–50. Our findings confirm the critical situation of the mountain bongo in the wild and highlight the need for conservation actions to reinforce the wild populations for the long-term conservation of this antelope.

Survival 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. [ABSTRACT FROM AUTHOR]

In the last decade, geolocators have been implemented to track birds and have provided insights into the migration patterns of small birds not previously available. These devices have been assumed to have minimal impact on survival, although formal survival analyses are often not conducted when geolocators are used. We deployed geolocators on 29 Cliff Swallows (Petrochelidon pyrrhonota) and compared their survival rates over 2 subsequent seasons to 95 birds caught at the same time and site but that had standard aluminum bands only. We recovered 1 geolocator with usable data. The migratory track for this bird indicated stopover behavior, more rapid movement in spring than in fall, and significant over-water travel during spring migration. We found that birds with geolocators had an annual survival probability of 0.07, compared to 0.60 for birds without geolocators. Although this result should be interpreted with caution due to small sample sizes, it suggests that geolocators may affect survival of small aerial insectivore species. Geolocators provide invaluable information on migratory routes of birds, but the effects of geolocators on survival should be further studied. [ABSTRACT FROM AUTHOR]

Conservation decisions are often based on population models that rely on underlying assumptions made about species' demographic parameters. The Rio Grande Cooter (Pseudemys gorzugi) is a conservation-dependent riverine turtle, but our understanding of its population dynamics has been limited due to the absence of long-term surveys. We used mark-recapture data collected between 2016 and 2022 from the Black River, New Mexico, USA, to evaluate P. gorzugi somatic growth parameters. Females reached larger maximum size than males but exhibited a slower growth rate. We observed only a slight difference in maximum length and Brody growth coefficient of turtles from different locations, but the growth coefficients were overall significantly lower than any other Pseudemys species. Turtles on the Black River represent the northernmost robust population of P. gorzugi. In light of the intense human use of the river and riparian areas coupled with the impacts of climate change, it is imperative to maintain commitment to conservation efforts to resist population declines given the slow somatic growth rate of the population. [ABSTRACT FROM AUTHOR]

Objective: Many mark–recapture models assume that releases and recaptures are discrete events, and researchers often aggregate continuous recapture data (e.g., passive integrated transponder [PIT] detections) into coarse temporal scales to satisfy this assumption. This temporal discretization could result in parameter biases by ignoring the individual heterogeneity in the time susceptible to mortality after recapture and the conditions experienced (e.g., temperature and predation risk) before and after recapture. Our objectives were to (1) estimate the amount of bias in survival and emigration rates due to different temporal discretization durations when recapture events occur continuously and (2) apply this semicontinuous model to estimate rates of early emigration and overwinter survival for Coho Salmon Oncorhynchus kisutch in a coastal California watershed. Methods: We developed a semicontinuous time multistate mark–recapture model to separately estimated emigration and survival rates throughout the year. We used weekly time‐varying occasions paired with discrete spatial states and conducted extensive simulation trials to explore potential model bias. We then applied the model to an existing 4‐year dataset of Coho Salmon PIT tag detections. Result: Our simulations indicated that that the amount of bias in survival and movement rates decreased as the temporal discretization duration decreased. The confidence interval of the bias estimates included zero with a duration of 8 days, indicating that this duration was sufficiently short to model movement and survival. Results from our Coho Salmon analysis suggest that overwinter survival rate ranged from 0.72 to 0.83, which is higher than previous estimates for Coho Salmon in this region. We estimate that a substantial proportion of smaller juveniles (0.21–0.28 annually) move to downstream nonnatal rearing habitats before the spring smolt migration. Conclusion: Our semicontinuous modeling approach can be implemented relatively easily and used to analyze continuous detection data to accurately estimate survival and movement rates. Our analysis of Coho Salmon PIT tag detections implies that previous low estimates of apparent overwinter survival of Coho Salmon were partially due to high movement rates to alternative rearing locations. This contrasts with conclusions from the previous research that suggested that overwinter survival was a major limiting factor for population recovery and implies that species recovery may be improved by considering multiple emigration patterns in the design of future research, monitoring, and restoration projects. Impact statementGrouping continuous mark–recapture data into single recapture events (e.g., monthly or seasonal) can bias estimates of survival and movement rates from mark–recapture models. [ABSTRACT FROM AUTHOR]

Intraspecific variation in vertebrate eye size is well known. Ecological factors such as light availability are often correlated with shifts in relative eye size. However, experimental tests of selection on eye size are lacking. Trinidadian killifish (Anablepsoides hartii) are found in sites that differ in predation intensity. Sites that lack predators are characterized by lower light, high killifish densities, low resource availability, and intense competition for food. We previously found that killifish in sites that lack predators have evolved a larger "relative" eye size (eye size corrected for body size) than fish from sites with predators. Here, we used transplant experiments to test how selection operates on eye size when fish that are adapted to sites with predators are translocated into sites where predators are absent. We observed a significant "population × relative eye size" interaction; the relationship between relative eye size and a proxy for fitness (rates of individual growth) was positive in the transplanted fish. The trend was the opposite for resident fish. Such results provide experimental support that larger eyes enhance fitness and are favoured in environments characterized by low light and high competition. Graphical Abstract [ABSTRACT FROM AUTHOR]

Accurate abundance estimates are essential for the development of effective conservation management strategies, yet they are difficult to produce for small populations that are elusive and sparsely distributed throughout their range. For such populations it is challenging to collect a representative dataset sufficient for robust estimation of detectability and abundance. Over a one‐year study, we used two methods to estimate abundance of a Nationally Critical, widely dispersed Bryde's whale population in the Hauraki Gulf, Aotearoa/New Zealand; (i) distance sampling from systematic line‐transect aerial surveys (n = 22 surveys, 9,944 km, total sightings 21–24 whales), and (ii) mark‐recapture (MR) using photo‐identification images collected from a platform‐of‐opportunity and small‐boat surveys (218 sampling occasions, 27 whales). From the aerial surveys, we estimated an average of 15 whales (95% CI = 6, 30; CV = 37%) at the sea‐surface at any time. For the boat‐based surveys, we developed a custom MR model to address seasonal and individual heterogeneity in capture probabilities and obtained an estimate of 72 distinct whales (95% CI = 38, 106; CV = 24%) in the population. These two approaches provide different perspectives on the abundance and dynamics of Bryde's whales. The aerial surveys estimate the average number of individuals present at any one time, whereas the MR model estimates the total number of animals that used the Gulf during the study. Although neither sampling method is optimal for estimating the abundance of this small, dispersed population, the use of two complementary approaches informs conservation managers about patterns of abundance and distribution over different temporal and spatial scales. It is common to have limited resources for marine research where model assumptions cannot be met. Here, we highlight pragmatic strategies showing how models can be customized to the population of interest to assist with monitoring species of conservation concern. [ABSTRACT FROM AUTHOR]

Objective: Obtaining demographic rates often requires complex open‐population capture–mark–recapture (CMR) study designs. Conducting such studies for small‐bodied fishes has been limited in part by excessive mortality after tagging procedures and poor tag retention. As new tag types emerge, information regarding fish survival and tag retention over varying time scales may benefit resource managers to effectively plan future CMR studies. The p‐Chip microtransponder is a 500‐ × 500‐ × 100‐μm tag that is inserted subcutaneously and is read with a handheld laser. Each tag contains a nine‐digit unique identification number. P‐Chip microtransponder tags have been used on a limited number of small‐bodied fishes, with relatively high rates observed for fish survival and tag retention. Information on posttagging survival and retention of p‐Chip microtransponder tags across a range of small‐bodied fish species and tagging locations is needed to inform their effectiveness in future CMR studies. Methods: We quantified survival and tag retention after p‐Chip microtransponder implantation in Creek Chub Semotilus atromaculatus and Northern Pearl Dace Margariscus nachtriebi in a laboratory environment, and retention of p‐Chip microtransponder tags in Northern Pearl Dace was also quantified over a year‐long field study. We marked 56 Creek Chub and 9 Northern Pearl Dace in the laboratory with p‐Chip microtransponder tags and compared them to an equal number of unmarked individuals over 90 days. We marked 1990 Northern Pearl Dace and conducted recapture events through four seasons (June, September, and October 2022 and June 2023) in four headwater streams of Nebraska. Result: Survival for Creek Chub was 85% (standard error [SE] = 5.9) and did not differ from control fish survival (95%; SE = 3.2) in the 90‐day laboratory experiment. Survival for Northern Pearl Dace was 89% (SE = 11.0) and did not differ from that of control fish (100%) in the laboratory experiment. Tag retention was 89% (SE = 4.6) for Creek Chub and 100% for Northern Pearl Dace in the laboratory. The p‐Chip microtransponder performed well during the CMR field study, with tag retention for Northern Pearl Dace at 94% across 374 days. Conclusion: Our results suggest that the p‐Chip microtransponder minimally affected small‐bodied fish survival and had high tag retention in both the laboratory and field studies. Thus, the p‐Chip microtransponder tag may be appropriate for use in small‐bodied fishes when individual identification is needed in a CMR study. Impact StatementP‐Chip microtransponder tags in small‐bodied fish show minimal effects on fish survival and high retention rates; therefore, these tags could be used for study designs that require individual capture and recapture data. [ABSTRACT FROM AUTHOR]

With ongoing insect declines, species expanding in distribution and abundance deserve attention, as understanding their success may help design conservation strategies for less successful species. Common causes of these successes include warmer climates, novel resources, and exploiting land use change, including land abandonment. These factors affect the nymphalid butterfly Neptis rivularis, developing on Spiraea spp. shrubs and reaching the north-western limits of its trans-Palearctic distribution in Central Europe. We combined mark-recapture, behaviour analysis, and distribution modelling to study N. rivularis in wetlands of the Třeboňsko Protected Landscape (IUCN category V). The long-living adults (up to 4 weeks) spent a considerable amount of time searching for partners, ovipositing and nectaring at Spiraea shrubs, alternating this with stays in tree crowns, where they located cool shelters, spent nights, and presumably fed on honeydew. They formed high-density populations (310 adults/ha), exploiting high host plant abundance. They adhered to floodplains and to conditions of relatively mild winters. The ongoing Spiraea encroachment of abandoned alluvial grasslands is, thus, a transient situation, ultimately followed by forest encroachment. Rewilding the habitats by introducing native ungulates presents an opportunity to restore the disturbance regime of the sites. The increased resource supply combined with a warming climate has opened up temperate Europe to colonization by N. rivularis. [ABSTRACT FROM AUTHOR]

Introduction: Recent minimum population estimates are critical for effective marine mammal conservation, yet such estimates are often lacking at the stock or management level. Throughout the Main Hawaiian Islands, pantropical spotted dolphins (PSD; Stenella attenuata attenuata) are comprised of a pelagic and three island-associated stocks (O‘ahu, 4-Islands, and Hawai‘i Island). The insular stocks, in particular, face multiple anthropogenic and natural threats such as vessel impacts, fisheries interactions, marine debris, climate change, and disease. Prior to this study, no abundance estimates of the 4-Islands (i.e., the Maui Nui region) PSD stock existed that were suitable for management use and inclusion in stock assessment report calculations. Methods: We generated annual mark-recapture abundance estimates of naturally marked adults in a POPAN-framework using photo-identification data collected from small-boat surveys during 2014–2022 in the Maui Nui region. We extrapolated these estimates to the wider population using dorsal fin mark rates. Results and discussion: We collected data on 62 groups of PSD, throughout all months of the year, and with an average group size of 55.70 (SD = 17.31). We analyzed encounter histories of 174 distinct individuals. Annual recapture rate averaged 1.84 (SD = 1.32) with a maximum of 7. Individuals detected per year averaged 35.67 (SD = 21.16) with a maximum of 77 in 2017. Overall mark rate was 0.495 (SE = 0.010), resulting in total annual abundance estimates that averaged 154.87 (SE = 14.25) and ranged from 105 (SE = 13) in 2014 to 232 (SE = 31) in 2017. Although abundance estimates fluctuated, generally 250 animals or less used the study area each year and we found no overall evidence of a trend. Our benchmark results revealed a small population in need of monitoring given the numerous threats facing this stock, the uncertainty of their impacts, and the decreased resiliency and recovery potential of small populations to negative demographic and environmental stochastic events. Our findings, including documenting long-term site fidelity and year-round presence of PSD in Maui Nui, further signify this area as one of future research and conservation importance. [ABSTRACT FROM AUTHOR]

Conservation monitoring is paramount for the gathering of information on species and populations in need of conservation actions. However, monitoring of the mountain bongo Tragelaphus eurycerus isaaci , a Critically Endangered antelope endemic to Kenya, has hitherto been limited to surveillance (i.e. focused on persistence of the species in particular areas), thus limiting the information that could be retrieved on the status and trends of these populations. Using a newly developed identification system, we implemented robust design mark–recapture using existing camera-trap records of four wild subpopulations of the bongo. We provide data on sex and age structure and the first estimates of population size in the wild. Males and calves seem to be suffering higher mortality than females, and only two of the four monitored populations include adults of both sexes and calves. The combined size of these two breeding populations is estimated to be 29–50. Our findings confirm the critical situation of the mountain bongo in the wild and highlight the need for conservation actions to reinforce the wild populations for the long-term conservation of this antelope. [ABSTRACT FROM AUTHOR]

Globally, hundreds of mammal species face the threat of extinction in the coming decades, and in many cases, their ecology remains poorly understood. Fundamental ecological knowledge is crucial for effective conservation management of these species, but it is particularly lacking for small, cryptic mammals. The Julia Creek dunnart (Sminthopsis douglasi), a threatened, cryptic carnivorous marsupial that occurs in scattered populations in the central west of Queensland, Australia, was once so poorly studied that it was believed extinct. Sporadic research since its rediscovery in the early 1990s has revealed that S. douglasi is distributed across land at risk from many threats. Fundamental knowledge of S. douglasi population density is urgently required to inform conservation management at key sites, yet the species has historically proven hard to detect. Indeed, the status of the largest known population of S. douglasi, in Bladensburg National Park, is unknown. Here, we conducted a population study on S. douglasi at two sites within Bladensburg National Park via live mark–recapture surveys during 2022 and 2023. From likelihood‐based spatially explicit capture–recapture (SECR) modelling we provide the first estimates of density and population size for S. douglasi. Live trapping resulted in captures of 49 individual S. douglasi (with 83 captures total, including recaptures). We estimated S. douglasi to occur at a density of 0.38 individuals ha−1 (0.25–0.58) at one site and 0.16 individuals ha−1 (0.09–0.27) at another site, with an estimated mean population size in suitable habitat at Bladensburg National Park of 1211 individuals (776–1646). Our S. douglasi density estimates were similar to that reported for other threatened small mammals in Australia. We also found evidence of extreme S. douglasi population fluctuations over time at Bladensburg National Park, which is of concern for its future conservation. Our study has provided the first estimate of density for S. douglasi, a threatened dasyurid species from the Mitchell Grass Downs of central western Queensland, Australia. Our research provides crucial population data to assist the management of this poorly studied species. We demonstrate a method that can be applied to species with low detection probability to ultimately help address the mammal extinction crisis faced by Australia and the rest of the world. [ABSTRACT FROM AUTHOR]

The hangul Cervus hanglu hanglu, a Critically Endangered mountain ungulate of Jammu and Kashmir, India, faces the imminent threat of population loss and extinction. Effective management of its largest viable population in Dachigam National Park in the Kashmir Himalaya requires reliable demographic information. Using 14 microsatellite markers we identified 293 individuals (208 females and 85 males) through faecal analysis, and generated data on the genetic status and population size of the hangul in its winter habitat. The mean expected and observed heterozygosities of 0.62 and 0.59 are comparable to those of several red deer Cervus elaphus populations elsewhere. The effective population sizes were 46.3 and 93.7 when the frequencies of rare alleles were considered to be 0.050 and 0.010, respectively. The average mean kinship of the population was 0.34, and there was no evidence of a recent bottleneck event. In genetic mark–recapture analysis the best model included an effect of sex on both detection and recapture probabilities. Detection of males was highest in November, coinciding with the hangul breeding season, whereas detection of females was highest in December. Our estimate of the hangul population using genetic mark–recapture with bootstrapping was 394 individuals. To our knowledge, this is the first study to use genetic data to estimate the population of the hangul. It will guide future studies of this subspecies and also serve as an impetus for identifying founder animals for captive breeding, and for connecting the population in Dachigam National Park with the other small, isolated populations to ensure the long-term survival of this subspecies.

Many freshwater turtles in the United States are considered species of greatest conservation need in the states in which they occur, including turtles in the genus Graptemys (map turtles and sawbacks). However, basic life-history information is still lacking for many Graptemys species, particularly details about their movements, home range, and habitat use. The objective of this study was to describe linear activity area (LAA) and basking-site fidelity for 2 federally threatened Graptemys species in Mississippi (Graptemysflavimaculata, Graptemys oculifera) via capture–mark–recapture events. For G. flavimaculata, 97 individuals (30 female, 67 male) were recaptured during the study at 3 sites. Mean LAA for females (138 ± 293 m; 0–1489 m) and males (308 ± 637 m; 0–3773 m) was statistically similar, but turtle LAAs from 2 upstream sites were longer than LAAs from a downstream site. The maximum single movement was 2877 m by a male; alternatively, many males and females were recaptured at the same basking log across multiple years. For G. oculifera, 28 individuals (14 female, 14 male) were recaptured during the study at 1 site and mean LAAs were statistically similar for females (130 ± 206 m; 4.6–747 m) and males (231 ± 357 m; 0–1310 m). Differences in LAAs among sites for G.flavimaculata may be associated with habitat differences observed among the sites (i.e., river size, hydrology, position on river continuum) or associated with different turtle densities. Basking-site fidelity appears to be strong in both species and is likely driven by deadwood persistence time and/or sexually divergent preferences in basking sites. Additional movement ecology studies are needed for Graptemys species to determine how differences in habitat, turtle densities, and deadwood interact to influence linear home ranges. [ABSTRACT FROM AUTHOR]

Synchronous variation in demographic parameters across species increases the risk of simultaneous local extinction, which lowers the probability of subsequent recolonization. Synchrony therefore tends to destabilize meta‐populations and meta‐communities. Quantifying interspecific synchrony in demographic parameters, like abundance, survival, or reproduction, is thus a way to indirectly assess the stability of meta‐populations and meta‐communities. Moreover, it is particularly informative to identify environmental drivers of interspecific synchrony because those drivers are important across species. Using a Bayesian hierarchical multisite multispecies mark–recapture model, we investigated temporal interspecific synchrony in annual adult apparent survival for 16 common songbird species across France for the period 2001–2016. Annual adult survival was largely synchronous among species (73%, 95% credible interval [47%–94%] of the variation among years was common to all species), despite species differing in ecological niche and life history. This result was robust to different model formulations, uneven species sample sizes, and removing the long‐term trend in survival. Synchrony was also shared across migratory strategies, which suggests that environmental forcing during the 4‐month temperate breeding season has a large‐scale, interspecific impact on songbird survival. However, the strong interspecific synchrony was not easily explained by a set of candidate weather variables we defined a priori. Spring weather variables explained only 1.4% [0.01%–5.5%] of synchrony, while the contribution of large‐scale winter weather indices may have been stronger but uncertain, accounting for 12% [0.3%–37%] of synchrony. Future research could jointly model interspecific variation and covariation in breeding success, age‐dependent survival, and age‐dependent dispersal to understand when interspecific synchrony in abundance emerges and destabilizes meta‐communities. [ABSTRACT FROM AUTHOR]

Objective: The common whelk Buccinum undatum is of great commercial and ecological importance, but little information is known regarding the gear selectivity of the fishery. Understanding gear selectivity is key for the long‐term sustainability of a stock and has applications in stock assessments and fishery management. Methods: We investigated the effect of gear (pots) on the selectivity of catch within the common whelk commercial fishery through a mark–recapture study and comparative gear trials across Wales. The size composition of the population in the water was estimated by dividing the numbers at size brought onboard by the selectivity of the pots. The selectivity of experimental pots (commercial pots that were modified to catch a wider size range) was estimated by comparing the size composition of whelks caught in the experimental gear to the estimated size composition of the population. Result: Peak selectivity of commercial pots occurred around the current minimum landing size (65 mm total shell length) for common whelks, with selectivity sloping off gradually for larger individuals and rapidly for undersized individuals. Across regions, less than 30% of the catch from baited lay‐down pots was discarded. Experimental pots were found to have a more variable but generally dome‐shaped selectivity curve similar to that of the commercial pots. Conclusion: The fishery appears to be well designed, with gear successfully targeting the legal‐sized catch, which is promising for the conservation of the stock if discards have a high survival rate. Experimental gear is ideal for stock assessment purposes, and methods developed to estimate the selectivity of the experimental pots reduce the need for further intensive mark–recapture studies as fishing gear evolves over time. Impact statementThe common whelk is regarded as a data‐poor stock; other than total landings, little information is currently known about the fishery. This study used mark–recapture surveys and comparative gear trials to estimate the selectivity of whelk pots and to determine the composition of whelks in the population. Our findings will facilitate the ongoing development of management strategies for this commercially important species. [ABSTRACT FROM AUTHOR]

Conservation reintroductions play a vital role in the recovery of threatened species, and clear goals and objectives are essential for evaluating their effectiveness. In this study, we assessed short‐term success (<18 months) of trial reintroductions of the Extinct in the Wild blue‐tailed skink (Cryptoblepharus egeriae) and Lister's gecko (Lepidodactylus listeri) on Christmas Island. Our evaluation criteria focused on body condition, reproduction, habitat suitability, survival and population growth. In 2018 and 2019, 170 C. egeriae and 160 L. listeri were translocated from a local captive breeding facility to a 2600 m2 outdoor fenced enclosure designed to exclude a predatory snake. Despite body condition declining immediately following release for both species, it had improved by 6 months post‐release. We also detected successful reproduction in both species. Apparent survival was high for C. egeriae but low for L. listeri, and population growth was only evident in C. egeriae. We were unable to determine whether low survival of L. listeri in the release site was due to high post‐release dispersal (beyond the exclosure) or mortality. Both species selected habitats that contained high rock and log cover and avoided areas with low ground cover. Appropriate assessment criteria, as utilized in this study, enable objective and timely evaluations of reintroduction success, thereby facilitating the improvement and refinement of reintroduction protocols. Our study showed that C. egeriae can establish (in the short‐ to medium‐term) in a site from which a principal threat has been excluded and undergo rapid population growth, whereas under current conditions L. listeri cannot. However, we also demonstrate that such medium‐term success may not lead to long‐term success, as the rapid increase in C. egeriae population was reversed between 29 and 31 months after release because the barrier used to exclude an invasive predator, the wolf snake (Lycodon capucinus), was breached. [ABSTRACT FROM AUTHOR]

Spatial models enable understanding potential redistribution of marine resources associated with ecosystem drivers and climate change. Stock assessment platforms can incorporate spatial processes, but have not been widely implemented or simulation tested. To address this research gap, an international simulation experiment was organized. The study design was blinded to replicate uncertainty similar to a real‐world stock assessment process, and a data‐conditioned, high‐resolution operating model (OM) was used to emulate the spatial dynamics and data for Indian Ocean yellowfin tuna (Thunnus albacares). Six analyst groups developed both single‐region and spatial stock assessment models using an assessment platform of their choice, and then applied each model to the simulated data. Results indicated that across all spatial structures and platforms, assessments were able to adequately recreate the population trends from the OM. Additionally, spatial models were able to estimate regional population trends that generally reflected the true dynamics from the OM, particularly for the regions with higher biomass and fishing pressure. However, a consistent population biomass scaling pattern emerged, where spatial models estimated higher population scale than single‐region models within a given assessment platform. Balancing parsimony and complexity trade‐offs were difficult, but adequate complexity in spatial parametrizations (e.g., allowing time‐ and age‐variation in movement and appropriate tag mixing periods) was critical to model performance. We recommend expanded use of high‐resolution OMs and blinded studies, given their ability to portray realistic performance of assessment models. Moreover, increased support for international simulation experiments is warranted to facilitate dissemination of methodology across organizations. [ABSTRACT FROM AUTHOR]

The hangul Cervus hanglu hanglu , a Critically Endangered mountain ungulate of Jammu and Kashmir, India, faces the imminent threat of population loss and extinction. Effective management of its largest viable population in Dachigam National Park in the Kashmir Himalaya requires reliable demographic information. Using 14 microsatellite markers we identified 293 individuals (208 females and 85 males) through faecal analysis, and generated data on the genetic status and population size of the hangul in its winter habitat. The mean expected and observed heterozygosities of 0.62 and 0.59 are comparable to those of several red deer Cervus elaphus populations elsewhere. The effective population sizes were 46.3 and 93.7 when the frequencies of rare alleles were considered to be 0.050 and 0.010, respectively. The average mean kinship of the population was 0.34, and there was no evidence of a recent bottleneck event. In genetic mark–recapture analysis the best model included an effect of sex on both detection and recapture probabilities. Detection of males was highest in November, coinciding with the hangul breeding season, whereas detection of females was highest in December. Our estimate of the hangul population using genetic mark–recapture with bootstrapping was 394 individuals. To our knowledge, this is the first study to use genetic data to estimate the population of the hangul. It will guide future studies of this subspecies and also serve as an impetus for identifying founder animals for captive breeding, and for connecting the population in Dachigam National Park with the other small, isolated populations to ensure the long-term survival of this subspecies. [ABSTRACT FROM AUTHOR]

Philopatric kin-based societies encourage a narrow breadth of conservative behaviours owing to individuals primarily learning from close kin, promoting behavioural homogeneity. However, weaker social ties beyond kin, and across a behaviourally diverse social landscape, could be sufficient to induce variation and a greater ecological niche breadth. We investigated a network of 457 photo-identified killer whales from Norway (548 encounters in 2008–2021) with diet data available (46 mixed-diet individuals feeding on both fish and mammals, and 411 exclusive fish-eaters) to quantify patterns of association within and between diet groups, and to identify underlying correlates. We genotyped a subset of 106 whales to assess patterns of genetic differentiation. Our results suggested kinship as main driver of social bonds within and among cohesive social units, while diet was most likely a consequence reflective of cultural diffusion, rather than a driver. Flexible associations within and between ecologically diverse social units led to a highly connected network, reducing social and genetic differentiation between diet groups. Our study points to a role of social connectivity, in combination with individual behavioural variation, in influencing population ecology in killer whales. [ABSTRACT FROM AUTHOR]

Population estimates are required for effective conservation of many rare marine species, but can be difficult to obtain. The critically endangered red handfish (Thymichthys politus) is a coastal anglerfish known only from two fragmented populations in southeast Tasmania, Australia. It is at a high risk of extinction due to low numbers, loss of habitat, and the impacts of climate change. To aid conservation efforts, we provide the first empirical population size estimates of red handfish and investigate other important aspects of the species' life history, such as growth, habitat association, and movement. We surveyed both red handfish local populations via underwater visual census on scuba over 3 years and used photographic mark‐recapture techniques to estimate biological parameters. In 2020, the local adult population size was estimated to be 94 (95% confidence interval [CI] 40–231) adults at one site, and 7 (95% CI 5–10) at the other site, suggesting an estimated global population of 101 adults. Movement of individuals was extremely limited at 48.5 m (± 77.7 S.D.) per year. We also found evidence of declining fish density, a declining proportion of juveniles, and increasing average fish size during the study. These results provide a serious warning that red handfish are likely sliding toward extinction, and highlight the urgent need to expand efforts for ex situ captive breeding to bolster numbers in the wild and maintain captive insurance populations, and to protect vital habitat to safeguard the species' ongoing survival in the wild. [ABSTRACT FROM AUTHOR]

Molt is an essential life-history event in birds and many mammals, as maintenance of feathers and fur is critical for survival. Despite this molt remains an understudied life-history event. Non-standard statistical techniques are required to estimate the phenology of molt from observations of plumage or pelage state, and existing molt phenology models have strict sampling requirements that can be difficult to meet under real-world conditions. We present an extended modelling framework that can accommodate features of real-world molt datasets, such as re-encounters of individuals, misclassified molt states, and/or molt state-dependent sampling bias. We demonstrate that such features can lead to biased inferences when using existing molt phenology models, and show that our model extensions can improve inferences about molt phenology under a wide range of sampling conditions. We hope that our novel modelling framework removes barriers for modelling molt phenology data from real-world datasets and thereby further facilitates the uptake of appropriate statistical methods for such data. Although we focus on molt, the modelling framework is applicable to other phenological processes that can be recorded using either ordered categories or approximately linear progress scores. [ABSTRACT FROM AUTHOR]

Fish that undertake juvenile migration pass through habitats that vary in mortality risk. The ability to identify regions of persistently low survival would improve fishery management. We conducted a field study combined with predictive modeling of survival in downstream migrating juvenile sea lamprey using a new micro-acoustic telemetry tag designed for implantation into small, slender-bodied fishes. Detection data were collected from eight receivers placed across a coastal riverine–wetland–lake complex. Juvenile sea lamprey initiated downstream movement near nautical twilight, stopped frequently, and were more likely to move during high river discharge. Estimated survival was highest in the riverine reach, declined through the river–wetland complex, and dropped precipitously in the drowned rivermouth lake. However, the high transmission rate and resulting short battery life of the microtransmitters (as configured) likely resulted in missed detections in the lower reaches. Simulation analyses suggested survival estimation could be improved by increasing the number of tagged lamprey and staggering release locations. We offer practical recommendations for the use of this new transmitter in field studies with small anguilliform fish. [ABSTRACT FROM AUTHOR]

We present the first estimate of population dynamics parameters for critically endangered Galápagos pink land iguanas, Conolophus marthae, leveraging mark‐recapture data collected between 2006 and 2021. Demographic parameters were estimated using the POPAN formulation of the Jolly–Seber model. This approach provided a solid and robust estimate, consolidating the results obtained from previous estimates based on the Lincoln–Petersen method evaluating only two sampling occasions. Our results suggest that the abundance of males was higher than that of females at each sampling occasion, probably due to differences in sex‐specific behavior during the reproductive season. Our analyses also provide no evidence of a change in population size during the sampling period, estimated at 150–270 adult individuals, while suggesting positive entry rates. Finally, by comparing the biometric features of first‐captured versus recaptured iguanas, we found that the former have more juvenile‐like characteristics (i.e., they are, on average, smaller) than the latter. Although juvenile pink iguanas have rarely been recorded (only four sampled juvenile‐like individuals in over 16 years of field work), our combined results provide the first clear indication that the only known C. marthae population actively recruits new members from younger age classes. Such recruitment may have prevented any measurable population decline in the last 16 years, but it was also not sufficient to clearly increase the population size. These results are of the utmost importance for the conservation of this species. They will guide future high‐priority actions: (i) aiming at increasing population size by removing or mitigating threats and (ii) increasing the number of individuals by implementing a headstart program and/or founding a second viable population, as identified in the recently published IUCN Conservation and Management Plan. [ABSTRACT FROM AUTHOR]

Abstract Survival 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.

Abstract Globally, hundreds of mammal species face the threat of extinction in the coming decades, and in many cases, their ecology remains poorly understood. Fundamental ecological knowledge is crucial for effective conservation management of these species, but it is particularly lacking for small, cryptic mammals. The Julia Creek dunnart (Sminthopsis douglasi), a threatened, cryptic carnivorous marsupial that occurs in scattered populations in the central west of Queensland, Australia, was once so poorly studied that it was believed extinct. Sporadic research since its rediscovery in the early 1990s has revealed that S. douglasi is distributed across land at risk from many threats. Fundamental knowledge of S. douglasi population density is urgently required to inform conservation management at key sites, yet the species has historically proven hard to detect. Indeed, the status of the largest known population of S. douglasi, in Bladensburg National Park, is unknown. Here, we conducted a population study on S. douglasi at two sites within Bladensburg National Park via live mark–recapture surveys during 2022 and 2023. From likelihood‐based spatially explicit capture–recapture (SECR) modelling we provide the first estimates of density and population size for S. douglasi. Live trapping resulted in captures of 49 individual S. douglasi (with 83 captures total, including recaptures). We estimated S. douglasi to occur at a density of 0.38 individuals ha−1 (0.25–0.58) at one site and 0.16 individuals ha−1 (0.09–0.27) at another site, with an estimated mean population size in suitable habitat at Bladensburg National Park of 1211 individuals (776–1646). Our S. douglasi density estimates were similar to that reported for other threatened small mammals in Australia. We also found evidence of extreme S. douglasi population fluctuations over time at Bladensburg National Park, which is of concern for its future conservation. Our study has provided the first estimate of density for S. douglasi, a threatened dasyurid species from the Mitchell Grass Downs of central western Queensland, Australia. Our research provides crucial population data to assist the management of this poorly studied species. We demonstrate a method that can be applied to species with low detection probability to ultimately help address the mammal extinction crisis faced by Australia and the rest of the world.

IntroductionRecent minimum population estimates are critical for effective marine mammal conservation, yet such estimates are often lacking at the stock or management level. Throughout the Main Hawaiian Islands, pantropical spotted dolphins (PSD; Stenella attenuata attenuata) are comprised of a pelagic and three island-associated stocks (O‘ahu, 4-Islands, and Hawai‘i Island). The insular stocks, in particular, face multiple anthropogenic and natural threats such as vessel impacts, fisheries interactions, marine debris, climate change, and disease. Prior to this study, no abundance estimates of the 4-Islands (i.e., the Maui Nui region) PSD stock existed that were suitable for management use and inclusion in stock assessment report calculations.MethodsWe generated annual mark-recapture abundance estimates of naturally marked adults in a POPAN-framework using photo-identification data collected from small-boat surveys during 2014–2022 in the Maui Nui region. We extrapolated these estimates to the wider population using dorsal fin mark rates.Results and discussionWe collected data on 62 groups of PSD, throughout all months of the year, and with an average group size of 55.70 (SD = 17.31). We analyzed encounter histories of 174 distinct individuals. Annual recapture rate averaged 1.84 (SD = 1.32) with a maximum of 7. Individuals detected per year averaged 35.67 (SD = 21.16) with a maximum of 77 in 2017. Overall mark rate was 0.495 (SE = 0.010), resulting in total annual abundance estimates that averaged 154.87 (SE = 14.25) and ranged from 105 (SE = 13) in 2014 to 232 (SE = 31) in 2017. Although abundance estimates fluctuated, generally 250 animals or less used the study area each year and we found no overall evidence of a trend. Our benchmark results revealed a small population in need of monitoring given the numerous threats facing this stock, the uncertainty of their impacts, and the decreased resiliency and recovery potential of small populations to negative demographic and environmental stochastic events. Our findings, including documenting long-term site fidelity and year-round presence of PSD in Maui Nui, further signify this area as one of future research and conservation importance.

Abstract Background Anadromy comprises a successful life-cycle adaptation for salmonids, with marine migration providing improved feeding opportunities and thus improved growth. These rewards are balanced against costs from increased energy expenditure and mortality risk. Anthropogenic-induced environmental changes that reduce benefits and/or increase costs of migration e.g., aquaculture and hydropower, may therefore result in adaptations disfavouring anadromy. We tagged brown trout (Salmo trutta) smolts (N = 175) and veteran migrants (N = 342), from five adjacent riverine populations located in Sognefjorden, the longest Norwegian fjord-system supporting anadromous brown trout populations (209 km). Over four years, 138 acoustic telemetry receivers were deployed to track migrations of tagged individuals from freshwater and throughout Sognefjorden. Detected movements were used to fit migration models and multi-state mark-recapture models of survival and movement for each life-stage. Seaward migration distance was modelled to examine the fitness consequences from alternate migration strategies, with these models used to simulate the extent of fjord-use by individuals and accompanying growth, fecundity and survival consequences. We compared these findings with mark-recapture data collected prior to aquaculture and hydropower development. Results The telemetry data revealed that the outermost-fjord region was utilised by all populations albeit by few individuals. However, historical recaptures were located at a greater distance from the river mouth (87.7 ± 70.3 km), when compared to maximum migration distances of present-day counterparts (58.6 ± 54.9 km). River of origin influenced observed migratory behaviour and differential survival was estimated for each population and life-stage. The simulations based on telemetry-data models revealed a 30% and 23% difference in survival among populations for smolts and veteran migrants, respectively. At the individual-level, a long-distance migration strategy was rewarded with enhanced fecundity. However, the main contribution to population-level fecundity was overwhelmingly derived from middle-distance migrants, due to higher mortality rates and limited numbers of long-distant migrants. Conclusions We conclude that present-day anadromy is precarious, but potential risk varies considerably between life-stages and populations, even within a single fjord system. Our findings suggest that selection for extended migration is under pressure, we therefore stress the importance of monitoring and management actions to secure genetic variation pertinent to preserve fitness gains of anadromy.

The abundance of the monarch butterfly (Danaus plexippus) in overwintering habitat has decreased over the past few decades. We investigated how meteorological conditions (temperature and precipitation) and flight speed affect the fall migration of marked and live-resighted Eastern North American monarch butterflies to better understand how climate change may affect their migration. We factorially simulated a range of flight speeds and maximum and minimum temperatures during migration for individual butterflies whose full live capture history was known. Within the allotted dates and time between marking and recapture, we used data from the nearest meteorological stations along the migration route that minimized the distance to recapture locations, to determine the flight speed and maximum and minimum temperature that monarchs use during fall migration. The mean flight speed that optimized the model for individual butterflies was 7.50 ± 5.00 km/h. The thermal conditions best fitting migration ranged from a mean minimum of 7.67 ± 5.42 °C to a mean maximum of 25.2 ± 4.73 °C. The low estimated upper temperature suggests that an increase in temperature due to climate change and an accompanying increase in metabolic demand, may reduce successful fall migration to overwintering sites, overwintering, or remigration the following spring. [ABSTRACT FROM AUTHOR]

Age and growth estimates are essential for life historymodeling in elasmobranchs and are used to informaccurate conservation andmanagement decisions. The nurse shark (Ginglymostoma cirratum) is abundant in coastal waters of the Atlantic Ocean, yet many aspects of their life history remain relatively understudied, aside from their reproductive behavior.We usedmark-recapture data of 91 individual G. cirratum from Bimini, The Bahamas, from 2003 to 2020, to calculate von Bertalanffy (vB) growth parameters, empirical growth rate, and age derived from the resulting length-at-age estimates. The Fabens method for estimating growth from mark-recapture methods was applied through a Bayesian framework using Markov chain Monte Carlo (MCMC) methods. This provided growth parameters with an asymptotic total length (L∞) of 303.28 cm and a growth coefficient (k) of 0.04 yr-1. The average growth rate for G. cirratum was approximately 8.68 ± 6.00 cm yr-1. This study also suggests that the previous maximum age for G. cirratum is likely underestimated, with the oldest individual predicted to be 43 years old. Our study is the first to present vB growth parameters and a growth curve for G. cirratum. It indicates that this species is slowgrowing and long-lived, which improves our understanding of their life history. [ABSTRACT FROM AUTHOR]

Simple Summary: Basic information on the ecology and behaviour of many aquatic insects is lacking because of the absence of studies. Here, we investigated whether demographic aspects such as survival, sex ratio, and population size are different between sexes and individuals of different ages of Teinopodagrion oscillans, a damselfly species endemic to the Andean region, living in a protected area. We also recorded the behaviour of this species and the area frequented by the adults near the water. Survival, recapture, and lifespan (14.1 ± 0.59 days) were similar for both sexes and all age groups. Mature males were larger, while the distance from the water where animals perched was similar for all individuals. Weather variations affected the demography of this population in a significant way. Individuals perch on any available support (≤0.1–12 m high) and show high fidelity to their perch site, with mature males making short flights from the perch to intercept other individuals and to hunt prey. The tandem position was formed on macrophytes, and females lay eggs by submersion of their abdomen. Our results provide crucial information for short- and long-term conservation decisions of the biodiversity in ecosystems of the Andean region. The demography and behaviour of Teinopodagrion oscillans was studied in a protected area in the Andean region of Colombia. Adult damselflies were individually marked, and using their recapture histories, we estimated survival, longevity, sex ratio, and population size using Cormack-Jolly-Seber models. Other aspects of their behaviour were recorded. Survival, recapture, and lifespan (14.1 ± 0.59 days) were similar for both sexes and all age groups. Mature males were larger, and the distance from the water was similar for all individuals. The most supported model was the time-dependent model for survival and recapture. This suggests that weather variations affect the demography of this population in a significant way. Individuals exhibited high fidelity to their site perch, perching with open wings near water on a variety of perches. Mature males make short flights from the perch to intercept conspecific and interspecific males and to hunt prey. The tandem position was formed on macrophytes, and then the pair flew away. Oviposition lasted for 11.23 min on average, with the females ovipositing by abdomen submersion. Our results offer insights into the demographic characteristics and behaviour of this species, providing crucial information for the short- and long-term, from the demography of one species to the conservation of ecosystems of the Andean region. [ABSTRACT FROM AUTHOR]

In an effort to ameliorate the impacts of climate change, forest managers in Central Europe increasingly turn to conifer species that produce higher yields and are better adapted to projected future climatic conditions. Though small mammals are an important component of the forest ecosystem, the impacts of enriching native broadleaf forests with conifers on small mammal communities are not well understood. We conducted mark–recapture surveys of small mammals to ascertain differences in their community structure among stands of two conifers (native Norway spruce Picea abies and non-native Douglas fir Pseudotsuga menziesii) and the dominant broadleaf in the region, European beech (Fagus sylvatica). After estimating the density of two common species, the yellow-necked mouse Apodemus flavicollis and bank vole Clethrionomys glareolus, we found that the population density of each is positively related to the proportion of beech and negatively to the proportion of conifers in each stand, though these effects of stand composition are smaller than the positive effect of herb cover. Increasing Norway spruce proportion reduced monthly survival of small mammals, while Douglas fir proportion had a positive effect on survival. We conclude that the two conifer species have similar impacts on small mammal density, though overall small mammal survival was significantly lower on plots with Norway spruce. This suggests that increasing the proportion of Douglas fir at the expense of Norway spruce may be possible without significantly changing local patterns of small mammal population density, but further research is necessary to elucidate the exact impacts of these two conifer species on small mammal demography and behavior. [ABSTRACT FROM AUTHOR]

Continuous predictors of survival present a challenge in the analysis of data from studies of marked individuals if they vary over time and can only be observed when individuals are captured. Existing methods to study the effects of such variables have followed one of two approaches. The first is to model the joint distribution of the predictor and the observed capture histories, and the second is to draw inference from the likelihood conditional on events that depend only on observed predictor values, called the trinomial model. Previous comparison of these approaches found that joint modelling provided more precise inference about the effect of the covariate while the trinomial model was less prone to issues of model mis‐specification. However, we believe that an important issue was missed. We show through mathematical analysis and numerical simulation that the trinomial model is not identifiable when the predictor has no effect on the survival probability. This also causes inferences from the trinomial model to be imprecise when the effect of the covariate on the survival probability is small. We also analyse data on the effect of body mass on the survival of meadow voles to demonstrate the importance of this issue in real applications. [ABSTRACT FROM AUTHOR]

Introduction: Knowledge on the mobility of threatened species is a clue to understanding population dynamics and is needed to develop appropriate conservation strategies. Here, we investigate movement patterns of the Bei-Bienko's Plump Bush-cricket (Isophya beybienkoi), an example of a flightless and critically endangered species endemic to the Slovak Karst (southern Slovakia, Central Europe). The capture-mark-recapture method was used to estimate the mobility of the species using fluorescent dye as a marking medium. We found that the mean (± SD) daily distance travelled by this species was only 3.2 ± 2.6 m, with significant differences between males (4.1 ± 3.0 m) and females (2.7 ± 2.1 m). Our results indicate that I. beybienkoi is a short-distance disperser. Males disappeared faster than females from the study plots (at maximum, two females were recaptured even after 41 days). The observed movement patterns suggest that the most urgent conservation measure for this species is to improve the habitat quality of sites, which suffer from overgrowth, and to maintain the quality of other suitable sites that might increase the size of the existing subpopulations. Implications for insect conservation: Our results show that I. beybienkoi is a short-distance disperser and wanders only within its optimal habitat. Hence, to incorporate movement behaviour into conservation, one of the measures that should mitigate this threat is to preserve or improve the quality of habitats that suffer from overgrowth, in order to increase the size of existing subpopulations. The observed movement patterns suggest that the species is probably incapable of responding to changes in the availability of suitable habitats by dispersing, indicating a limited exchange of individuals between isolated populations. Thus, to enhance structurally diverse mosaic of high-quality habitats, restoration of migration corridors former used as movement corridors for grazing animals may support the dispersal of the threatened bush-cricket. [ABSTRACT FROM AUTHOR]

Context: Passage efficiency is an important metric for quantifying the success of fish-passage remediation. Mark-recapture methods are typically employed to estimate fish-passage efficiency. Although biotelemetry methods have become a benchmark standard for such studies, they remain unfeasible for many small-bodies species because of the excessive size of electronic tags. Aims: This study compares two commonly deployed marking methods that are potentially suitable for estimating passage efficiency for small-bodied species, namely, visible implant elastomer (VIE) tagging and batch immersion staining with Rhodamine B. Methods: The critical swimming speeds and passage efficiency at a remediated culvert of Galaxias maculatus were compared for VIE-tagged, Rhodamine B-stained and control treatments. Key results Both critical swimming speeds and passage efficiency at the culvert were significantly lower in VIE-tagged Galaxias maculatus than in both control fish and fish stained with Rhodamine B. Conclusions Rhodamine B may be a suitable batch immersion stain for short-term (<4 day), non-destructive mark-recapture studies in small-bodied fishes, but VIE-tagging methods may result in underestimation of passage efficiency. Implications: It is important to evaluate the impact of marking techniques on the outcomes of mark-recapture studies to ensure that estimates of passage efficiency are accurate. Improving fish passage is essential for the recovery of freshwater biodiversity. Mark-recapture methods are often used to measure the effectiveness of efforts to restore river connectivity. This study shows that the method used to mark fish can significantly affect estimates of passage efficiency for a small-bodied fish that is distributed widely in the Southern Hemisphere. [ABSTRACT FROM AUTHOR]

Photographs of Antarctic blue whales were collected as part of the IWC’s SOWER cruises from 1987/88 to 2008/09. Photo‐ID data from 15 cruises were used in a pilot study that conducted capture‐recapture analysis to produce estimates of super‐population abundance for the circumpolar Antarctic from 1992/93 to 2008/09 and for IWC Management Area III from 2004/05 to 2006/07. The circumpolar estimates are 3,178 (95% CI 534 to 24,239) Antarctic blue whales (left‐side photographs) and 1,109 (95% CI 451 to 3,215) (right‐side photographs) for the years 1991/92 to 2008/09. Estimates of super‐population abundance for Area III are 1,318 (95% CI 515 to 3,716) (left‐side photographs) and 939 (95% CI 421 to 2,323) (right‐side photographs). The SOWER photo‐ ID database provides a starting point for improved estimates of population trends in the future as photographs of new individuals and additional recaptures of Antarctic blue whales are obtained. [ABSTRACT FROM AUTHOR]

The impacts of natural disasters on marine mammals are poorly understood and difficult to study, which can hamper management responses following such events.This study provides the first distribution and abundance assessment of New Zealand fur seal (NZFS: Arctocephalus forsteri) colonies around Kaikōura, New Zealand, since a 7.8 magnitude earthquake in November 2016 caused substantial changes to both the local marine and terrestrial environments, and led to the reconstruction of a major highway that runs adjacent to NZFS colonies.Mark–recapture and direct counts in the 2022–2023 breeding season estimated pup production for NZFS breeding colonies along the Kaikōura coast. Using established multipliers, pup estimates were used to provide the first comprehensive population estimate for Kaikōura's NZFS population since the earthquake.Three new colonies and three new subcolonies were assessed and recorded, additional to reassessments of two established colonies. Overall, Kaikōura's NZFS population has grown and spread post‐earthquake, with an upper total population estimate of between 21,560 and 28,327 animals in the 2022–2023 breeding season. Some sites, such as Lynch's Reef, appear to have benefited from earthquake‐induced coastal uplift, with pup production increasing. Contrastingly, the estimated 2,401 (±99) pups produced at Ōhau Point in 2023 is similar to pre‐earthquake estimates. This indicates that the earthquake has disrupted previously documented growth at this site. The distribution of NZFS breeding at Ōhau Point has also changed substantially since the last pre‐earthquake assessment.From these findings, alterations to the Ōhau Point New Zealand Fur Seal Sanctuary and similar protections at other locations on the Kaikōura coast are suggested, as greater numbers of NZFSs are now accessible to human interaction and disturbance. The results demonstrate both how natural disasters and subsequent infrastructure modifications can impact coastal species and how conservation measures may need to be amended accordingly. [ABSTRACT FROM AUTHOR]

AbstractThe Clouded Apollo, Parnassius mnemosyne is a charismatic West Palaearctic butterfly, threatened in some European countries and listed in Appendix IV of the Habitats’ Directive. We investigated a large lowland population of the species inhabiting a complex of irregularly coppiced light forest and adjacent wet meadows in the anthropogenic landscape in the valley of the Narew river in NE Poland. A mark-release-recapture (MRR) method was used over 4 years to estimate population size, adult catchability, daily survival and lifespan. The beginning and length of the flight period (which lasted 4–6 weeks) differed over the years and was clearly related to weather conditions (temperature, sunshine) in April, i.e. the most important period for larval development. The seasonal population size varied from 555 to 942 adults. In contrast to some previous studies, the sex ratio turned out to be well balanced, although the catchability of males was significantly higher than that of females in each year. The quality of the wings deteriorated during the season in both sexes, but it was generally better in the case of females, which indicates that they are less active. Inter-seasonal variation in the lifespan (6.36–12.45 days) is more difficult to interpret, but it is worth noting that individuals lived the longest in the coldest and least sunlit flight period. The temporal fragmentation index (i.e. the ratio of flight-period length to adult lifespan) also varied (3.37–5.97) but was generally relatively low, which suggests that there is no threat of reduction of the effective population size at the moment. Nevertheless, the investigated population may be at risk of decline due to the observed intensification of meadow use and especially the possible conversion of grasslands into cornfields.

Age and growth estimates are essential for life history modeling in elasmobranchs and are used to inform accurate conservation and management decisions. The nurse shark (Ginglymostoma cirratum) is abundant in coastal waters of the Atlantic Ocean, yet many aspects of their life history remain relatively understudied, aside from their reproductive behavior. We used mark-recapture data of 91 individual G. cirratum from Bimini, The Bahamas, from 2003 to 2020, to calculate von Bertalanffy (vB) growth parameters, empirical growth rate, and age derived from the resulting length-at-age estimates. The Fabens method for estimating growth from mark-recapture methods was applied through a Bayesian framework using Markov chain Monte Carlo (MCMC) methods. This provided growth parameters with an asymptotic total length (L∞) of 303.28 cm and a growth coefficient (k) of 0.04 yr-1. The average growth rate for G. cirratum was approximately 8.68 ± 6.00 cm yr-1. This study also suggests that the previous maximum age for G. cirratum is likely underestimated, with the oldest individual predicted to be 43 years old. Our study is the first to present vB growth parameters and a growth curve for G. cirratum. It indicates that this species is slow-growing and long-lived, which improves our understanding of their life history.

When assessing the abundance of small mammals using traditional methods, an abundance index that is the number of individuals per unit of trapping effort is usually applied. Due to the different relationships of species to various traps and baits, the true ratio of species in nature may not coincide with the estimated one. In most cases, the presence of a nonresident component in the population size remains outside the attention of researchers, while dispersal is a key element for many demographic processes. A method is proposed for calculating the density (individuals per area) of resident and nonresident animals when using mark–recapture live-traps arranged in lines. For three mass species of small forest mammals (red-backed vole, common shrew, and masked shrew), the dynamics of the density of the resident and nonresident population were studied over 18 years. In most cases, the red-backed vole dominated in the population of small mammals. According to the average long-term data, the proportion of nonresident individuals in the population of the three species did not differ, averaging 12.6% of the total density. The dependence of the level of nonresident activity in the red-backed vole on the density of resident animals was shown. In shrews, the density of nonresidents did not depend on the density of resident animals. This technique allows for a wide range of ecological problems to be solved, and it can be used to monitor the state and structure of communities of small mammals. [ABSTRACT FROM AUTHOR]

The Clouded Apollo, Parnassius mnemosyne is a charismatic West Palaearctic butterfly, threatened in some European countries and listed in Appendix IV of the Habitats' Directive. We investigated a large lowland population of the species inhabiting a complex of irregularly coppiced light forest and adjacent wet meadows in the anthropogenic landscape in the valley of the Narew river in NE Poland. A mark-release-recapture (MRR) method was used over 4 years to estimate population size, adult catchability, daily survival and lifespan. The beginning and length of the flight period (which lasted 4-6 weeks) differed over the years and was clearly related to weather conditions (temperature, sunshine) in April, i.e. the most important period for larval development. The seasonal population size varied from 555 to 942 adults. In contrast to some previous studies, the sex ratio turned out to be well balanced, although the catchability of males was significantly higher than that of females in each year. The quality of the wings deteriorated during the season in both sexes, but it was generally better in the case of females, which indicates that they are less active. Inter-seasonal variation in the lifespan (6.36-12.45 days) is more difficult to interpret, but it is worth noting that individuals lived the longest in the coldest and least sunlit flight period. The temporal fragmentation index (i.e. the ratio of flight-period length to adult lifespan) also varied (3.37-5.97) but was generally relatively low, which suggests that there is no threat of reduction of the effective population size at the moment. Nevertheless, the investigated population may be at risk of decline due to the observed intensification of meadow use and especially the possible conversion of grasslands into cornfields. [ABSTRACT FROM AUTHOR]

Mark–recapture surveys are commonly used to monitor translocated populations globally. Data gathered are then used to estimate demographic parameters, such as abundance and survival, using Jolly–Seber (JS) models. However, in translocated populations initial population size is known and failure to account for this may bias parameter estimates, which are important for informing conservation decisions during population establishment. Here, we provide methods to account for known initial population size in JS models by incorporating a separate component likelihood for translocated individuals, using a maximum‐likelihood estimation, with models that can be fitted using either R or MATLAB. We use simulated data and a case study of a threatened lizard species with low capture probability to demonstrate that unconstrained JS models may overestimate the size of translocated populations, especially in the early stages of post‐release monitoring. Our approach corrects this bias; we use our simulations to demonstrate that overestimates of population size between 78% and 130% can occur in the unconstrained JS models when the detection probability is below 0.3 compared to 1%–8.9% for our constrained model. Our case study did not show an overestimate; however accounting for the initial population size greatly reduced error in all parameter estimates and prevented boundary estimates. Adopting the corrected JS model for translocations will help managers to obtain more robust estimates of the population sizes of translocated animals, better informing future management including reinforcement decisions, and ultimately improving translocation success. [ABSTRACT FROM AUTHOR]