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The Lesser Flamingo Phoeniconaias minor is a Near Threatened species known to be highly gregarious and that can concentrate in large numbers at core foraging and breeding sites, yet is also known to disperse widely in search of suitable foraging habitat. The density of flamingos at occupied sites, together with frequent dispersal between foraging sites, poses significant challenges to obtaining reliable counts and associated population estimates. Our study tested the use of unmanned aerial vehicles (drones) imagery and high-resolution satellite imagery for producing density estimates of Lesser Flamingos at the only known breeding site in South Africa (Kamfers Dam, Northern Cape Province). We implemented a supervised classification approach using multiple supervised classification algorithms, including xgbTree, randomForest, nnet and GBM. The four supervised classification models performed very well at classifying flamingos from both drone and satellite imagery, with classification accuracies ranging between 0.98 and 0.99. The inclusion of an additional predictor (other than RGB bands) yielded the highest variable importance score and greatly increased model accuracy and predictive performance. Estimates of adult flamingos from drone imagery acquired across nesting mudflats on 5 February (n = 1 320) and 14 February (n = 330) 2019 suggested a 75% decline in incubating adults. Furthermore, a total of 16 134 (15 973–16 295) flamingos were estimated from drone imagery on 1 March 2019, and 17 291 (17 118–17 290) flamingos from satellite imagery on 19 March 2019. The modelled size of the creche across dates suggested a loss of 234 birds (4.5%) during the period of assessment, with the highest count estimating 5 218 juveniles. Our study successfully implemented machine learning classifiers that were able to detect and derive highly accurate counts of Lesser Flamingos from both drone and satellite imagery. This use of machine learning could greatly improve the efficiency of monitoring and associated conservation efforts underway for the Lesser Flamingo. [ABSTRACT FROM AUTHOR]

Background and aim: Fecal incontinence (FI) is defined as the unintended loss of solid or liquid stool. FI adversely affects the patient's quality of life. However, due to stigma, lack of awareness, and underdiagnosis, there is a notable gap in the knowledge regarding its prevalence. This study aimed to conduct a systematic review and meta-analysis of published literature reporting on FI prevalence and estimate the number of people afflicted by FI. Methods: A systematic review was conducted following the PRISMA 2020 guidelines, using the Embase, MEDLINE, CINHAL, and PubMed databases to identify relevant publications in the English language. Two reviewers independently screened the articles and extracted data. The reference sections and content of the review papers were also evaluated. Thirty-two articles were selected and included. A meta-analysis of proportions was performed using RStudio software. A sub-analysis was conducted to account for the variation between sample population age groups to minimize heterogeneity. The pooled prevalence was extrapolated to the Canadian population and a sample of ten densely populated countries to estimate the number of people affected by FI. Results: The Mean pooled FI prevalence in men and women was 7% (95% CI: 6-9%) and 10% (95% CI: 8-12%), respectively. The sub-analysis mean pooled prevalence of FI inmen andwomenwas 8% (95% CI: 6-10%) and 10% (95% CI: 8-12%), respectively. The authors estimate that between 1 and 1.5 million Canadians and 320 to 500 million people in the ten most populous countries suffer from FI. Conclusion: Fecal incontinence is a prevalent underdiagnosed condition requiring appropriate and timely treatment to improve a patient's quality of life. [ABSTRACT FROM AUTHOR]

Florida is a stronghold for the continental U.S. breeding population of Wilson's Plover (Anarhynchus wilsonia), but data gaps exist in areas logistically challenging to survey. We estimated the species distribution and abundance in the Florida Keys by surveying 45 potential nesting areas. We used the independent double-observer method in a subset of the surveyed nesting areas (n = 20) to estimate the species' detection probability and unbiased abundance during the onset of the nesting season (23–26 Apr 2019). We developed 4 models to assess the effects of observer-group and nesting habitat availability on detectability and abundance. The most supported model included a positive effect of habitat availability on the number of breeding pairs and constant detection probability. Using the detection probability from our best models, we estimated 82 breeding Wilson's Plover pairs (95% CI: 74–142) in the surveyed areas. We documented that 18% of the statewide Wilson's Plover breeding population is in the Florida Keys. This critical component of the breeding population is vulnerable to local declines because of limited available habitat and the predicted habitat loss due to climate change. Our methodology is relevant to researchers across the Wilson's Plover breeding range interested in estimating the species' abundance and applies to other shorebird species globally. [ABSTRACT FROM AUTHOR]

Objective: As part of a large‐scale hydroelectric project, the mean annual flow of the Rupert River (northern Quebec, Canada) was reduced by 52% at its mouth in 2009. To protect fish habitat, an ecological flow regime that was modulated according to the biological seasons was implemented downstream from the diversion point. An 8‐year monitoring program, including 2 years before partial diversion, was carried out to verify the effectiveness of this mitigation measure on the total annual abundance of anadromous Coregoninae (Cisco Coregonus artedi and Lake Whitefish C. clupeaformis) larvae, which was used as biological indicator of recruitment success. The monitoring also aimed to determine the effects of flow modification on the timing of the larval drift and the spatial distribution of larvae in a river cross section. Methods: Each year, sampling consisted of installing drift nets during the entire downstream larval migration in a river cross section of the lower Rupert River. Drift nets were systematically placed to ensure representative sampling of the river section. Result: Prior to flow reduction, the estimated total number of larvae varied between 1.8 and 8.6 million. Over the following 6 years, the estimated larval population has remained steady at 3–4 million. Otherwise, larval drift characteristics have not changed since the flow reduction, as (1) the duration of the larval drift is the same as before, about 1 month in May and early June, with a peak period of about 8 days; (2) rise in water temperature in spring is a determining factor in the timing of larval drift; and (3) the larvae drift mainly near the surface of the water. Conclusion: The monitoring results indicate that the ecological flow regime implemented in the Rupert River was adequate to maintain anadromous coregonine populations. Impact statementThe establishment of a ecological flow regime has ensured the successful recruitment of anadromous Cisco and Lake Whitefish populations in the Rupert River (northern Quebec, Canada), the flow of which has been partially diverted for hydroelectric purposes. [ABSTRACT FROM AUTHOR]

Introduction: Seabirds and other insular birds are an important part of marine ecosystems and are increasingly threatened worldwide. Phenology, abundance, distribution, and breeding success are important baseline parameters needed to evaluate population trends and dynamics, identify biodiversity hotspots and potential breeding sites, and assess habitat selection. In the Red Sea basin, reliable and complete data on birds are lacking for islands in most of the Important Bird Areas (IBA). Such data are now especially important since development projects have started at several of these locations. Here, we assess the distribution, abundance, phenology, and population trends of 13 bird species that breed in the Duba Islands, Al Wajh Bank, and Al Lith Islands. Breeding success and habitat selection for six species were also assessed. Methods: Between December 2020 and August 2023, more than 90 islands were visited multiple times with different frequencies. All nests were counted, and the area occupied by the different colonies was georeferenced. Breeding success was assessed by visiting selected colonies multiple times until the chicks were ready to fledge. Habitat selection was determined by analyzing the habitat found in the georeferenced colonies. Results: More than 25,000 nests were counted each year, mainly in the summer, on more than 75 islands. Of the 13 species studied, the most abundant and widespread species was the White-cheeked tern, and the second most widespread was the Osprey. Discussion: We estimate that the Al Wajh Bank hosts the following percentages of global breeding populations: Crab plover: 5%, Sooty gull: 17%-35%, White-eyed gull: 15%, Bridled tern: 1%, White-cheeked tern: 4%, and Lesser crested tern: 2%, making the area a regional and global hotspot for these species. Some of the islands occupied by breeding birds are slated for development for tourismactivities as part of the Kingdom's tourism expansion plans. At the same time, there are several ambitious conservation programs underway in these areas. To be effective, such programs require reliable and comprehensive data of the kind presented here. [ABSTRACT FROM AUTHOR]

Background and aimFecal incontinence (FI) is defined as the unintended loss of solid or liquid stool. FI adversely affects the patient’s quality of life. However, due to stigma, lack of awareness, and underdiagnosis, there is a notable gap in the knowledge regarding its prevalence. This study aimed to conduct a systematic review and meta-analysis of published literature reporting on FI prevalence and estimate the number of people afflicted by FI.MethodsA systematic review was conducted following the PRISMA 2020 guidelines, using the Embase, MEDLINE, CINHAL, and PubMed databases to identify relevant publications in the English language. Two reviewers independently screened the articles and extracted data. The reference sections and content of the review papers were also evaluated. Thirty-two articles were selected and included. A meta-analysis of proportions was performed using RStudio software. A sub-analysis was conducted to account for the variation between sample population age groups to minimize heterogeneity. The pooled prevalence was extrapolated to the Canadian population and a sample of ten densely populated countries to estimate the number of people affected by FI.ResultsThe Mean pooled FI prevalence in men and women was 7% (95% CI: 6-9%) and 10% (95% CI: 8-12%), respectively. The sub-analysis mean pooled prevalence of FI in men and women was 8% (95% CI: 6-10%) and 10% (95% CI: 8-12%), respectively. The authors estimate that between 1 and 1.5 million Canadians and 320 to 500 million people in the ten most populous countries suffer from FI.ConclusionFecal incontinence is a prevalent underdiagnosed condition requiring appropriate and timely treatment to improve a patient’s quality of life.

Reliable estimates of population trends are important for prioritizing and implementing wildlife management actions. Abundance estimates are the most informative metric of population status but are difficult and costly to achieve for rare or elusive species. For bat species that are highly mobile and nocturnal, abundance estimates are usually only possible at their roosts. Although they are relatively easy to census in individual roosts, it is often unclear whether observed trends are representative of broader populations trends. Dual‐frame sampling is useful for monitoring wildlife populations that exhibit site fidelity and are highly visible but where the proportion of the population in known sites is unknown. We adapted a dual‐frame sampling approach to estimate abundance of Townsend's big‐eared bats (Corynorhinus townsendii) hibernating in a system of >800 caves at Lava Beds National Monument (LBNM) in northern California, USA, in 2013–2022. Beginning with a list of opportunistically discovered hibernacula, we expanded inference to the entire system by randomly selecting sites and stratifying survey effort according to number of bats observed during previous counts. Following 4 years of surveys, we began substituting survey‐informed estimates for some site types to improve efficiency of the monitoring effort. We estimated that a mean of 2,216 ± 112 (SE) bats hibernated at the study site annually and observed fluctuations of up to 22% around the mean population estimate and as much as 21% from the previous year. Despite annual fluctuations, we did not detect a trend in the number of hibernating bats at LBNM over the study period, underlining the challenges of detecting population trends in long‐lived species not exposed to pronounced stressors. Because our analytical approach generates reliable estimates of trend while accommodating annual variability in survey effort among years, it should be attractive to wildlife managers faced with shifting priorities and resources. [ABSTRACT FROM AUTHOR]

The UK breeding population estimate comprised 50,750 male Eurasian Woodcocks (95% CI: 42,935–59,251) in Britain and 937 males (95% CI: 274–1714) in Northern Ireland. The British population has continued to decline since 2013. To produce UK, British and regional estimates of breeding population size for Eurasian Woodcocks, and to assess the population change since 2003. The 2023 Breeding Woodcock Survey enlisted volunteer surveyors to count birds across a stratified sample of 1230 squares in England, Scotland, Wales, and Northern Ireland. The established 'roding count' methodology consists of up to three dusk visits, each lasting 75 min, during May and/or June. The results were used to calculate presence and mean density across 48 strata based on wooded area and regions, and extrapolated to produce regional and national estimates of population size. The population in Britain in 2023 was estimated at 50,750 male Woodcocks (95 CI: 42,935–59,251), representing an 8% decline since 2013, and a 35% decline since 2003. Despite small population increases in Wales and England since 2013, the continuing decline was driven by a 49.5% reduction in the population estimate for North Scotland. In 2023, Northern Ireland's breeding population of Eurasian Woodcocks was estimated at 937 males (95% CI: 274–1714), which is the first estimate produced using this species-specific method. Nationally, populations of Eurasian Woodcocks continue to decline, but the 2013–2023 declines were not as severe as those recorded between 2003 and 2013. The diverging population trends between North Scotland and the rest of Britain raise questions regarding regional variation in habitat suitability/availability and factors influencing overwinter survival. Recommendations are made for future versions of the Breeding Woodcock Survey regarding the composition of the random sample of squares, the treatment of incomplete data, and the sampling of non-woodland habitat. [ABSTRACT FROM AUTHOR]

A reliable assessment of the population size of threatened species is crucial for making informed decisions about their conservation and management. However, there is a lack of comprehensive knowledge on the population of the eastern Black Crowned Crane (Balearica pavonina ceciliae), which is globally recognized as a threatened taxon experiencing a declining population trend. Here, we investigated the density, abundance and factors that influence flock size in the wetlands of the Gambella region in Ethiopia. We used line transects to collect data during dry and wet seasons. Population density and abundance were estimated using DISTANCE software, whereas factors influencing crane flock size were evaluated using a generalized linear model. We found that crane density ranged from 444 to 965 birds per sq km in the dry season and from 62 to 105 individuals per sq km in the wet season. We estimated that the population size within the designated survey areas as 7634 during the dry season and 866 during the wet season. Furthermore, for the broader survey region that encompasses permanent wetlands, the estimated population ranged from 9138 to 19,849 individuals in the dry season and from 1272 to 2166 individuals in the wet season. We found that grazing intensity and proximity to woodlands and rivers had significant positive impacts on crane flock size, whereas an increase in wetland water depth and grass height remarkably reduced flock size. As a result, wetland habitat degradation-related problems are not currently a threat to cranes in this region, but are likely to increase in the future due to large-scale agricultural expansion. The crane population size we estimated in Gambella is high, three to four times higher than the estimate from the entirety of Ethiopia. Our research underscores the global significance of Gambella wetlands as an important habitat for cranes. However, to obtain an accurate population estimate in this region, it is imperative to include seasonal wetlands, savannah grasslands, farmlands and the extended wetlands of South Sudan, which are hydrologically connected to the wetlands of Gambella region. To achieve this, comprehensive surveys and estimations should incorporate various techniques, such as aerial surveys, satellite telemetry, and high-resolution satellite imagery.

Since the 1990s, the number of lions (Panthera leo) has declined by about 43% across African range states. Reliable lion population estimates can contribute to effective management and inform local and international conservation policies. Though many survey methods have been used to estimate lion abundance, an assessment of their usefulness and effectiveness is lacking.We reviewed and identified available methods used to estimate lion populations, then investigated their feasibility, cost‐effectiveness and suitability to achieve primary objectives.We identified 12 methods in two categories: direct (minimum counts, call‐in surveys, capture–recapture, opportunistic sightings, remote cameras, distance‐based and aerial counts) and indirect (track counts, secondary information, prey‐based, genetic samples and roar counts).We identified 48 studies (57%) in which lion population estimation was not repeatable. Additionally, 38% did not provide any measure of precision. About 28% of the studies were conducted specifically for management purposes, while remaining studies focused on population estimates and dynamics.Because data from these studies have influenced local management and global lion conservation policies, we recommend basing future policies and management on repeatable, precise and accurate population estimates supported by appropriate and cost‐effective experimental designs. In most cases, these estimates are obtained through actual lion counts derived from direct observation methods including call‐in, capture–recapture and remote camera surveys or through reliable animal signs such as genetic samples. [ABSTRACT FROM AUTHOR]

IntroductionSeabirds and other insular birds are an important part of marine ecosystems and are increasingly threatened worldwide. Phenology, abundance, distribution, and breeding success are important baseline parameters needed to evaluate population trends and dynamics, identify biodiversity hotspots and potential breeding sites, and assess habitat selection. In the Red Sea basin, reliable and complete data on birds are lacking for islands in most of the Important Bird Areas (IBA). Such data are now especially important since development projects have started at several of these locations. Here, we assess the distribution, abundance, phenology, and population trends of 13 bird species that breed in the Duba Islands, Al Wajh Bank, and Al Lith Islands. Breeding success and habitat selection for six species were also assessed.MethodsBetween December 2020 and August 2023, more than 90 islands were visited multiple times with different frequencies. All nests were counted, and the area occupied by the different colonies was georeferenced. Breeding success was assessed by visiting selected colonies multiple times until the chicks were ready to fledge. Habitat selection was determined by analyzing the habitat found in the georeferenced colonies.ResultsMore than 25,000 nests were counted each year, mainly in the summer, on more than 75 islands. Of the 13 species studied, the most abundant and widespread species was the White-cheeked tern, and the second most widespread was the Osprey.DiscussionWe estimate that the Al Wajh Bank hosts the following percentages of global breeding populations: Crab plover: 5%, Sooty gull: 17%–35%, White-eyed gull: 15%, Bridled tern: 1%, White-cheeked tern: 4%, and Lesser crested tern: 2%, making the area a regional and global hotspot for these species. Some of the islands occupied by breeding birds are slated for development for tourism activities as part of the Kingdom’s tourism expansion plans. At the same time, there are several ambitious conservation programs underway in these areas. To be effective, such programs require reliable and comprehensive data of the kind presented here.

Wildlife managers often rely on population estimates, but estimates can be challenging to obtain for geographically widespread species. Spotlight surveys provide abundance data for many species and, when conducted over wide spatial scales, have potential to provide population estimates of geographically widespread species. The bare‐nosed wombat (Vombatus ursinus) has a broad geographical range and is subject to spotlight surveys. We used 19 years (2002–2020) of annual spotlight surveys to provide the first estimates of population abundance for two of the three extant bare‐nosed wombat subspecies: V. u. ursinus on Flinders Island; and V. u. tasmaniensis on the Tasmanian mainland. Using distance sampling methods, we estimated annual rates of change and 2020 population sizes for both subspecies. Tasmanian mainland surveys included habitat data, which allowed us to also look for evidence of habitat associations for V. u. tasmaniensis. The average wombat density estimate was higher on Flinders Island (0.42 ha−1, 95% CI = 0.25–0.79) than on the Tasmanian mainland (0.11 ha−1, CI = 0.07–0.19) and both wombat subspecies increased over the 19‐year survey period with an estimated annual growth rate of 2.90% (CI = −1.7 to 7.3) on Flinders Island and 1.20% (CI = −1.1 to 2.9) on mainland Tasmania. Habitat associations for V. u. tasmaniensis were weak, possibly owing to survey design; however, we detected regional variation in density for this subspecies. We estimated the population size of V. u. ursinus to be 71,826 (CI = 43,913–136,761) on Flinders Island, which when combined with a previously published estimate of 2599 (CI = 2254–2858) from Maria Island, where the subspecies was introduced, provides a total population estimate. We also estimated 840,665 (CI = 531,104–1,201,547) V. u. tasmaniensis on mainland Tasmania. These estimates may be conservative, owing to individual heterogeneity in when wombats emerge from burrows. Although these two subspecies are not currently threatened, our population estimates provide an important reference when assessing their population status in the future, and demonstrate how spotlight surveys can be valuable to inform management of geographically widespread species. [ABSTRACT FROM AUTHOR]

Abstract Wildlife managers often rely on population estimates, but estimates can be challenging to obtain for geographically widespread species. Spotlight surveys provide abundance data for many species and, when conducted over wide spatial scales, have potential to provide population estimates of geographically widespread species. The bare‐nosed wombat (Vombatus ursinus) has a broad geographical range and is subject to spotlight surveys. We used 19 years (2002–2020) of annual spotlight surveys to provide the first estimates of population abundance for two of the three extant bare‐nosed wombat subspecies: V. u. ursinus on Flinders Island; and V. u. tasmaniensis on the Tasmanian mainland. Using distance sampling methods, we estimated annual rates of change and 2020 population sizes for both subspecies. Tasmanian mainland surveys included habitat data, which allowed us to also look for evidence of habitat associations for V. u. tasmaniensis. The average wombat density estimate was higher on Flinders Island (0.42 ha−1, 95% CI = 0.25–0.79) than on the Tasmanian mainland (0.11 ha−1, CI = 0.07–0.19) and both wombat subspecies increased over the 19‐year survey period with an estimated annual growth rate of 2.90% (CI = −1.7 to 7.3) on Flinders Island and 1.20% (CI = −1.1 to 2.9) on mainland Tasmania. Habitat associations for V. u. tasmaniensis were weak, possibly owing to survey design; however, we detected regional variation in density for this subspecies. We estimated the population size of V. u. ursinus to be 71,826 (CI = 43,913–136,761) on Flinders Island, which when combined with a previously published estimate of 2599 (CI = 2254–2858) from Maria Island, where the subspecies was introduced, provides a total population estimate. We also estimated 840,665 (CI = 531,104–1,201,547) V. u. tasmaniensis on mainland Tasmania. These estimates may be conservative, owing to individual heterogeneity in when wombats emerge from burrows. Although these two subspecies are not currently threatened, our population estimates provide an important reference when assessing their population status in the future, and demonstrate how spotlight surveys can be valuable to inform management of geographically widespread species.

Reliable data on Atlantic Goliath Grouper abundance are prerequisite to informed management decisions, particularly as the State of Florida reopened a limited harvest on the species in 2023 after a 32-year moratorium. Limited data exist for this purpose and fisheries data have been unavailable for over three decades due to a fishery closure that began in 1990. The purpose of this study was to compare absolute abundance estimates of Goliath Grouper between two years using an efficient, cost-effective method developed by Koenig. An underwater tagging method was used to collect mark and resight data for use in a Peterson deterministic model. These data were collected at the same spawning aggregation sites off Jupiter, Florida near the time of the new moon in September 2013 and August 2022. We found that Goliath Grouper abundance had declined at all but one of six sites since 2013. Because data were not collected during the intervening years, interannual variability is unknown. However, given the highly age-structured spawning stock of adult Goliath Grouper on the spawning grounds, the lower abundances measured in 2022 may reflect a real decline in the population rather than just representing a weak year of adult recruitment to these spawning sites. [ABSTRACT FROM AUTHOR]

Colony size in social insects is one of the most important factors in shaping their self-organized system. It affects a wide variety of traits such as foraging and defense strategies, social immune responses, the degree of polymorphism, and reproductive output. However, colony size estimation of subterranean termites in the field has been challenging, due to their extremely cryptic biology and multiple site–nesting behavior. Since natural selection favors workers that maximize the number of their siblings, the amount of egg production may reflect the number of workers in the colony. Here, we report a method for inferring colony size in the field using total egg production in each colony from a subterranean termite, Reticulitermes speratus. Our investigation of field colonies revealed that the body weight of queens reaches a peak and had the largest variance in June and July and accurately predicts the number of eggs laid by the queen per 24 h. Using laboratory-reared colonies, we found that the total egg production in each colony is proportional to the number of workers. We also estimated the colony size of 198 field colonies and found that the median and maximum colony size was 24,500 and 451,800 workers per colony. The method for inferring colony size presented here may also be applicable to termite species with a clear seasonality in egg production. The colony size estimate will contribute to understanding the life history strategies and social systems of termites. [ABSTRACT FROM AUTHOR]

The ladder snake Zamenis scalaris was first reported in 2006 in Formentera (Balearic Islands, Spain), until then a snake‐free Mediterranean island. Since 2016, intense control campaigns have been carried out and, for the first time, snake captures over 2017–2020 have been used to analyze the sex ratio, age, fat percentage, population density, and seasonality of this invasive population. The male‐biased sex ratio found in the present work could be the result of capture biases caused by different detection probabilities between sexes. A reduction of snake body length over time was observed, which could indicate a depletion of the larger snakes due to intense snake capture. The highest capture frequencies of both sexes were reported in May and June, coinciding with the mate searching period in the species native range and indicating that snakes increase their movements during this period. Size‐specific survivorship curves indicated a drop in survivorship at medium sizes, which suggested a survival cost associated with reproduction, presumably due to increased mortality during the mating season. Population density decreased from 1.812 snakes/ha in 2017 to 0.669 snakes/ha in 2020. Evidence obtained in the present work has allowed to evaluate the main ecological aspects of Z. scalaris and the current state of the population of this invasive snake on the island of Formentera. Results showed that the population is well established in Formentera, but prolonged control campaigns have caused its decline. This study becomes a starting point to improve the management and control programs of invasive snake populations in the Balearic Islands. Long‐term control as well as the improvement of the detection and capture of adult females are strongly recommended to attempt the eradication of Z. scalaris in Formentera. [ABSTRACT FROM AUTHOR]

The Mountain Plover (Charadrius montanus) primarily inhabits lowland grasslands of North America, where its populations have decreased due to habitat loss. Currently, little information exists on the species' population size and habitat at wintering sites. Between 2007 and 2012, we estimated population density of the Mountain Plover and characterized habitat at its wintering sites in northeastern Mexico. We estimated plover density using the perpendicular distance method along 44 2-km length transects. We characterized foraging and roosting habitat by evaluating the height, vegetation cover, and importance value of herbaceous and shrubby plants in 60 quadrants of 1 m2 and 25 m2, respectively. Mountain Plover density declined over the five seasons, with highest density of 0.35 ind/ha in 2008-2009, beginning to decrease during the third season with 0.26 ind/ha in 2010-2011, and recording the lowest density of 0.15 ind/ha in 2011-2012. Vegetation cover with herbaceous and shrubby layers was 62% in foraging sites and 38% in roosting sites, with grasses of Aristida haradii, Bouteloua karwinskii, B. dactyloides, and the shrub Atriplex canescens providing greatest cover. Our results indicate a persistent population decline of the Mountain Plover at its wintering sites in northeastern Mexico. Based on our habitat assessment, future conservation strategies for the Mountain Plover should ensure the protection of grasslands with high plant diversity and high vegetation cover. [ABSTRACT FROM AUTHOR]

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Estimating animal populations is essential for conservation. Censusing large congregations is especially important since these are priorities for protection, but efficiently counting hundreds of thousands of moving animals remains a challenge. We developed a deep learning‐based system using consumer cameras that not only counts but also records behavioral information for large numbers of flying animals in a range of lighting conditions including near darkness. We built a robust training set without human labeling by leveraging data augmentation and background subtraction. We demonstrate this approach by estimating the size of a straw‐colored fruit bat (Eidolon helvum) colony in Kasanka National Park, Zambia with cameras encircling the colony to record evening emergence. Detection of bats was robust to deteriorating lighting conditions and changing backgrounds. Combined over five days, our population estimates ranged between 750,000 and 976,000 bats with a mean of 857,233. In addition to counts, we extracted wingbeat frequency, flight altitude, and local group polarity for 639,414 individuals. This open access method is an inexpensive but powerful approach that, in addition to radial emergences from central locations, can also be applied to unidirectional movements of flying groups, such as migratory streams of birds. [ABSTRACT FROM AUTHOR]

New Zealand fur seals (Arctocephalus forsteri) are expanding in numbers and distribution throughout New Zealand. The exception is the West Coast of the South Island, where there is documented decline due to decades of mortalities related to fishery. There are fur seal colonies south of these West Coast colonies, in Fiordland, which have never been accurately documented or monitored. Even for those that are documented, there are few records of pup numbers and no population estimates. Here, pups at colonies from Doubtful/Pateā, Dusky, and Breaksea Sound, and Chalky Inlet were observed, and their numbers either counted directly or estimated using mark-recapture methods in February 2021. From these pup counts a coarse minimum population estimate of between 14–24 thousand fur seals is calculated for lower Fiordland. The pup counts and population estimates indicated the fur seal numbers are higher than previously recorded from estimates of walk through, boat or helicopter observations. During onshore surveys and from anecdotal evidence, it was noted that fur seals were rearing pups in forested areas. This paper outlines suggestions for the future monitoring of these colonies given, location, diverse geology and the difficulty of monitoring colonies on exposed west coast areas of New Zealand's Fiordland. [ABSTRACT FROM AUTHOR]

Endemic species are threatened by invasive species, habitat loss, and climate change. Endemic species are also an important group that maintains biodiversity. Understanding population dynamics of endemic species is needed to maintain or restore their populations. Advancements in models that describe population dynamics of endemic species and species of conservation need has been made possible by the application of novel quantitative methods. One such modeling tool is state-space modeling. These models provide a flexible framework to describe population dynamics using simple mortality models and more complex integrated population models. Here we develop a state-space model to describe survival and population size of the Sicklefin Redhorse (Catostomidae: Moxostoma sp.), a species of conservation concern from two rivers located in North Carolina, USA. This model is structured to combine information across similar rivers and to account for complex interactions of sex, time, variable sampling effort, and river discharge. Survival of Sicklefin Redhorse was found to vary by sex, and annual variability was not consistent across rivers. Discharge was negatively related to capture probability for males. Capture probabilities also differed across sex. Population estimates revealed a large difference between sex where males outnumbered females each year in both rivers. We conclude that electrofishing is not an efficient capture method but when used, should consider discharge. Discharge was not included in the survival model, however, the 3 years with the lowest survival in the Little Tennessee River coincided with the three lowest discharge years in the time series. Future work should investigate the difference in survival between the rivers.

Summary: The Sierra Madre Sparrow Xenospiza baileyi is an endangered Mexican endemic and a bunchgrassland specialist with a disjunct range: a relatively larger population in the south-eastern Trans-Mexican Volcanic Belt, and a smaller and poorly studied population in the Sierra Madre Occidental. In the latter, known distribution and abundance consists of four localities with a maximum of 28 individuals recorded in one of them. We surveyed the Sierra Madre Sparrow in 30 sites with suitable habitat, meadows or "bajíos" with bunchgrasses, in the municipalities of Durango, Pueblo Nuevo, San Dimas, and Canatlán in the Sierra Madre Occidental of Durango. We detected a total of 193 individuals in nine (30%) of the sites (392 ha), conducting intensive searches throughout them. Bunchgrasses in confirmed meadows were composed mainly of Muhlenbergia macroura , M. rigida , M. speciosa , M. rigens , and Piptochaetium fimbriatum. Total bunchgrass area within a meadow was a significant positive predictor of the Sierra Madre Sparrow presence, while total meadow area was not a significant predictor of its abundance. Seven of the confirmed localities were previously unknown, and two of them harboured 55% of the observed individuals: Ex Hacienda Coyotes (Pueblo Nuevo) and La Lobera (San Dimas). The estimated population size is at least four times higher than any previous record (28) or suggested (40–50) for the Sierra Madre Occidental and raises an opportunity and a challenge for conserving this genetically distinct population of the Sierra Madre Sparrow in the region. [ABSTRACT FROM AUTHOR]

The Russian breeding population of barnacle geese Branta leucopsis has shown a rapid increase in numbers since 1980, which has coincided with a southwest-wards breeding range expansion within the Russian Arctic. Here barnacle geese also started to occupy coastal and marsh land habitats, in which they were not know to nest on their traditional breeding grounds. While these changes have been well documented by studies and observations throughout the new breeding range of barnacle geese, observations are lacking from the traditional breeding grounds on Novaya Zemlya, as this area is remote and difficult to access. This is especially relevant given rapid climate warming in this area, which may impact local distribution and population size. We used GPS-tracking and behavioural biologging data from 46 individual barnacle geese captured on their wintering grounds to locate nest sites in the Russian Arctic and study nesting distribution in 2008–2010 and 2018–2020. Extrapolating from nest counts on Kolguev Island, we estimate the breeding population on Novaya Zemlya in 2018–2020 to range around 75,250 pairs although the confidence interval around this estimate was large. A comparison with the historical size of the barnacle goose population suggests an increase in the breeding population on Novaya Zemlya, corresponding with changes in other areas of the breeding range. Our results show that many barnacle geese on Novaya Zemlya currently nest on lowland tundra on Gusinaya Zemlya Peninsula. This region has been occupied by barnacle geese only since 1990 and appears to be mainly available for nesting in years with early spring. Tracking data are a valuable tool to increase our knowledge of remote locations, but counts of breeding individuals or nests are needed to further corroborate estimates of breeding populations based on tracking data. [ABSTRACT FROM AUTHOR]

Gravel rooftops are important for nesting Least Terns (Sternula antillarum) in Florida. A network of partners from the Florida Shorebird Alliance (FSA partners) monitor roof-nesting Least Terns by conducting street surveys - a count of flying adults seen from the ground. We used double sampling to adjust street survey data and produce a population estimate for the 2018 nesting season (1 May–20 June). In 2018, FSA partners conducted street surveys at 96% (n = 138) of the active rooftop colonies in the state. In a random subsample (n = 62), we conducted direct counts of breeding adults and produced a detection ratio of 0.61, a ratio estimate of 59.28 ± 5.01 breeding adults/rooftop, and an adjusted population estimate of 8,180 ± 692 breeding adults (95% CI: 6,825–9,536). Cross-validation tests using data collected before and after the 2018 study produced accurate and unbiased population estimates derived from the detection ratio and street surveys. We used available street survey data from 2015 to 2020 and found a 7% population increase. We suggest validating the detection ratio every three years to develop accurate abundance and trend estimates of Florida's roof-nesting Least Terns. [ABSTRACT FROM AUTHOR]

Summary: Since 2005, the world population of Great Bustards Otis tarda has decreased at an annual rate of 3.23%. The current world total is estimated at 31,000–36,000 birds, 34% (range 30–38%) less than 16 years ago. The declines have been observed in nine of 17 countries with extant breeding populations, with highest values in China (-89%) and European Russia (-72%). Marked decreases have also occurred in the Iberian Peninsula, which is still the stronghold for the species with 70–75% of the world population. Within Iberia, declines are particularly alarming in Portugal (-50%), although perhaps even more concerning in Spain, where the -28% (range 25–30%) decrease implies a loss of more than 8,000 individuals. Increases have been only recorded in Germany, Austria, and at a smaller scale in Hungary (respectively, 202%, 91%, and 5%), thanks to continued and intensive conservation actions, and also in the small group breeding in Romania, likely due to dispersal from the increasing West Pannonian population. The isolated populations of Morocco and Iran are on the brink of extinction. More surveys are still needed in Russia, Ukraine, Kazakhstan, China, and Mongolia, to confirm numbers and trends. It is urgent to reinforce conservation actions worldwide to stop negative demographic trends and ensure the survival of the species. If current trends continue, IUCN should perhaps consider whether (a) conditions are met to upgrade the species' Red List category from globally 'Vulnerable' to 'Endangered', and (b) the two subspecies should be treated as separate conservation units and require different conservation strategies. [ABSTRACT FROM AUTHOR]

Nordmann's Greenshank (Tringa guttifer) is a globally endangered species that has received little research attention. It is threatened by rapid habitat loss, an incomplete network of protected sites, and lack of long-term data on population dynamics. Citizen science data can be combined with survey data to support population estimation and conservation gap analysis. From 2020 to 2021, Nordmann's Greenshank was surveyed in Tiaozini, Xiaoyangkou, and Dongling on the southern coast of Jiangsu Province, China, and the global population of the species was re-evaluated using the data obtained. We integrated citizen science data from eBird and the China Bird Report from 2000 to 2020 with the survey results to identify important habitats harboring over 1% of its total population, and compared this data with existing protected areas to identify gaps in its global conservation. Our survey found that Tiaozini supported at least 1194 individuals. Consequently, its global population was re-estimated to be 1500-2000. Moreover, 45 important habitats were identified based on citizen data and survey results. Although 44.4% and 50.0% of the priority sites in the world and China, respectively, are located outside protected areas, the Conservation Effectiveness Index (C) is 68.4% and 71.1%, respectively, showing that the current coverage of protected areas for this part of its range is reasonable. This study presents the most complete and recent population data to date. Tiaozini is the most important migration stopover site for Nordmann's Greenshanks. The species is under threat in terms of breeding, wintering, and stopover sites. Therefore, we suggest improving monitoring, establishing new protected sites to complete the habitat protection network, and improving the effectiveness of existing habitat protection strategies, including further developing high tide roosting sites.

Regular harbour seal (Phoca vitulina) population censuses are necessary to monitor fluctuations in the population size and to inform seal management. In this paper, the status of the Icelandic harbour seal population is presented, along with trends in the population over a 40-year period. In total, 13 full aerial censuses were carried out during the moulting season (July-August) between 1980 and 2020. The most recent census from 2020 yielded an estimate of 10,319 (CI 95%= 6,733-13,906) animals, indicating that the population is 69.04% smaller than when systematic monitoring of the population commenced in 1980 (33,327 seals). The observed decrease puts the population on the national red list for threatened populations. Trend analyses indicate that most of the decline occurred during the first decade, when the population decreased about 50% concurrently with large human induced removals of harbour seals. After that point, the population decline slowed down but continued, and currently the population seems to fluctuate around a stable minimum level. The sensitive conservation status of the population underlines the need to assess and sustainably manage current threats to the population, including human induced removals, anthropogenic disturbance, and various environmental factors such as contaminants, climate change and fluctuation in prey availability. Furthermore, it is urgent to continue regular censuses and to increase monitoring of population demographic factors.

This study investigated the distribution, numbers and conservation threats of the West African Crested Tern, which was recently elevated to full species after it was split from the Royal Tern with an American and African subspecies. In the period 1998–2019, a total of 13 West African coastal islands were identified as breeding localities, stretching from Mauritania to Guinea. All the islands are isolated, usually sandy and subject to erosion. There was great yearly variation in the numbers of breeding pairs within and between sites. A complete census of all breeding locations in 2015 and 2019 resulted in estimates of 79 000 and 77 000 pairs, respectively. The threats identified are predation, human disturbance, nest flooding and loss of breeding habitat as a result of coastal erosion. Predation of eggs and chicks by Sacred Ibises and especially Great White Pelicans may heavily impact on the species' breeding output. Human disturbance is slight because most of the breeding islands are within protected areas. Flooding of nests has increasingly been observed in recent years, occurring at nine of 11 islands occupied by the terns in 2015. Most islands are subject to erosion, which has resulted in substantial loss of suitable breeding habitat over the 22-year study period. Two important islands have become completely unsuitable. We conclude that West African Crested Terns have an uncertain future. Food shortage resulting from industrial fishing is suspected, and the effects of climate change might negatively impact on habitat suitability and food availability. Monitoring of the total population at three-year intervals is recommended. [ABSTRACT FROM AUTHOR]

Robust estimates of demographic parameters are critical for effective wildlife conservation and management but are difficult to obtain for elusive species. We estimated the breeding and adult population sizes, as well as the minimum population size, in a high‐density brown bear population on the Shiretoko Peninsula, in Hokkaido, Japan, using DNA‐based pedigree reconstruction. A total of 1288 individuals, collected in and around the Shiretoko Peninsula between 1998 and 2020, were genotyped at 21 microsatellite loci. Among them, 499 individuals were identified by intensive genetic sampling conducted in two consecutive years (2019 and 2020) mainly by noninvasive methods (e.g., hair and fecal DNA). Among them, both parents were assigned for 330 bears, and either maternity or paternity was assigned to 47 and 76 individuals, respectively. The subsequent pedigree reconstruction indicated a range of breeding and adult (≥4 years old) population sizes: 128–173 for female breeders and 66–91 male breeders, and 155–200 for female adults and 84–109 male adults. The minimum population size was estimated to be 449 (252 females and 197 males) in 2019. Long‐term continuous genetic sampling prior to a short‐term intensive survey would enable parentage to be identified in a population with a high probability, thus enabling reliable estimates of breeding population size for elusive species. [ABSTRACT FROM AUTHOR]

Monitoring population changes and trends is a central task in conservation. However, obtaining detailed information for wide and low accessible areas, such as remote islands, is challenging, and cannot be achieved with conventional approaches, such as capture–mark–recapture protocols (CMR). In this paper, we show that combining N-mixture models with ecological niche modeling allows assessing reliable estimates of population size over large target areas on short time intervals. We used it to estimate the population size of a subspecies of the Italian wall lizards (Podarcis siculus calabresiae) endemic to the Island of Montecristo (10.39 km2 in surface). During a single week, we first generated a niche model of the species based on satellite images sampled few days before sampling. Then, we estimated lizard abundance through Bayesian N-mixture models on repeated counts (n = 3) along transects (n = 6), settled in different areas of habitat suitability defined on the basis of the niche model. Finally, we estimated in approximately 20.000 the total number of lizards living in the Island by extrapolating the values computed on transects to the areas of the islands with the same suitability estimated by the niche model. The procedure can be easily repeated allowing monitoring the status of conservation of the species in the island of Montecristo. More in general, this procedure has the potential to be applied to monitor any other species of conservation interest in remote areas whenever detailed satellite images are available. [ABSTRACT FROM AUTHOR]

Abstract From January to June 2021, mark-recapture and biometric data were collected from a population of blue crab, Cardisoma crassum Smith, 1870, from Ponuga, in Veraguas, Panama. Recapture histories of 163 crabs indicate strong burrow fidelity. During the dry season (January-March) burrow fidelity was 73.2 %, while in the rainy season (April-June) it was 50.7 %. Population was estimated at 2,569 crabs in 10.93-ha with a density of 0.024 ind. m-2. Cephalothorax width averaged 63.62 ± 6.37 mm for males (50.95-78.01 mm, N = 83) and 61.90 ± 5.47 mm for females (53.21-77.78 mm, N = 80). Blue crab reproductive season was traditionally known to take place just during the rainy season. Here, we report ovigerous females in February and March (dry season), suggesting reproduction may occur throughout the year in Panama. This is the first report of burrow fidelity and continuous biometry measurements in natural conditions for C. crassum. Burrow fidelity seems to be closely related to abiotic factors and is different between dry and rainy seasons.

Reliable data on Atlantic Goliath Grouper abundance are prerequisite to informed management decisions, particularly as the State of Florida reopened a limited harvest on the species in 2023 after a 32-year moratorium. Limited data exist for this purpose and fisheries data have been unavailable for over three decades due to a fishery closure that began in 1990. The purpose of this study was to compare absolute abundance estimates of Goliath Grouper between two years using an efficient, cost-effective method developed by Koenig. An underwater tagging method was used to collect mark and resight data for use in a Peterson deterministic model. These data were collected at the same spawning aggregation sites off Jupiter, Florida near the time of the new moon in September 2013 and August 2022. We found that Goliath Grouper abundance had declined at all but one of six sites since 2013. Because data were not collected during the intervening years, interannual variability is unknown. However, given the highly age-structured spawning stock of adult Goliath Grouper on the spawning grounds, the lower abundances measured in 2022 may reflect a real decline in the population rather than just representing a weak year of adult recruitment to these spawning sites.

The effect of gull predation on sympatric seabirds has garnered much attention and management action in recent decades. In Witless Bay, Newfoundland, Canada, gulls depredate significant numbers of Leach’s Storm-petrels (Hydrobates leucorhous) annually. We quantified this predation on Gull Island in Witless Bay, and its effects on the storm-petrel population, by estimating the annual gull predation rate using strip transects to count storm-petrel carcasses and predicting storm-petrels’ population growth rate by repeating an island-wide breeding census. Using methods that account for island topography, we found that the Leach’s Storm-petrel breeding population on Gull Island declined to roughly 180,000 pairs in 2012 (95% CI: 130,000–230,000), a decrease of 6% per year since the last census in 2001 (352,000 pairs). Based on carcass counts, gulls, mostly American Herring Gulls (Larus argentatus smithsonianus), depredated 118,000–143,000 Leach’s Storm-petrels in 2012. Studies of storm-petrel recruitment, the contribution of the large non-breeding component of the population to gulls’ diets, and the consequences of gulls’ storm-petrel diet on the gulls themselves are needed to better predict the trajectory of both species into the future.

Undertaking accurate counts is an important part of managing cave-dwelling bats species such as the little bent-wing bat (Miniopterus australis) population at Mt Etna. A thermal camera and automated counting system were trialled to see if the technology would work at Mt Etna with the goal of producing accurate counts of bats. Although the heat radiating from the rock meant that the background at Mt Etna was not perfect, the automated system was able to recognise and count the bats as they emerged. The number of bats emerging from the cave varied from 82 677 in 2017/18 through to 139 783 in 2018/19. These estimates are within the range of those made in the 1960 to 1980s, which suggests that the population is stable, but we are unsure of the accuracy of these previous counts. These results demonstrate that it is possible to obtain accurate counts of reasonably large bat populations such as Bat Cleft and the methodology may have application for other gregarious and nocturnal species whose numbers can be difficult to count at night. Obtaining accurate counts of bats using caves is important for management but when numbers are large, it is difficult to do accurately and regularly. In this study we obtained counts of Australia's largest insectivorous bat colony using an automated system. The results suggest that over 100 000 little-bent-wing bats use Bat Cleft each year, and the population is likely stable. Photograph by J. Augusteyn. [ABSTRACT FROM AUTHOR]

The Central Valley of California provides important breeding habitat to numerous species of wetland-dependent birds, despite the loss of over 90% of naturally occurring wetlands. A majority of shorebirds breeding in this region rely on shallow-flooded habitat adjacent to sparsely vegetated uplands as provided by rice (Oryza sativa), managed wetlands, and other habitats. We estimated the current extent of potential breeding shorebird habitat provided by rice and managed permanent and semi-permanent wetlands in each of four major planning regions of the Central Valley, and estimated the average breeding densities and current population sizes of two species of shorebirds: the Black-Necked Stilt (Himantopus mexicanus) and American Avocet (Recurvirostra americana). Using a population status framework based on principles of conservation biology, we estimated that stilt populations are small (

Recreational fishing for Rainbow Trout (Oncorhynchus mykiss) is important economically in California. We determined the upstream and downstream distribution of Rainbow Trout in a southern California stream, and classified all available habitat within that area as riffle, pool, cascade-pool-complex, and flatwater. Approximately 10% (based on length) of each habitat type was sampled using depletion electrofishing. We estimated Rainbow Trout abundance, both

Cape Parrots Poicephalus robustus inhabit forest patches in South Africa with <1 800 individuals remain in the wild. A small, genetically isolated population occurs in the northern part of its range in the Limpopo province. There, annual counts indicated ∼100 remain, but count numbers fluctuate substantially between years creating uncertainty over population trends. To inform approaches to the monitoring of Cape Parrot populations in the Limpopo province, we investigated how local abundance counts varied within and across years at known parrot 'hotspots'. Monthly counts were done at these sites during 2013–2015 and 2020–2021. We found large variability in counts both within and amongst years, although this differed between sites. Observations of behaviour suggest that a site close to overnight roosts was more reliable, whereas those close to food sources were more variable likely linked to fruit availability. The highest numbers were recorded at a pecan nut orchard away from the indigenous forest. To better understand population trends of this small, isolated population we recommend annual counts are complemented with a series of focused counts at pecan nut orchards, which are monitored with greater intensity during the fruiting season. [ABSTRACT FROM AUTHOR]

Swayne's hartebeest Alcelaphus buselaphus swaynei was once widely distributed in the Horn of Africa. By the early 20th century, however, it was extirpated across most of its range and is now limited to two relict populations in the Ethiopian Rift Valley and categorized as Endangered on the IUCN Red List. In this study, we estimated the size and genetic diversity of these two remaining populations, with a particular focus on competition with livestock. We used a total block count method for both Swayne's hartebeest and livestock population counts, and faecal samples for a population genetic analysis. We estimated the total population of Swayne's hartebeest to be 1,528, with 518 individuals in Senkele Swayne's Hartebeest Sanctuary and 1,010 individuals in Maze National Park. Livestock densities were 212 and 153 times those of Swayne's hartebeest in Senkele Swayne's Hartebeest Sanctuary and Maze National Park, respectively. Among 73 mitochondrial D-loop sequences (34 from Senkele Swayne's Hartebeest Sanctuary and 39 from Maze National Park), we found 22 haplotypes (Senkele 12, Maze 16, shared 6). Population genetic parameters suggest only weak sub-structuring between the two populations (FST = 0.164). Despite the positive population trends in both protected areas, the spatial overlap with livestock may lead to future population decline as a result of resource competition and disease transmission. We therefore recommend further translocation to other protected areas within the species' former range. [ABSTRACT FROM AUTHOR]

The spotted hyena is positioned at the top of food chains and has the ability to influence the diversity of herbivores. Knowledge of this predator through research can assist in effective management decisions which will ensure ecosystem integrity. A study on population estimation and livestock loss by the spotted hyenas was conducted from January 2019 to December 2020 in the Damota community managed forests. Data was collected through distance sampling techniques, and the economic impacts of spotted hyena predation on livestock were quantified using a questionnaire survey with randomly selected households. Twenty-five transects were monitored over a period of two consecutive years. A mean of 113 ± 0.51 individuals of spotted hyena was observed per 100 km2. The density of spotted hyena was 1.34 ± 0.42 and 0.69 ± 0.12 individuals/km2 and 0.55 ± 0.97 and 0.75 ± 0.14 individuals/km2 in farm and forest during 2019 and 2020, respectively. The mean sex ratio of the adult male to adult female was 0.56:1.00 and 0.74:1.00 during the dry and wet seasons, respectively. Moreover, the mean sex ratio of adult to cub was 1:0.25 and 1:0.29 during the dry and wet seasons, respectively. Respondents indicated a total loss of 377 livestock due to the depredation of spotted hyenas over the past five years. The total estimated economic loss caused by depredation, theft, and diseases was US$ 47,885. On average, US$ 9577 per year (US$ 26 per day) has been lost over the past five years. The average annual depredation per household was 0.98 head of livestock worth US$ 95.6. Among depredated livestock, 64.8% of sheep were lost by spotted hyena, followed by donkey (16.4%). Therefore, livestock management practices, assessment of spotted hyena population, and economic loss are very important for carnivore conservation and scaling up human livelihood development.

Accurate and ecologically relevant wildlife population estimates are critical for species management. One of the most common survey methods for forest mammals – line transects for animal sign with distance sampling – has assumptions regarding conversion factors that, if violated, can induce substantial bias in abundance estimates. Specifically, for sign (e.g. nests, dung) surveys, a single number representing total time for decay is used as a multiplier to convert estimated sign density into animal density. This multiplier is likely inaccurate if not derived from a study reflecting the spatiotemporal variation in decay times. Using dung decay observations from three protected areas in Gabon, and a previous study in Nouabalé‐Ndoki National Park (Congo), we developed Weibull survival models to adaptively predict forest elephant (Loxodonta cyclotis) dung decay based on environmental variables from field collected and remotely sensed data. Seasonal decay models based on remotely sensed covariates explained 86% of the variation for the wet season and 79% for the dry season. These models included canopy cover, cloud cover, humidity, vegetation complexity and slope as factors influencing dung decay. With these models, we assessed sensitivity of elephant density estimates to spatiotemporal environmental heterogeneity, showing that our methods work best for large‐scale studies >50 km2. We simulated decay studies with and without these variables in four Gabonese national parks and reanalyzed two previous surveys of elephants in Minkébé National Park, Gabon. Disregarding spatial and temporal variation in decay rate biased population estimates up to 1.6 and 6.9 times. Our reassessment of surveys in Minkébé National Park showed an expected loss of 78% of forest elephants over ten years, but the elephant abundance was 222% higher than previously estimated. Our models incorporate field or remotely sensed variables to provide an ecological context essential for accurate population estimates while reducing need for expensive decay field studies. [ABSTRACT FROM AUTHOR]

For over 40 years, biopsy darting has been increasingly used to obtain DNA and other samples from cetaceans; however, its application to other species is more recent. We assessed the performance of helicopter-based biopsy darting of polar bears (Ursus maritimus) on the spring sea ice. Our aim was to provide an overview and evaluation of our protocols for others considering helicopter-based biopsy darting. We shot 55 biopsy darts at 46 polar bears. Most darts (n = 51; 93%) hit the bear, but four of these were likely glancing shots that did not collect a biopsy sample. Mean chase time by the helicopter was short ( x ¯ = 23 s; range = 8–60 s), but chase time was significantly greater for bears with cubs than those without. There was no significant difference in chase time between bears that ran from the helicopter and those that charged it, but missed shots occurred more frequently for bears initially charging the aircraft, necessitating a second shot. We observed minor reactions (flinching or glancing backward) by 24% of the bears to the dart itself; however, all bears had a flight or fight response to the helicopter. All but one dart was retrieved. The dart success rate—the percentage of darts that hit the bear and collected a tissue (skin) sample—was 88%. However, only 53% collected more than a minimal amount of fat. All of the skin samples collected yielded DNA. Our study, along with the experiences of others, demonstrates that biopsy darting of polar bears has potential for genetic tagging of individuals for capture-mark-recapture studies. While we provide further information on equipment, protocols, and performance of helicopter-based biopsy darting, work remains to improve equipment and protocols, and better assess the impacts to affected individuals. We encourage further research on biopsy darting terrestrial mammals to spur technological advancements and guide the development of best practices. [ABSTRACT FROM AUTHOR]

Abstract Background Injecting drug use is known to contribute significantly to the spread of the HIV epidemic in many parts of the developing world. Due to the hidden nature and stigma of the problem, it is difficult to study using routine surveys. Therefore, this study aims to estimate the number of people who inject drugs in Addis Ababa, Ethiopia, and to describe the epidemiological and social situation related to HIV among people who inject drugs. Methods The study used rapid assessment methods, followed by combined methods of estimating populations, using nomination and multiplier methods. The combined methods used two datasets: the first includes the proportion of people who use services within a year as a multiplier, and the second, a count of the list of people with a problem who used the specific service within a year as a benchmark. The rapid assessment incorporated different qualitative tools to elicit information related to injectable drugs, using existing data sources, in-depth interviews, and focus group discussions. Results The study estimated a total of 4068; with 95% CI (3196, 5207) people who inject drugs (PWIDs) in Addis Ababa. The study found people who inject drugs were young in age, male, with a lower educational status, unmarried, and living in small clerical business. People who inject drugs and participated in the study were more likely to use additional substances like alcohol, khat, and cannabis. The most common form of injectable drug used was heroin, and most of the people who inject drugs reported sharing syringes and needles. A high proportion of study subjects also disclosed having positive test results for HIV, hepatitis B, and C. Conclusion The population size of people who inject drugs in Addis Ababa is high. Lack of service in harm reduction in the city has made PWIDs vulnerable and at higher risk for HIV/AIDs and hepatitis B and C. Therefore, responsible bodies must start implementing the essential harm reduction strategies given by the World Health Organization.

Estimates of abundance are essential to manage and conserve marine species. Numerous methods are available to determine population size, but the suitability of methods for schooling fishes and the associated precision can vary depending on the species and system. Here, we developed and compared three mark-recapture/resight methods to assess the most robust method to estimate the abundance of silver trevally (Pseudocaranx georgianus). While the recapture rate was similar across the methods, the swim pass method (resighting) recorded the largest number of individuals (mean ± standard error 211 ± 14.9) and had the lowest coefficient of variation (CV; 4.5%-12%) compared to 360-video (resighting, 45 ± 2.1 individuals surveyed, 14.8%-22.2% CV) and large-scale capture methods (recapture, 30 ± 3.8 individuals surveyed, 17.3%-26.5% CV). The inclusion of individual identification into the abundance estimator models for large-scale capture did not change the abundance estimates and showed similar resolution between the models (CV 18.2%-26.7%). We showed that the swim pass method is logistically easy to implement and generates precise estimates of silver trevally abundance. This new method provides a low-cost, time-efficient resighting method that can be adapted to suit similar aggregating pelagic species interacting with wildlife tourism operations, enabling researchers to rapidly estimate the abundance of species that have been previously difficult to count., (© 2024 The Author(s). Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles.)

Aim: To evaluate how the spatial distribution of a heavily exploited marine gastropod (i.e. Queen conch) varies in response to a number of known biotic and abiotic variables within and between study areas that vary in environmental conditions. Location: Three study areas in the north‐eastern Caribbean, Anguilla, Saba Bank and St. Eustatius. Methods: A novel towed video system and complemented belt transects to estimate adult queen conch densities throughout its depth range. Bayesian hierarchical spatial models (integrated nested Laplace approximations) modelled distribution patterns of adult conch. Results: Our study revealed patchy distribution patterns of adult conch caused by spatial dependency. This dependency is most likely related to aggregating behaviour during spawning events. Environmental variables, such as algal cover, distance to the open ocean and depth, showed important nonlinear effects on conch abundance, although these differed among study areas. Intermediate and deep areas (ca. 17–45 m) contain most of the reproductive output of conch in the study areas and are highly important for the reproductive capacity. Main conclusions: The general patchy distribution pattern and the lack of strong generic relationships between biotic and abiotic factors and adult conch abundance and distribution are likely to be at least partly due to spatial dependency and location‐specific factors, which affect different phases of the conch's life history. The depth distribution of conch also indicates that surveying areas at depths beyond the practical limitation of divers is of great importance to obtain more reliable population estimates. [ABSTRACT FROM AUTHOR]

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Nile crocodile survival is threatened by water pollution, habitat loss, extensive water abstraction for irrigation, domestic use and industrial development and overexploitation of fisheries resources in water systems in Zimbabwe. This review assessed the abundance, distribution and population trends of Nile crocodiles (Crocodylus niloticus Laurent, 1768), and explored the effects of ranching, trophy hunting and human-crocodile conflicts (HCC) on its conservation status in water systems of Zimbabwe. Scoping reviews of available literature and analysis of recurrent themes indicated that crocodile censuses were concentrated in the warmer northern and southern parts of the country. Ranching and trophy hunting have contributed to the increases in crocodile populations. Human encroachment and wetland degradation have increased HCC in fringe communities proximate to protected areas consequently inducing negative perceptions and hurt-rage which threatens crocodile populations. Overall, there is an increase in crocodile populations in sampled areas. Nonetheless, there is a need to assess the abundance, distribution and population trends, and delineate hotspots of suitable habitats and contextual challenges in less sampled areas before stating the national crocodile population estimate. Implementing astute crocodile conservation efforts involving locals is key in HCC mitigation. However, it implores the need for development of pro human-crocodile co-existence and circumstantial HCC resolution policies. For posterity, the conservation status of crocodiles in Zimbabwe should be ascribed as Vulnerable or Near Threatened rather than the current Least Concern or Low Risk status.