Dynamic Occupancy Models Research Articles

Spatio‐temporal patterns of carnivore guild related to their prey in a Mediterranean landscape

AbstractSmall mammal populations fluctuate significantly in abundance over time, affecting the entire food web. However, changes in their occupancy across a landscape receive less attention. While habitat features are relevant for some predators, diet specialization and prey distribution and abundance might play an important role in shaping predator populations. Using a multi‐season occupancy analysis, we examined the spatio‐temporal patterns of Mediterranean mesocarnivores—common genet, stone marten and red fox—focusing on the factors that influence their occupancy dynamics, particularly small mammal occupancy as a prey resource. Data was collected from December 2020 to May 2021 in the Sant Llorenç del Munt i l'Obac Natural Park using a camera‐trap grid. We analysed small mammal occupancy dynamics and used these as covariates in predator occupancy models to explore predator–prey relationships. Additionally, we included the occurrence of each carnivore as a predictor for interspecific analysis, and kernel density functions were used to assess daily activity overlaps. Results showed that interspecific competition significantly affected mesocarnivore occupancy, as genet occupancy was negatively correlated with the red fox occupancy. Although prey occurrence did not influence mesocarnivore occupancy, it did affect detectability, with genet and stone marten detectability being positively related to small mammal presence and high daily activity overlap between predators and prey. This suggests that mesopredators respond rapidly to prey abundance, highlighting the intricate temporal dependence between predator activity and prey occupancy. Dynamic occupancy and activity models provide a deeper understanding of predator–prey relationships at the local scale.

Spatiotemporal occupancy patterns of chronic wasting disease.

Chronic wasting disease (CWD) among cervids in Kansas has seen a consistent rise over the years, both in terms of the number of infections and its geographical spread. In this study, we assessed the occupancy patterns of CWD among white-tailed deer and mule deer across the state. Using surveillance data collected since 2005, we applied a dynamic patch occupancy model within a Bayesian framework, incorporating various environmental covariates. Using principal components analysis, 13 fully orthogonal components representing cervid habitat, soil, and elevation were derived. Competing models with different temporal patterns were fit, and the best model selected based on Watanabe-AIC values and AUC value of 0.89. The occupancy pattern produced by this model revealed a steady progression of the disease toward the east and southeast of the state. A random forest analysis of covariates at annual intervals indicated that geographic location, elevation, areas occupied by mixed forests, and several soil attributes (pH, clay content, depth to restrictive layer, available water content, and bulk density) explained most of the variability in the surveillance data (R 2 = 0.96). The findings reported in this study are the first for the state of Kansas but are consistent with previous findings from other geographic jurisdictions in the US and Canada. This consistency underscores their value in designing surveillance and management programs.

Bringing circuit theory into spatial occupancy models to assess landscape connectivity

Abstract Occupancy models were originally developed to better understand species distribution while accounting for imperfect detection. Because species distribution is not only shaped by habitat quality but also by the ability of individuals to reach suitable habitats, spatial dynamic occupancy models have been proposed to extend the original framework by defining that site colonisation was a function of the Euclidean distance to occupied sites. However, not all sites in the landscape are equally accessible due to the presence of barriers, that of corridors, etc. To account for connectivity between sites, the Euclidean distance has recently been replaced by a least‐cost path distance, which explicitly accounts for landscape resistance, but assumes that individuals will follow the optimal route. To relax this assumption, we first developed a new spatial occupancy model that incorporates commute‐time distance derived from circuit theory to model accessibility across sites. This distance has the advantage of modelling movement as a random walk and accounting for the fact that colonisation could be achieved from multiple paths. Our approach allows for the explicit estimation of landscape connectivity from detection/non‐detection data and a direct measure of connectivity uncertainty. We implemented the model in the Bayesian framework using the nimble R package, which allows useful R connectivity functions to be called from within the model. Second, we carried out a simulation study to assess the performance of our model by considering four scenarios depicting an increasing level of landscape resistance. Third, to illustrate our new approach, we studied the recolonisation of two carnivores in France. We quantified the degree to which rivers facilitate Eurasian otter (Lutra lutra) colonisation and highways impede Eurasian lynx (Lynx lynx) colonisation. Overall, spatial occupancy models provide a flexible framework to accommodate any distance metric designed to align with species dispersal ecology.

Ecological dynamics and coexistence patterns of wild and domestic mammals in an abandoned landscape

The issue of agricultural land abandonment in southern Europe has raised concerns about its impact on biodiversity. While abandoned areas can lead to positive developments like creating new habitats and restoring native vegetation, they can also result in human–wildlife conflicts, particularly in areas with extensive farming and free‐ranging livestock. To understand habitat selection and use of livestock and wild ungulates, it is essential to study their spatial and temporal distribution patterns. In this context, we conducted a long‐term large mammal monitoring project using camera traps in the Peneda‐Gerês National Park in northern Portugal. Our primary focus was on exploring habitat preferences, occupancy dynamics, and potential spatial use correlations between domestic and wild species, utilizing dynamic occupancy models. Most wild species exhibited stable area use patterns, while domestic species experienced marginal declines, and the Iberian ibex displayed signs of repopulation. We observed distinct effects of habitat variables on occupancy, colonization, and extinction, revealing species‐specific patterns of habitat utilization. Human disturbance had a notable impact on domestic species but did not affect wild ones. Camera sensitivity emerged as a critical factor, enhancing detection probability for all species. Additionally, habitat and weather variables exerted varying effects on detection probabilities, underscoring the necessity of accounting for these factors in modeling the detection process. We found shared habitat preferences between cattle and horses, both positively correlated with wolves, suggesting potential human–wildlife conflicts. Despite extensive spatial overlap, domestic and wild species seem to exhibit ecological independence possibly due to distinct strategies and low predation pressure. Overall, the study emphasizes the multifaceted factors influencing habitat use. The observed species associations contribute to understanding ecological relationships and potential resource competition, emphasizing the importance of considering environmental variables for effective wildlife conservation and management.

Dynamic occupancy in a peripheral population of Myotis septentrionalis during disease outbreak

ContextOnce common, the northern long-eared bat (Myotis septentrionalis) has experienced declines > 90% due to white-nose syndrome (WNS). This severe mortality has resulted in their listing under the Endangered Species Act and made them a conservation priority. However, their broad distribution, variability in habitat use, and population instability make developing range-wide conservation strategies difficult. To understand how conservation of M. septentrionalis may vary across its range, we examined shifts in M. septentrionalis site occupancy on the edge of their historic range following severe WNS mortality.ObjectivesOur goal was to determine how mortality from white-nose syndrome affects site occupancy of M. septentrionalis at the southern edge of their historic range. Understanding which areas will remain occupied during disease related mortality will help inform management during disease outbreaks.MethodsWe used 11 years (2007–2017) of mist-netting records to construct dynamic occupancy models of M. septentrionalis in northern Georgia, USA. Occupancy was updated annually, with the initial period defined as all years prior to the winter of 2012–2013, which corresponds to when white-nose syndrome entered the study area. We assessed occupancy using landscape metrics at the home range (65 ha) and landscape (491 ha) scales, year since WNS occurrence in the study area, distance to karst, and distance to nearest WNS positive county. We estimated probability of detection using Julian date and sampling effort.ResultsInitial site occupancy was positively associated with percent deciduous forest cover at the home range scale. As M. septentrionalis populations declined from WNS, a site becoming unoccupied was negatively correlated with mean contiguity of forest at the home range scale and largest patch of forest and mean elevation at the landscape scale. Site occupancy declined precipitously in the years following WNS, dropping from 70.75% (41.76–96.98% [95% CI]) occupancy pre-WNS to 0.3% (0.3–20.5% [95% CI]) by the final year of the study.ConclusionsOur results demonstrated that sites occupied by M. septentrionalis closer to the historic range edge were more vulnerable to becoming unoccupied after disease arrival. We recommend managers on the periphery of the historic range focus conservation efforts on high elevation forested areas nearer to the range core.

Dynamic occupancy modelling of Asian elephants (Elephas maximus) reveals increasing landscape use in Nepal

Large mammals with general habitat needs can persist throughout mixed used landscapes, however, human-wildlife conflict frequently leads to their restriction to protected areas. Conservation efforts, especially for reducing conflicts with humans, can enhance tolerance of humans towards species like Asian elephants (Elephas maximus) in human-dominated landscapes. Here, we examine how elephant use in the Chure Terai Madhesh Landscape (CTML) covering the entire elephant range of Nepal changed between 2012 and 2020 in relationship to protection status and environmental conditions. We systematically surveyed ~ 42,000 km2 of potential habitat, by dividing the study area into 159 grid cells of 15 × 15 km2 and recorded elephant signs during the cool, dry season in three years (2012, 2018 and 2020). We analyzed the survey data in a single-species, multi-season (dynamic) occupancy modeling framework to test hypotheses regarding the influence of environmental conditions and protected area status on landscape use by elephants over time. The best-supported model included protected area effects on initial use, colonization, and detection probability as well as temporal variation in colonization and detection probability. Initial use and colonization rates were higher in protected areas, however elephants increasingly used cells located both inside and outside the protected areas, and the difference in use between protected areas and outside declined as elephants use became prevalent across most of the landscape. While elephant use was patchily distributed in the first year of surveys consistent with past descriptions of four sub-populations, elephant use consolidated into a western and eastern region in subsequent years with a gap in their distribution occurring between Chitwan and Bardiya National Parks. Our manuscript highlights the increasing landscape use by elephants in both protected areas and areas outside protected areas and suggests that management interventions that focus on reducing conflicts can promote greater use of both protected areas and areas outside of protected areas.

Multi-generational dispersal and dynamic patch occupancy reveals spatial and temporal stability of seascapes

The success of non-native species (NNS) invasions depends on patterns of dispersal and connectivity, which underpin genetic diversity, population establishment and growth. In the marine environment, both global environmental change and increasing anthropogenic activity can alter hydrodynamic patterns, leading to significant inter-annual variability in dispersal pathways. Despite this, multi-generational dispersal is rarely explicitly considered in attempts to understand NNS spread or in the design of management interventions. Here, we present a novel approach to quantifying species spread that considers range expansion and network formation across time using the non-native Pacific oyster, Magallana gigas (Thunberg 1793), as a model. We combined biophysical modelling, dynamic patch occupancy models, consideration of environmental factors, and graph network theory to model multi-generational dispersal in northwest Europe over 13 generations. Results revealed that M. gigas has a capacity for rapid range expansion through the creation of an ecological network of dispersal pathways that remains stable through time. Maximum network size was achieved in four generations, after which connectivity patterns remained temporally stable. Multi-generational connectivity could therefore be divided into two periods: network growth (2000−2003) and network stability (2004–2012). Our study is the first to examine how dispersal trajectories affect the temporal stability of ecological networks across biogeographic scales, and provides an approach for the assignment of site-based prioritisation of non-native species management at different stages of the invasion timeline. More broadly, the framework we present can be applied to other fields (e.g. Marine Protected Area design, management of threatened species and species range expansion due to climate change) as a means of characterising and defining ecological network structure, functioning and stability.

Western spotted skunk spatial ecology in the temperate rainforests of the Pacific Northwest

AbstractA major threat to small mammalian carnivore populations is human‐induced land use change, but conservation and management are inhibited by limited knowledge about their ecology and natural history. To fill a key knowledge gap of the western spotted skunk (Spilogale gracilis), we investigated their spatial ecology at the landscape and home range scale in the temperate rainforests of the Oregon Cascades during 2017–2019. For the landscape scale analysis, we used detections of western spotted skunks at 112 baited camera traps and fitted a dynamic occupancy model to investigate spatial distribution and drivers of inter‐seasonal and inter‐annual changes in occupancy. Concurrently, we radio‐collared 25 spotted skunks (9 female, 16 male) and collected 1583 relocations. Using continuous‐time movement models, we estimated large home range sizes for both male and female spotted skunks, relative to their body mass, and highly overlapping home ranges that indicated a lack of territoriality. Using these home ranges, we fitted a resource selection function using environmental covariates that we assigned to various hypotheses such as resources, predator avoidance, thermal tolerance, and disturbance. Overall, western spotted skunks were widely distributed across our study area (seasonal occupancy up to 63.7 ± 5.3%) and highly detectable (weekly detection probability = 41.2%). At both spatial scales, spotted skunks selected wetter areas and local valleys, which we attributed to areas with more food resources. At the home range scale, spotted skunks selected locations with lower predation risk and areas surrounded by more previously logged forests. In this montane environment, inter‐seasonal contractions in the spatial distributions of spotted skunks were strongly driven by their response to cold temperature and accumulated snow. This was especially evident when seasonal occupancy declined significantly following a severe heavy snow event in February 2019. Given that there is little information available on the natural history of the western spotted skunk, these results provide essential information about their ecology to focus future monitoring efforts and may help identify potential threats (e.g., forest management, severe snow events, or wildfires) to this species.

To stay or not to stay? Temporal shifts in dung beetle occupancy in a cloud forest landscape

Abstract Dynamic occupancy model estimates the probabilities of occupancy, detection, extinction and colonization of individuals throughout seasons and is, thus, a useful tool for identifying whether individuals select a site to improve population phenology and fitness. We used multi‐season dynamics occupancy models to assess how abiotic factors (monthly variation, percentage of forest and edge and temperature) and biotic factors (female abundance) affect the demographic dynamics of coprophagous beetles Deltochilum mexicanum and Dichotomius satanas that differ in their habitat preferences in a human‐modified landscape in a cloud forest in Mexico. For both species, we captured a total of 1069 individuals with a density of 48.2 individuals per trap in forest areas and 14.8 individuals per trap in non‐forest areas. The species differed in their spatiotemporal occupancy dynamics in the landscape. Specifically, we found that monthly variation, percentage of forest cover and percentage of edge affected the models for both species. Each species showed a specific set of explanatory covariates for the model parameters, indicating that phenological and demographic regulatory mechanisms act as drivers of the spatiotemporal occupancy in a year period. We highlight the importance of considering abiotic factors (landscape characteristics) as drivers of occupancy, especially in highly heterogeneous landscapes. Such understanding is relevant to establish the effects of the landscape on the distribution and occurrence of dung beetles by determining how forest and generalist species differ in colonization and extinction patterns with respect to their phenology.

Making sense of wildlife habitat use on active oil sands mines: Quasi‐experiments, occupancy models, trends assessments and upland habitat reclamation

Abstract Intensive resource extraction activity in the oil sands of Canada alters the quantity, structure and distribution of native ecosystems, which in turn creates substantive challenges for conservation, land management and habitat reclamation. Progressive reclamation occurs on active mine sites in the Athabasca oil sands region (AOSR) of Canada, along with concurrent assessments of reclamation effectiveness. Yet, little is known about the ability of reclaimed habitats to mitigate for the short‐ and long‐term impacts associated with open‐pit mines and provide functional habitat for wildlife. We used a robust quasi‐experiment that combined camera trap data from an observational study with an innovative occupancy model to assess the effectiveness of upland reclamation to provide habitat for wildlife in the AOSR. The dynamic occupancy models were applied to 15 years of camera trap data to assess wildlife usage patterns of nine species of wildlife over seven types of habitats. The habitats sampled ranged from mining‐disturbed habitats reclaimed to upland forest ecosites common in the region, habitats disturbed by natural (fire) and human disturbances (clear‐cut logging), with comparisons to mostly intact mature forests. Our results indicate that the nine species of wildlife assessed used habitats in a manner consistent with expectations: some preferred disturbance‐dominated habitats while others used mature forest to a higher degree. We demonstrate that the application of dynamic occupancy models to camera trap data reliably discerned these trends, providing the means to predict wildlife usage patterns in an ever‐changing landscape, including one containing bitumen extraction as a contributor to landscape‐level modifications. Practical implication: Our work illustrates how continued monitoring of wildlife using camera traps contributes to assessments of reclamation effectiveness with respect to wildlife occurrence, distribution and usage patterns in anthropogenically and naturally disturbed landscapes. Evaluating the effectiveness of reclamation is especially important given the expected increase in habitat reclamation on active oil sands mines over the next several decades, coupled with the need to ensure that disturbed habitats regain ecological function able to sustain wildlife in the future.

Mesocarnivore sensitivity to natural and anthropogenic disturbance leads to declines in occurrence and concern for species persistence.

Understanding mesocarnivore responses to both natural and anthropogenic disturbance is crucial for understanding species' potential to maintain landscape persistence into the future. We examined the response of five mesocarnivore species (bobcat, coyote, fisher, gray fox, and red fox) to both types of disturbances and climatic conditions. The Northeastern U.S. has experienced multiple large-scale disturbances, such as a mass defoliation event following larval spongy moth outbreak and high densities of infrastructure that divide the natural landcover into roadless zones where these species inhabit. Using dynamic occupancy models in a Bayesian framework, we aimed to (1) examine variation in species' responses over a 4-year study by estimating variation in site-level occupancy, colonization and extirpation of each species in the state of Rhode Island relative to natural disturbance (i.e., defoliation event), anthropogenic disturbance (i.e., parceling of natural landcover bounded by roads, distance to roads), and climate (i.e., seasonal precipitation) and (2) compare current occurrence trends to predicted asymptotic occupancy to identify key variables contributing to distribution instability. Our findings indicated declines in the occurrence of both fox species, and fisher. There was variation in mesocarnivore response to disturbance among the species. We found gray fox and fisher occupancy dynamics to be sensitive to all forms of disturbance and coyote occurrence was positively associated with anthropogenic disturbance. Although bobcat and red fox were predicted to respond positively to future climate scenarios, fisher and gray fox were not, and persistence of fisher and gray fox in a landscape of disturbance relies on large areas with high forest and shrubland cover. With the wide-spread spongy moth outbreak across much of southern New England, our findings indicate that efforts to conserve forested lands may be crucial in maintaining the persistence of several mesocarnivore species in this region experiencing large-scale disturbance.

Woody plant encroachment drives population declines in 20% of common open ecosystem bird species.

Grassy ecosystems cover more than 40% of the world's terrestrial surface, supporting crucial ecosystem services and unique biodiversity. These ecosystems have experienced major losses from conversion to agriculture with the remaining fragments threatened by global change. Woody plant encroachment, the increase in woody cover threatening grassy ecosystems, is a major global change symptom, shifting the composition, structure, and function of plant communities with concomitant effects on all biodiversity. To identify generalisable impacts of encroachment on biodiversity, we urgently need broad-scale studies on how species respond to woody cover change. Here, we make use of bird atlas, woody cover change data (between 2007 and 2016) and species traits, to assess: (1) population trends and woody cover responses using dynamic occupancy models; (2) how outcomes relate to habitat, diet and nesting traits; and (3) predictions of future occupancy trends, for 191 abundant, southern African bird species. We found that: (1) 63% (121) of species showed a decline in occupancy, with 18% (34) of species' declines correlated with increasing woody cover (i.e. losers). Only 2% (4) of species showed increasing population trends linked with increased woody cover (i.e. winners); (2) Open habitat specialist, invertivorous, ground nesting birds were the most frequent losers, however, we found no definitive evidence that the selected traits could predict outcomes; and (3) We predict open habitat loser species will take on average 52 years to experience 50% population declines with current rates of encroachment. Our results bring attention to concerning region-wide declining bird population trends and highlight woody plant encroachment as an important driver of bird population dynamics. Importantly, these findings should encourage improved management and restoration of our remaining grassy ecosystems. Furthermore, our findings show the importance of lands beyond protected areas for biodiversity, and the urgent need to mitigate the impacts of woody plant encroachment on bird biodiversity.

Regional and local factors interact to shape colonization and extinction dynamics of invasive Hydrilla verticillata in a patchy landscape.

Understanding the response of species to global change requires disentangling the drivers of their distributions across landscapes. Colonization and extinction processes, shaped by the interplay of landscape-level and local patch-level factors, are key determinants of these distributions. However, disentangling the influence of these factors, when larger-scale processes manifest at local scales, remains a challenge. We addressed this challenge by investigating the colonization and extinction dynamics of the aquatic plant, Hydrilla verticillata, in a complex riverine rock pool system. This system, with hundreds of rock pools experiencing varying flooding frequencies, provided a natural laboratory to examine how a single landscape-level disturbance can differentially impact colonization and extinction depending on local patch characteristics to shape species distributions. Using 5 years of data across over 500 sites and more than 5000 surveys, we employed dynamic occupancy models to model colonization, extinction, and changes in Hydrilla patch occupancy while accounting for imperfect detection. Our results revealed that larger, infrequently flooded pools closer to the river were more likely to be colonized. In contrast, local extinction of Hydrilla was more likely in smaller pools closer to the river that flooded frequently. These findings underscore the importance of considering context-dependence in species distribution models. The same landscape-level disturbance (flooding) had opposing effects on colonization and extinction, with the direction and magnitude of these effects varying with local patch characteristics. Our study highlights the need for integrating local and landscape-level factors, and considering how larger-scale processes play out at the patch level, to understand the complex dynamics that shape species distributions.

Boom and bust: the effects of masting on seed predator range dynamics and trophic cascades

AbstractAimSpatiotemporal variation in resource availability is a strong driver of animal distributions. In the northern hardwood and boreal forests of the northeastern United States, tree mast events provide resource pulses that drive the population dynamics of small mammals, including the American red squirrel (Tamiasciurus hudsonicus), a primary songbird nest predator. This study sought to determine whether mast availability ameliorates their abiotic limits, enabling red squirrel elevational distributions to temporarily expand and negatively impact high‐elevation songbirds.LocationNortheastern United States.MethodsWe used two independent datasets to evaluate our hypotheses. First, we fit a dynamic occupancy model using data from camera trap surveys to evaluate red squirrel distributional responses to pulses in the tree mast. We also assessed population responses using systematic auditory surveys analysed with an open‐population binomial mixture model. Further, we used modelled red squirrel abundance in nest‐survival models to evaluate whether their abundance is correlated with the daily nest survival of three songbird species.ResultsThe tree mast provided a critical resource pulse that resulted in a two‐fold increase in the annual elevational distribution of red squirrels. The elevational distribution of red squirrels ranged from a minimum of ~450 m (range: 663–1145 m asl) following two consecutive years without a masting event to a maximum of over 1000 m (range: 443–1545 m asl) after a large mast event. The daily nest survival of three songbird species tended to decline with an increase in the abundance of red squirrels.Main ConclusionsTree mast is a central biological phenomenon in many temperate and boreal forests. This study reveals how this resource pulse results in range changes in a small mammal that is both a seed and bird predator, as well as prey for many carnivores. Thus, understanding this phenomenon can inform the conservation and management of northern forests, including breeding songbirds.

Building pondscapes for amphibian metapopulations.

The success of ponds constructed to restore ecological infrastructure for pond-breeding amphibians and benefit aquatic biodiversity depends on where and how they are built. We studied effects of pond and landscape characteristics, including connectivity, on metapopulation dynamics of 12 amphibian species in Switzerland. To understand the determinants of long-term occupancy (here summarized as incidence), environmental effects on both colonization and persistence should be considered. We fitted dynamic occupancy models to 20years of monitoring data on a pond construction program to quantify effects of pond and landscape characteristics and different connectivity metrics on colonization and persistence probabilities in constructed ponds. Connectivity to existing populations explained dynamics better than structural connectivity metrics, and simple metrics (distance to the nearest neighbor population, population density) were useful surrogates for dispersal kernel-weighted metrics commonly used in metapopulation theory. Population connectivity mediated the persistence of conservation target species in new ponds, suggesting source-sink dynamics in newly established populations. Population density captured this effect well and could be used by practitioners for site selection. Ponds created where there were 2-4 occupied ponds within a radius of ∼0.5km had >3.5 times higher incidence of target species (median) than isolated ponds. Species had individual preferences regarding pond characteristics, but breeding sites with larger (≥100m2) total water surface area, that temporarily dried, and that were in surroundings with maximally 50% forest benefitted multiple target species. Pond diversity will foster amphibian diversity at the landscape scale.

Broad-scale acoustic monitoring of koala populations suggests metapopulation stability, but varying bellow rate, in the face of major disturbances and climate extremes.

Population trends are lacking for most threatened species, especially those that are cryptic and difficult to survey. Recent developments in passive acoustics and semi-automated call recognition provide a cost-effective option to systematically monitor populations of vocal species. We assessed recent trends for the koala Phascolarctos cinereus, an iconic marsupial, based on 7 years of acoustic monitoring across 224 forested sites. The study period overlapped with a severe drought and extensive megafires in 2019 followed by 2 years of extremely high rainfall. Dynamic occupancy modelling with a range of covariates at multiple landscape scales found that initial occupancy was related to elevation (-ve), NDVI (+ve) and previous selective harvesting (16-30-year age class; weakly +ve). Extinction probability increased with the extent of high-severity fire. Colonisation probability was related to a range of factors, with the top model showing a decrease with increasing lagged annual rainfall. However, the null model was also supported, suggesting weak associations for colonisation. Using these relationships, koala occupancy was found to be high and stable over the study period. Fire did not influence regional trends because koalas often persisted with low- to moderate-severity fire and because high-severity fire was limited to 11% of their habitat. In contrast, bellow rate varied across years, being initially low and declining immediately after the 2019 fires, with the driver of these changes unclear. Neither timber harvesting nor low-severity fire influenced koala occupancy or bellow rate. Given the extensive area of koala habitat in the region, our results point to the presence of a large population in these public forests, and in recent years, stable occupancy (albeit with site-scale reductions in density with high-severity fire). Ongoing monitoring is crucial for tracking future changes, especially with predictions of more frequent, severe forest fires due to climate change.

Effects of resource availability and interspecific interactions on Arctic and red foxes' winter use of ungulate carrion in the Fennoscandian low-Arctic tundra.

In the Arctic tundra, predators face recurrent periods of food scarcity and often turn to ungulate carcasses as an alternative food source. As important and localized resource patches, carrion promotes co-occurrence of different individuals, and its use by predators is likely to be affected by interspecific competition. We studied how interspecific competition and resource availability impact winter use of carrion by Arctic and red foxes in low Arctic Fennoscandia. We predicted that the presence of red foxes limits Arctic foxes' use of carrion, and that competition depends on the availability of other resources. We monitored Arctic and red fox presence at supp lied carrion using camera traps. From 2006 to 2021, between 16 and 20 cameras were active for 2 months in late winter (288 camera-winters). Using a multi-species dynamic occupancy model at a week-to-week scale, we evaluated the use of carrion by foxes while accounting for the presence of competitors, rodent availability, and supplemental feeding provided to Arctic foxes. Competition affected carrion use by increasing both species' probability to leave occupied carcasses between consecutive weeks. This increase was similar for the two species, suggesting symmetrical avoidance. Increased rodent abundance was associated with a higher probability of colonizing carrion sites for both species. For Arctic foxes, however, this increase was only observed at carcasses unoccupied by red foxes, showing greater avoidance when alternative preys are available. Supplementary feeding increased Arctic foxes' carrion use, regardless of red fox presence. Contrary to expectations, we did not find strong signs of asymmetric competition for carrion in winter, which suggests that interactions for resources at a short time scale are not necessarily aligned with interactions at the scale of the population. In addition, we found that competition for carcasses depends on the availability of other resources, suggesting that interactions between predators depend on the ecological context.

Changes in Wolf Occupancy and Feeding Habits in the Northern Apennines: Results of Long-Term Predator-Prey Monitoring.

The comprehension of the factors that have influenced the recent changes in wolf (Canis lupus) range and diet that have occurred in our study area, characterized by a highly heterogeneous landscape, can shed light on their current process of expansion toward the plain. Wolf presence was monitored using a standardized protocol from 2007 to 2022 by carrying out eight monitoring sessions organized in seasonal surveys, during which, we collected wolf presence data. To model wolf range dynamics, we used dynamic occupancy models considering land cover types and wild ungulate abundances as covariates. Moreover, we studied the wolf diet through scat analysis, identifying the consumed items from undigested remains. Wolf occupancy in the study area progressed from mountains to lower hills gradually; the observed range dynamics were driven by prey abundance and human presence: in particular, the probability of colonization increased with roe deer (Capreolus capreolus) abundance, whereas the probability of extinction increased with urban areas. The wolf diet showed a gradual shift from the prevalent consumption of wild boar (2007-2008 and 2011-2012) to the prevalent consumption of roe deer (continuously increasing from 2015 onward). Our results might be related to a specific adaptation of the predator to the local ecology of the most consumed species: the roe deer.

Occupancy trends of overwintering coastal waterbird communities reveal guild-specific patterns of redistribution and shifting reliance on existing protected areas.

Climate change and anthropogenic stressors are redistributing species and altering community composition globally. Protected areas (PAs) may not sufficiently protect populations of species undergoing distributional shifts, necessitating that we evaluate existing PAs and identify areas for future protection to conserve biodiversity across regional and temporal scales. Coastal waterbirds are important indicators of marine ecosystem health, representing mobile, long-lived, higher trophic-level consumers. Using a 20-year citizen science dataset (1999-2019) with a before-after control-intervention sampling framework for habitat protection, we applied dynamic occupancy models to assess winter occupancy trends along the Pacific coast of Canada. Specifically, we sought to understand potential drivers of regional declines, spatial commonalities among guilds, and changes in habitat use before and after PA designation, as well as between PAs and non-PAs. Occupancy trends varied regionally, with greater declines in the south compared to the north. Regional differences underlined potential range shifts, particularly for species with traits linked to temperature tolerance, movement, and high productivity foraging, as cold-tolerant, migratory benthivores and piscivores wintered farther north relative to 20 years ago or retreated to cold-water fjords. While 21 of 57 (36.8%) species responded positively to PA designation (before-after), greater occupancy declines tended to occur in PAs established pre-1999 relative to non-PAs (control-intervention). Since PAs are currently concentrated in the south, negative associations were most apparent for species retreating northward, but existing PAs may have a stabilizing or transitory effect on southern wintering species shifting into the region from farther south. We emphasize that conservation strategies must balance persistence of current communities with preserving the climate-adapted biodiversity of tomorrow by accounting for community-level effects of species moving into and out of existing PAs. Incorporating range shifts into PA planning by predicting distributional changes will allow conservation practitioners to identify priority habitats, such as cold-water refugia, for persistent wildlife communities.

Occupancy, relative abundance and activity patterns of three sympatric deer in ponds of Calakmul Biosphere Reserve, Campeche

Calakmul Biosphere Reserve is one of the largest tropical forests in the Americas, home to three species of deer, the white-tailed deer, Odocoileus virginianus, the Yucatan brown brocket deer, Odocoileus pandora, and the Central American red brocket deer, Mazama temama. Important ecological aspects on the conservation of these species have been poorly studied. The aim of this study was to determine the occupancy, relative abundance and activity patterns of these species through 9 years of camera-trapping in ponds of a Neotropical Forest in southern Mexico, contributing to the understanding of the ecological patterns and conservation of Neotropical deer. To determine abundance, occupancy and activity patterns, 18 ponds were monitored from 2014 to 2022. The general relative abundance index was used to calculate abundance and the temporal kernel density was used to evaluate the overlap in daily activity of the species. The dynamic occupancy model was used to obtain the occupancy, colonization, extinction and detection of deer, while species co-occurrence occupancy models were used to assess the interaction of water and species. White-tailed deer were the most abundant (Table 1) during the nine years of the study, with low pond occupancy, but with a high probability of colonization. The brown brocket deer was the one with the highest probability of occupancy, showing a low abundance (Table 1), followed by the red brocket deer, with a very low occupancy and abundance (Table 1). Interaction with water was positive in two of the three analyzed species and activity was diurnal for Odocoileus species and cathemeral for Mazama (Fig. 3). The use of ponds by deer is varied in quantity and activity, but they are important places for their development. The protection of the ponds should be fundamental for the conservation of the species in the area, being one of the few semi-perennial water sources and places of food and shelter for wildlife.