Search

Abundance measures are almost non-existent for several bird species threatened with extinction, particularly range-restricted Neotropical taxa, for which estimating population sizes can be challenging. Here we use data collected over 9 years to explore the abundance of 11 endemic birds from the Sierra Nevada de Santa Marta (SNSM), one of Earth's most irreplaceable ecosystems. We established 99 transects in the "Cuchilla de San Lorenzo" Important Bird Area within native forest, early successional vegetation, and areas of transformed vegetation by human activities. A total of 763 bird counts were carried out covering the entire elevation range in the study area (~175–2,650 m). We applied hierarchical distance-sampling models to assess elevation- and habitat-related variation in local abundance and obtain values of population density and total and effective population size. Most species were more abundant in the montane elevational range (1,800–2,650 m). Habitat-related differences in abundance were only detected for 5 species, which were more numerous in either early succession, secondary forest, or transformed areas. Inferences of effective population size indicated that at least 4 endemics likely maintain populations no larger than 15,000–20,000 mature individuals. Inferences of species' area of occupancy and effective population size were lower than most values previously described, a possible consequence of increasing anthropogenic threats. At least 4 of the endemics exceeded criteria for threatened species listing and a thorough evaluation of their extinction risk should be conducted. Population strongholds for most of the study species were located on the northern and western slopes of the SNSM between 1,500 and 2,700 m. We highlight the urgent need for facilitating effective protection of native vegetation in premontane and montane ecosystems to safeguard critical habitats for the SNSM's endemic avifauna. Follow-up studies collecting abundance data across the SNSM are needed to obtain precise range-wide density estimations for all species. [ABSTRACT FROM AUTHOR]

Variation in late Holocene artiodactyl (e.g., deer, pronghorn, bighorn sheep) hunting in northern California has often been examined from a behavioral ecological perspective to understand past foraging and land-use practices and related changes in human behavior, including settlement patterns, technological change, social signaling, large-scale resource intensification, and anthropogenic resource depression. However, rarely are past climate records and proxies of human population density coupled with zooarchaeological estimates of artiodactyl abundance to evaluate the ecological and anthropogenic drivers of changes in species representation over time. To better understand changes in human behavior related to past large game hunting, we disentangle the causal relationships between late Holocene climate change, human demography, and artiodactyl abundance to assess whether climate change, human hunting, or both impacted the abundance of artiodactyls in zooarchaeological assemblages from northeastern California. We evaluate how climatic variability and inferred human settlement density impacted artiodactyl abundance using modeled paleoclimatic reconstructions, distributions of radiocarbon dates, and faunal data derived from 35 archaeological sites and 37,319 individual faunal specimens. Using piecewise structural equation models, we assess the direct and mediating effects between climate, human settlement density, and artiodactyl abundance and determine the individual effects of these variables on large game species representation in zooarchaeological assemblages. We find that expanding human settlement density and related increases in logistical foraging—not late Holocene climate change—directly impacts the relative abundance of artiodactyls in these assemblages. Moreover, our findings reveal that the effects of climate change are entirely mediated through human settlement density. While our study is unable to decipher if observed changes in human behavior were motivated by goals related to energetic maximization or costly signaling, our study does provide a useful framework for separating the effects of human- and climate-induced explanations for variation in species composition in faunal assemblages. [ABSTRACT FROM AUTHOR]

Primates are declining worldwide and rapid infrastructure expansion, particularly roads, threatens their habitat. New roads fragment habitats allowing anthropogenic activities to occur in once pristine ecosystems; this is particularly impactful in tropical areas with high endemic biodiversity, as is occurring with primates in Colombia. However, temporal assessments of how roads impact local biodiversity are rare. We conducted a comprehensive assessment of the exposure of Colombian primates to roads from 1970 to 2015. Using a spatially explicit and species‐specific approach, we estimated the critical road density and the critical patch size primate species can withstand before going locally extinct. Then, overlapping 15 primate species (~40% of the primate species present in Colombia) ranges with Colombia's road networks over time, we determined the road expansion scope within each habitat and consequent fragmentation. Comparing the species critical road density and patch size, we determined the degree of road exposure of each species over time and its vulnerability to local extinction. Our results show that between 1970 and 2015, there were nearly 40 000 km2 where at least one species was at risk of local extinction, due to road expansion, principally in the Andean and Caribbean regions. Primates in these regions faced the greatest exposure to road impacts, with an average 16% increase in the amount of affected habitat during this period. Species in most need of conservation based on road exposure rankings are: Cebus versicolor, Aotus griseimembra, Ateles hybridus, Saguinus leucopus and Saguinus oedipus. Our study contributes to understanding road impacts on local biodiversity in one of the biodiversity hotspots across the tropics and highlights the need of infrastructure accounting for the necessary mitigation and conservation actions. [ABSTRACT FROM AUTHOR]

Connectivity is essential for the maintenance of genetic diversity and stability of wildlife populations. Drought and changing precipitation regimes have caused natural aquatic amphibian breeding habitats to disappear or become isolated and have led to the replacement of natural surface water with artificial livestock water tanks. Terrestrial movement is the only means of responding to aquatic threats in arid landscapes and to allow population connectivity. Aridity may present an impenetrable barrier in hydrologically fragmented environments. We used a facultatively paedomorphic and federally endangered salamander to assess the challenges of movement across arid working lands. Sonoran tiger salamanders (Ambystoma mavortium stebbinsi) are endemic to the San Rafael Valley of southeastern Arizona, United States of America, where they depend on livestock water tanks as breeding habitat. The ecology of this species' metamorphs outside of stock tanks is virtually unknown. To assess survival on the landscape during terrestrial movement we used radio‐transmitters to track 78 adult metamorphosed salamanders over 2 years. Sonoran tiger salamanders moved up to 1 km from the tank edge, and average distances moved of over 400 m were higher than most Ambystoma species. However, during the study period, none reached neighboring stock tanks. We found high mortality due to predation and desiccation. Individuals that dispersed to terrestrial habitat in summer survived longer than individuals that dispersed in spring. High mortality suggests terrestrial movement is exceptionally risky and may contribute to isolated subpopulations and elevated levels of inbreeding. Conservation actions that improve and maintain artificial aquatic habitats as well as increase connectivity may improve long‐term management for pond‐breeding amphibians in arid regions. [ABSTRACT FROM AUTHOR]

Dietary analysis in wildlife is fundamental for understanding their flexible response to seasonal changes and developing effective conservation management measures. Taihangshan macaque (Macaca mulatta tcheliensis) is the northernmost population of rhesus macaque, currently only distributed in the southern Mt. Taihangshan area. This area belongs to a semi‐arid region resulting in limited plant food availability for Taihangshan macaques, with seasonal variation. Herein, we used a chloroplast trnL DNA metabarcoding approach to identify the plant diet diversity and composition from 100 fecal samples of Taihangshan macaque in four seasons (spring, summer, autumn, and winter) from 2020 to 2021. The results revealed that (1) a total of 48 distinct families, 88 genera, and 52 species within the 105 food items that were consumed by Taihangshan macaques throughout the year; (2) the diversity of food items exhibited significant differences across the four seasons; (3) Rosaceae, Rhamnaceae, Fagaceae, and Poaceae are the preferential food items for Taihangshan macaques and have different relative abundances, fluctuating with seasonal variation. DNA metabarcoding can expand our understanding of the repertoire of food items consumed by Taihangshan macaques by detecting some consumed food items in this population that were not yet discovered using traditional methods. Therefore, the integrative results from traditional methods and DNA metabarcoding can provide a fundamental understanding of dietary composition to guide the conservation management of Taihangshan macaques. [ABSTRACT FROM AUTHOR]

Bottlenose dolphin (Tursiops) populations, also described as the Burrunan dolphins, consist of a resident population of approximately 150 individuals in Port Phillip Bay (PPB), Victoria. Previous reports indicate distribution across a small southern region of PPB; however, little is known about their full distribution patterns across the entire PPB region. Here, we investigate the spatiotemporal distribution of the Burrunan dolphins across four zones representative of PPB benthic habitats and bathymetry to gain a better understanding of the potential drivers of the population's habitat use. Port Phillip Bay, Victoria, Australia. One hundred and twenty‐nine boat‐based surveys were undertaken between March 2015 and August 2021, encompassing 181 sightings. Generalised linear models (GLMs) were used to investigate annual, seasonal and zonal variation. We found no variation in sighting frequencies between years. Austral summer and winter had a significantly higher sighting frequency than autumn. We found that Burrunan dolphins utilise the entire bay, further extending the species range, and show a significantly higher number of sightings in the southern zone than in any other zones. Overlaying dolphin sightings with known oceanographic characteristics within PPB, we found bathymetry and benthic habitats were potential drivers for the Burrunan dolphins distribution and habitat use within the bay, with the dolphins significantly favouring the 5–10 and 10–15 m contour depths. These results show a more widespread distribution across the bay than previously documented. We recommend expansion of the current marine protected areas in the north and south of the bay. This study has increased our understanding of the vital habitat for the Burrunan dolphin populations. By providing evidence‐based conservation recommendations, we hope to improve and contribute to future research, conservation management plans and effective marine protected areas across PPB for the resident Burrunan dolphin population. [ABSTRACT FROM AUTHOR]

The responsiveness of the hypothalamic–pituitary‐adrenocortical axis to stressors is crucial for wild animals to survive and adapt to environmental changes without compromising individual welfare. We analysed the influence of prior weather conditions, seasonality, the influx of ecotourism, and nutrition on stress levels in a wild population of red deer in a Mediterranean hunting reserve in the Pre‐Pyrenees, Spain. We used faecal cortisol metabolites as a proxy for physiological and psychological stress, and faecal triiodothyronine metabolites as an indicator of nutritional stress. Faecal analyses were chosen because it is a non‐invasive technique that does not alter an individual's behaviour, and it is easy to conduct in a wild population, something which presents added challenges due to the lack of a controlled environment. Our results indicate that prior weather conditions, rather than just seasonality, best explained the variations in these hormones within seasons and among years. On the contrary, the results showed that high levels of the cortisol hormone did not necessarily correspond to low levels of the triiodothyronine hormone. This could be a sign of acute nutritional stress in this population. Finally, we did not find an effect of the ecotourism influx on cortisol levels, suggesting that this deer population tolerates the presence of tourists. [ABSTRACT FROM AUTHOR]

The distribution and population density of the Critically Endangered Tarzan Chameleon (Calumma tarzan) in eastern humid forests of Madagascar was studied using line transect-distance sampling. Based on the results from species distribution models, eight sites were visited over a four-month period from February 2020 to March 2021. In total, 46 transects of 1 km were investigated in 23 different forest fragments to understand the distribution of C. tarzan. Another 28 transects of 200 m in length were surveyed to estimate population density. Among the 23 investigated forest fragments, C. tarzan was confirmed from 14 fragments belonging to five sites. All 14 records are completely new and represent a significant range extension for the species. Calumma tarzan is distributed within an elevation range of 604–1048 m above sea level. An analysis of the population of the species across sites show that density varies broadly and ranges from 25 to 78 individuals per hectare. This study fills important knowledge gap on a Critically Endangered and endemic chameleon species and is vital to the development of urgently needed conservation strategy for the Tarzan Chameleon. [ABSTRACT FROM AUTHOR]

Considerable work has examined the distribution of species under projected climate change, but empirical data are needed to support predicting change in abundance.I analysed populations of 17 saproxylic beetle species collected twice nightly from mid‐May to mid‐October from 2004 to 2015 at lights in Shizuoka, Japan, to investigate effects of two 100‐year hot summers (2010 and 2013) and correlated changes with June, July and August maximum temperatures. The first analysis examined the effect of heat stress and the second examined how populations tracked changes in temperature.I hypothesised that the responses would be species‐specific and could be related to interspecific variation in body size, voltinism, primary food source and the strength of density dependence.Heat stress was associated with population declines of five species during the same year and five other species in the following year. Conifer feeders were more likely to decline during the same year as the heat stress. Only one species tracked variation in maximum June temperature. Larger, later emerging species were more strongly detrimentally affected by high June temperatures than smaller, early emerging species. There was no relation between the response to heat stress and tracking June temperatures across species.The influence of summer temperature on saproxylic beetles was detectable from relatively short time series and occurred in a species‐specific manner. The effect of heat stress was more readily detected than correlated changes in abundance and temperature. Short time series may help reveal the response of insect populations to changing temperatures. [ABSTRACT FROM AUTHOR]

Simple Summary: The red fox (Vulpes vulpes), a member of the Canidae family, is found on all continents except Antarctica. In Croatia, red foxes are indigenous wild species that inhabit both the coastal and continental regions of the country. Neoplastic diseases are the leading cause of mortality in pet dogs, but wild members of the Canidae family can also develop tumors. Tumors in non-domestic canids are scarce; however, the true prevalence and diversity of these tumors are likely underestimated due to limited research. So far, only a limited number of tumors have been observed among the red fox population, either in their natural habitat or in captivity. The lack of wide-scale research on the incidence of neoplasia in the population of wild carnivora species in Croatia underscores the need for further investigation to enhance our understanding of tumors in foxes. In this study, conducted on a sample of 1890 red foxes, five tumor or tumor-like lesions were identified. These included two Meibomian gland adenomas, two collagenous hamartomas, and one teratoma. This research is the first of this kind in Croatia, shedding light on the occurrence and types of tumors in the red fox population. The red fox, found on all continents except Antarctica, occupies diverse habitats. In Croatia, it is an indigenous wild species with a population density of 0.7 animals per square kilometer. While tumors in wild animals from the Canidae family are scarce, the true prevalence and diversity of tumors are likely underestimated due to limited research. So far, a limited number of tumors have been observed among the red fox population, either in their natural habitat or in captivity. As part of the National Rabies Control Program, we examined 1890 red fox carcasses over a four-year period. Our focus was on identifying abnormalities on the skin and internal organs that suggest potential neoplastic proliferation. Five red foxes, three males and two females, were found to have growths resembling potential tumors. Their age distribution spanned from 2 to 7 years. Microscopic investigation revealed two collagenous hamartomas, two Meibomian gland adenomas, and one intra-abdominal teratoma within a cryptorchid testis. This retrospective study aims to provide a comprehensive description of tumor and tumor-like lesions observed in free-range red foxes from Croatia, marking the first research of its kind in Croatia. [ABSTRACT FROM AUTHOR]

Bat population estimates are typically made during winter, although this is only feasible for bats that aggregate in hibernacula. While it is essential to measure summer bat population sizes for management, we lack a reliable method. Acoustic surveys should be less expensive and more efficient than capture surveys, and acoustic activity data are already used as indices of population size. Although we currently cannot differentiate individual bats by their calls, we can enter call counts, information on signal and detection angles, and weather data into generalized random encounter models to estimate bat density. We assessed the utility of generalized random encounter models for estimating Indiana bat (Myotis sodalis) population density with acoustic data collected at 51 total sites in six conservation areas in northeast Missouri, 2019–2021. We tested the effects of year, volancy period, conservation area, and their interactions on estimated density. Volancy period was the best predictor, with average predicted density increasing 60% from pre‐volancy (46 bats/km2) to post‐volancy (74 bats/km2); however, the magnitude of the effect differed by conservation area. We showed that passive acoustic surveys yield informative density estimates that are responsive to temporal changes in bat population size, which suggests this method may be useful for long‐term monitoring. However, we need more information to choose the most appropriate values for the density estimation formula. Future work to refine this approach should include assessments of bat behavior and detection parameters and testing the method's efficacy in areas where population sizes are known. [ABSTRACT FROM AUTHOR]

The depopulation of rural areas in both developed and developing countries has become a complex problem with important implications for issues of equality and sustainability. We present a spatial exploratory analysis of the multidimensional factors related to the depopulation of Spain's rural areas. Using highly granular population data to estimate experienced population density allows us to highlight significant differences compared to the conventional administrative boundary in terms of the usual definition of densities. Based on this, we develop a new typology of declining rural areas that takes into account access to urban areas. While most rural areas have been suffering depopulation over the last decades, our results also show that rural areas themselves are not a homogeneous group and that rural areas show strong heterogeneity along different dimensions associated with growth and decline. [ABSTRACT FROM AUTHOR]

Wildlife conservation strategies focused on one season or population segment may fail to adequately protect populations, especially when a species' habitat preferences vary among seasons, age-classes, geographic regions, or other factors. Conservation of golden eagles (Aquila chrysaetos) is an example of such a complex scenario, in which the distribution, habitat use, and migratory strategies of this species of conservation concern vary by age-class, reproductive status, region, and season. Nonetheless, research aimed at mapping priority use areas to inform management of golden eagles in western North America has typically focused on territory-holding adults during the breeding period, largely to the exclusion of other seasons and life-history groups. To support population-wide conservation planning across the full annual cycle for golden eagles, we developed a distribution model for individuals in a season not typically evaluated–winter–and in an area of the interior western U.S. that is a high priority for conservation of the species. We used a large GPS-telemetry dataset and library of environmental variables to develop a machine-learning model to predict spatial variation in the relative intensity of use by golden eagles during winter in Wyoming, USA, and surrounding ecoregions. Based on a rigorous series of evaluations including cross-validation, withheld and independent data, our winter-season model accurately predicted spatial variation in intensity of use by multiple age- and life-history groups of eagles not associated with nesting territories (i.e., all age classes of long-distance migrants, and resident non-adults and adult "floaters", and movements of adult territory holders and their offspring outside their breeding territories). Important predictors in the model were wind and uplift (40.2% contribution), vegetation and landcover (27.9%), topography (14%), climate and weather (9.4%), and ecoregion (8.7%). Predicted areas of high-use winter habitat had relatively low spatial overlap with nesting habitat, suggesting a conservation strategy targeting high-use areas for one season would capture as much as half and as little as one quarter of high-use areas for the other season. The majority of predicted high-use habitat (top 10% quantile) occurred on private lands (55%); lands managed by states and the Bureau of Land Management (BLM) had a lower amount (33%), but higher concentration of high-use habitat than expected for their area (1.5–1.6x). These results will enable those involved in conservation and management of golden eagles in our study region to incorporate spatial prioritization of wintering habitat into their existing regulatory processes, land-use planning tasks, and conservation actions. [ABSTRACT FROM AUTHOR]

Large carnivores such as the jaguar Panthera onca are particularly susceptible to population decline and local extinction as a result of habitat loss. Here we report on the long-term monitoring of a local jaguar population in a mixed land-use area in the eastern lowlands of Bolivia from March 2017 to December 2019. We recorded 15 jaguar individuals and four reproduction events (five offspring from three females), suggesting that our study area harbours a resident breeding population. Seven iterations of spatially explicit capture–recapture models provided density estimates of 1.32–3.57 jaguars per 100 km2. Jaguar capture rates were highest in forested areas, with few to no jaguar captures in pastures used for livestock. Massive deforestation after the survey period reduced the proportion of dense forest cover by 33%, shrinking the availability of suitable jaguar habitat and placing the resident jaguar population at risk. We use the jaguar as an indicator species to highlight the threat of habitat destruction in the Chiquitano region and we emphasize the importance of intact forest patches for jaguar conservation. [ABSTRACT FROM AUTHOR]

Although the spotted hyaena (Crocuta crocuta) has been widely considered to be resilient to human disturbance, the species is now thought to be undergoing widespread population declines. Nevertheless, only a handful of population density estimates are available for the species, despite the importance of this information for informing conservation management. This is a consequence of both a lack of surveys and logistical challenges associated with processing spotted hyaena data. In this study, we collaborated with a cohort of students to process camera trap data from the Ruaha‐Rungwa landscape initially collected to estimate lion (Panthera leo) and leopard (Panthera pardus) population density. By doing so, we provide the first spatially explicit population density estimates for spotted hyaena in Tanzania, via spatially explicit capture‐recapture (SECR) modelling. We also examine the relationship between population densities of spotted hyaena, lion and leopard at each site. Spotted hyaena densities varied from 3.55 ± 0.72 adults and sub‐adults per 100 km2 in a miombo (Brachystegia‐Julbernardia) woodland area of Ruaha National Park, to 10.80 ± 1.08 per 100 km2 in a prey‐rich open woodland savannah habitat in Ruaha National Park, with intermediate densities recorded in Rungwa Game Reserve and MBOMIPA Wildlife Management Area. Our results suggest that spotted hyaena density is influenced by prey availability and protection, and the species may be less resilient to human pressures than widely thought. Spotted hyaena densities were generally positively correlated with densities of lion and leopard, suggesting that prey availability and anthropogenic disturbance had a greater impact than interspecific effects in shaping large carnivore densities in this system. Overall, our study provides some of the first insights into an under‐studied species in an under‐researched part of its range, while shedding light into the impact of anthropogenic versus interspecific effects in shaping population status of spotted hyaena in human‐impacted African systems. [ABSTRACT FROM AUTHOR]

This article discusses the impact of extreme rainfall on the yellow-bellied toad Bombina variegata, an endangered species found in Europe. The toad typically breeds in small ponds, but heavy rain can flush out the tadpoles and even destroy their habitats. The study conducted in southern Poland found that after a torrential downpour, tadpole numbers decreased in all the ponds surveyed, with natural ponds being the most affected. The findings highlight the potential dangers of heavy rainfall on breeding sites and suggest the need for conservation efforts to consider the location of breeding ponds in relation to stream banks and local relief. Additionally, the article emphasizes the potential impact of climate change on the toad's population, as changes in local rainfall patterns can increase the risk of flash floods and further endanger the species. [Extracted from the article]

Northern bobwhite (Colinus virginianus) populations have declined across much of their range. In response to these declines, wildlife biologists and managers have increased survey efforts and tried to optimize detection and capitalize on technological advances to improve population estimates and cost‐effectiveness. Our objective was to determine how environmental conditions influence detection of the reproduction call, or whistle, of masked bobwhite (C. v. ridgwayi), an endangered subspecies of northern bobwhite, using autonomous recording units (ARUs). We estimated the call intensity of the masked bobwhite reproduction call as 112 ± 0.5 decibels (mean ± SE) at 10 cm. We then broadcasted 16,284 calls during 17 trials to compare manual and automated call detection in recordings collected with ARUs. We used these data to model detectability of a bobwhite reproduction call, for when the bird is present and available, as a function of distance and weather conditions using generalized linear mixed models with trial as a random effect. Regardless of detection type, one model structure was competitive and suggested detection probability was a function of distance, wind speed, and wind direction. Detectability decreased with increased distance and wind speed and was influenced by wind direction. We demonstrate the use of our results to predict the probability of detecting a reproduction call during ARU‐based monitoring efforts. By understanding the effects of environmental factors on the detection of a bobwhite reproductive call, bobwhite surveys can be improved. [ABSTRACT FROM AUTHOR]

Designing monitoring with adequate certainty to evaluate management actions can be challenging, especially for elusive species in relatively inaccessible habitats. The diamond‐backed terrapin (Malaclemys terrapin) is considered a high priority species for management in all states within its range. Among key threats to terrapin populations is bycatch mortality in crab pots, prompting states throughout the species' range to consider crabbing regulations and creating a need for a monitoring approach able to evaluate the success of any new crabbing regulations to benefit terrapins. Because terrapins occupy extensive and often difficult to access estuarine habitat, it is hard to collect sufficient data to estimate population responses accurately and precisely for management. To assist state managers with decisions regarding monitoring bycatch reduction regulations, we modeled 12 years of terrapin capture‐recapture data. We used estimates from those models to simulate capture‐recapture data pre‐ and post‐implementation of bycatch reduction that resulted in a 0.20 absolute increase in mean apparent survival probability. Results indicated weak reliability of a monitoring approach using only manual seining of tidal creeks to detect a real management effect, with a positive management effect detected at the 95% certainty level only 34% of the time. When we considered 85% and 75% certainty thresholds, we detected a positive effect on survival among 61% and 75% of simulations, respectively. Low within‐year recapture probability and the effect of tide amplitude on terrapin availability indicate there is low feasibility of improving monitoring precision at a single site, requiring monitoring of more sites to improve confidence in the detection of the management effect. The number of sites monitored depends on the acceptable level of certainty. We recommend that researchers and management entities that use seining assess the level of certainty they require to evaluate management actions and increase the number of sites sampled to meet that level of certainty. Additionally, the use of multiple monitoring methods and integrated models should be explored to reduce uncertainty and to allow for easier monitoring of more populations over broader spatial scales. [ABSTRACT FROM AUTHOR]

Aim: Unspecific bone uptake is one of the main limitations of PET imaging with some PSMA-targeting radiopharmaceuticals, especially with [18F]PSMA-1007. We explored the potential association between osteoporosis and the occurrence of unspecific [18F]PSMA-1007 bone uptake investigating markers which might correlate with bone mineral density. Materials and methods: We retrospectively analyzed treatment-naïve patients with a confirmed diagnosis of prostate adenocarcinoma who underwent staging [18F]PSMA-1007 positron emission tomography (PET). Qualitative image analysis was performed independently by three experienced nuclear medicine physicians. Patients were divided in two groups according to the presence/absence of unspecific bone uptake. Clinical information, blood count parameters (assessed within 3 months to the PET scan), body mass index (BMI), and bone density as estimated by computed tomography were collected. The Kruskal–Wallis and t-test were used to compare parameters. Results: We analyzed 77 patients: 29 of them (38%) had unspecific bone uptake at [18F]PSMA-1007 PET, most commonly in the pelvic bones (69%) and ribs (62%). We did not find any significant difference in clinical parameters in the two groups. In patients with unspecific bone uptake, white blood cell, and neutrophil counts were significantly higher; in the same group, we observed lower values of BMI and bone density, although not statistically different. Conclusions: We observed unspecific bone uptake on [18F]PSMA-1007 PET in more than 1/3 of patients. In this exploratory analysis, we found a significant correlation between blood count parameters and unspecific [18F]PSMA-1007 bone uptake. We may speculate that [18F]PSMA-1007 unspecific bone uptake could be associated with osteoporosis. This hypothesis needs to be further investigated in larger populations and exploring more specific markers of osteoporosis. [ABSTRACT FROM AUTHOR]

Spatial population synchrony, defined as spatial covariation in population density fluctuations, exists across different temporal and spatial scales. Determining the degree of spatial synchrony is useful for inferring environmental drivers of population variability in the wake of climate change. In this study, we applied novel statistical methods to detect spatial synchrony patterns of Calanus finmarchicus on the Northeast U.S. Shelf at multiple spatiotemporal scales using unevenly distributed data. Our results reveal that C. finmarchicus subpopulations connected by advection are not necessarily in synchrony, indicating that the degree of synchrony is likely influenced by heterogeneity of local habitats. In addition, regionally synchronous environmental conditions (e.g., sea surface temperature) may not play as significant a role in influencing subregional population dynamics as was previously hypothesized. Overlooking the spatial heterogeneity of synchronous patterns at different time scales could lead to erroneous inferences of potential environmental drivers responsible for C. finmarchicus variability. [ABSTRACT FROM AUTHOR]

Megaherbivores play "outsized" roles in ecosystem functioning but are vulnerable to human impacts such as overhunting, land‐use changes, and climate extremes. However, such impacts—and combinations of these impacts—on population dynamics are rarely examined using empirical data. To guide effective conservation actions under increasing global‐change pressures, we developed a socially structured individual‐based model (IBM) using long‐term demographic data from female giraffes (Giraffa camelopardalis) in a human‐influenced landscape in northern Tanzania, the Tarangire Ecosystem. This unfenced system includes savanna habitats with a wide gradient of anthropogenic pressures, from national parks, a wildlife ranch and community conservation areas, to unprotected village lands. We then simulated and projected over 50 years how realistic environmental and land‐use management changes might affect this metapopulation of female giraffes. Scenarios included: (1) anthropogenic land‐use changes including roads and agricultural/urban expansion; (2) reduction or improvement in wildlife law enforcement measures; (3) changes in populations of natural predators and migratory alternative prey; and (4) increases in rainfall as predicted for East Africa. The factor causing the greatest risk of rapid declines in female giraffe abundance in our simulations was a reduction in law enforcement leading to more poaching. Other threats decreased abundances of giraffes, but improving law enforcement in both of the study area's protected areas mitigated these impacts: a 0.01 increase in giraffe survival probability from improved law enforcement mitigated a 25% rise in heavy rainfall events by increasing abundance 19%, and mitigated the expansion of towns and blockage of dispersal movements by increasing abundance 22%. Our IBM enabled us to further quantify fine‐scale abundance changes among female giraffe social communities, revealing potential source–sink interactions within the metapopulation. This flexible methodology can be adapted to test additional ecological questions in this landscape, or to model populations of giraffes or other species in different ecosystems. [ABSTRACT FROM AUTHOR]

Many gibbon species are threatened with extinction, including the endangered northern yellow-cheeked crested gibbon, Nomascus annamensis. Assessing gibbon populations and understanding how human disturbances and environmental factors impact these populations is vital for effective conservation planning. In 2010, auditory surveys revealed that Veun Sai-Siem Pang National Park (VSSP) in Cambodia contains one of the largest known N. annamensis populations in the world, with an estimated 456 (95% CI 421–490) gibbon groups. Illegal selective logging is common in the park, but the impact of continued logging on the gibbon population has not been investigated. To determine any change in the N. annamensis population since 2010, between January and April 2019 we conducted auditory surveys at 13 sites that were at least 4 km apart. We surveyed each site for three days, each day recording the gibbon calls heard over 3.25 hours from three listening posts located 500 m apart. At the same sites, we assessed the logging intensity using transects and ecological plots. Gibbon densities can be influenced by various environmental factors such as canopy height and forest type. Therefore, in addition to investigating the relationship between the density of N. annamensis groups and logging, we included five additional environmental variables in our acoustic spatial capture-recapture models. Our best fit model with the lowest AIC value included canopy height, forest type, distance to villages, and logging. We estimate that there are 389 (95% CI 284–542) N. annamensis groups currently in VSSP. Selective logging is widespread in the park, primarily targeting four tree species. The estimated felling time of these logged trees, together with previous reports, indicate that the species most targeted in VSSP varies over time. To conserve the N. annamensis population in VSSP, it is crucial that action is taken to reduce illegal logging. [ABSTRACT FROM AUTHOR]

In the Anthropocene era, understanding the impact of climate change on niche shift, species distribution, and habitat change is increasingly important for the conservation of biodiversity. In this respect, species distribution models have been considered an important tool over the last decade. The present study illustrates distributional change, niche dynamics and climatic shifts of Saraca asoca (Roxb.) De Wilde in India, a proven medicinal plant and a listed threatened species by IUCN, under different climate change scenarios using MaxEnt. The robustness of the model was satisfactory (AUC = 0.936), indicating a good fit. There could be a significant gain in suitable habitat between the present and future scenarios, ranging from a minimum of 52,275.17 km² (RCP 2.6) to a maximum of 95,994.62 km² (RCP 4.5). In the future, the suitable habitat range would shift towards colder regions of India, where cultivation of S. asoca could be taken up, thus enabling effective management of the natural habitat and population of the species. This study will help understand the effects of climate change on S. asoca and its implications for conservation of the species. [ABSTRACT FROM AUTHOR]

The Karner blue butterfly (Lycaeides melissa samuelis, or Kbb), a federally endangered species under the U.S. Endangered Species Act in decline due to habitat loss, can be further threatened by climate change. Evaluating how climate shapes the population trend of the Kbb can help in the development of adaptive management plans. Current demographic models for the Kbb incorporate in either a density-dependent or density-independent manner. We instead created mixed density-dependent and -independent (hereafter "endo-exogenous") models for Kbbs based on long-term count data of five isolated populations in the upper Midwest, United States during two flight periods (May to June and July to August) to understand how the growth rates were related to previous population densities and abiotic environmental conditions, including various macro- and micro-climatic variables. Our endo-exogenous extinction risk models showed that both density-dependent and -independent components were vital drivers of the historical population trends. However, climate change impacts were not always detrimental to Kbbs. Despite the decrease of population growth rate with higher overwinter temperatures and spring precipitations in the first generation, the growth rate increased with higher summer temperatures and precipitations in the second generation. We concluded that finer spatiotemporally scaled models could be more rewarding in guiding the decision-making process of Kbb restoration under climate change. [ABSTRACT FROM AUTHOR]

Introduction: The coastal form of pantropical spotted dolphins (Stenella attenuata graffmani) is commonly found along the Pacific coast of Costa Rica. Within Golfo Dulce, a fiord-like-embayment bordering the Osa Peninsula, pantropical spotted dolphins are sympatric with inshore bottlenose dolphins (Tursiops truncatus) and these marine predators provide an important source of revenue for local communities through boat-based tours. Objective: Here we estimated the population size and demographic parameters of the coastal pantropical spotted dolphins in Golfo Dulce. Methods: The study area was surveyed using non-random boat surveys. Upon encounter, dolphins were individually photo-identified using natural marks in their dorsal fins to estimate population abundance and survival using three emigration scenarios. Results: A total of 280 dolphins were photoidentified, 65 % of which were observed only once. A total of 30 models were produced, and only two were considered to be parsimonious. Both models explain seasonal apparent survival and its variation due to heterogeneity in capture-recapture probability, one under no emigration (ΔQAICc = 0.00) and the other under random emigration (ΔQAICc = 1.72). We deemed the latter to be a more realistic model as it better reflects our in-situ observations. Under this preferred model the population size of pantropical spotted dolphins in Golfo Dulce varied from 187.30 individuals (CI: 168.67 - 208.02, CV: 0.11) to 367.88 individuals (CI: 341.51 - 396.31, CV: 0.07), with no significant differences in abundance due to seasonality and very high apparent survival (S = 0.98, CI: 0.68 - 0.99, SE: 0.02). Conclusions: The number of identified dolphins and the proportion of individuals seen only once suggest the fluid movement of the population in and out of the gulf. However, the population size and demographic estimates are characterized by several identified individuals regularly recaptured inside the gulf. This group of dolphins appears to favor the inner basin as a critical foraging habitat. Given the increase of anthropogenic impacts within Golfo Dulce, future management and conservation efforts will require the recognition of an ecologically discrete population unit of coastal pantropical spotted dolphins within the gulf. [ABSTRACT FROM AUTHOR]

Bioenergetic models are tools that allow the evaluation of the effect of environmental variables on fish growth. Successful implementation of this approach has been achieved in a few elasmobranch species. Our objective was to develop a bioenergetic model for Mustelus schmitti. The model developed showed a good fit to the field data available and accurately described the growth of this species. The practical example developed in this study provides novel population estimates of prey consumption and daily ration for the species. Results also indicate that this species would be susceptible to the effects of climate change. In the simulated climate change scenarios, the energy budget of M. schmitti was significantly altered, with increased food consumption and impaired growth. While there exists a number of limitations for the model developed in this article, namely its limitation to immature individuals, and its restricted temperature model, it provides an important tool for the management of this and other shark populations under heavy exploitation. [ABSTRACT FROM AUTHOR]

Several methods exist to estimate the census population size such as capture‐recapture (CR) methods, which require the direct or indirect capture and recapture of numerous animals across a large area. These methods are difficult to apply to small and medium‐sized carnivorous mammals because of their elusive nature, and also do not work if the sampling method is lethal at first physical capture, a problem relevant when analyzing data from exploited populations. We present a method that uses dead recoveries from hunting bags and other sources of mortality to estimate population size. Each individual is physically trapped once at the end of its capture history (dead recovery), and is considered recaptured on previous trapping occasions if it is genetically identified as the parent of one or several young. We used this parentage information to build capture histories of aged and sexed individuals, and then applied classic CR models for closed populations. We applied this method to the stone marten (Martes foina), an elusive medium‐sized carnivorous mammal in the Bresse Region of France (911 km2) and for which reliably estimating population size remains challenging but important for efficient management. To estimate the robustness of our approach, we also simulated population pedigrees with known population size and determined its accuracy, precision, and sensitivity to the true population size and sampling intensity. Stone marten population size was estimated at N^ $\hat{N}$ = 1,748 ± 341 (SD) individuals leading to a population density of D^ $\hat{D}$ = 1.92 ± 0.37 individuals/km2, which is within the range of the few previous density estimations of the species in rural or urban areas. Our method was not affected by population size, and reached the required levels of accuracy and precision to be effective in wildlife management for a given range of sampling intensity. It therefore demonstrated its widespread use in improving estimates of population size from age‐ and sex‐structured pedigree data coming from multi‐year dead recoveries. [ABSTRACT FROM AUTHOR]

Motion‐sensitive cameras are popular as non‐invasive monitoring tools, and several methods have been developed to estimate population densities from camera data. These methods frequently rely on auxiliary movement data including the distance traveled by an individual in a day and the proportion of the day that an animal spends moving when individual recognition is not possible. The estimation of these movement parameters is time‐consuming, which could limit the applicability of cameras to estimate population density. To investigate the relevance of measuring movement parameters for the target population, we monitored 54 wildlife populations of red deer (Cervus elaphus), fallow deer (Dama dama), roe deer (Capreolus capreolus), wild boar (Sus scrofa), and red fox (Vulpes vulpes) in different seasons through Europe with cameras. We estimated 91‐day ranges and activity levels. We fitted mixed models for day range and activity level as response variables to assess if the inter‐population variability in movement was explained by a set of a priori relevant geographical, environmental, biological, and management predictors. We then explored the bias in density estimates obtained in 25 independent populations when using predicted movement data. There was high intra‐species variation in day range and activity level among species and populations. Only species explained a small proportion of this variability; other predictor variables did not. We observed bias in densities when predicting the day range and activity for independent populations. Considering the intra‐species variability in movement parameters and the consequent unacceptable bias in density estimates, we recommend that monitoring and conservation programs estimate movement parameters for the target population and survey populations from camera data for more accurate density estimates. While this increases the handling time needed to estimate densities, it is worth the cost because of the reliability of camera‐based methodologies to estimate needed movement parameters. [ABSTRACT FROM AUTHOR]

Large carnivores face numerous threats, including habitat loss and fragmentation, direct killing, and prey depletion, leading to significant global range and population declines. Despite such threats, leopards (Panthera pardus) persist outside protected areas throughout most of their range, occupying diverse habitat types and land uses, including peri-urban and rural areas. Understanding of leopard population dynamics in mixed-use landscapes is limited, especially in South Africa, where the majority of leopard research has focused on protected areas. We use spatially explicit capture-recapture models to estimate leopard density across a mixed-use landscape of protected areas, farmland, and urban areas in the Overberg region of the Western Cape, South Africa. Data from 86 paired camera stations provided 221 independent captures of 25 leopards at 50 camera trap stations with a population density estimate of 0.64 leopards per 100 km2 (95% CI: 0.55–0.73). Elevation, terrain ruggedness, and vegetation productivity were important drivers of leopard density in the landscape, being highest on elevated remnants of natural land outside of protected areas. These results are similar to previous research findings in other parts of the Western Cape, where high-lying natural vegetation was shown to serve as both a refuge and a corridor for leopard movement in otherwise transformed landscapes. Given the low leopard density and the prevalence of transformed land intermixed with patches of more suitable leopard habitat, prioritising and preserving connectivity for leopards is vital in this shared landscape. Ecological corridors should be developed in partnership with private landowners through an inclusive and multifaceted conservation strategy which also incorporates monitoring of and rapid mitigation of emerging threats to leopards. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we utilized the methods of spatiotemporal analysis to reveal and visualize the areas in the Russian Federation where an increased density of wild boar population might be related to the concentration of African swine fever (ASF) cases in wild boar. We demonstrated the areas (at the municipality level), where the elevated wild boar population density has continued to rise in recent years, that may be treated as high-risk areas, subject to the application of enhanced surveillance and population control measures. African swine fever (ASF) is an infectious disease that affects both domestic pigs (DPs) and wild boar (WB). The WB population plays an important role in the spread of ASF as the WB acts as a natural reservoir of the virus and transmits it to other susceptible wild and domestic pigs. Our study was aimed at revealing the areas with a high concentration of the WB population, and their potential relationships with the grouping of ASF cases in WB during the course of the ASF spread in the Russian Federation (2007–2022). We collected the annual data on WB numbers by municipalities within the regions of the most intensive ASF spread. We then conducted spatiotemporal analysis to identify clustering areas of ASF cases and compare them with the territories with a high density of WB population. We found that some of the territories with elevated ASF incidence in WB demonstrated spatial and temporal coincidence with the areas with a high WB population density. We also visualized the zones ("emerging hot spots") with a statistically significant rise in the WB population density in recent years, which may be treated as areas of paramount importance for the application of surveillance measures and WB population control. [ABSTRACT FROM AUTHOR]

The conservation and management of wildlife populations, particularly for threatened and endangered species are greatly aided with abundance, growth rate, and density measures. Traditional methods of estimating abundance and related metrics represent trade‐offs in effort and precision of estimates. Pedigree reconstruction is an emerging, attractive alternate approach because its use of one‐time, noninvasive sampling of individuals to infer the existence of unsampled individuals. However, advances in pedigree reconstruction could improve its utility, including forming a measure of precision for the method, establishing required spatial sampling effort for accurate estimates, ascertaining the spatial extent of abundance estimates derived from pedigree reconstruction, and assessing how population density affects the estimator's performance. Using established relationships for a stochastic, spatially explicit simulated moose (Alces americanus) population, pedigree reconstruction provided accurate estimates of the adult moose population size and trend. Novel bootstrapped confidence intervals performed as expected with intensive sampling but underperformed with moderate sampling efforts that could produce abundance estimates with low bias. Adult population estimates more closely reflected the total number of adults in the extant population, rather than number of adults inhabiting the area where sampling occurred. Increasing sampling effort, measured as the proportion of individuals sampled and as the proportion of a hypothetical study area, yielded similar asymptotic patterns over time. Simulations indicated a positive relationship between animal density and sampling effort required for unbiased estimates. These results indicate that pedigree reconstruction can produce accurate abundance estimates and may be particularly valuable for surveying smaller areas and low‐density populations. [ABSTRACT FROM AUTHOR]

Host-pathogen dynamics are influenced by many factors that vary locally, but models of disease rarely consider dynamics across spatially heterogeneous environments. In addition, theory predicts that dispersal will influence host-pathogen dynamics of populations that are linked, although this has not been examined empirically in natural systems. We examined the spatial dynamics of a patchy population of tiger moths and its baculovirus pathogen, in which habitat type and weather influence dynamics. Theoretical models of host-baculovirus dynamics predict that such variation in dynamics between habitat types could be driven by a range of factors, of which we predict two are likely to be operating in this system: (1) differences in the environmental persistence of pathogens or (2) differences in host intrinsic rates of increase. We used time series models and monitored infection rates of hosts to characterize population and disease dynamics and distinguish between these possibilities. We also examined the role of host dispersal (connectivity) and weather as important contributors to dynamics, using time series models and experiments. We found that the population growth rate was higher, delayed density dependence was weaker, and long-period oscillations had lower amplitudes in high-quality habitat patches. The infection rate was higher on average in high-quality habitat, and this was likely to have been driven by higher mean population densities and no differences in pathogen persistence in different habitats (delayed density dependence). Time series modeling and experiments also showed an interactive effect of temperature and precipitation on moth population growth rates (likely caused by variation in host plant quality and quantity), and an effect of connectivity. Our results showed that spatial heterogeneity, connectivity, climate, and their interactions were important in driving host-baculovirus dynamics. In particular, our study found that connected patches and spatial heterogeneity generated differences in dynamics that only partially aligned with theoretical predictions. [ABSTRACT FROM AUTHOR]

The article proposes a hypothesis for the functioning of a diatom population under conditions of clearly defined water column stratification. It is assumed that cells in the upper illuminated water layer accumulate biomass based on photosynthesis. In the lower layer, which is rich in minerals, cells replenish their intracellular reserves. Movement from one layer to another allows cells to compensate for lack of resources. Sinking occurs as a result of sedimentation and lifting results from the release of carbon dioxide microbubbles during respiration. This hypothesis was used to construct an agent-based model of a diatom population. Calculations have shown that vertical movements maintain the existence of the population. Different regimes of surface illumination make it possible to obtain various distributions of cell numbers in the upper and lower water layers, which is consistent with the data of expeditionary observations. [ABSTRACT FROM AUTHOR]

Sex-specific differences in habitat selection and space use are common in ungulates. Yet, it is largely unknown how this behavioral dimorphism, ultimately leading to sexual segregation, translates to population-level patterns and density gradients across landscapes. Alpine chamois (Rupicapra rupicapra r.) predominantly occupy habitat above tree line, yet especially males may also take advantage of forested habitats. To estimate male and female chamois density and determinants thereof, we applied Bayesian spatial capture-recapture (SCR) models in two contrasting study areas in the Alps, Germany, during autumn. We fitted SCR models to non-invasive individual encounter data derived from genotyped feces. Sex-specific densities were modeled as a function of terrain ruggedness, forest canopy cover, proportion of barren ground, and site severity. We detected pronounced differences in male and female density patterns, driven primarily by terrain ruggedness, rather than by sex-specific effects of canopy cover. The positive effect of ruggedness on density was weaker for males which translated into a higher proportion of males occupying less variable terrain, frequently located in forests, compared to females. By estimating sex-specific variation in both detection probabilities and density, we were able to quantify and map how individual behavioral differences scale up and shape spatial patterns in population density. Non-invasive fecal genotyping on Alpine chamois (Rupicapra rupicapra) in combination with spatial capture recapture models reveal sex-specific density patterns, which are driven by environmental features. [ABSTRACT FROM AUTHOR]

Simple Summary: We estimated the population density and the population size of feral donkeys in northwest Saudi Arabia. The estimated overall population density was 1.03 (0.19 SE) donkey/km2 and an abundance at ~1135 individuals. The negative impact of feral donkeys on natural resources included overgrazing, habitat fragmentation, and competition for resources with native species. Our study adds evidence to the detrimental impacts of feral donkeys and calls for urgent actions to control the presence of feral donkeys in the region. We recommend humane eradication for controlling the feral donkeys as it would be the most efficient and applicable action that can significantly abate the feral donkeys' negative impacts. The feral donkey (Equus asinus L.) is an invasive species in Saudi Arabia and can cause severe damage to natural and cultural heritage. Over the last 30 years, feral donkeys have become a serious problem, as their abundance and geographic distribution has increased drastically. The impacts of feral donkeys are not well documented, and information about their abundance and distribution is lacking, certainly in Saudi Arabia, which hampers the implementation of effective management plans. Accordingly, we used the minimum population number approach (MPN) to determine the number of feral donkeys in this part of northwest Saudi Arabia. A total of 1135 feral donkeys were encountered in the region. The area around Khaybar harbors ~25% (n = 338) of the feral donkey population, whereas Tayma and AlGhrameel nature reserves were the least-inhabited sites (almost absent). The average population density of feral donkeys was estimated as 1.03 (0.19 SE) donkey/km2. We documented the negative ecological impact of feral donkeys on natural resources, which constituted overgrazing that resulted in habitat fragmentation and competition for resources with native species. We propose urgent actions to control the presence of feral donkeys in the region and suggest humane eradication as the most efficient and applicable to significantly reduce the negative impacts of feral donkeys. [ABSTRACT FROM AUTHOR]

Noninvasive data collection methods are increasingly used to monitor endangered, cryptic, or otherwise difficult to observe wildlife populations. Spatial capture‐recapture and count‐based statistical methods are often used to model these data to derive population estimates, each with their own advantages. The goal of our study was to integrate these 2 data sources and model structures to maximize the use of single‐season surveys in which capture‐recapture and count‐based data are collected. We formulated a Bayesian spatial, closed integrated population model (cIPM) that leverages scat DNA‐based spatial capture‐recapture and camera‐based spatial count sub‐models to derive sex and age class‐specific population estimates. Our cIPM has the advantage of sharing the spatial scaling (σ) parameter directly between sub‐models and drawing proposed individuals from the same data‐augmented superpopulation for each sub‐model. This allows for separate estimation of sex and age‐class groups simultaneously without any assumptions of population structure or conversions between model output types. We applied our cIPM to a wild population of Roosevelt elk (Cervus canadensis roosevelti, Karuk: íshyuux) during winter 2018–2019 in their winter range within Karuk Ancestral Territory in northern California, USA. We also conducted a simulation study to test our cIPM on a known population consisting of 2 age classes and 2 sexes. The cIPM was able to estimate most population, detection, and σ parameters with good accuracy, including population size. The assignment of sex and age was biased, however, resulting in fewer juvenile males, more juvenile females, and more adult males. Our cIPM applied to the data estimated approximately 310 (95% CI = 235–411) female adults, 90 (95% CI = 57–134) male adults, 75 (95% CI = 43–149) female calves, and 23 (95% CI = 12–47) male calves. These estimates were different from those that would have been made had we relied on common assumptions such as equal calf sex ratios, though this ratio was likely biased towards females based on our simulation results. Our methods are widely applicable and maximize the amount of information available to managers and researchers from any single‐season survey in which separate data sources capturing sex and age‐class information are obtained. [ABSTRACT FROM AUTHOR]

The China-Pakistan Economic Corridor is of great importance in the Belt and Road Initiative. Meteorological and hydrological disasters frequently occur under the background of global change in the China-Pakistan Economic Corridor region. Risk assessment of meteorological and hydrological disasters can greatly contribute to disaster prevention and mitigation in this area. In this review, the integrated risk assessment was performed on the magnitude and likelihood of potential losses caused by hydrometeorological disasters (such as floods, droughts, terrestrial rain, and extreme high/low temperatures). Specifically, a systematic framework of risk assessment was constructed, where the hazards, exposure, and vulnerability were taken as the factors of increased risk, whereas, resilience was a factor of reduced risk. Meteorological and hydrological data was collected from 1961 to 2015, including the maximum and minimum temperatures, and precipitation, as well as the standardized precipitation evapotranspiration index (SPEI). The terrain data (such as elevation and slope) was supplemented with socio-economic indicators, including population density, population structure, proportion of cultivated land area, cropped area, road density, and GDP. A weighted sum method was proposed to integrate the subjective analytic hierarchy process and objective entropy theory (analytic hierarchy process-entropy weight methodology), in order to obtain the weights of hazard and vulnerability indicators. Finally, the integrated risk assessment of meteorological and hydrological disasters was conducted using the risk matrix and Borda count method. The region was classified into different risk levels. The results indicate that: 1) The high-risk areas of hydrometeorological disasters were located mainly in Sindh and Punjab Provinces of Pakistan, covering approximately 9% of the total area of the China-Pakistan Economic Corridor. 2) The comprehensive vulnerability of the exposed elements showed that Balochistan, Sindh, Punjab, and Khyber Pakhtunkhwa Provinces in Pakistan shared relatively higher vulnerability levels, while Kashgar in China exhibited a relatively lower vulnerability level. The higher exposure level in Punjab was attributed to the high population density. The high sensitivity level was found in the eastern part of Sindh and the western part of Balochistan. However, the recovery capacity in Punjab was relatively high, which reduced the overall vulnerability. 3) Different regions of risk levels were divided using the risk matrix method. High-risk areas were distributed mainly in Sindh Province, the northern and southern regions of Punjab Province, the part areas of Khyber Pakhtunkhwa Province, and the western region of Balochistan Province. Meanwhile, the low-risk areas were distributed mainly in Gilgit-Baltistan (northern region) of Pakistan and Kashgar region of China. The areas with the low, moderate-low, moderate, and high integrated risk levels accounted for 14.09%, 17.27%, 37.70%, and 30.94% of the total, respectively. The percentage of high-risk zones was 66.50%, 60.00%, and 47.57%, respectively, in Sindh Province, Azad Kashmir in Pakistan, and Punjab Province. 51 counties were classified as the high-risk category at the county level. Furthermore, the highest comprehensive risk levels were found in Islamabad and Lahore of Pakistan after risk elimination using the Borda count method, whereas, the lowest comprehensive risk levels were in the Wuqia County of China and Ziarat County of Pakistan. The findings can also provide valuable technical references for the prevention and mitigation of hydrometeorological disasters in the China-Pakistan Economic Corridor. [ABSTRACT FROM AUTHOR]

Assuming a non-neutral impact of space, an explicit assessment of metropolitan hierarchies based on local regression models produces a refined description of population settlement patterns and processes over time. We used Geographically Weighted Regressions (GWR) to provide an enriched interpretation of the density gradient in Greece, estimating a spatially explicit rank–size relationship inspired by Zipf's law. The empirical results of the GWR models quantified the adherence of real data (municipal population density as a predictor of metropolitan hierarchy) to the operational assumptions of the rank–size relationship. Local deviations from its prediction were explained considering the peculiarity of the metropolitan cycle (1961–2011) in the country. Although preliminary and exploratory, these findings decomposed representative population dynamics in two stages of the cycle (namely urbanization, 1961–1991, and suburbanization, 1991–2011). Being in line with earlier studies, this timing allowed a geographical interpretation of the evolution of a particularly complex metropolitan system with intense (urban) primacy and a weak level of rural development over a sufficiently long time interval. Introducing a spatially explicit estimation of the rank–size relationship at detailed territorial resolutions provided an original contribution to regional science, covering broad geographical scales. [ABSTRACT FROM AUTHOR]

New Zealand's economically vital exotic pastures are unique in their low complexity making them highly susceptible to invasive pest species such as the Argentine stem weevil Listronotus bonariensis. This field-based contribution further examined the ecology of the adult weevil and its parasitoid control agent Microctonus hyperodae. This included factors that affect field sampling accuracy, interpretation of population density and parasitism estimates. Compared to adult population estimates measured via turf flotation, suction sampling (G-vac) showed c.30% under-estimation of population densities while parasitism rates were over-estimated by c.26%. The bionomic implications of the sampling biases are discussed as they relate to the recently observed sharp declines in L. bonariensis parasitism. The weevil's field parasitism rates showed no relationship to population density again confirming the parasitoid's very high host searching efficiency. This study also coincided with meteorological conditions (>30°C) that resulted in a very large L. bonariensis 'swarming' event. The mass emigration from the experimental plots left only a low residual population of parasitised weevils that typically do not fly. Therefore, measured L. bonariensis populations and their M. hyperodae parasitism levels cannot always be presumed to be solely the result of population dynamics in situ. [ABSTRACT FROM AUTHOR]

Climate and landcover change can have synergistic impacts on wildlife populations, but the pervasiveness of these threats and factors that buffer them remain unclear despite important implications for conservation. I evaluated the additive and interactive effects of spatiotemporal variation in temperature, precipitation, and landcover change on annual territory occupancy, colonization, and extinction of a threatened top‐predator, the ferruginous pygmy‐owl (Glaucidium brasilianum), across a vast binational region of the Sonoran Desert over 16 years. I also assessed how local habitat quality and regional population size mediate impacts of these stressors. Despite significant bivariate associations between occupancy and temperature, precipitation, and landcover change, evidence for interactions was much greater than for additive effects. Occupancy of territories imbedded in increasingly disturbed landscapes declined at greater rates with warming winter temperatures, but the temperature had little effect in intact landscapes suggesting they buffer impacts of climate warming. Occupancy increased markedly with precipitation due likely to major positive impacts on prey, but again, interactive effects were stronger given territories of higher quality amplified benefits of precipitation. Impacts of landcover change and habitat quality on extinction depended markedly on regional population sizes. When populations were small and few potential colonists were present, high‐quality habitat and low landcover change failed to reduce extinction. When populations were large, however, high‐quality habitat and more intact landscapes, which best foster dispersal, reduced extinction. Hence, complex interacting processes linked to the effects of precipitation and habitat quality on carrying capacity, landcover change on habitat connectivity and vulnerability to rising temperatures, and local population sizes simultaneously drove dynamics. Efforts to identify and protect high‐quality habitat and limit landcover change can enhance conservation but will be most efficient in intact landscapes. Efforts to enhance local habitat quality and quantity, and directly augment populations should consider broader landscape contexts linked to habitat connectivity and potential source populations. [ABSTRACT FROM AUTHOR]

Freshwater mussels are an ancient group of molluscs that are considered ecosystem engineers because of the many important functions they perform, including biofiltration and biodeposition. Associations between mussel declines and increased sedimentation are well documented, but the direct effects of suspended sediment (SS) concentrations on mussel functioning are poorly understood.This study investigated the effects of SS concentrations on the clearance and biodeposition rates of the Australian hyriid river mussel Alathyria jacksoni. Clearance rates of algae and sediment and biodeposition rates were measured in aquaria containing 3 L of aerated water for 1 hr, with six different concentrations of SS (bentonite clay: 0, 1, 10, 40, 100 and 300 mg/L). Clearance rates were estimated using flow cytometry and chlorophyll‐a with both methods giving similar results. Biodeposition rates were estimated by weighing the mussel biodeposits at the end of each trial.We found that SS concentrations did not have a significant effect on the clearance rates of algae, which ranged from 0.033 to 0.438 L mussel−1 hr−1, with an overall median of 0.118 L mussel−1 hr−1. By contrast, increasing SS concentrations had a significant effect on the clearance of sediment from the water column, with clearance rates peaking at 10 mg/L and declining thereafter. Clearance rates of suspended sediment ranged from 0.046 to 0.512 L mussel−1 hr−1, with an overall median of 0.182 L mussel−1 hr−1.We further detected a significant effect of SS concentration on the production of biodeposits, with inorganic and organic content in the biodeposits increasing as sediment concentrations increased. These results indicated that as SS concentrations increase, A. jacksoni rejects more inorganic and organic material in the form of pseudofaeces. This added maintenance work may result in an energetic cost to the mussel, and have potential consequences for growth, reproduction, and survival.Finally, population estimates of A. jacksoni in the lower Ovens River, Australia were combined with the clearance rates observed in the experiment, to estimate the potential impact mussel populations have in the clearance of total suspended matter from the open water of an unregulated south‐eastern Australian lowland river. A. jacksoni occurred patchily throughout the 35‐km section of the river surveyed, with an average overall mean and maximum density of 0.68, and 35 individuals/m, respectively. We estimate that under scenarios of 1 and 300 mg/L SS, the lower Ovens River mussel population can potentially clear up to 2–4 ML water/day, which equates to c. 1–2% of the average daily discharge in late summer, while transferring around 5.4–15.6 kg/day dry weight of organic material to the river bed.Increased SS concentrations negatively affect freshwater mussels around the world and many respond by reducing their clearance rates, but this was not the case for A. jacksoni. Instead, A. jacksoni increased production of inorganic and organic biodeposits rejecting more food particles in the form of pseudofaeces. For A. jacksoni and other species showing this response, the added energetic cost has the potential to impact growth rates, reproduction, and population dynamics. [ABSTRACT FROM AUTHOR]

The size and density of a population are essential parameters in primate ecology and conservation. Such information, however, is still scarce for many forest primate species. The Djaffa Mountains guereza (Colobus guereza gallarum) is an endemic Ethiopian taxon for which data about its distribution and population size are missing. Therefore, we aimed to estimate the abundance and population size of the Djaffa Mountains guereza in four forests in the Ahmar Mountains southeast of the Ethiopian Rift Valley. We conducted line-transect surveys in the forests. Within an area of 183 km 2 , we sampled 19 transects covering a distance of 75.9 km. We encountered 73 guereza clusters which most likely represent social groups. Since the detection distances and cluster sizes did not differ among the four forests, we applied a conventional distance sampling (CDS) model and estimated a population density of 20.6 clusters per square kilometer, i.e., 109.6 individuals per square kilometer or 20 061 individuals within the complete study area. This abundance is relatively high compared to other C. guereza taxa. However, given that the habitat and population of C. g. gallarum are already highly fragmented, further monitoring of the population and exploration of the possibilities of reconnecting its habitat should be priorities for the conservation of this taxon. [ABSTRACT FROM AUTHOR]

Animal movement is the mechanism connecting landscapes to fitness, and understanding variation in seasonal animal movements has benefited from the analysis and categorization of animal displacement. However, seasonal movement patterns can defy classification when movements are highly variable. Hidden Markov movement models (HMMs) are a class of latent‐state models well‐suited to modeling movement data. Here, we used HMMs to assess seasonal patterns of variation in the movement of pronghorn (Antilocapra americana), a species known for variable seasonal movements that challenge analytical approaches, while using a population of mule deer (Odocoileus hemionus), for whom seasonal movements are well‐documented, as a comparison. We used population‐level HMMs in a Bayesian framework to estimate a seasonal trend in the daily probability of transitioning between a short‐distance local movement state and a long‐distance movement state. The estimated seasonal patterns of movements in mule deer closely aligned with prior work based on indices of animal displacement: a short period of long‐distance movements in the fall season and again in the spring, consistent with migrations to and from seasonal ranges. We found seasonal movement patterns for pronghorn were more variable, as a period of long‐distance movements in the fall was followed by a winter period in which pronghorn were much more likely to further initiate and remain in a long‐distance movement pattern compared with the movement patterns of mule deer. Overall, pronghorn were simply more likely to be in a long‐distance movement pattern throughout the year. Hidden Markov movement models provide inference on seasonal movements similar to other methods, while providing a robust framework to understand movement patterns on shorter timescales and for more challenging movement patterns. Hidden Markov movement models can allow a rigorous assessment of the drivers of changes in movement patterns such as extreme weather events and land development, important for management and conservation. [ABSTRACT FROM AUTHOR]

Plant genetic resources (PGR) underpin the security of global agriculture. Rapid global climate change presents formidable challenges for ex situ and in situ PGR management programs that operate over extended timeframes. The U.S. Department of Agriculture National Plant Germplasm System (NPGS) maintains more than 605,000 PGR accessions representing over 16,300 plant species in 20 genebank locations. These PGR are maintained in cold storage as seeds and vegetative tissues that must be periodically regenerated; or as actively growing plants in fields, greenhouses, screenhouses, and in vitro; or in some cases within in situ reserves. The complicated relationships between crops and their growth environments present unique challenges regarding PGR maintenance under a changing climate. Here we present potential effects of climate change on ex situ PGR maintenance and reproductive success, pollinators and beneficial insects, pathogens and pests, infrastructure considerations, and wild populations within NPGS in situ reserves. We provide a novel tool that summarizes past US temperature and precipitation data alongside future climate projections to guide ongoing planning for the effects of climate change for NPGS genebanks throughout the United States. A series of case studies exemplify instances where climate change has already impacted NPGS PGR management. Ongoing improvements to NPGS PGR management in response to climate change require continued observations of the current effects, careful and innovative planning, and creative approaches to ensure that PGR are successfully conserved for future generations. Core Ideas: Plant genetic resources (PGR) are crucial for continued crop improvement that underpins global food security.Climate change can threaten PGR safeguarded by the USDA‐ARS National Plant Germplasm System (NPGS).Approaches developed by the NPGS to adapt its PGR management operations to climate change are reviewed.The new NPGS Climate Futures Application delivers key estimates for future climatic conditions at NPGS locations.The NPGS's PGR management operations can adjust to climate change using current experience and those estimates. [ABSTRACT FROM AUTHOR]

Simple Summary: The timely monitoring of the population fluctuations of endangered species and discovering their causes are critical for biodiversity conservation in mountainous areas. To monitor population dynamics and explore the effects of climate and habitat on the population distribution of the hazel grouse, a second-class protected animal in China, infrared cameras were installed in Hunchun, China (Jilin Province). The hazel grouse preferred stable climate conditions. A distribution close to paved roads in the summer benefitted birds' survival and breeding, but the activity of local people in the mountain disturbed them significantly in autumn. We report here how the hazel grouse has responded to anthropogenic disturbances in the mountains of northeast China over a decade, and we call for further attention to this species that is sensitive to climatic fluctuations at high latitudes. Habitat, climate, and human disturbances have important effects on wildlife, and these are especially critical for threatened species. In this study, we used infrared camera traps to monitor the population dynamics of the hazel grouse (Tetrastes bonasia) from 2012 to 2021 in northeast China and explore the effects of habitat, climate, and human disturbance on their distribution. We analyzed 16 environmental variables related to significant differences between presence recordings and absence recordings within and between seasons. Temperatures and roads influenced the distribution of the hazel grouse, but topography and vegetation types did not. The hazel grouse preferred deciduous forest and oak forest from spring to autumn. This study provides ecological information to help guide the mountain habitat management of the hazel grouse in national parks. [ABSTRACT FROM AUTHOR]

Primate encounter rates often vary throughout the year due to seasonal differences in activity, ecology, and behaviour. One notably extreme behaviour is continuous hibernation. Although a rare adaptation in primates, the dwarf lemurs of Madagascar (genus Cheirogaleus) enter obligate hibernation each year during the dry season, after spending the wet season consuming high-energy foods. Whilst seasonal changes in activity in some Cheirogaleus populations are well-known, many species remain little-studied, and there is no specific information on their encounter rates, nor when they enter and emerge from hibernation. This uncertainty critically affects reliable calculation of population density estimates for these highly threatened lemurs. In this study, we assessed how encounter rates of the fat-tailed dwarf lemur (C. medius) vary seasonally in the transitional forests of the Sahamalaza-Iles Radama National Park, northwest Madagascar, during a 4-year period. We established a system of line transects (N = 60) throughout our study area, on which we conducted distance sampling of C. medius. We then used our distance sampling data to calculate encounter rate and population density data. We found encounter rates of C. medius to be significantly higher during the wet season compared with the dry season. Furthermore, encounter rates of C. medius were particularly low from May–August. These results provide some evidence to suggest the time period that C. medius hibernate in Sahamalaza-Iles Radama National Park. These findings underpin the importance of careful study design when surveying threatened species with seasonal differences in activity, such as those that hibernate. This study also demonstrates the importance of species-specific behavioural data for accurate population density assessment, which is required to inform conservation action. [ABSTRACT FROM AUTHOR]

Simple Summary: Wildlife researchers and managers can choose from several techniques to estimate the number of animals in a population. Camera traps and drones are increasingly common and cost-effective options that can estimate the number and density of wildlife. We compared three simple methods that are used to estimate the number and density of deer in Pilot Mountain State Park: (1) mark–resighting and (2) N-mixture modeling, both using camera trap data, and (3) extrapolating transect counts from thermal videos collected from an aerial drone. We found that all three methods provided similar estimates of the population's density, with complementary strengths and weaknesses: drone surveys collected data quickly and precisely, mark–resight ratios provided estimates of different demographic groups, and N-mixture modeling revealed changes in density across different habitat qualities and seasons. Camera traps and drone surveys both leverage advancing technologies to study dynamic wildlife populations with little disturbance. Both techniques entail strengths and weaknesses, and common camera trap methods can be confounded by unrealistic assumptions and prerequisite conditions. We compared three methods to estimate the population density of white-tailed deer (Odocoileus virgnianus) in a section of Pilot Mountain State Park, NC, USA: (1) camera trapping using mark–resight ratios or (2) N-mixture modeling and (3) aerial thermal videography from a drone platform. All three methods yielded similar density estimates, suggesting that they converged on an accurate estimate. We also included environmental covariates in the N-mixture modeling to explore spatial habitat use, and we fit models for each season to understand temporal changes in population density. Deer occurred in greater densities on warmer, south-facing slopes in the autumn and winter and on cooler north-facing slopes and in areas with flatter terrain in the summer. Seasonal density estimates over two years suggested an annual cycle of higher densities in autumn and winter than in summer, indicating that the region may function as a refuge during the hunting season. [ABSTRACT FROM AUTHOR]