Species Occupancy Research Articles

A near-range plant invasion homogenizes riparian vegetation but leads to more productive bird communities

AbstractBiological invasions are a leading driver of biodiversity loss and population declines worldwide. While much research has focused on understanding the effects of long-distance (e.g., cross-continental) invasion, the potential impacts of species that invade close to or within their native ranges are relatively understudied. We investigated the effects of the near-range introduction of a non-native plant, New Mexico locust (Robinia neomexicana), on riparian plant and bird communities in northwestern Colorado, USA. By surveying plant and bird communities and examining nest success and productivity in riparian forest with and without locust, we evaluated the following ecological responses to invasion: (1) tree and shrub richness and density; (2) bird species richness, occupancy, and abundance; and (3) avian reproductive success. Our results demonstrate biotic homogenization of the plant community with increasing intensity of locust invasion, yet we found little evidence for negative effects on avian habitat use or reproductive success. Instead, locust invasion showed a positive effect on nest productivity, with significantly higher brood sizes and numbers of young fledged for nests in invaded habitats compared to those where locust was absent. Because climate change is already leading to shifts in species distribution patterns, we suggest that understanding the ecological consequences of plant invasions that occur within or near historic ranges will advance the science and practice of invasive species biology in a changing world. Our findings of mostly neutral to positive effects of locust suggest that near-range plant invasions may not always negatively impact community structure.

Spatial and temporal changes in occupancy frequency distribution patterns of freshwater macrophytes in Finland.

A useful method for characterizing biological numerous assemblages at regional scales is the species occupancy frequency distribution (SOFD). An SOFD shows the number or proportion of study sites each species occurred. Species that occur at only a few sites are termed satellite species, while species that occur at many sites are termed core species.This study is the first to document and assess SOFD patterns in aquatic macrophytes. It characterizes SOFD patterns of freshwater macrophyte assemblages in Finland at two spatial and two temporal scales. For this, I analyzed three published datasets on freshwater macrophyte distributions: two from studies conducted at a local scale and the third from large national surveys. One local study and the national study also included data on temporal variation in species occupancy frequencies.In the national study, the number of core and satellite species varied slightly between the older and the newer survey, respectively. Among the 113 waterbodies surveyed as part of the national study, the SOFD followed a unimodal satellite pattern. However, for the older dataset (from the 1930s), a bimodal symmetric pattern also fit the SOFD data well. At the local scale, I observed geographical variation in SOFD patterns. The dataset from southern Finland followed a unimodal satellite SOFD pattern; data from central Finland instead displayed a bimodal symmetric SOFD pattern, although they also fit equally well with a bimodal truncated pattern. Moreover, temporal patterns in central Finland seemed to demonstrate a shift from a bimodal symmetric to a bimodal asymmetric SOFD probably.Geographical variation in the SOFD pattern may be due to variation in the regional species pool. The temporal changes in SOFD pattern may be due to lake eutrophication and anthropogenic disturbance around waterbodies, which may increase number of macrophyte species.

Mammal responses to reduced-impact logging in Amazonian forest concessions

Production forests are a dominant feature of most tropical forest landscapes and it is therefore important to understand the effects of timber extraction on the resident fauna. Here we investigate the effects of reduced-impact logging (RIL) on medium- to large-sized terrestrial mammals in two Jamari National Forest logging concessions, south-western Brazilian Amazonia. We used camera traps to survey the terrestrial mammal fauna. Bayesian multi-species occupancy models (MSOMs) were performed to assess the effect of logging intensity and density of logging roads on site-level species richness, occupancy and detection rates. Species richness was negatively affected by logging status and by increasing logging intensity, and positively affected by road density. Occupancy and detection rates of individual species were largely unrelated to model predictors, although responses across species tended to be consistent with that observed for species richness. Despite negative effects of logging on species richness, no individual species were lost at the landscape level, suggesting that concessions managed under RIL techniques may be a reasonable compromise between economic and conservation interests.

Optimising sampling and analysis protocols in environmental DNA studies

Ecological surveys risk incurring false negative and false positive detections of the target species. With indirect survey methods, such as environmental DNA, such error can occur at two stages: sample collection and laboratory analysis. Here we analyse a large qPCR based eDNA data set using two occupancy models, one of which accounts for false positive error by Griffin et al. (J R Stat Soc Ser C Appl Stat 69: 377–392, 2020), and a second that assumes no false positive error by Stratton et al. (Methods Ecol Evol 11: 1113–1120, 2020). Additionally, we apply the Griffin et al. (2020) model to simulated data to determine optimal levels of replication at both sampling stages. The Stratton et al. (2020) model, which assumes no false positive results, consistently overestimated both overall and individual site occupancy compared to both the Griffin et al. (2020) model and to previous estimates of pond occupancy for the target species. The inclusion of replication at both stages of eDNA analysis (sample collection and in the laboratory) reduces both bias and credible interval width in estimates of both occupancy and detectability. Even the collection of > 1 sample from a site can improve parameter estimates more than having a high number of replicates only within the laboratory analysis.

Lemur paparazzi: Arboreal camera trapping and occupancy modeling as conservation tools for monitoring threatened lemur species

Primate species face growing risks of extinction throughout the world. To better protect their populations, effective monitoring techniques are needed. The goal of this study was to evaluate the use of arboreal camera traps and occupancy modeling as conservation tools for threatened lemur species. This project aimed to (1) estimate the occupancy and detection probabilities of lemur species, (2) investigate factors potentially affecting lemur habitat use, and (3) determine whether ground or arboreal cameras are better for surveying lemur assemblages. We conducted camera trapping research in five forest fragments (total trap nights = 1770; 900 arboreal trap nights (134 photo events); 870 ground trap nights (2 photo events)) and reforestation areas (total trap nights = 608; 1 photo event) in Kianjavato, Madagascar from May to September 2019. We used arboreal trap data from fragments to estimate occupancy for five species: the red-fronted brown lemur (Eulemur rufifrons; ψ = 0.54 ± SD 0.03), Jolly's mouse lemur (Microcebus jollyae; ψ = 0.14 ± 0.17), the greater dwarf lemur (Cheirogaleus major; ψ = 0.42 ± 0.30), the red-bellied lemur (Eulemur rubriventer; ψ = 0.24 ± 0.03), and the black-and-white ruffed lemur (Varecia variegata; ψ = 0.24 ± 0.08). Tree diameter, elevation, distance to village, and canopy connectivity were important predictors of occupancy, while camera height, canopy connectivity, fragment ID, and fragment size predicted detection. Arboreal cameras recorded significantly higher species richness compared with ground cameras. We suggest expanded application of arboreal camera traps in future research, but we recommend longer trapping periods to better sample rarer species. Overall, arboreal camera trapping combined with occupancy modeling can be a highly efficient and useful approach for monitoring and predicting the occurrence of elusive lemur species and has the potential to be effective for other arboreal primates and canopy taxa across the globe.

Occupancy and detection of Wavyrayed Lampmussel (Lampsilis fasciola) in Ontario, Canada1

Freshwater mussels (Bivalvia: Unionidae) are the most imperilled taxon in Canada. To facilitate species recovery efforts, an understanding of species distribution and habitat that supports species persistence is needed. Detecting mussels presents unique challenges and requires considerable effort owing to their complex life histories and widespread declines. Here, observations of the imperilled Wavyrayed Lampmussel (Lampsilis fasciola Rafinesque, 1820) from the Grand and Thames rivers, Ontario, Canada, were used to quantify species detection and occupancy probabilities, and the relationship between occupancy probability and substrate size. The best model for the data included a river-specific covariate for detection and an intercept model for occupancy. Detection probability of Wavyrayed Lampmussel was higher in the Grand River than in the Thames River. Limited variation in substrate size measurements restricted occupancy modelling, but field measurements qualitatively aligned with previous habitat descriptions. Overall, knowledge of species detection and occupancy probabilities for Wavyrayed Lampmussel will not only enhance the understanding of species distribution and habitat associations, but also ensure that the response of the species to threats and recovery actions are captured.

Conservation monitoring of a polluted urban river: an occupancy modeling study of birds in the Yamuna of Delhi

Given that ecological knowledge of large urban river systems is extremely sparse due to logistics and accessibility an occupancy modeling study was conducted on the resident birds of Delhi. River Yamuna passing through Delhi is a refuge for several resident and migratory species of birds but its water quality has been deteriorating due to ever growing population, contributing most of its pollution load in the urban center. The objectives of this study were 1) to determine whether the occupancy of common waterbirds varied between differential polluted sections of the river, 2) to better understand the associations between habitat variables and use of the river habitat by common waterbirds and 3) to identify whether any species or groups of species could be useful as indicators for habitat quality. The occupancy parameter Ψ was estimated for 17 common resident species among 68 species, recorded from 176 sampling locations during 2018, on the banks of river. Species occupancy was estimated as a function of habitat variables such as physico-chemical characteristic of water, solid waste, percent area of surface and emergent vegetation and human disturbance at each sampling site. The results suggest that Little Grebe (Tachybaptus ruficollis), Grey Heron (Ardea cinerea), Grey-headed Swamphen (Porphyrio poliocephalus), Eurasian Coot (Fulica atra), Common Moorhen (Gallinuala chloropus), Purple Heron (Ardea purpurea) and Little Cormorant (Microcarbo niger) are negatively associated with the Total Dissolved Solute (TDS). Interestingly, occupancy of Black-winged Stilt (Himantopus himantopus) is negatively associated with pH but positively with solid waste strongly suggesting its preference for the polluted sections of the river, possibly due to the increased availability of food. For river Yamuna, estimates of Ψ for various birds forms a baseline to study future trends. This study also indicates that species like Black-winged Stilt, can serve as an indicator of contaminated water bodies. The challenges posed by increasing urbanization and pollution to riparian bird habitats in urban areas can be effectively dealt with by incorporating such ecological knowledge with habitat restoration and conservation efforts.

Factors affecting the spatial distribution and co‐occurrence of two sympatric mountain ungulates in southern Mongolia

AbstractCo‐occurrence of ungulates in multi‐species assemblages has fascinated ecologists because these species seemingly belong to the same guild – feeding on plants. Across large parts of the high mountains of Central Asia, ibex (Capra sibirica) and argali (Ovis ammon), both predominantly grazers, co‐occur at local and regional scales. However, little is known about the ecological and anthropogenic factors that influence their spatial distribution, co‐occurrence and habitat use. We examined factors affecting the distribution and co‐occurrence of these two sympatric species in Tost Tosonbumba Nature Reserve in southern Mongolia using an occupancy modeling approach. Specifically, we used single species occupancy models to examine the influence of road density, livestock density, terrain ruggedness and elevation on occupancy of these two species separately. We then assessed how these two species influence each other's distribution by using multi‐species occupancy models. The model‐averaged occupancy probabilities for ibex and argali were 0.64 ± 0.3 se and 0.44 ± 0.2 se, respectively. Terrain ruggedness positively influenced ibex distribution, while it negatively affected the occupancy of argali. We found limited evidence of relationship with factors associated with human disturbance. The species interaction factor, which indicates the level of co‐occurrence, suggested that ibex and argali occurred independent of each other ( = 0.72 ± 0.3 se). Together, our results imply that there was limited co‐occurrence between the two species and that this was largely driven by terrain ruggedness at the scale of the home range. These results suggest that topography plays an important role in enabling these two species to co‐occur at the regional scale.

Fine‐grain beta diversity of Palaearctic grassland vegetation

AbstractQuestionsWhich environmental factors influence fine‐grain beta diversity of vegetation and do they vary among taxonomic groups?LocationPalaearctic biogeographic realm.MethodsWe extracted 4,654 nested‐plot series with at least four different grain sizes between 0.0001 m² and 1,024 m² from the GrassPlot database, covering a wide range of different grassland and other open habitat types. We derived extensive environmental and structural information for these series. For each series and four taxonomic groups (vascular plants, bryophytes, lichens, all), we calculated the slope parameter (z‐value) of the power law species–area relationship (SAR), as a beta diversity measure. We tested whether z‐values differed among taxonomic groups and with respect to biogeographic gradients (latitude, elevation, macroclimate), ecological (site) characteristics (several stress–productivity, disturbance and heterogeneity measures, including land use) and alpha diversity (c‐value of the power law SAR).ResultsMean z‐values were highest for lichens, intermediate for vascular plants and lowest for bryophytes. Bivariate regressions of z‐values against environmental variables had rather low predictive power (mean R² = 0.07 for vascular plants, less for other taxa). For vascular plants, the strongest predictors of z‐values were herb layer cover (negative), elevation (positive), rock and stone cover (positive) and the c‐value (U‐shaped). All tested metrics related to land use (fertilization, livestock grazing, mowing, burning, decrease in naturalness) led to a decrease in z‐values. Other predictors had little or no impact on z‐values. The patterns for bryophytes, lichens and all taxa combined were similar but weaker than those for vascular plants.ConclusionsWe conclude that productivity has negative and heterogeneity positive effects on z‐values, while the effect of disturbance varies depending on type and intensity. These patterns and the differences among taxonomic groups can be explained via the effects of these drivers on the mean occupancy of species, which is mathematically linked to beta diversity.

Borealization and its discontents: drivers of regional variation in plant diversity across scales in interior Alaska

AbstractQuantitative studies of regional variation in plant diversity across eastern Beringia (northern Alaska and adjacent areas) are lacking due to an absence of datasets of sufficient scale and scope. We interrogated a landscape‐scale plant diversity dataset collected across two regions of interior Alaska with different disturbance, topographic, and climate attributes to investigate hypotheses regarding drivers of plant species richness. Our approach integrated a multi‐scale sampling design with an analytical framework focused on quantifying how components of plant diversity (growth forms, biogeographic groups, and dominant species) respond to site factors that vary along landscape gradients. Our results revealed essential similarities in both the composition of the overall floras and the influences on local and meso‐scale species richness across both regions. However, these continuities at smaller scales contrasted with differences in landscape‐level distribution of plant diversity patterns along elevation gradients. Our findings suggest that local drivers of richness and occupancy interacted with differing macro‐scale attributes (e.g., relative continentality) to produce distinctive landscape‐level diversity patterns. Our results confirm that high levels of local and meso‐scale plant richness in interior Alaska depend on conditions that foster richness of herbaceous and northerly distributed species groups. However, we found that important differences in landscape‐level richness patterns were driven by regional differences in climate, topoedaphic variables, and disturbance. In the warmer region, woody species and boreal plant communities extended to higher elevations and common species occupancy showed marginally greater influence of fire. Overall richness was relatively low in alpine areas of the warmer region but heterogeneous edaphic and topographic circumstances stimulated higher species turnover in lower elevations there, increasing landscape‐level richness. In contrast, in the cooler region, woody species showed restricted distribution across the elevation gradient while site attributes associated with increased species richness aligned with the elevation gradient and thus peak richness occurred in the alpine zone. Our results show how total and growth‐form richness, as well as community composition, vary regionally in relation to important drivers (including growing season warmth) across interior Alaska. Consequently, our study provides new insights into the potential trajectories of future change in biodiversity patterns in this rapidly warming region.

Declines in Common and Migratory Breeding Landbird Species in South Korea Over the Past Two Decades

Population declines in terrestrial bird species have been reported across temperate regions in the world and are attributed to habitat loss, climate change, or other direct mortality sources. North American and European studies indicate that long-distance migrants, common species, and species associated with grasslands and agricultural lands are declining at the greatest rates. However, data from East Asia on avian population trends and associated drivers are extremely sparse. We modeled changes in occupancy of 52 common breeding landbird species in South Korea between 1997–2005 and 2013–2019. Thirty-eight percent of the species showed evidence of declines, and seven of these were declining severely (46–95%). Occupancy of Black-capped Kingfisher (Halcyon pileata) populations have dropped the most precipitously over the study period. Among declining species, long-distance migrants (9/20) and common species (14/20) showed more rapid declines than other groups. Declines of five species were associated with climate change, and two species appeared to be affected by land-cover change. However, causes of change in occupancy of other species (46/52) remains cryptic. Based on our results, we suggest an immediate re-evaluation of species’ conservation status and legal protection levels for seven severely declining species in South Korea, and a dedicated survey design and analysis effort for the continued monitoring landbird populations. Because many species exhibiting declines migrate from beyond national boundaries, international collaborations will be required to better quantify population trends across the full annual cycle, and to understand mechanisms for these declines.

Grazing affects vegetation diversity and heterogeneity in California vernal pools.

Disturbance often increases local-scale (α) diversity by suppressing dominant competitors. However, widespread disturbances may also reduce biotic heterogeneity (β diversity) by making the identities and abundances of species more similar among patches. Landscape-scale (γ) diversity may also decline if disturbance-sensitive species are lost. California's vernal pool plant communities are species rich, in part because of two scales of β diversity: (1) within pools, as species composition changes with depth (referred to here as vertical β diversity), and (2) between pools, in response to dispersal limitation and variation in pool attributes (referred to here as horizontal β diversity). We asked how grazing by livestock, a common management practice, affects vernal pool plant diversity at multiple hierarchical spatial scales. In terms of abundance-weighted diversity, grazing increased α both within local pool habitat zones and at the whole-pool scale, as well as γ at the pasture scale without influencing horizontal or vertical β diversity. In terms of species richness, increases in α diversity within habitat zones and within whole pools led to small decreases in horizontal β diversity as species occupancy increased. This had a dampened effect on species richness at the γ (pasture) scale without any loss of disturbance-sensitive species. We conclude that grazing increases species richness and evenness (α) by reducing competitive dominance, without large disruptions to the critical spatial heterogeneity (β) that generates high landscape-level diversity (γ).

Does trait-based joint species distribution modelling reveal the signature of competition in stream macroinvertebrate communities?

The occupancy and abundance of species are jointly driven by local factors, such as environmental characteristics and biotic interactions, and regional-scale factors, such as dispersal and climate. Recently, it has been shown that biotic interactions shape species occupancies and abundances beyond local extents. However, for small ectothermic animals, particularly for those occurring in freshwater environments, the importance of biotic interactions remains understudied. Species-to-species associations from joint species distribution models (i.e. species associations while controlling for environmental characteristics) are increasingly used to draw hypotheses of which species possibly show biotic interactions. We studied whether species-to-species associations from joint species distribution models show signs of competition using a hypothesis testing framework in stream macroinvertebrate communities at regional extent. We sampled aquatic macroinvertebrates from 105 stream sites in western Finland encompassing a latitudinal gradient of c. 500 kilometres. We hypothesized that if competition drives these associations (H1) functionally, similar species are mostly negatively associated, whereas functionally dissimilar species show random associations. We further hypothesized that the relationship between functional dissimilarity and the strength of association is more pronounced (H2) for abundances rather than occupancies, (H3) at small grain (i.e. stream site) rather than at large grain (i.e. river basin), and (H4) among species having weak dispersal ability than among species with high dispersal ability. Stream macroinvertebrates showed both negative and positive species-to-species associations while controlling for habitat characteristics. However, the negative associations were mostly at large grain (river basin) rather than at small grain (stream site), in occupancy rather than abundance, and not related to species functional dissimilarity or to their dispersal ability. Thus, all our hypotheses considering possible competition (H1-H4) were rejected. Competition does not appear to be a major driving force of stream macroinvertebrate communities at the spatial grain sizes considered. The observed positive associations in occupancy at small grain (stream site) may be attributed to species' similar microhabitat preferences, whereas at large grain (river basin), they may stem from metacommunity dynamics. Our results highlight that species traits were necessary to interpret whether or not species-to-species associations from joint species distribution models resulted from biotic interactions.

Multi-species occupancy modeling provides novel insights into amphibian metacommunity structure and wetland restoration.

A fundamental goal of community ecology is to understand species-habitat relationships and how they shape metacommunity structure. Recent advances in occupancy modeling enable habitat relationships to be assessed for both common and rare species within metacommunities using multi-species occupancy models (MSOM). These models account for imperfect species detection and offer considerable advantages over other analytical tools commonly used for community analyses under the elements of metacommunity structure (EMS) framework. Here, we demonstrate that MSOM can be used to infer habitat relationships and test metacommunity theory, using amphibians. Repeated frog surveys were undertaken at 55 wetland sites in southeastern Australia. We detected 11 frog species from three families (Limnodynastidae, Myobatrachidae, and Pelodryadidae). The rarest species was detected at only one site whereas the most common species was detected at 42 sites (naive occupancy rate 0.02-0.76). Two models were assessed representing two competing hypotheses; the best-supported model included the covariates distance to the nearest site (connectivity), wetland area, presence of the non-native eastern mosquitofish (Gambusia holbrooki), proportion cover of emergent vegetation, an interaction term between Gambusia and emergent vegetation cover, and the proportion canopy cover over a site. Hydroperiod played no detectable role in metacommunity structure. We found species-habitat relationships that fit with current metacommunity theory: occupancy increased with wetland area and connectivity. There was a strong negative relationship between occupancy and the presence of predatory Gambusia, and a positive interaction between Gambusia and emergent vegetation. The presence of canopy cover strongly increased occupancy for several tree frog species, highlighting the importance of terrestrial habitat for amphibian community structure. We demonstrated how responses by amphibians to environmental covariates at the species level can be linked to occupancy patterns at the metacommunity scale. Our results have clear management implications: wetland restoration projects for amphibians and likely other taxa should maximize wetland area and connectivity, establish partial canopy cover, and eradicate Gambusia or provide aquatic vegetation to mitigate the impact of this non-native fish. We strongly advocate the use of MSOM to elucidate the habitat drivers behind animal occupancy patterns and to derive unbiased occupancy estimates for monitoring programs.

Post-white-nose syndrome passive acoustic sampling effort for determining bat species occupancy within the mid-Atlantic region

We assessed the sampling effort requirements for detecting the presence of extant bat species following the impact of white-nose syndrome in the mid-Atlantic region of the United States. We acoustically sampled 27,796 nights across 846 sites between 15 May and 15 August 2016–2018 within the District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia. We developed simulations to determine the number of sites required to document bat species when each site was sampled different numbers of nights. We examined these simulations with respect to land cover, physiographic region, and time period. We generally found that sampling a greater number of sample sites within a survey area increased detection more than increasing the number of nights at individual sampling sites. The sampling effort required to detect a given bat species varied by species, as well as land-cover type and physiographic region. Our results suggest that land managers and researchers should use caution in using protocols developed with other objectives, e.g., the U.S. Fish and Wildlife Service endangered and threatened bat species and the North American Bat monitoring programs’ methods are designed relative to their specific needs. Unfortunately, neither protocol may be adequate for accurately detecting bat communities within all mid-Atlantic areas.

Forest patch characteristics affect reptile occurrence in north‐western Madagascar

AbstractCharacterising species–landscape associations is relevant for conservation planning and management in response to environmental transformation. The occurrence of reptiles is linked to landscape structure that allows for thermoregulation, shelter and feeding, but the relative importance of these factors is unknown for many tropical and subtropical species. We used community‐level occupancy modelling and remote sensing to investigate the effects of vegetation structure and anthropogenic development on reptile occurrence in a Malagasy dry forest during the dry season (June and July). The occupancy estimates for some species revealed that species occupancy increased for more densely vegetated sites situated closer to the forest edge. The proximity of anthropogenic transformation did not significantly affect the occurrence of species except for Uroplatus guentheri which showed preference for sites away from settlements. Because most species and those most sensitive to habitat transformation were associated with edges of intact forest patches with denser green vegetation, these areas should form the focus of efforts to conserve reptiles in tropical dry forests. We also demonstrate how setting and scale can affect how habitat‐use patterns are interpreted and the importance of local, species‐specific studies.

High‐density camera trap grid reveals lack of consistency in detection and capture rates across space and time

AbstractCounts of independent photo events from camera traps are commonly used to make inference about species occupancy, the density of unmarked populations, and the relative abundance of species across time and space. These applications rest on the untested assumption that data collected from individual cameras are representative of the landscape location in which they are placed, and that nearby cameras would record similar data when any additional micro‐site differences are accounted for. We established a high‐density camera trapping grid (100 × 100 m; 27 cameras) in Virginia, USA, to explicitly test these assumptions, investigating variation in capture rates and detection probabilities for a range of terrestrial mammals during four 2‐month seasonal surveys. Despite controlling for numerous habitat and placement factors, we documented, across all 5 focal species, large ranges and coefficients of variation in both capture rate and detection probabilities, which were similar to those seen across 2 sets of independent forest sampling sites from a larger, more typical camera trap sampling design. We also documented a lack of spatial autocorrelation in capture rate at any distance. Measured local covariates relevant to the camera viewshed (stem density, camera height, log presence, effective detection distance [EDD], total dbh of oak trees) rarely explained any significant portion of observed variation in capture rates or detection probabilities across the grid. The influence of EDD, measured here for the first time for individual camera stations, was inconsistently important and varied in direction of effect depending on species and season. Our study indicates single‐camera stations may fail to sample animal presence and frequency of use in a robust and repeatable way, primarily resulting from the influence of both idiosyncrasies in animal movement and measured and unknown micro‐site characteristics. We recommend spatial replication within sites (e.g., small‐scale shifting of cameras or use of multiple stations) should be considered to minimize impacts of relevant micro‐site characteristics, some of which may be difficult to identify.

Assessing mammal species richness and occupancy in a Northeast Asian temperate forest shared by cattle

AbstractAimAsian forests are becoming increasingly degraded and fragmented by the extensive intensification of anthropogenic activities; these activities threaten wildlife and ecosystem sustainability. Facing a defaunation crisis, managers need more information on species assemblages to guide conservation efforts. We tested the relative influence of natural and anthropogenic factors on mammalian species richness and occupancy in temperate forests in Northeast Asia.LocationNortheast China.MethodsCamera‐trapping data and multispecies occupancy models were used to estimate the species richness of a terrestrial mammal community in a working landscape and assess community‐, group‐, and species‐specific responses to natural and anthropogenic features while accounting for imperfect detection. Species were grouped based on body size, diet and activity pattern.ResultsWe deployed 138 cameras and photographed 21 mammalian species over 22,976 trap days across the China–Russia border. Both natural and anthropogenic correlates varied in their importance in predicting the presence of different animals. Vegetation cover and cattle were found to have significantly positive and negative influences on community‐level mammalian occupancy, respectively. The positive relationship with vegetation cover was most evident for large or diurnal species; the negative relationship with cattle was most evident for diurnal and wild ungulate species. Large species occupancy was also negatively associated with human settlements. The predicted richness across each station varied from 5 to 14 unique species, and species had a mean occupancy probability of 0.45 (95% credible interval = 0.09–0.86). Species richness was generally the lowest in livestock grazing areas and close to human settlements. Human influence is more important than the influences of vegetation and environmental variables.Main conclusionsOur results highlight that livestock grazing was the primary human disturbance that had a negative impact on species occupancy and richness. Multispecies occupancy models helped to identify drivers of biodiversity declines and will inform conservation strategies in human‐dominated landscapes in Northeast Asian forests. We suggest that landscape conservation planning seeks to maximize forest protection and ecosystem services such as biodiversity and carbon storage.

The relationship between landscape features and domestic species on the occupancy of native mammals in urban forests

Landscape features such as roads, hiking trails, and forest edge are prevalent features of urban forests. These features can negatively influence biodiversity through fragmentation and facilitate the penetration of invasive species, particularly predators such as domestic dogs and cats. This study examined how these landscape features affect the distribution of native and domestic mammals and how domestic species affect the occupancy and activity patterns of native mammals. To this end, we conducted camera trap surveys in forested urban and suburban parks in Indiana and Kentucky, USA, to record the presence of native species (deer, raccoons, coyote, and opossums) and non-native predators (domesticated cats and dogs) in relation to distance to nearest roads, hiking trails, and forest edge. We found negative correlations between proximity to roads, hiking trails, and forest edge and the occupancy of the native species with this effect extending up to 300 m. We also found evidence that the presence of dog and cat was negatively correlated with the occupancy for all native species. We recommend park management consider the impact of roads, hiking trails, and forest edge when designing parks and the enforcement of dog leash regulations for the conservation of large mammals in urban parks.

Towards a better understanding of grass bed dynamics using remote sensing at high spatial and temporal resolutions

Wetlands conservation and resilience capacities are key issues in many places over the globe. Understanding these issues will benefit from a precise knowledge of seagrass species occupancy and coverage over time and over space. Such information can be obtained from remote sensing images and their classification thanks to a vegetation index, to be used in a complementary manner to field work inventories. Sentinel-2 data, which are available with a frequent revisit time (<5 days) and a high spatial resolution (10m pixel size) can be used to map grassbeds at the surface or slightly below the surface of permanent lagoons, hence enabling the characterization of its seasonal dynamics, which was not possible with previous remote-sensing tools. We have proved the feasibility of such a method in the natural reserve of the Bagnas (Herault, France) where Stuckenia pectinata coverage can be tracked over a full year thanks to Sentinel-2 images and field work. Inter-annual dynamics (seasonal growth and senescence) can be mapped over time with 10m resolution and will be extended to pluriannual studies thanks to the long-term objective of the Sentinel-2 mission. This opens the way to a concerted management of natural reserves based on data analysis and field knowledge, a better understanding of seagrass coverage with fluctuating environmental conditions, and predictive mechanistic and/or stochastic models of future qualitative trends.