Habitat Occupancy Research Articles

Beating the heat: ecology of desert bobcats

BackgroundRelative to temperate regions, little is known about bobcats (Lynx rufus) in the Sonoran Desert portion of their range, in part due to the difficulty of sampling an elusive carnivore in harsh desert environments. Here, we quantify habitat selection and evaluate diet of bobcats at Kofa National Wildlife Refuge, Arizona, USA, using multiple sampling techniques including GPS telemetry, camera traps, and DNA metabarcoding.ResultsHome ranges during the hot season were smaller than during the cool season. Camera trapping failed to yield a high enough detection rate to identify habitat occupancy trends but third-order resource selection from GPS-collar data showed a preference for higher elevations and rugged terrain at lower elevations. Diet composition consisted of a diverse range of available small prey items, including a higher frequency of avian prey than previously observed in bobcats.ConclusionsDesert bobcats in our study maintained smaller home ranges and primarily consumed smaller prey than their more northern relatives. This study illustrates the benefit of employing multiple, complementary sampling methods to understand the ecology of elusive species.

Habitat occupancy of sloth bear Melursus ursinus in Chitwan National Park, Nepal.

Mammals have experienced a massive decline in their populations and geographic ranges worldwide. The sloth bear, Melursus ursinus (Shaw, 1791), is one of many species facing conservation threats. Despite being endangered in Nepal, decades of inattention to the situation have hindered their conservation and management. We assessed the distribution and patterns of habitat use by sloth bears in Chitwan National Park (CNP), Nepal. We conducted sign surveys from March to June, 2020, in 4 × 4 km grids (n = 45). We collected detection/non‐detection data along a 4‐km trail that was divided into 20 continuous segments of 200 m each. We obtained environmental, ecological, and anthropogenic covariates to understand determinants of sloth bear habitat occupancy. The data were analyzed using the single‐species single‐season occupancy method, with a spatially correlated detection. Using repeated observations, these models accounted for the imperfect detectability of the species to provide robust estimates of habitat occupancy. The model‐averaged occupancy estimate for the sloth bear was 69% and the detection probability was 0.25. The probability of habitat occupancy by sloth bears increased with the presence of termites and fruits and in rugged, dry, open, undisturbed habitats. Our results indicate that the sloth bear is elusive, functionally unique, and widespread in CNP. Future conservation interventions and action plans aimed at sloth bear management must adequately consider their habitat requirements.

Cool runnings: behavioural plasticity and the realised thermal niche of basking sharks

Long-distance migrations by marine vertebrates are often triggered by pronounced environmental cues. For the endangered basking shark (Cetorhinus maximus), seasonal changes in water temperature are frequently proposed as a cue for aggregation within (and dispersal from) coastal hotspots. The inference is that such movements reflect year-round occupancy within a given thermal ‘envelope’. However, the marked variance in timing, direction and depth of dispersal movements hint at a more nuanced explanation for basking sharks. Here, using data from pop-off archival transmitters deployed on individuals in Irish waters, we explored whether autumnal decreases in water temperature triggered departure from coastal habitats and how depth and location shaped the sharks’ realised thermal environment over time. Temperature was not an apparent driver of dispersal from coastal seas, and variance in daily temperature ranges reflected occupancy of different habitats; coastal mixed/stratified and offshore subtropical/tropical waters. Furthermore, individuals that moved offshore and into more southern latitudes off Africa, exhibited a distinct daily cycle of deep dives (00:00–12:00, 200 m–700 m; 12:00–00:00, 0–300 m), experiencing a more extreme range of temperatures (6.8–27.4 °C), including cooler minimum temperatures, than those remaining in European coastal habitat (9.2–17.6 °C). Collectively, these findings challenge the supposition that temperature serves as a universal driver of seasonal dispersal from coastal seas and prompts further studies of deep-water forays in offshore areas.

Determinants of habitat occupancy and spatial segregation of primates in the central Western Ghats, India.

Primates are among the globally imperiled fauna requiring urgent conservation interventions to protect their habitat. Information on species distribution and factors influencing it are vital to species management and habitat protection. In this study, we assessed habitat occupancy of the lion-tailed macaque (Macaca silenus), bonnet macaque (M. radiata), and black-footed gray langur (Semnopithecus hypoleucos) that occur in the Kudremukh Wildlife Division, a large protected area network in the central Western Ghats. We examined the influence of habitat variables on the occupancy probability of these primates. We carried out four temporally replicated detection/non-detection surveys to assess detection probability and site occupancy of the primate species. We surveyed 244 sites of 5 Km2, with each site surveyed for 4 days, to assess detection probability and site occupancy. Among the three species, the langur had the highest habitat occupancy estimate (0.66 ± 0.05SE) and the lion-tailed macaque had the lowest estimate (0.28 ± 0.08SE). The habitat occupancy estimate for the bonnet macaque was (0.56 ± 0.05SE). Wet and semi-evergreen forest cover and mean elevation positively influenced the lion-tailed macaque's occurrence. Covariates influencing bonnet macaque's occurrence were plantations, semi-evergreen and moist deciduous forests, and non-forest areas. Mean elevation negatively affected its occurrence. Wet evergreen forests and plantations positively influenced the occurrence of the langur. We examined spatial segregation between the species based on their site occupancy. Pairwise comparisons revealed a significant negative association between the bonnet macaque and the other two primates. However, we found a significant positive association between the lion-tailed macaque and the langur. We discuss these results and their implications for conservation of primates in the region. Given the cost-effectiveness of carrying out surveys at large spatial scales, we recommend occupancy surveys for future surveys of forest primates.

Population status, habitat occupancy and conservation threats to Mugger crocodile (Crocodylus palustris) in Ghodaghodi lake complex, Nepal

Mugger crocodile is a keystone species of slow flowing fresh water ecosystem. Few studies regarding status and distribution of Vulnerable Mugger have been conducted in Nepal. However, studies on ecology and other aspects of the species are limited. The goal of this study was to determine the Mugger crocodile's population status, habitat occupancy, and conservation threats in the Ghodaghodi lake complex, located in the western lowlands of Nepal. A detailed survey was conducted on 18 lakes of the lake complex in February, 2021. The population status of the Mugger was surveyed by walking along the entire boundary line of each lake. For habitat survey, perimeter of all the lakes of the complex was divided into the number of stations spaced at 500 m intervals. Habitat factors associated with the presence and absence of the Mugger were analyzed using Generalized Linear Model under binary logistic regression and likelihood ratio test was performed to test predictors for statistical significance. During the survey, 26 muggers were recorded. The probability of sighting Mugger in the lake complex was significantly differ by distance to settlement, distance to river, and human disturbances, among the nine habitat variables examined. Similarly, habitat modification and illegal fishing were ranked as most severe threats to Mugger crocodile in the lake complex. The concerned authorities, responsible for managing the lake complex shall pay attention on controlling the major identified threats like habitat modification, illegal fishing, unmanaged infrastructure development, and pollution in the lake complex in order to support future conservation of Vulnerable Mugger population in the area. Furthermore, a detailed and extensive study is suggested to investigate the movement of Muggers between different lakes of the complex as well as from Ghodaghodi lake complex to the nearby rivers during breeding season in order to support effective planning and execution of habitat management activities of this Vulnerable species.

Modifying regeneration strategies classification to enhance the understanding of dominant species growth in fire-prone forest in Southwest China

In fire-prone ecosystems, plant species having different post-fire regeneration strategies (PFRS) coexist at the local scale while showing different growth dynamics. To evaluate the effect of PFRS on species regeneration, we investigated the plant communities burned in different years in the central Yunnan Province, Southwest China. Several indicators describing plant growth and population importance were measured to compare the regeneration of four dominant tree species, including one facultative seeders (FS) and three obligate resprouters (OR). Partial correlation and mixed linear effect modeling were applied to disentangle the contribution of intrinsic and environmental factors to the interspecific variation in post-fire regeneration. We identified two subtypes of plant growth strategy in the early post-fire stage for OR species; i.e., number growth (OR ​+ ​N) priority and height growth (OR ​+ ​H) priority for sprouting stems. Generally, the FS and OR species varied in height growth rate with different temporal dynamics. The OR ​+ ​N species occupied post-fire space horizontally with more resprouts and larger coverage than OR ​+ ​H and FS species at the earlier stage. In contrast, the OR ​+ ​H species generally had far less resprouts per clump, more variations in stem height and basal diameter. Factor analysis showed that the variation of post-fire plant regeneration was not effectively explained by environmental factors (R2 ​< ​20%); however, the linear mixed models with the modified PFRS as a random effect substantially increased the explanation. The differentiated regeneration dynamics and growth priorities in the four dominant tree species indicated a critical dichotomy of habitat occupation strategy for the resprouter species during the early stage of post-fire forest restoration. Our study uncovered a trade-off between height versus number growth priority in the post-fire tree growth strategy and provides a novel perspective in understanding the living space occupying (niche partitioning) process and species coexistence in post-fire forest community assembly.

Koalas of the Clarke Connors Range

The extent and causes of koala population declines are reported for koalas of southeast Queensland, but less is known about the trajectories of populations in other regions of the state. We describe the koala population of the Clarke Connors Range in central Queensland and contrast elements of their distribution, health and genetics with information from two other study sites in Queensland. Koalas were found across the study area, were mostly located in Eucalyptus drepanophylla or E. tereticornis and had wide variability in ranging movements (2.4–2246 ha). Approximately 40% of females carried young in spring and 3 of 29 koalas sampled returned PCR positive chlamydial swabs (all urogenital). We postulate that sympathetic land management approaches may have enhanced habitat occupancy across some areas of the Clarke Connors Range and concur with anecdotal reports that this is a significant population of koalas in Queensland and potentially one of national importance.

Ecological specialization, rather than the island effect, explains morphological diversification in an ancient radiation of geckos.

Island colonists are often assumed to experience higher levels of phenotypic diversification than continental taxa. However, empirical evidence has uncovered exceptions to this 'island effect'. Here, we tested this pattern using the geckos of the genus Pristurus from continental Arabia and Africa and the Socotra Archipelago. Using a recently published phylogeny and an extensive morphological dataset, we explore the differences in phenotypic evolution between Socotran and continental taxa. Moreover, we reconstructed ancestral habitat occupancy to examine if ecological specialization is correlated with morphological change, comparing phenotypic disparity and trait evolution between habitats. We found a heterogeneous outcome of island colonization. Namely, only one of the three colonization events resulted in a body size increase. However, in general, Socotran species do not present higher levels or rates of morphological diversification than continental groups. Instead, habitat specialization explains better the body size and shape evolution in Pristurus. Particularly, the colonization of ground habitats appears as the main driver of morphological change, producing the highest disparity and evolutionary rates. Additionally, arboreal species show very similar body size and head proportions. These results reveal a determinant role of ecological mechanisms in morphological evolution and corroborate the complexity of ecomorphological dynamics in continent-island systems.

Landscape habitat occupancy and distribution of the Wild Ground Pangolin (Smutsia temminckii) in Zimbabwe’s Protected Areas (PAs)

The Smutsia temminckii is the only species of pangolin known to exist in Zimbabwe and is considered vulnerable under the IUCN Red List of threatened species. Distribution of wild S. temminckii in protected areas (PAs) and associated environmental variables are not well defined in Zimbabwe. The study sort to relate key environmental variables (Altitude, rainfall, temperature and vegetation type) to habitat occupancy and distribution of S. temminckii. Data was collected from forty-eight stations based on S.temminckii sightings historical records spanning ten years (2011-2021) done by field rangers, tourists and scientific services research personnel. A review of available literature was done from online sources and station records. A distribution map based on S. temminckii sightings across various PAs in Zimbabwe was developed for this study. Results of this study reveal that S. temminckii occupy PAs in South East low-veld areas, Northwestern Zimbabwe, Mid Zambezi Valley and Nyanga NP. No historical data on S. temminckii sighting in central PAs located in ecological regions IIa, IIb and III of Zimbabwe. Climatic conditions associated with S. temminckii distribution, except for Nyanga NP, are average temperatures above 220C and rainfall between 400mm to 900mm per annum. Landscapes ideal for S. temminckii habitat occupancy have an altitude between 262m-2000m above sea level. Associated vegetation types for habitat occupancy of S. temminckii are the Zambezian and mopane woodlands as well as montane forest grasslands mosaic of Nyanga NP. Future studies should focus on establishing distribution of S. temminckii outside PA, population status and density to inform conservation of this rare and unique species around Zimbabwe.

Historical avifaunal change and current effects of hiking and road use on avian occupancy in a high‐latitude tundra ecosystem

Tourism is increasing in tundra ecosystems across the world, yet its influence on bird communities and its interaction with other drivers of change is poorly known. To help fill this gap, we paired an interview‐based survey of 11 people with local knowledge of Denali National Park and Preserve, with an occupancy study of 15 bird species in relation to road proximity, traffic volume and hiking. Interviewees noted declines in American Golden PloverPluvialis dominica, Arctic TernSterna paradisaea, Long‐tailed JaegerStercorarius longicaudusand Northern WheatearOenanthe oenantheover the past five decades. Our occupancy study confirmed these reports as we detected no Arctic Terns, few Northern Wheatears, and found both plovers and jaegers to be sensitive to hiking. Occupancy of tundra and shrub habitats by American Golden Plover, American Tree SparrowSpizelloides arborea, Lapland LongspurCalcarius lapponicus, Long‐tailed Jaeger and Willow PtarmiganLagopus lagopusdeclined with increasing hiking intensity. We found that occupancy probability of tundra by Horned LarkEremophia alpestrisincreased, while that of the shrub‐tolerant Wilson’s WarblerCardellina pusilladecreased, with distance from the park road. Detection of species varied based on survey length, noise, start time, presence of a trail and date. The knowledge gained from this study reveals a loss in avian diversity over the past few decades that has the potential to cause a shifted baseline syndrome, and ongoing threats of hiking to sensitive tundra‐breeding birds. Park managers should seek to balance human recreation with the needs of sensitive tundra‐breeding birds to further protect species of conservation concern. This may be done by not building new trails in tundra, limiting access to tundra hiking areas during the early breeding season, reducing the spatial extent of hiking by improving maintained trails and designating a single, maintained path in areas with multiple unofficial hiking tracks, educating tourists about tundra‐nesting birds and closing especially important nesting areas to the public.

Hard times for catadromous fish: the case of the European eel (Anguilla anguilla, L. 1758)

Catadromous fish species are very important organisms for their ecological, economical, and cultural value. For its complex life species catadromous fish result in worldwide decline since the beginning of the 20th century. Among the most iconic catadromous species, the European eel Anguilla anguilla L. 1758 has aroused considerable interest since very ancient times. Because, to date, many aspects of their life cycle remain relatively unknown, to implement our knowledge about the main natural and anthropogenic threats to its survivorship and identify possible solutions to preserve it, in this narrative review, we present the state of the knowledge about the life cycle, habitat occupancy, recruitment, and migration patterns of the European eel and about the major threats most likely have contributed to the decline of eels’ populations.

Population genetics and independently replicated evolution of predator-associated burst speed ecophenotypy in mosquitofish.

Many species show replicated ecophenotypy due to recurring patterns of natural selection. Based on the presence or absence of pursuit predators, at least 17 species of fish repeatedly differentiated in body shape in a manner that increases burst swimming speed and the likelihood of predator escape. The predator-associated burst speed (PABS) ecophenotype is characterized by a small head and trunk and enlarged caudal region. Mechanisms promoting replicated phenotype-environment association include selection (without evolution), a single instance of adaptive evolution followed by biased habitat occupation, repeated instances of local adaptation, or adaptive phenotypic plasticity. Common garden rearing of mosquitofish, Gambusia affinis, demonstrated a likely heritable basis for PABS phenotypy, but it is unknown whether populations are otherwise genetically distinct or whether replicated ecophenotypy represents a single or replicated instances of adaptation. To genetically characterize the populations and test hypotheses of single or multiple adaptations, we characterized variation in 12 polymorphic DNA microsatellites in the previously studied G. affinis populations. Populations were genetically distinct by multilocus analysis, exhibited high allelic diversity, and were heterozygote deficient, which effects were attributed to G. affinis's shoaling nature and habitat patchiness. Genetic and phenotypic distances among populations were correlated for non-PABS but not PABS morphology. Multilocus analysis demonstrated ecophenotype polyphyly and scattered multivariate genetic structure which support only the replicated-adaptation model. As all of the diverse tests performed demonstrated lack of congruence between patterns of molecular genetic and PABS differentiation, it is likely that divergent natural selection drove multiple instances of adaptive evolution.

Distal Humeral Morphology Indicates Locomotory Divergence in Extinct Giant Kangaroos

Previous studies of the morphology of the humerus in kangaroos showed that the shape of the proximal humerus could distinguish between arboreal and terrestrial taxa among living mammals, and that the extinct “giant” kangaroos (members of the extinct subfamily Sthenurinae and the extinct macropodine genus Protemnodon) had divergent humeral anatomies from extant kangaroos. Here, we use 2D geometric morphometrics to capture the shape of the distal humerus in a range of extant and extinct marsupials and obtain similar results: sthenurines have humeral morphologies more similar to arboreal mammals, while large Protemnodon species (P. brehus and P. anak) have humeral morphologies more similar to terrestrial quadrupedal mammals. Our results provide further evidence for prior hypotheses: that sthenurines did not employ a locomotor mode that involved loading the forelimbs (likely employing bipedal striding as an alternative to quadrupedal or pentapedal locomotion at slow gaits), and that large Protemnodon species were more reliant on quadrupedal locomotion than their extant relatives. This greater diversity of locomotor modes among large Pleistocene kangaroos echoes studies that show a greater diversity in other aspects of ecology, such as diet and habitat occupancy.

The Contribution of Aquatic Plants to the Trophic Ecology of a Sand Dune Lizard in Southern Brazil

Trophic subsidy is an ecological process consisting in the transference of nutrients between adjacent habitats, allowing the occupancy of less productive habitats by several species. We tested for the existence of trophic subsidy provided by aquatic plants of temporary ponds in maintaining individuals of the sand dune lizard Liolaemus occipitalis in southern Brazil. This lizard is a sit-and-wait predator restricted to coastal sand dunes. As these sand dunes occur in a mosaic of temporary ponds, we hypothesized the existence of a nutritional/energetic dependence of lizards from adjacent aquatic habitats. Our evaluation was based on carbon and nitrogen stable isotope analysis in association with gut content analysis of lizards sampled along an entire inundation cycle. Stomach contents revealed no seasonal variation in consumed prey item composition. Nevertheless, we detected changes in prey group composition. The volumetric contribution of Diptera increased over inundation classes (increase = 5%; peak = 61%). Carbon and nitrogen stable isotope ratios indicated that the L. occipitalis trophic web is mainly maintained by terrestrial sources. Isotope ratios also indicated the existence of aquatic contributions to tissue formation, but, despite its tendency to increase over the inundation process (10.7–13.3%), this trend lacks statistical support. We conclude that the studied population of L. occipitalis partially depends on trophic subsidy from aquatic sources and that any conservation plan for this endangered lizard species should take into account the preservation of non-habitats like temporary ponds.

Habitat occupancy by Spruce Grouse (Canachites canadensis) in the south of its range in Quebec, Canada

Studying habitat occupancy at the margins of the distributions of species can be helpful in clarifying the requirements of species and planning management measures. Spruce Grouse (Canachites canadensis (Linnaeus, 1758)), a bird species associated with northern short-needle coniferous forests in North America, has its southeastern range limit where coniferous forests are mixed with temperate deciduous forests and agricultural lands. Some isolated populations are found in these habitats. Using a single-season occupancy modelling approach, we investigated habitat use by Spruce Grouse, accounting for imperfect detection, in the lowlands of the St. Lawrence River in southern Quebec, Canada. We conducted call-response surveys of Spruce Grouse over three years at 279 sites (59 sites in 2007, 100 sites in 2008, and 120 sites in 2009). At the site level, the probability of occupancy was 21% (95% confidence interval (CI) = 10.7%–37.9%) and probability of detection was 54% (95% CI = 34.7%–73.0%). Based on the covariates in the models, occurrence increased with higher cover of coniferous trees and low deciduous shrubs, and decreased with higher cover of deciduous trees. Finally, detection probability was highest at the beginning of the survey (50% in late April) and was influenced by year.

Flesh fly (Diptera: Sarcophagidae): male terminalia, diversity and expanded geographical distribution from India

Despite its veterinary, medical and forensic importance, the biodiversity of sarcophagid flies (Diptera: Sarcophagidae) has remained poorly investigated in India. We have performed a survey of Sarcophagidae species in connection with a study conducted on Diptera, which exposed the flesh fly diversity in and around the campus of the University of Calicut, Kerala, India. The survey was conducted using traps baited with decomposing fish and chicken liver and by the sweeping method. Eleven species were collected, including four species recorded from this state for the first time, one of which is new to the Indian mainland and the second record after Sundarbans Biosphere Reserve. Male terminalia of Sinonipponia bengalensis, Parasarcophaga choudhuryi, Boettcherisca karnyi, and Boettcherisca nathani are illustrated. This result expands the knowledge on the geographical distribution and habitat occupancy of sarcophagid species as well as their forensic relevance and provides a background for future systematic investigations.

Ontogenetic spatial constraints of sub‐arctic marine fish species

AbstractMarine species may respond and adapt to climate change through shifting spatial distributions, but options may be limited by the occupancy of essential habitats which are anchored in space. Limited knowledge of when spatial constraints are most likely to occur in marine fish life cycles has impeded the development of realistic distribution forecasts. In this study, we develop and implement analytical techniques to identify spatial constraints, defined by both the consistency through which a particular geographic area is used year after year, and by the extent of such area with respect to the entire population range. This approach is applied to simulated data and to ten case‐studies including six groundfish species from three subarctic marine systems. Our analyses illustrate that the early phase of the species’ life cycle is more spatially constrained than older life stages. We detected significant species‐specific variability in both the degree to which species are anchored in space throughout their life cycle, and the ontogenetic changes in the geographic association. There is an indication that this variability can be explained by the species life history strategy, highlighting the need to extend similar analyses to other species and regions. The presence of ontogenetic spatial constraints, particularly during early life stages, indicates restrictions exist to changes in spatial distribution and questions the assertion that global warming will uniformly result in an increase in abundance and harvest at higher latitudes and decreases at lower latitudes. Our study develops ecological and analytical insights that are critical for accurate projections of species distributions under different climate change scenarios.

Mixed stock analysis of genetic compositions of lake sturgeon (Acipenser fulvescens) mixtures in Lake Michigan: hierarchical spatial heterogeneity and evidence of improving recruitment in Wisconsin spawning populations

Information regarding site occupancy of fish that migrate long distances during nonspawning periods together with estimates of recruitment trends for individual populations can be informative for management, especially when individuals from different spawning populations intermix and are sampled or harvested together. Tendencies for individuals from different populations to preferentially occupy specific regions increases vulnerability to anthropogenic and natural disturbances. Using mixed stock analysis (MSA), we estimated population-specific occupancy of lake sturgeon (Acipenser fulvescens) in open-water and nearshore regions of Lake Michigan across a hierarchy of spatial scales. Open-water mixture composition differed between Lake Michigan’s eastern and western basins. Significant heterogeneity in habitat occupancy was also observed at microgeographic scales throughout open-water regions of Green Bay, indicating nonrandom occupancy to regions proximal to natal streams. Estimates of relative recruitment levels determined from MSA extensions indicated increasing recruitment trends for spawning populations associated with Wisconsin tributaries (Oconto–Peshtigo, Fox, and Menominee rivers). Our lake sturgeon results demonstrate the utility of genetic data for informing management efforts for spatially structured, highly migratory species. Similar analyses could prove beneficial for species with similar characteristics.

The Evolution of Alternative Buoyancy Mechanisms in Freshwater Fish Eggs

Alternative reproductive tactics (ARTs) are behavioural, morphological, and physiological traits associated with alternative reproductive phenotypes within a population or species. ARTs are widespread in nature, and are a particular feature of teleost fishes. However, few studies have examined egg buoyancy mechanisms in the context of the evolution of ARTs in freshwater fishes. In marine fishes, egg buoyancy is achieved chiefly through hydration. While the buoyancy of freshwater fish eggs has been suggested to be determined primarily through the presence of oil droplets, the majority (60%) of freshwater pelagic eggs do not possess an oil droplet. We applied a physical model of buoyancy to understand the contributions of oil droplets and hydration to the buoyancy of pelagic freshwater fish eggs. We further used phylogenetic regression to estimate the effect of the relative size of the perivitelline space, habitat and parental care on the occurrence of oil droplets, while controlling for non-independence among species due to phylogenetic relatedness. Our analysis demonstrates that the probability of oil droplets in freshwater pelagic eggs exhibits a significant negative relationship with the size of perivitelline space, which may reflect a trade-off relating to energy allocation in contrasting habitats. We also demonstrate a positive association between the probability of oil droplets and the provision of parental care and occupancy of lentic habitats. These findings indicates the evolution of contrasting buoyancy mechanisms as novel ARTs in freshwater fishes. A theoretical model in combination with empirical analysis indicate the evolution of novel ARTs in freshwater fishes as adaptive responses to flow conditions.

Leopard (Panthera pardus) occupancy in the Chure range of Nepal.

Conservation of large carnivores such as leopards requires large and interconnected habitats. Despite the wide geographic range of the leopard globally, only 17% of their habitat is within protected areas. Leopards are widely distributed in Nepal, but their population status and occupancy are poorly understood. We carried out the sign‐based leopard occupancy survey across the entire Chure range (~19,000 km2) to understand the habitat occupancy along with the covariates affecting their occupancy. Leopard signs were obtained from in 70 out of 223 grids surveyed, with a naïve leopard occupancy of 0.31. The model‐averaged leopard occupancy was estimated to be 0.5732 (SE 0.0082) with a replication‐level detection probability of 0.2554 (SE 0.1142). The top model shows the additive effect of wild boar, ruggedness, presence of livestock, and human population density positively affecting the leopard occupancy. The detection probability of leopard was higher outside the protected areas, less in the high NDVI (normalized difference vegetation index) areas, and higher in the areas with livestock presence. The presence of wild boar was strong predictor of leopard occupancy followed by the presence of livestock, ruggedness, and human population density. Leopard occupancy was higher in west Chure (0.70 ± SE 0.047) having five protected areas compared with east Chure (0.46 ± SE 0.043) with no protected areas. Protected areas and prey species had positive influence on leopard occupancy in west Chure range. Similarly in the east Chure, the leopard occupancy increased with prey, NDVI, and terrain ruggedness. Enhanced law enforcement and mass awareness activities are necessary to reduce poaching/killing of wild ungulates and leopards in the Chure range to increase leopard occupancy. In addition, maintaining the sufficient natural prey base can contribute to minimize the livestock depredation and hence decrease the human–leopard conflict in the Chure range.