Scale‐dependent responses to forest cover displayed by frugivore bats

Despite vast evidence of species turnover displayed by Neotropical bat communities in response to forest fragmentation, the exact shape of the relationship between fragment area and abundance for individual bat species is still unclear. Bats’ ample variation in diet, morphology, and movement behaviour can potentially influence species’ perception of the landscape. Thus, studies describing fragment area at a single spatial scale may fail to capture the amount of forest available from the perspective of individual bat species. In the present paper, we study the influence of forest cover on bats inhabiting a fragmented forest in Mexico, focusing on some of the most common frugivore species: Artibeus jamaicensis, Carollia spp. (C. brevicauda/C. perspicillata) and Sturnira spp. (S. lilium/S. ludovici). We quantified forest cover at scales ranging from 50 to 2000 m, and measured the influence of forest cover on bat capture success, a surrogate for abundance. The three species displayed positive and significant scale‐dependent associations with forest cover. Abundance of A. jamaicensis increased with forest cover measured at scales ranging between 500 and 2000 m, while Carollia spp. responded more strongly to variation in forest cover measured at scales 100–500 m. For Sturnira spp., abundance was a function of presence of creeks near mist‐netting sites, and amount of secondary forest present at a 200 m scale. The observed variation in responses to forest cover can be explained in light of interspecific differences in diet, home range, and body size. Our results illustrate a method for measuring the effect of forest fragmentation on mobile species and suggest that changes in abundance in fragmented landscapes emerge from the interaction between species’ traits and landscape structure.     

Multilevel landscape utilization of the Siberian flying squirrel: Scale effects on species habitat use

Animals use and select habitat at multiple hierarchical levels and at different spatial scales within each level. Still, there is little knowledge on the scale effects at different spatial levels of species occupancy patterns. The objective of this study was to examine nonlinear effects and optimal‐scale landscape characteristics that affect occupancy of the Siberian flying squirrel, Pteromys volans, in South‐ and Mid‐Finland. We used presence–absence data (n = 10,032 plots of 9 ha) and novel approach to separate the effects on site‐, landscape‐, and regional‐level occupancy patterns. Our main results were: landscape variables predicted the placement of population patches at least twice as well as they predicted the occupancy of particular sites; the clear optimal value of preferred habitat cover for species landscape‐level abundance is a surprisingly low value (10% within a 4 km buffer); landscape metrics exert different effects on species occupancy and abundance in high versus low population density regions of our study area. We conclude that knowledge of regional variation in landscape utilization will be essential for successful conservation of the species. The results also support the view that large‐scale landscape variables have high predictive power in explaining species abundance. Our study demonstrates the complex response of species occurrence at different levels of population configuration on landscape structure. The study also highlights the need for data in large spatial scale to increase the precision of biodiversity mapping and prediction of future trends.     

Tree Selection and Landscape Analysis of Eastern Red Bat Day Roosts

ABSTRACT Declining bat populations and increasing demands on forest resources have prompted researchers to investigate tree roost selection of forest bats. Few studies, however, have investigated different spatial scales and landscape pattern as criteria for selection of tree roosts. In 1999 and 2000, we radiotracked 23 eastern red bats (Lasiurus borealis) to 64 day roosts. Using univariate and multivariate comparisons, we tested roost tree variables with random tree data at 3 circular spatial scales: roost tree, plot, and landscape. We found 15 variables that were entered in a stepwise discriminant analysis to best differentiate between the roost and random samples; 11 (73.3%) were landscape variables measured with a geographic information system. On average (x̄ ± SE), red bats roosted in deciduous trees (42.0 ± 2.1 cm dbh) that were located in plots with more (3.1 ± 0.1 m²) basal area, higher (84.0 ± 1.3) percentage of canopy closure, and lower (27.2 ± 2.2) percentage of groundcover than random plots. At the landscape scale (by percent magnitude), red bat buffers (1,000-m-radius circle) had significantly less development (81.6%), less feeding operations (70.4%), more deciduous (52.9%) and pine forest (63.8%), and fewer local roads (5.4%) but more trails (94.1%), open water (61.4%), wetland areas (80.4%), and stream areas (63.1%) than random buffers. Red bat roost trees were significantly closer (χ² = 22.0088, df = 1, P < 0.001) to trails (106.2 ± 13.3 m) than to streams (279.4 ± 28.5 m). Our results suggest that red bats in our study area select roosts in mature riparian forests near trails, open water, and wetlands. The high percentage of landscape values in the discriminant analysis lends support to using landscape metrics as an investigative technique of resource selection. We recommend that managers consider landscape factors when protecting red bat day-roost habitat.     

Occurrence of lemurs in landscapes and their species-specific scale responses to habitat loss

Studies on the impact of habitat loss on species occurrence consistently find that the amount of habitat (measured as patch area) is a major determinant of species occurrence at a patch-level. However, patch-level research may fail to detect important patterns and processes only observable at a landscape-level. A landscape-level approach that incorporates species-specific scale responses is needed to better understand what drives species occurrence. Our aim was to determine the landscape-level scale of effect of habitat amount on the occurrence of three species of nocturnal lemurs (Cheirogaleus medius, Microcebus murinus, and M. ravelobensis). We surveyed line transects to determine the occurrence of three lemur species within a fragmented landscape of deciduous dry forest and anthropogenic grassland in northwestern Madagascar. To determine the scale of effect of habitat loss on lemur occurrence, we compared logistic regression models of occurrence against habitat amount among eight different landscape scales using Akaike's Information Criterion values. We found differing scale responses among the lemurs in our study. Occurrence of C. medius responded to habitat amount at scales between 0.5–4 ha, M. murinus at scales between 1 and 4 ha and M. ravelobensis at scales between 0.125 and 4 ha. We suggest that the scale of effect for C. medius is mediated by their ability to hibernate. A relatively lower scale-response for Microcebus spp. likely reflect their omnivorous diet, small habitat requirements, and limited dispersal ability. Differences in scale responses between M. murinus and M. ravelobensis are likely a result of differing dispersal ability and responses to edge effects between these species. Our study is among the first on lemurs to show the value of a landscape-level approach when assessing the effects of habitat loss on species occurrence.     

Untangling associations between chironomid taxa in Neotropical streams using local and landscape filters

1. Analyses of species association have major implications for selecting indicators for freshwater biomonitoring and conservation, because they allow for the elimination of redundant information and focus on taxa that can be easily handled and identified. These analyses are particularly relevant in the debate about using speciose groups (such as the Chironomidae) as indicators in the tropics, because they require difficult and time‐consuming analysis, and their responses to environmental gradients, including anthropogenic stressors, are poorly known. 2. Our objective was to show whether chironomid assemblages in Neotropical streams include clear associations of taxa and, if so, how well these associations could be explained by a set of models containing information from different spatial scales. For this, we formulated a priori models that allowed for the influence of local, landscape and spatial factors on chironomid taxon associations (CTA). These models represented biological hypotheses capable of explaining associations between chironomid taxa. For instance, CTA could be best explained by local variables (e.g. pH, conductivity and water temperature) or by processes acting at wider landscape scales (e.g. percentage of forest cover). 3. Biological data were taken from 61 streams in Southeastern Brazil, 47 of which were in well‐preserved regions, and 14 of which drained areas severely affected by anthropogenic activities. We adopted a model selection procedure using Akaike’s information criterion to determine the most parsimonious models for explaining CTA. 4. Applying Kendall’s coefficient of concordance, seven genera (Tanytarsus/Caladomyia, Ablabesmyia, Parametriocnemus, Pentaneura, Nanocladius, Polypedilum and Rheotanytarsus) were identified as associated taxa. The best‐supported model explained 42.6% of the total variance in the abundance of associated taxa. This model combined local and landscape environmental filters and spatial variables (which were derived from eigenfunction analysis). However, the model with local filters and spatial variables also had a good chance of being selected as the best model. 5. Standardised partial regression coefficients of local and landscape filters, including spatial variables, derived from model averaging allowed an estimation of which variables were best correlated with the abundance of associated taxa. In general, the abundance of the associated genera tended to be lower in streams characterised by a high percentage of forest cover (landscape scale), lower proportion of muddy substrata and high values of pH and conductivity (local scale). 6. Overall, our main result adds to the increasing number of studies that have indicated the importance of local and landscape variables, as well as the spatial relationships among sampling sites, for explaining aquatic insect community patterns in streams. Furthermore, our findings open new possibilities for the elimination of redundant data in the assessment of anthropogenic impacts on tropical streams.     

Predicting Species Distributions Using Record Centre Data: Multi-Scale Modelling of Habitat Suitability for Bat Roosts

Conservation increasingly operates at the landscape scale. For this to be effective, we need landscape scale information on species distributions and the environmental factors that underpin them. Species records are becoming increasingly available via data centres and online portals, but they are often patchy and biased. We demonstrate how such data can yield useful habitat suitability models, using bat roost records as an example. We analysed the effects of environmental variables at eight spatial scales (500 m – 6 km) on roost selection by eight bat species (Pipistrellus pipistrellus, P. pygmaeus, Nyctalus noctula, Myotis mystacinus, M. brandtii, M. nattereri, M. daubentonii, and Plecotus auritus) using the presence-only modelling software MaxEnt. Modelling was carried out on a selection of 418 data centre roost records from the Lake District National Park, UK. Target group pseudoabsences were selected to reduce the impact of sampling bias. Multi-scale models, combining variables measured at their best performing spatial scales, were used to predict roosting habitat suitability, yielding models with useful predictive abilities. Small areas of deciduous woodland consistently increased roosting habitat suitability, but other habitat associations varied between species and scales. Pipistrellus were positively related to built environments at small scales, and depended on large-scale woodland availability. The other, more specialist, species were highly sensitive to human-altered landscapes, avoiding even small rural towns. The strength of many relationships at large scales suggests that bats are sensitive to habitat modifications far from the roost itself. The fine resolution, large extent maps will aid targeted decision-making by conservationists and planners. We have made available an ArcGIS toolbox that automates the production of multi-scale variables, to facilitate the application of our methods to other taxa and locations. Habitat suitability modelling has the potential to become a standard tool for supporting landscape-scale decision-making as relevant data and open source, user-friendly, and peer-reviewed software become widely available.     

小兴安岭天然针阔混交林主要树种空间格局及其关联性

在小兴安岭天然针阔混交林1.1 hm~2的固定样地内,本文调查和统计了其物种组成和林分径级结构。运用空间点格局分析方法中的O-ring函数,对种群的空间分布格局及其关联性进行分析。结果表明:样地内共有乔木树种15种,重要值排在前四位的依次为红皮云杉(Picea koraiensis)、枫桦(Betula costata)、春榆(Ulmus davidiana)和色木槭(Acer mono),红皮云杉和枫桦属于样地内的优势种,重要值分别为15.81%和11.10%。林下更新状态良好,枫桦的径级结构有呈正态分布的趋势,其余三种均呈现倒"J"形。O-ring函数结果证实,四个主要树种的种群空间分布格局相似,均在0—5 m小尺度上呈聚集分布,随着尺度的增大,逐渐变为随机分布;红皮云杉与其他三个主要种群之间在较大尺度上均呈现显著正相关或无相关,在小尺度上仅与枫桦呈极显著正相关;色木槭在较小尺度上与其他三个种群呈弱负相关性,随着尺度的增大,逐渐变为无相关性。     

Scale-dependent patterns of macrofaunal distribution in soft-sediment intertidal habitats along a large-scale estuarine gradient

We investigated the pattern of distribution of intertidal soft-bottom fauna in streams and lagoons of the Uruguayan coast at three spatial scales. The Río de la Plata and the Atlantic Ocean produce on this coast a large-scale gradient in salinity, defining a freshwater (west), an estuarine (central) and a marine (east) region. Within each region, there are several streams and coastal lagoons (sites) that define a second scale of variability. A third scale is given by intertidal gradients within each site. Species richness and total abundance was low in the freshwater west region and high in the central and east regions. The community in the west region was characterized by the clam Curbicula fluminea; in the other regions, it was dominated mainly by the polychaete Heteromastus similis. The polychaete Nephtys fluviatilis was more abundant in the east region, while another polychaete, Laeonereis acuta, characterized the central region. Sediment fractions did not vary significantly at this scale. At the scale of the sites, species richness and total macrofaunal abundance were higher in coastal lagoons than in streams. Coarse sands were more common in coastal lagoons, while medium and fine sand characterized the sediment in streams. Within each site, species richness and total abundance increased towards the lower intertidal level; the macrofauna of the upper levels were a subsample of the fauna occurring at the lower levels. There was also a significantly lower proportion of fine sand at the upper level. At regional scales, the observed patterns may be indirectly or directly related to the gradient in salinity, through differential physiological tolerance to osmotic stress. At the scale of the sites, variability may be explained mainly by geomorphological and sedimentological differences between lagoons and streams. Variation among levels may be related to gradients in desiccation, colonization and predation.     

Input, retention, and invertebrate colonization of allochthonous litter in streams bordered by deciduous broadleaved forest, a conifer plantation, and a clear-cut site in southwestern Japan

In headwater streams, conifer plantation forestry may affect stream communities through the quantity and quality of basal resources (allochthonous litter). We compared (1) the seasonal patterns of litter input from the riparian canopy, (2) those for the abundance of benthic and drifting litter in streams, and (3) the density of litter-associated invertebrates among streams bordered by deciduous broadleaved forest, a plantation of Japanese cedar (Cryptomeria japonica), and a clear-cut site, to extract the characteristics of conifer-plantation streams in terms of litter dynamics and benthic invertebrates. The results illustrate differences in litter input and in-stream processes between the broadleaved and plantation sites, although the total annual inputs from canopy were similar. In the broadleaved site, high litter storage was limited to winter, probably because pulsed inputs of litter in autumn were retained on the streambed but rapidly processed. In contrast, litter input was more constant at the plantation site, and litter was stored throughout the year. Although the litter-patch-specific density of total invertebrates was similar between the broadleaved and plantation sites, estimates of the reach-scale, habitat-weighted density considering differences in the coverage area of litter patches revealed considerable differences. Although the habitat-weighted density of total invertebrates was lower at the plantation site than at the broadleaved site in winter, it was noticeably higher at the plantation site in summer, owing to the seasonal stability of benthic litter abundance. Our results emphasized the importance of considering the spatiotemporal availability of benthic litter when assessing the effects of conifer plantations on stream ecosystems.     

Multi-Scale,Direct and Indirect Effects of the Urban Stream Syndrome on Amphibian Communities in Streams

Urbanization affects streams by modifying hydrology, increasing pollution and disrupting in-stream and riparian conditions, leading to negative responses by biotic communities. Given the global trend of increasing urbanization, improved understanding of its direct and indirect effects at multiple scales is needed to assist management. The theory of stream ecology suggests that the riverscape and the surrounding landscape are inextricably linked, and watershed-scale processes will also affect in-stream conditions and communities. This is particularly true for species with semi-aquatic life cycles, such as amphibians, which transfer energy between streams and surrounding terrestrial areas. We related measures of urbanization at different scales to frog communities in streams along an urbanization gradient in Melbourne, Australia. We used boosted regression trees to determine the importance of predictors and the shape of species responses. We then used structural equation models to investigate possible indirect effects of watershed imperviousness on in-stream parameters. The proportion of riparian vegetation and road density surrounding the site at the reach scale (500-m radius) had positive and negative effects, respectively, on species richness and on the occurrence of the two most common species in the area ( Crinia signifera and Limnodynastesdumerilii ). Road density and local aquatic vegetation interacted in influencing species richness, suggesting that isolation of a site can prevent colonization, in spite of apparently good local habitat. Attenuated imperviousness at the catchment scale had a negative effect on local aquatic vegetation, indicating possible indirect effects on frog species not revealed by single-level models. Processes at the landscape scale, particularly related to individual ranging distances, can affect frog species directly and indirectly. Catchment imperviousness might not affect adult frogs directly, but by modifying hydrology it can disrupt local vegetation and prove indirectly detrimental. Integrating multiple-scale management actions may help to meet conservation targets for streams in the face of urbanization.     

鄂西南亚热带山地常绿落叶阔叶混交林物种多度分布格局

基于七姊妹山自然保护区内6 hm~2监测样地多度数据,通过累计经验分布曲线(ECDF)表征该样地内不同生活型功能群的物种-多度分布格局,并采用6种模型对各功能群不同取样尺度物种等级-多度曲线进行拟合并检验其拟合效果,分析多度格局与模型拟合在不同尺度间的差异,探讨其背后的生态学过程与机制。结果表明:(1)各尺度下落叶种比常绿种的物种数多,物种多样性指数更大,但个体数相对较少;不同功能群稀有种比例排序为:落叶种所有种常绿种。(2)6种模型中的断棍模型的拟合效果较差;中大尺度(50 m×50 m、100 m×100 m)上不同生活型树种多度分布能接受的模型较少,除大尺度的常绿树种外,拟合最优模型均为对数正态分布模型,大尺度的常绿树种拟合最优模型为中性模型;小尺度上(20 m×20 m)常绿树种的最优模型为对数正态分布模型,落叶树种最优模型为生态位优先模型,所有树种在小尺度最优模型为Zipf-Mandelbrot模型。研究认为,随着尺度逐渐扩大,中性过程较生态位过程对物种-多度格局的解释力度更大,落叶树种物种多度格局的形成机制较常绿树种更接近于样地所有树种物种-多度格局的形成机制。     

Habitat fragmentation and the prevalence of parasites (Diptera,Streblidae) on three Phyllostomid bat species

Ectoparasitism in bats seems to be influenced strongly by the type of roost preferred by the hosts, and group size; however, the effect of habitat loss and fragmentation on the prevalence of ectoparasites in bats has scarcely been studied. In northeastern Yucatan, Mexico, we estimated the prevalence of infestation by Streblidae flies in three phyllostomid bat species with different roost preferences (caves, trees, or both) in two types of landscape matrices (tropical semi‐deciduous forest and man‐made pastures) that differed in area of forest cover and the number of forest fragments. Habitat fragmentation and the presence of a contrasting matrix may limit the availability of roosts (trees) and the movement of bats across the landscape. Accordingly, we hypothesized higher prevalence of Streblidae infestation in the pasture matrix and in the group of bats that roost in trees. Bat abundance was higher in the pasture matrix; however, the prevalence of infestation was significantly higher in the continuous forest matrix and in bats that roosted in caves. The prevalence of some species of Streblidae was affected by habitat fragmentation in species that roost in caves, such as Desmodus rotundus, as well as those using foliage and caves, such as Artibeus jamaicensis. Our results provide evidence that some species of Streblidae may respond differently to habitat fragmentation than their hosts, generating changes to bat‐ectoparasite interactions in fragmented areas. Environmental variations involving roosts, not evaluated in this study, may influence our results, since these factors affect ectoparasite abundance and reproduction.     

Ecology and conservation of insectivorous bats in fragmented areas of macadamia production in eastern Australia

Microbats perform important ecological services in agro‐ecosystems, but several species are globally threatened by loss of roosting and breeding habitats. The successful conservation of bats in agricultural land requires adequate knowledge of their ecology. Using ultrasonic recorders, we studied the activity of insectivorous bats in areas of macadamia production in eastern Australia at two spatial scales: across woodland‐orchard transects at the local scale and across three levels of fragmentation at the landscape scale. At the local scale, activity patterns of ‘clutter’ and ‘edge’ specialists were consistently higher in woodland patches, gradually decreasing towards isolated orchards, where only a few ‘open’ specialists were active. At the landscape scale, bat community activity was affected by the level of fragmentation, partly because three of the most recorded taxa (Austronomus australis, Saccolaimus flaviventris and Miniopterus australis) had their highest activity in less‐fragmented areas. A distance‐based model explained 24% of the bat community activity based on a combination of six environmental variables. Canonical correspondence analysis showed that a number of bat taxa were associated with open areas of macadamia, whereas other taxa were associated with increasing values of landscape composition, and arthropod and water availability. In addition, total bat activity was highly correlated with foraging rate. These results suggest that most bat taxa were influenced by proximity to woodland and the degree of fragmentation, and only few taxa were able to exploit isolated orchards. Environmental factors that promote bat activity could be exploited to strengthen conservation efforts. Preserving remnant woodland and promoting habitat heterogeneity will benefit several bat species. In particular, the foraging activity of ‘edge’ specialists could be fostered by increasing landscape connectivity and maintaining unobstructed water bodies near macadamia orchards. Considering that bats forage as they navigate these areas, conservation efforts could also bring benefits to farmers through pest‐reduction services.     

Separating the effects of water quality and urbanization on temperate insectivorous bats at the landscape scale

Many local scale studies have shown that bats respond to water quality degradation or urbanization in a species‐specific manner. However, few have separated the effects of urbanization versus water quality degradation on bats, in single city or single watershed case studies. Across North Carolina, USA, we used the standardized North American Bat Monitoring Program mobile transect protocol to survey bat activity in 2015 and 2016 at 41 sites. We collected statewide water quality and urban land cover data to disentangle the effects of urbanization and water quality degradation on bats at the landscape scale. We found that statewide, water quality degradation and urbanization were not correlated. We found that bats responded to water quality degradation and urbanization independently at the landscape scale. Eptesicus fuscus and Lasiurus cinereus negatively responded to water quality degradation. Lasiurus borealis and Perimyotis subflavus positively responded to water quality degradation. Lasionycteris noctivagans did not respond to water quality degradation but was more active in more urbanized areas. Tadarida brasiliensis positively responded to urbanization and was less active in areas with degraded water quality. We show that bat–water quality relationships found at the local scale are evident at a landscape scale. We confirm that bats are useful bioindicators for both urbanization and water quality degradation. We suggest that water quality can be used to predict the presence of bat species of conservation concern, such as P. subflavus, in areas where it has not been studied locally.     

Breeding season habitat associations and population declines of British Hawfinches Coccothraustes coccothraustes

Capsule At both landscape and local scales, breeding persistence in a declining Hawfinch population was greatest where broadleaved woodland cover was high, while at a fine scale, nest sites were associated with openings in the woodland canopy.

Aims To assess which components of habitat are associated with Hawfinch occupancy at landscape (10-km), local (tetrad) and fine (nest) spatial scales, during a period of population decline and range contraction.

Methods Bird Atlas 2008–11 data were used to determine areas of Hawfinch loss and persistence over 20 years. Current habitat was measured and compared to look for correlates that helped explain the differing status at both 10-km and tetrad scales. Fine scale habitat data collected at nest sites were compared with random locations to investigate within-wood nest site selection.

Results At both 10-km and tetrad scales, Hawfinch persistence is more likely where woodland cover is greater. Recent woodland management was less evident in tetrads where the species persisted. At the nest site scale, the only relationship detected was for nests to be close to canopy openings.

Conclusions Maintaining and increasing broadleaved woodland area is likely to benefit Hawfinch. Within woods, maintenance and creation of open areas may enhance nesting opportunities.     

Pattern of land mosaics affecting butterfly assemblage at Mt Ikoma, Osaka, Japan

We studied the effects of habitat mosaics on butterfly assemblage on multiple spatial scales: landscape, landscape element, local habitat, and microhabitat, based on the transect counts conducted along a 3.84 km route. The transect route, including 21 local habitats, passed through two distinct areas: 1.65 km of a secondary deciduous Quercus forest and the grove of a shrine in Hiraoka, and 2.19 km of a mosaic of secondary deciduous Quercus forest, grassland, and farmland in Narukawa. The diversity of the landscape elements and species richness were higher in Narukawa than in Hiraoka; the landscape mosaic enhanced the species richness in Narukawa. However, the diversity indices and specialist species (univoltine tree feeder) were decreased in this mosaic landscape. The species richness at local habitats was also increased by the mosaic of microhabitats, such as the herbaceous layer, glade, and mantle in the local habitats, whereas it was decreased by an abundant shrub layer. The ratios of species richness to abundance in the local habitats were lower than expected based on random sampling from the total of Hiraoka and Narukawa. This means that local assemblages were non-random samples from an assemblage on the landscape or regional scale, and were made up by the process of habitat selection of butterfly species in the assemblages on the landscape or regional scale. For conservation of butterfly assemblages, we recommend that woodlands should be kept without fragmentation, but with glades or small grasslands, and with clearance of the shrub layer along the path.     

Habitat associations of bats in a working rangeland landscape

Land‐use change has resulted in rangeland loss and degradation globally. These changes include conversion of native grasslands for row‐crop agriculture as well as degradation of remaining rangeland due to fragmentation and changing disturbance regimes. Understanding how these and other factors influence wildlife use of rangelands is important for conservation and management of wildlife populations. We investigated bat habitat associations in a working rangeland in southeastern North Dakota. We used Petterson d500x acoustic detectors to systematically sample bat activity across the study area on a 1‐km point grid. We identified calls using Sonobat autoclassification software. We detected five species using this working rangeland, which included Lasionycteris noctivagans (2,722 detections), Lasiurus cinereus (2,055 detections), Eptesicus fuscus (749 detections), Lasiurus borealis (62 detections), and Myotis lucifugus (1 detection). We developed generalized linear mixed‐effects models for the four most frequently detected species based on their ecology. The activity of three bat species increased with higher tree cover. While the scale of selection varied between the four species, all three investigated scales were explanatory for at least one bat species. The broad importance of trees to bats in rangelands may put their conservation needs at odds with those of obligate grassland species. Focusing rangeland bat conservation on areas that were treed prior to European settlement, such as riparian forests, can provide important areas for bat conservation while minimizing negative impacts on grassland species.     

Fine‐scale heterogeneity in beetle assemblages under co‐occurring Eucalyptus in the same subgenus

Aim Insect biodiversity is often positively associated with habitat heterogeneity. However, this relationship depends on spatial scale, with most studies focused on differences between habitats at large scales with a variety of forest tree species. We examined fine‐scale heterogeneity in ground‐dwelling beetle assemblages under co‐occurring trees in the same subgenus: Eucalyptus melliodora A. Cunn. ex Schauer and E. blakelyi Maiden (Myrtaceae). Location Critically endangered grassy woodland near Canberra, south‐eastern Australia. Methods We used pitfall traps and Tullgren funnels to sample ground‐dwelling beetles from the litter environment under 47 trees, and examined differences in diversity and composition at spatial scales ranging from 100 to 1000 m. Results Beetle assemblages under the two tree species had distinctive differences in diversity and composition. We found that E. melliodora supported a higher richness and abundance of beetles, but had higher compositional similarity among samples. In contrast, E. blakelyi had a lower abundance and species richness of beetles, but more variability in species composition among samples. Main conclusions Our study shows that heterogeneity in litter habitat under co‐occurring and closely related eucalypt species can influence beetle assemblages at spatial scales of just hundreds of metres. The differential contribution to fine‐scale alpha and beta diversity by each eucalypt can be exploited for conservation purposes by ensuring an appropriate mix of the two species in the temperate woodlands where they co‐occur. This would help not only to maximize biodiversity at landscape scales, but also to maintain heterogeneity in species richness, trophic function and biomass at fine spatial scales.     

Occupancy models including local and landscape variables are useful to assess the distribution of a salamander species at risk

Numerous amphibian species are at risk of extinction worldwide. Therefore, reliable estimations of the distribution and abundance of these species are necessary for their conservation. Generally, amphibians are difficult to detect in the wild, which compromises the accuracy of long-term population monitoring and management. Occupancy models are useful tools to assess how environmental variables, at a local and at a landscape scale, affect the distribution and abundance of organisms taking into account species imperfect detectability. In this study, we evaluated with an environmental multiscale approach the seasonal variation of the occupation area of the threatened salamander, Ambystoma ordinarium along its distribution range. We obtained readings in 60 streams of physicochemical variables associated with habitat quality and landscape features. We found that detection and occupation probability of A. ordinarium are seasonally associated with different environmental variables. During the dry season, detectability was positively associated with temperature and stream depth, whereas occupancy was positively associated with the proportion of crops in the landscape and stream elevation. In the rainy season, the detection probability was not explained by any variable considered, and occupancy was negatively associated with stream's electrical conductivity and dissolved oxygen. Based on the estimation of occupied sites, we showed that A. ordinarium presents a more restricted distribution range than previously projected. Therefore, our results reveal the importance of evaluating the accuracy of distribution estimates for the conservation of threatened species as A. ordinarium.     

Urbanisation at Multiple Scales Is Associated with Larger Size and Higher Fecundity of an Orb-Weaving Spider

Urbanisation modifies landscapes at multiple scales, impacting the local climate and changing the extent and quality of natural habitats. These habitat modifications significantly alter species distributions and can result in increased abundance of select species which are able to exploit novel ecosystems. We examined the effect of urbanisation at local and landscape scales on the body size, lipid reserves and ovary weight of Nephila plumipes, an orb weaving spider commonly found in both urban and natural landscapes. Habitat variables at landscape, local and microhabitat scales were integrated to create a series of indexes that quantified the degree of urbanisation at each site. Spider size was negatively associated with vegetation cover at a landscape scale, and positively associated with hard surfaces and anthropogenic disturbance on a local and microhabitat scale. Ovary weight increased in higher socioeconomic areas and was positively associated with hard surfaces and leaf litter at a local scale. The larger size and increased reproductive capacity of N.plumipes in urban areas show that some species benefit from the habitat changes associated with urbanisation. Our results also highlight the importance of incorporating environmental variables from multiple scales when quantifying species responses to landscape modification.