Human activities, especially conversion and degradation of habitats, are causing global biodiversity declines. How local ecological assemblages are responding is less clear--a concern given their ...importance for many ecosystem functions and services. We analysed a terrestrial assemblage database of unprecedented geographic and taxonomic coverage to quantify local biodiversity responses to land use and related changes. Here we show that in the worst-affected habitats, these pressures reduce within-sample species richness by an average of 76.5%, total abundance by 39.5% and rarefaction-based richness by 40.3%. We estimate that, globally, these pressures have already slightly reduced average within-sample richness (by 13.6%), total abundance (10.7%) and rarefaction-based richness (8.1%), with changes showing marked spatial variation. Rapid further losses are predicted under a business-as-usual land-use scenario; within-sample richness is projected to fall by a further 3.4% globally by 2100, with losses concentrated in biodiverse but economically poor countries. Strong mitigation can deliver much more positive biodiversity changes (up to a 1.9% average increase) that are less strongly related to countries' socioeconomic status.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
In temperate regions, winter is characterized by cold temperatures and low food availability. Heterothermic animals can bridge this period by entering a state of torpor characterized by decreased ...body temperature and reduced metabolic rate. Hibernation site choice is crucial since temperature conditions in the hibernaculum will impact torpor. We analysed temperature-dependent hibernation site use of Barbastella barbastellus. Bats and temperature were monitored in an underground system (1999-2019) and standalone bunkers (2007-2019) in Western Poland. During the winter of 2017-2018 we analysed the thermal variability of the hibernacula. Seasonal variation is higher in bunkers and thus temperatures get colder in winter than in the underground system. On the other hand, short-term variability (thermal variability index) in the bunkers was lower than in the underground system. This makes bunkers a more stable environment to hibernate for cold dwelling bats in warm winters, when temperatures in the bunkers do not get below freezing. Bats use both the warm underground system and the colder bunkers. During the last decade, a continuous series of warm winters occurred and the population of barbastelle bats partly moved from the underground system to the bunkers. These present temperature increases broadened the range of potential hibernation sites for barbastelles. Our study indicates that long-term trends, seasonal variation and short-term variability in temperatures are all important and should be analysed to investigate hibernaculum use by bats. Our study shows that small hibernation sites may become more important in the future.
Habitat loss and degradation, driven largely by agricultural expansion and intensification, present the greatest immediate threat to biodiversity. Tropical forests harbour among the highest levels of ...terrestrial species diversity and are likely to experience rapid land-use change in the coming decades. Synthetic analyses of observed responses of species are useful for quantifying how land use affects biodiversity and for predicting outcomes under land-use scenarios. Previous applications of this approach have typically focused on individual taxonomic groups, analysing the average response of the whole community to changes in land use. Here, we incorporate quantitative remotely sensed data about habitats in, to our knowledge, the first worldwide synthetic analysis of how individual species in four major taxonomic groups—invertebrates, ‘herptiles’ (reptiles and amphibians), mammals and birds—respond to multiple human pressures in tropical and sub-tropical forests. We show significant independent impacts of land use, human vegetation offtake, forest cover and human population density on both occurrence and abundance of species, highlighting the value of analysing multiple explanatory variables simultaneously. Responses differ among the four groups considered, and—within birds and mammals—between habitat specialists and habitat generalists and between narrow-ranged and wide-ranged species.
There is growing recognition that with sympathetic management, plantation forests may contain more biodiversity than previously thought. However, the extent to which they may support bat populations ...is contentious. Many studies have demonstrated active avoidance of coniferous plantations and attributed this to the lack of available roost sites and low invertebrate density. In contrast, other work, carried out in plantation dominated landscapes have shown that certain bat species are able to exploit these areas. However, the extent to which bats use plantations for roosting and foraging, or simply move through the plantation matrix to access more favourable sites is unclear. We radio tracked female Pipistrellus pygmaeus over two summers to establish the extent to which individual bats use Sitka Spruce plantations in southern Scotland for foraging and roosting and assess the implications for felling operations on bats. Maternity roosts identified (n = 17) were in all in buildings and most were large (> 500 individuals). We found no evidence of bats roosting in mature Sitka Spruce crop trees, although several bats used roosts in old or dead beech and oak trees as an alternative to their main maternity roost. Home ranges were much larger (mean 9.6 ± 3.12 km2) than those reported from other studies (0.6-1.6 km2), and it is likely that roost availability rather than food abundance constrains P. pygmaeus use of Sitka Spruce plantations. At the landscape scale, most individuals selected coniferous habitats over other habitat types, covering large distances to access plantation areas, whilst at a local scale bats used forest tracks to access water, felled stands or patches of broadleaf cover within the plantation. Sitka Spruce plantations support a high abundance of Culicoides impuctatus, the Highland midge which may act as a reliable and plentiful food source for females during lactation, an energetically expensive period. The use of felled stands for foraging by bats has implications for forest management as wind turbines, following small-scale felling operations, are increasingly being installed in plantations; wind turbines have been associated with high bat mortality in some countries. Decisions about siting wind turbines in upland plantations should consider the likelihood of increased bat activity post felling.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The multimammate mice (Mastomys natalensis) is the most-studied rodent species in sub-Saharan Africa, where it is an important pest species in agriculture and carrier of zoonotic diseases (e.g. Lassa ...virus). Here, we provide a unique dataset that consists of twenty-nine years of continuous monthly capture-mark-recapture entries on one 3 ha mosaic field (MOSA) in Morogoro, Tanzania. It is one of the most accurate and long-running capture-recapture time series on a small mammal species worldwide and unique to Africa. The database can be used by ecologists to test hypotheses on the population dynamics of small mammals (e.g. to test the effect of climate change), or to validate new algorithms on real long-term field data (e.g. new survival analyses techniques). It is also useful for both scientists and decision-makers who want to optimize rodent control strategies and predict outbreaks of multimammate mice.
Social network analysis has achieved remarkable popularity in disease ecology, and is sometimes carried out without investigating spatial heterogeneity. Many investigations into sociality and disease ...may nevertheless be subject to cryptic spatial variation, so ignoring spatial processes can limit inference regarding disease dynamics.
Disease analyses can gain breadth, power and reliability from incorporating both spatial and social behavioural data. However, the tools for collecting and analysing these data simultaneously can be complex and unintuitive, and it is often unclear when spatial variation must be accounted for. These difficulties contribute to the scarcity of simultaneous spatial‐social network analyses in disease ecology thus far.
Here, we detail scenarios in disease ecology that benefit from spatial‐social analysis. We describe procedures for simultaneous collection of both spatial and social data, and we outline statistical approaches that can control for and estimate spatial‐social covariance in disease ecology analyses.
We hope disease researchers will expand social network analyses to more often include spatial components and questions. These measures will increase the scope of such analyses, allowing more accurate model estimates, better inference of transmission modes, susceptibility effects and contact scaling patterns, and ultimately more effective disease interventions.
Social network analysis is increasingly widespread in disease ecology, but is often carried out without investigating spatial processes. The authors describe how uniting spatial and social network analyses can augment disease ecology investigations, outlining tools and methodology to do so.
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•Keyhole felling for turbine installation is common in upland plantations.•Despite evidence that bats make use of plantations, the impacts of felling are unknown.•We found that bat ...activity either increased or stayed the same post harvesting.•Species-specific increases in activity were greatest in small/recently felled stands.•Siting wind turbines in conifer plantations may result in increased bat mortality.
Commercial coniferous plantations are often assumed to be poor habitats for bats. As a result, the impact of forest management practices on bats, such as clear felling, has received little attention, particularly in Europe. However, there is growing evidence from multiple regions that bats do make use of plantation landscapes, and as interest in siting onshore wind turbines in upland conifer plantations grows, there is an urgent need to examine whether felling prior to turbine installation is likely to put foraging bats at risk of collision. In the first study of its kind, we use a “before – after – control – impact” study to explore the short-term impacts of clear fell harvest on bat activity in commercial plantations. Thirty-one mature stands of Sitka Spruce were surveyed using acoustic detectors in three large, upland Sitka Spruce plantations in Britain. Eleven stands were felled between 2013 and 2015, and 26 of the original 31 stands were resurveyed in 2015. The change in total bat activity and species- or genus-specific bat activity was modelled before and after felling occurred at both felled and control stands using generalised linear models. There was no change in overall bat activity at felled sites compared to control sites, but activity of Nyctalus species was 23 times higher following felling. Total Pipistrellus spp. activity doubled at felled sites post-harvesting, although this was mainly driven by increased activity at a few felled sites. When P. pygmaeus and P. pipistrellus were considered separately, activity increased slightly but non-significantly. The size of the felled area influenced activity (for bats overall and Pipistrellus spp.), with 90% higher activity in smaller felled stands (less than 5ha−1) compared to larger felled stands (greater than 30ha−1). For P. pipistrellus, activity in felled areas decreased with the duration since harvesting; the greatest activity occurred in stands felled within two months compared to those harvested more than 16months previously. Higher activity for some groups following felling may occur due to the creation of more edge habitat, which is preferred by both Pipistrellus species we recorded. An increase in activity following the small-scale felling (‘key-holing’) required for the installation of turbines could put foraging bats at risk from collisions with turbines. Further investigation of the influence of both size of clear fell patch, timing of felling and changes in invertebrate abundance due to felling are required to establish the potential risk of key-holing and turbine installation to foraging bats.
Commercial plantations are primarily managed for timber production, and are frequently considered poor for biodiversity, particularly for mammalian species. Bats, which constitute one fifth of mammal ...species worldwide, have undergone large declines throughout Europe, most likely due to widespread habitat loss and degradation. Bat use of modified landscapes such as urban or agricultural environments has been relatively well studied, however, intensively managed plantations have received less attention, particularly in Europe. We assessed three of the largest, most intensively managed plantations in the UK for the occurrence of bats, activity levels and relative abundance in response to environmental characteristics at multiple spatial scales, using an information theoretic approach. We recorded or captured nine species; Pipistrellus pipistrellus and P. pygmaeus were the most commonly recorded species on acoustic detectors and female P. pygmaeus were the most commonly captured. The influence of environmental characteristics on bat activity varied by species or genus, although all bat species avoided dense stands. Occurrence and activity of clutter and edge adapted species were associated with lower stand densities and more heterogeneous landscapes whereas open adapted bats were more likely to be recorded at felled stands and less likely in areas that were predominantly mature conifer woodland. In addition, despite morphological similarities, P. pipstrellus and P. pygmaeus were found foraging in different parts of the plantation. This study demonstrates that with sympathetic management, non-native conifer plantations may have an important role in maintaining and supporting bat populations, particularly for Pipistrellus spp.
•Many studies have demonstrated active avoidance by bats of non-native conifer plantations.•We found a wide range of bat species using Sitka Spruce plantations, particularly Pipistrellus species.•A high proportion of the Pipistrellus spp. captured were lactating females.•Responses to local and landscape-scale habitat characteristics differed between species and foraging guilds.•Increasing roost provision and maintaining thinning should benefit bat populations in plantations.
Abstract
Assessing how bats respond to habitat attributes requires an integrative approach to reliably predict direct community‐level effects. We focused on hipposiderid and pteropodid bats because ...of their diverse resource use patterns, body size ranges, and dispersal abilities. We combined an array of bat species‐level characteristics with key forest stand characteristics that may covary with habitat use. Twelve stations were sampled in the Lomami and Yangambi landscapes, Democratic Republic of the Congo. We investigated whether species‐level flight ability of bats and forest stand characteristics can affect bat commuting flights and community‐level estimates of both species detection and habitat occupancy. We captured bats for 108 trap‐nights. Three sampling events (early evening, middle of the night, and early morning) were replicated for each survey night. Hipposiderids showed an early evening flight peak, while flight activity of pteropodids was constant throughout the night, but increased around the middle of the night. Species capture probability decreased with higher wing loading in hipposiderids and was negatively correlated with higher wing aspect ratio in pteropodids. Forest occupancy of hipposiderids increased along the gradient towards waterways, while pteropodid occurrence was not directly linked to measured forest stand variables. This suggests a consequence of habitat patterns at larger spatial scales, which would need clarifying through additional data collection. We discuss these findings in terms of resource‐use strategies of clutter‐tolerant and clutter‐intolerant species. We argue that the occurrence of specific bat species and their habitat use patterns can serve as surrogate measures of ecosystem health.
RESUMÉ
Evaluer la réponse des chauves‐souris aux attributs de l'habitat nécessite une approche intégrative pour prédire de manière fiable les effets directs au niveau de la communauté. Cette étude s'est concentrée sur deux familles de chauves‐souris, les Hipposideridae et les Pteropodidae, en raison de la diversité de leurs modes d'utilization des ressources, de leurs tailles et de leurs capacités de dispersion. Nous avons combiné un ensemble de traits au niveau des espèces de chauves‐souris avec des caractéristiques clés de la forêt tropicale humide susceptibles de covarier avec l'utilization de l'habitat. Douze stations ont été échantillonnées dans les paysages de Lomami et de Yangambi en République Démocratique du Congo. L'étude visait à examiner si la capacité de vol des chauves‐souris au niveau de l'espèce et les caractéristiques du peuplement forestier peuvent influencer l'activité de vol des chauves‐souris et les estimations au niveau de la communauté de la détection des espèces et de l'occupation des habitats. Nous avons capturé des chauves‐souris pendant 108 nuits‐pièges. Trois événements d'échantillonnage (début de soirée, milieu de la nuit et début de matinée) ont été répétés pour chaque nuit de capture. Les Hipposideridae ont montré un pic de vol en début de soirée, tandis que l'activité de vol des Pteropodidae était constante tout au long de la nuit, mais augmentait vers le milieu de la nuit. La probabilité de capture des espèces diminuait avec l'augmentation de la charge alaire chez les Hipposideridae et était négativement corrélée avec l'augmentation du rapport d'aspect des ailes chez les Pteropodidae. La probabilité d'occupation des peuplements forestiers par les Hipposideridae augmentaient le long du gradient vers les cours d'eau, tandis que l'occurrence des Pteropodidae dans les forêts n'était pas directement liée aux variables d'habitat mesurées. Cela suggère une conséquence des schémas de structuration d'habitats à des échelles spatiales plus larges, qui nécessitent des données supplémentaires pour être clarifiées. Nous avons discuté de ces résultats en termes de stratégies d'utilization des ressources chez les espèces tolérantes et intolérantes à l'encombrement des forêts. Nous soutenons que la présence d'espèces de chauves‐souris présentant des traits spécifiques et leurs modes d'utilization de l'habitat peuvent servir de mesures de substitution de la santé de l'écosystème.
Abstract
Bats exhibit a variety of life‐history traits that can serve as valuable surrogate metrics of terrestrial ecosystem health. Here, we investigate how sonotype activity of hipposiderid bats ...covaries with habitat structure at finer spatial scales. We recorded passive echolocation calls and measured key habitat attributes in six rainforests in the Lomami and Yangambi landscapes, Democratic Republic of the Congo. Using bat passes as a measure of sonotype activity, we clustered echolocation calls based on call structure similarity to control for within‐sonotype variation in activity. Over 432 h of recording, we detected 370 passes matching a hipposiderid sonotype in three subgroups, recovering eight potential species. Open habitats negatively affected sonotype activity in the
Hipposideros
subgroup, which was associated with higher echolocation frequencies. Indeed, activity peaked in the early evening when mean post‐sunset temperature was above the nocturnal average and declined until early morning when mean temperatures dropped below the nightly average. All habitat variables were marginally correlated with the activity of the
Doryrhina
subgroup, whereas
Macronycteris
was more active in open habitats. Our findings indicate a probable flexibility of habitat use in lower echolocating bats and point to three possible foraging guilds that modulate hipposiderid bat responses to habitat structure.
Résumé
Les chauves‐souris présentent une variété de traits d'histoire de vie qui peuvent servir de métriques de substitution précieuses pour la santé des écosystèmes terrestres. Ici, nous étudions comment l'activité des sonotypes de chauves‐souris Hipposideridae covarie avec la structure de l'habitat à des échelles spatiales plus fines. Nous avons enregistré des appels d'écholocalisation passive et mesuré les principaux attributs de l'habitat dans six forêts pluviales des paysages de Lomami et de Yangambi, en République démocratique du Congo. En utilisant les passages de chauves‐souris comme mesure de l'activité du sonotype, nous avons regroupé les appels d'écholocalisation sur la base de la similarité de la structure des appels afin de contrôler la variation de l'activité au sein du sonotype. Au cours de 432 heures d'enregistrement, nous avons détecté 370 passages correspondant à un sonotype d'Hipposideridae en trois sous‐groupes, composés de huit espèces potentielles. Les habitats ouverts ont eu un impact négatif sur l'activité des sonotypes dans le sous‐groupe des
Hipposideros
qui était associé à des fréquences d'écholocalisation plus élevées. En effet, l'activité a été maximale en début de soirée, lorsque la température moyenneaprès le coucher du soleil était supérieure à la moyenne nocturne et a diminué jusqu'au début de la matinée, lorsque les températures moyennes ont chuté en dessous de la moyenne nocturne. Toutes les variables relatives à l'habitat étaient en corrélation marginale avec l'activité du sous‐groupe de
Doryrhina
, tandis que les
Macronycteris
étaient plus actifs dans des habitats ouverts. Nos résultats indiquent une flexibilité probable de l'utilisation de l'habitat chez les chauves‐souris écholocatrices inférieures et soulignent trois guildes de recherche de nourriture possibles qui modulent les réponses des chauves‐souris Hipposideridae à la structure de l'habitat.
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