55 research outputs found

    Anthropogene Landnutzung im Farmland der sĂŒdlichen Kalahari : ein Verlust von DiversitĂ€t bei Kleinkarnivoren?

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    Anthropogene Landnutzung in ariden Savannen verĂ€ndert die strukturelle DiversitĂ€t der Vegetation und bedroht damit die Artenvielfalt der Flora und Fauna von etwa 20% der LandoberflĂ€che der Erde. Ziel meiner Dissertation war es, den Einfluss von Landnutzung auf die Abundanz und DiversitĂ€t von Kleinkarnivoren und ihrer Beutetiere zu untersuchen. Dabei sollten Bioindikatoren identifiziert werden, die eine EinschĂ€tzung der DiversitĂ€t im Farmmosaik der sĂŒdlichen Kalahari ermöglichen. Entlang eines WeideintensitĂ€tsgradienten analysierte ich mit Hilfe freilandökologischer Methoden die komplexen ZusammenhĂ€nge zwischen BeweidungsintensitĂ€t, struktureller DiversitĂ€t der Vegetation, BeuteverfĂŒgbarkeit und DiversitĂ€t von Kleinkarnivoren. Nach den Ergebnissen dieser Studie in der sĂŒdlichen Kalahari kann ich folgende Aussagen ĂŒber die anthropogene Störung der IntegritĂ€t von ariden Savannensystemen durch Beweidung treffen: 1. Eine Steigerung der Bestockungsdichten von Weidetieren fĂŒhrte zu drastischen VerĂ€nderungen der Zusammensetzung und strukturellen DiversitĂ€t der Vegetation. Dabei sank mit zunehmendem Beweidungsdruck der Anteil an GrĂ€sern an der Vegetationsbedeckung bei gleichzeitigem Anstieg der Strauchvegetation. Die HeterogenitĂ€t des Habitats, gemessen in Anzahl von Strauchpatches (Ăž>4m) pro Hektar, zeigte einen unimodalen Verlauf bei steigender Strauchbedeckung und damit bei steigender WeideintensitĂ€t. Maximale HabitatheterogenitĂ€t wurde bei einer Strauchbedeckung von ca. 20% festgestellt. 2. Die beobachteten VerĂ€nderungen der Vegetation wirkten sich sowohl auf Tierarten aus, die sich direkt von pflanzlicher Kost ernĂ€hren als auch auf solche am Ende einer Nahrungskette: Die Effekte zunehmender Strauchbedeckung (und damit steigender BeweidungsintensitĂ€t) auf die relative HĂ€ufigkeit der wichtigsten Beutetiere von Kleinkarnivoren unterschieden sich zwischen den einzelnen Gruppen. Es bestand eine lineare negative Korrelation fĂŒr Orthopteren, wĂ€hrend unimodale Antwortmuster fĂŒr KĂ€fer mit maximaler Abundanz bei einer Strauchbedeckung von ca. 15% und fĂŒr Nagetiere bei ca. 12,5% festgestellt wurden, wohingegen keine Korrelation fĂŒr Termiten ermittelt werden konnte. 3. Am Beispiel der Nagetiergemeinschaft konnte die wesentliche Bedeutung der rĂ€umlichen Skala fĂŒr das Auflösungsvermögen von Abundanz- und DiversitĂ€tsmuster gezeigt werden. Ihre Muster und damit die Auswirkungen von Beweidung wurden ausschließlich auf einer großen rĂ€umlichen Skala (250ha) identifiziert, nicht jedoch auf der Skala des mittleren Aktionsraums (1ha). Ein wichtiges Fazit dieser Ergebnisse ist, dass zuerst diejenige rĂ€umliche Skala identifiziert werden muss, auf der ein Organismus mit Habitatstrukturen (Z.B. geeigneten NahrungsplĂ€tzen) interagiert, um die Effekte von VerĂ€nderungen der strukturellen Zusammensetzung von Habitaten verstehen zu können. Dabei fĂŒhrte steigende Grasbedeckung zu einer exponentiellen SĂ€ttigung der Gesamtabundanz sowie der DiversitĂ€t der Nagetiere. Dagegen wurde bei Zunahme der Strauchbedeckung ein unimodales Muster fĂŒr Gesamtabundanz und DiversitĂ€t festgestellt. 4. Obwohl ein hoher Strauchanteil sich durchgehend negativ auf die BeuteverfĂŒgbarkeit auswirkte, haben StrĂ€ucher eine besondere Bedeutung fĂŒr die Artenvielfalt in diesem Lebensraum, da sie als Schutz- und Nistplatz wichtige Funktionen erfĂŒllen. Am Beispiel von Fuchsmangusten (Cynictis penicillata) konnte ich exemplarisch die zentralen Funktionen von StrĂ€uchern und ihren Einfluss auf den Reproduktionserfolg dieser Art zeigen. Interessanterweise waren die Auswirkungen von StrĂ€uchern inkonsistent fĂŒr unterschiedliche rĂ€umliche Skalen. Im Mikrohabitat haben Strauchstrukturen positive Eigenschaften (Schutzfunktionen). Fuchsmangusten legten ihre Bauten meistens unter StrĂ€uchern an, um ein EinstĂŒrzen durch Huftrampeln zu verhindern und ihr PrĂ€dationsrisiko durch Greifvögel zu reduzieren. FĂŒr die Anlage ihrer Reproduktionsbauten wĂ€hlten sie Strauchstrukturen mit einem Durchmesser von mindestens sechs Metern (bevorzugt der Art Acacia hebeclada) und außerdem, wenn sich im Umkreis von 10 Metern kein weiterer Strauchpatch befand. Auf einer grĂ¶ĂŸeren rĂ€umlichen Skala (im Umfeld von einem Hektar um Reproduktionsbauten) wurden FlĂ€chen mit einer Strauchbedeckung prĂ€feriert, die geringer war, als zufĂ€llige FlĂ€chen im Habitat. Dabei wirkte sich zunehmende Strauchbedeckung auch negativ auf die GruppengrĂ¶ĂŸe und den Reproduktionserfolg dieser Art aus. FĂŒr eine erfolgreiche Reproduktion bei Fuchsmangusten scheint die Strauchbedeckung im Umfeld von einem Hektar um die Reproduktionsbauten einen Schwellenwert zwischen 10 und 15% nicht ĂŒberschreiten zu dĂŒrfen. Dies ist mit der sinkenden BeuteverfĂŒgbarkeit (Nagetiere und Arthropoden) bei zunehmender Strauchbedeckung zu begrĂŒnden. 5. Aufgrund der dramatischen Auswirkungen von Verbuschung auf die BeuteverfĂŒgbarkeit von Kleinkarnivoren unterschieden sich die Abundanzen der einzelnen Kleinkarnivoren deutlich zwischen diesen Farmen. Die Abundanz der jeweiligen Einzelarten konnte ĂŒber Regressionsmodelle mit Vegetationsparameter oder BeutetierverfĂŒgbarkeit erklĂ€rt werden. Im Gegensatz dazu war die Strauchbedeckung die beste erklĂ€rende Variable fĂŒr Gesamtabundanz und DiversitĂ€t der Gilde. Sie integriert habitatspezifische Eigenschaften, wie die VerfĂŒgbarkeit von vier Beutetiergruppen, die KonnektivitĂ€t von Nahrungspatches mit hoher QualitĂ€t, das PrĂ€dationsrisiko durch Greifvögel sowie das Nistplatzangebot. Dabei sank mit zunehmender Strauchbedeckung die Gesamtabundanz, wĂ€hrend fĂŒr die DiversitĂ€t ein unimodales Muster mit maximaler DiversitĂ€t bei einer Strauchbedeckung von ca. 12,5% festgestellt wurde. FĂŒr eine EinschĂ€tzung der DiversitĂ€t von Kleinkarnivoren eignet sich die Ginsterkatze (Genetta genetta) als Indikatorart. Interessanterweise war die Strauchbedeckung ein noch besserer Bioindikator fĂŒr die EinschĂ€tzung der DiversitĂ€t von Kleinkarnivoren. 6. Die Schlussfolgerung meiner Ergebnisse ist, dass die DiversitĂ€t der Kleinkarnivoren einen Großteil der BiodiversitĂ€t der UntersuchungsflĂ€chen in der sĂŒdlichen Kalahari widerspiegelt. Dabei integriert die Kleinkarnivorengilde als Indikatorvariable neben der zoologischen DiversitĂ€t (i) auch die strukturelle DiversitĂ€t der Vegetation (ii) sowie die strukturelle Organisation im Nahrungsnetz (iii). Kleinkarnivoren erhalten dadurch einen Status einer Indikatorgilde und eignen sich damit sehr gut zur Beurteilung der sĂŒdlichen Kalahari oder einer anderen Weidelandschaft arider Savannen. 7. Das fĂŒr den Naturschutz wichtigste Ergebnis meiner Arbeit ist, dass höchste DiversitĂ€t aller Untersuchungsorganismen bei einer Strauchbedeckung zwischen 10 und 15%, also einer mittleren BeweidungsintensitĂ€t von ca. 3,5 LSU/ l00ha, festgestellt wurde. Daher wirken sich mĂ€ĂŸige Bestockungsdichten durchaus positiv auf die DiversitĂ€t aus, wĂ€hrend eine Überbeweidung einen dramatischen RĂŒckgang der Artenvielfalt in diesem Lebensraum verursacht

    Quantification of areal extent of soil erosion in dryland urban areas: an example from Windhoek, Namibia

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    Soil erosion, while often studied in dryland settings for rural regions, has only occasionally been studied in urban settings. This study maps and quantifies areal extent and severity of water erosion in a dryland city (Windhoek, Namibia) using a snap-shot field survey approach. The results show that nearly 56% of the city could be affected by water erosion with signs of accelerated erosion in the form of rills and gullies. These occur mainly in the underdeveloped, informal and semi-formal areas of the city. Factors influencing the extent of erosion in Windhoek include vegetation cover and type, socio-urban factors, and to a lesser extent, slope. A comparison of an interpolated field survey erosion map with a conventional erosion assessment tool (the Universal Soil Loss Equation) highlights a mismatch in the spatial patterns found, underlining the inapplicability of traditional non-urban erosion tools to urban settings and emphasises the need to develop new erosion assessment and management methods for urban environments. Measures for controlling water erosion in the city need to be site-specific as the extent of erosion varied greatly across the city

    Influence of roads on space use by European hares in different landscapes

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    © The Author(s) 2022Context Roads are ubiquitous in human inhabited landscapes, and can impact animal movement and population dynamics, due to barrier effects, road mortality, but also by providing resources at road verges. Thus, we need a better understanding of how roads, in interaction with seasonal changes in habitat structure, affect space use and habitat selection of the animals that persist in these landscapes. Objectives Here, we used the European hare (Lepus europaeus) as model species to investigate how human-induced changes in landscape composition—measured as road density, land cover type, and field size—affect home range location, seasonal habitat selection and road crossings, which are likely to correlate with wildlife-vehicle collision risk. Methods We collected > 240,000 GPS positions of 90 hares from three populations (one in Denmark and two in Germany) that differed regarding agricultural intensification and road density. Using this data, we analyzed home range location and habitat selection (using step-selection functions) in relation to roads, habitat composition, and seasonality, and quantified how these factors affected road crossings by hares. Results In comparatively more heterogeneous landscapes, hares established home ranges in areas with lower road densities compared to the surrounding area, but not in more simple landscapes. Moreover, hares generally avoided main roads and selected for minor roads during the vegetation growth seasons, especially in areas with comparatively less heterogeneous habitat structure. Hares crossed more main roads when moving greater distances, with movement distances being comparatively larger in simpler landscapes. Conclusions Our findings emphasize that it is important to distinguish between road types, as different roads can have different impacts on animals (e.g., small roads providing foraging opportunities via roadside vegetation and large roads being avoided). Moreover, animals in comparatively more heterogeneous landscapes are better able to adjust their habitat selection to avoid main roads than animals inhabiting simpler landscapes. More generally, homogenous landscapes increase the space use requirements of animals, leading to increased probability of road crossings, which in turn might affect population dynamics via increased road mortality risk.publishedVersio

    Partitioning of water between differently sized shrubs and potential groundwater recharge in a semiarid savanna in Namibia

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    Introduction: Many semiarid regions around the world are presently experiencing significant changes in both climatic conditions and vegetation. This includes a disturbed coexistence between grasses and bushes also known as bush encroachment, and altered precipitation patterns with larger rain events. Fewer, more intense precipitation events might promote groundwater recharge, but depending on the structure of the vegetation also encourage further woody encroachment.Materials and Methods: In this study, we investigated how patterns and sources of water uptake of Acacia mellifera (blackthorn), an important encroaching woody plant in southern African savannas, are associated with the intensity of rain events and the size of individual shrubs. The study was conducted at a commercial cattle farm in the semiarid Kalahari in Namibia (MAP 250 mm/a). We used soil moisture dynamics in different depths and natural stable isotopes as markers of water sources. Xylem water of fifteen differently sized individuals during eight rain events was extracted using a Scholander pressure bomb.Results and Discussion: Results suggest the main rooting activity zone of A. mellifera in 50 and 75 cm soil depth but a reasonable water uptake from 10 and 25 cm. Any apparent uptake pattern seems to be driven by water availability, not time in the season. Bushes prefer the deeper soil layers after heavier rain events, indicating some evidence for the classical Walter’s two-layer hypothesis. However, rain events up to a threshold of 6 mm/day cause shallower depths of use and suggest several phases of intense competition with perennial grasses. The temporal uptake pattern does not depend on shrub size, suggesting a fast upwards water flow inside. ή2H and ή18O values in xylem water indicate that larger shrubs rely less on upper and very deep soil water than smaller shrubs. It supports the hypothesis that in environments where soil moisture is highly variable in the upper soil layers, the early investment in a deep tap-root to exploit deeper, more reliable water sources could reduce the probability of mortality during the establishment phase. Nevertheless, independent of size and time in the season, bushes do not compete with potential groundwater recharge. In a savanna encroached by A. mellifera, groundwater will most likely be affected indirectly

    Savanna resilience to droughts increases with the proportion of browsing wild herbivores and plant functional diversity

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    1. Maintaining the resilience and functionality of savannas is key to sustaining the ecosystem services they provide. This maintenance is largely dependent on the resilience of savannas to stressors, such as prolonged droughts. The resilience to drought is largely determined by the interaction of herbivores and the functional composition of vegetation. So far, our understanding and ability to predict the response of savannas to drought under different types of rangeland use and as a function of vegetation composition are still limited. 2. In this study, we used the ecohydrological, spatially-explicit savanna model EcoHyD to determine if the resilience of a savanna rangeland towards prolonged droughts can be enhanced by the choice of rangeland use type (grazer-dominated, mixed-feeders or browser-dominated) and animal density. We evaluated the ability of a Namibian savanna system to withstand droughts and recover from droughts based on its perennial grass cover and the overall species composition. 3. Generally, we determined a low resilience under high grazer densities. Most importantly, we found that functional diversification of herbivores and plants acted as resilience insurance against droughts, leading to greater resistance and recovery of perennial grasses. In particular, a higher proportion of herbivores allowed for higher resilience, probably also due to a short-term switch to more drought-resistant or unpalatable species. 4. In this case, herbivore diversification was of high self-regulatory value by reestablishing trophic complexity, reducing the need for additional management interventions. 5. Synthesis and applications: Savanna systems will be more resistant to drought if (i) a dense perennial grass cover is maintained, protecting the topsoil from heat-induced water losses and erosion, encompassing functionally important species that are particularly well adapted to water stress and that are palatable, if (ii) the grazing pressure is adjusted to the productivity of the system, and (iii) the herbivore community includes browsers

    A model assessment of alternative land-use strategies

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    Changing climatic conditions and unsustainable land use are major threats to savannas worldwide. Historically, many African savannas were used intensively for livestock grazing, which contributed to widespread patterns of bush encroachment across savanna systems. To reverse bush encroachment, it has been proposed to change the cattle-dominated land use to one dominated by comparatively specialized browsers and usually native herbivores. However, the consequences for ecosystem properties and processes remain largely unclear. We used the ecohydrological, spatially explicit model EcoHyD to assess the impacts of two contrasting, herbivore land-use strategies on a Namibian savanna: grazer- versus browser-dominated herbivore communities. We varied the densities of grazers and browsers and determined the resulting composition and diversity of the plant community, total vegetation cover, soil moisture, and water use by plants. Our results showed that plant types that are less palatable to herbivores were best adapted to grazing or browsing animals in all simulated densities. Also, plant types that had a competitive advantage under limited water availability were among the dominant ones irrespective of land-use scenario. Overall, the results were in line with our expectations: under high grazer densities, we found heavy bush encroachment and the loss of the perennial grass matrix. Importantly, regardless of the density of browsers, grass cover and plant functional diversity were significantly higher in browsing scenarios. Browsing herbivores increased grass cover, and the higher total cover in turn improved water uptake by plants overall. We concluded that, in contrast to grazing-dominated land-use strategies, land-use strategies dominated by browsing herbivores, even at high herbivore densities, sustain diverse vegetation communities with high cover of perennial grasses, resulting in lower erosion risk and bolstering ecosystem services

    Integrating movement ecology with biodiversity research - exploring new avenues to address spatiotemporal biodiversity dynamics

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    Movement of organisms is one of the key mechanisms shaping biodiversity, e.g. the distribution of genes, individuals and species in space and time. Recent technological and conceptual advances have improved our ability to assess the causes and consequences of individual movement, and led to the emergence of the new field of ‘movement ecology’. Here, we outline how movement ecology can contribute to the broad field of biodiversity research, i.e. the study of processes and patterns of life among and across different scales, from genes to ecosystems, and we propose a conceptual framework linking these hitherto largely separated fields of research. Our framework builds on the concept of movement ecology for individuals, and demonstrates its importance for linking individual organismal movement with biodiversity. First, organismal movements can provide ‘mobile links’ between habitats or ecosystems, thereby connecting resources, genes, and processes among otherwise separate locations. Understanding these mobile links and their impact on biodiversity will be facilitated by movement ecology, because mobile links can be created by different modes of movement (i.e., foraging, dispersal, migration) that relate to different spatiotemporal scales and have differential effects on biodiversity. Second, organismal movements can also mediate coexistence in communities, through ‘equalizing’ and ‘stabilizing’ mechanisms. This novel integrated framework provides a conceptual starting point for a better understanding of biodiversity dynamics in light of individual movement and space-use behavior across spatiotemporal scales. By illustrating this framework with examples, we argue that the integration of movement ecology and biodiversity research will also enhance our ability to conserve diversity at the genetic, species, and ecosystem levels

    A comprehensive analysis of autocorrelation and bias in home range estimation

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    Home range estimation is routine practice in ecological research. While advances in animal tracking technology have increased our capacity to collect data to support home range analysis, these same advances have also resulted in increasingly autocorrelated data. Consequently, the question of which home range estimator to use on modern, highly autocorrelated tracking data remains open. This question is particularly relevant given that most estimators assume independently sampled data. Here, we provide a comprehensive evaluation of the effects of autocorrelation on home range estimation. We base our study on an extensive data set of GPS locations from 369 individuals representing 27 species distributed across five continents. We first assemble a broad array of home range estimators, including Kernel Density Estimation (KDE) with four bandwidth optimizers (Gaussian reference function, autocorrelated-Gaussian reference function [AKDE], SilvermanÂŽs rule of thumb, and least squares cross-validation), Minimum Convex Polygon, and Local Convex Hull methods. Notably, all of these estimators except AKDE assume independent and identically distributed (IID) data. We then employ half-sample cross-validation to objectively quantify estimator performance, and the recently introduced effective sample size for home range area estimation ((Formula presented.)) to quantify the information content of each data set. We found that AKDE 95% area estimates were larger than conventional IID-based estimates by a mean factor of 2. The median number of cross-validated locations included in the hold-out sets by AKDE 95% (or 50%) estimates was 95.3% (or 50.1%), confirming the larger AKDE ranges were appropriately selective at the specified quantile. Conversely, conventional estimates exhibited negative bias that increased with decreasing (Formula presented.). To contextualize our empirical results, we performed a detailed simulation study to tease apart how sampling frequency, sampling duration, and the focal animalÂŽs movement conspire to affect range estimates. Paralleling our empirical results, the simulation study demonstrated that AKDE was generally more accurate than conventional methods, particularly for small (Formula presented.). While 72% of the 369 empirical data sets had >1,000 total observations, only 4% had an (Formula presented.) >1,000, where 30% had an (Formula presented.) <30. In this frequently encountered scenario of small (Formula presented.), AKDE was the only estimator capable of producing an accurate home range estimate on autocorrelated data.Fil: Noonan, Michael J.. National Zoological Park; Estados Unidos. University of Maryland; Estados UnidosFil: Tucker, Marlee A.. Senckenberg Gesellschaft FĂŒr Naturforschung; . Goethe Universitat Frankfurt; AlemaniaFil: Fleming, Christen H.. University of Maryland; Estados Unidos. National Zoological Park; Estados UnidosFil: Akre, Thomas S.. National Zoological Park; Estados UnidosFil: Alberts, Susan C.. University of Duke; Estados UnidosFil: Ali, Abdullahi H.. Hirola Conservation Programme. Garissa; KeniaFil: Altmann, Jeanne. University of Princeton; Estados UnidosFil: Antunes, Pamela Castro. Universidade Federal do Mato Grosso do Sul; BrasilFil: Belant, Jerrold L.. State University of New York; Estados UnidosFil: Beyer, Dean. Universitat Phillips; AlemaniaFil: Blaum, Niels. Universitat Potsdam; AlemaniaFil: Böhning Gaese, Katrin. Senckenberg Gesellschaft FĂŒr Naturforschung; Alemania. Goethe Universitat Frankfurt; AlemaniaFil: Cullen Jr., Laury. Instituto de Pesquisas EcolĂłgicas; BrasilFil: de Paula, Rogerio Cunha. National Research Center For Carnivores Conservation; BrasilFil: Dekker, Jasja. Jasja Dekker Dierecologie; PaĂ­ses BajosFil: Drescher Lehman, Jonathan. George Mason University; Estados Unidos. National Zoological Park; Estados UnidosFil: Farwig, Nina. Michigan State University; Estados UnidosFil: Fichtel, Claudia. German Primate Center; AlemaniaFil: Fischer, Christina. Universitat Technical Zu Munich; AlemaniaFil: Ford, Adam T.. University of British Columbia; CanadĂĄFil: Goheen, Jacob R.. University of Wyoming; Estados UnidosFil: Janssen, RenĂ©. Bionet Natuuronderzoek; PaĂ­ses BajosFil: Jeltsch, Florian. Universitat Potsdam; AlemaniaFil: Kauffman, Matthew. University Of Wyoming; Estados UnidosFil: Kappeler, Peter M.. German Primate Center; AlemaniaFil: Koch, FlĂĄvia. German Primate Center; AlemaniaFil: LaPoint, Scott. Max Planck Institute fĂŒr Ornithologie; Alemania. Columbia University; Estados UnidosFil: Markham, A. Catherine. Stony Brook University; Estados UnidosFil: Medici, Emilia Patricia. Instituto de Pesquisas EcolĂłgicas (IPE) ; BrasilFil: Morato, Ronaldo G.. Institute For Conservation of The Neotropical Carnivores; Brasil. National Research Center For Carnivores Conservation; BrasilFil: Nathan, Ran. The Hebrew University of Jerusalem; IsraelFil: Oliveira Santos, Luiz Gustavo R.. Universidade Federal do Mato Grosso do Sul; BrasilFil: Olson, Kirk A.. Wildlife Conservation Society; Estados Unidos. National Zoological Park; Estados UnidosFil: Patterson, Bruce. Field Museum of National History; Estados UnidosFil: Paviolo, Agustin Javier. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Nordeste. Instituto de BiologĂ­a Subtropical. Instituto de BiologĂ­a Subtropical - Nodo Puerto IguazĂș | Universidad Nacional de Misiones. Instituto de BiologĂ­a Subtropical. Instituto de BiologĂ­a Subtropical - Nodo Puerto IguazĂș; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Nordeste; ArgentinaFil: Ramalho, Emiliano Esterci. Institute For Conservation of The Neotropical Carnivores; Brasil. Instituto de Desenvolvimento Sustentavel MamirauĂĄ; BrasilFil: Rösner, Sascha. Michigan State University; Estados UnidosFil: Schabo, Dana G.. Michigan State University; Estados UnidosFil: Selva, Nuria. Institute of Nature Conservation of The Polish Academy of Sciences; PoloniaFil: Sergiel, Agnieszka. Institute of Nature Conservation of The Polish Academy of Sciences; PoloniaFil: Xavier da Silva, Marina. Parque Nacional do Iguaçu; BrasilFil: Spiegel, Orr. Universitat Tel Aviv; IsraelFil: Thompson, Peter. University of Maryland; Estados UnidosFil: Ullmann, Wiebke. Universitat Potsdam; AlemaniaFil: Ziឝba, Filip. Tatra National Park; PoloniaFil: Zwijacz Kozica, Tomasz. Tatra National Park; PoloniaFil: Fagan, William F.. University of Maryland; Estados UnidosFil: Mueller, Thomas. Senckenberg Gesellschaft FĂŒr Naturforschung; . Goethe Universitat Frankfurt; AlemaniaFil: Calabrese, Justin M.. National Zoological Park; Estados Unidos. University of Maryland; Estados Unido

    Evaluating expert-based habitat suitability information of terrestrial mammals with GPS-tracking data

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    Aim Macroecological studies that require habitat suitability data for many species often derive this information from expert opinion. However, expert-based information is inherently subjective and thus prone to errors. The increasing availability of GPS tracking data offers opportunities to evaluate and supplement expert-based information with detailed empirical evidence. Here, we compared expert-based habitat suitability information from the International Union for Conservation of Nature (IUCN) with habitat suitability information derived from GPS-tracking data of 1,498 individuals from 49 mammal species. Location Worldwide. Time period 1998-2021. Major taxa studied Forty-nine terrestrial mammal species. Methods Using GPS data, we estimated two measures of habitat suitability for each individual animal: proportional habitat use (proportion of GPS locations within a habitat type), and selection ratio (habitat use relative to its availability). For each individual we then evaluated whether the GPS-based habitat suitability measures were in agreement with the IUCN data. To that end, we calculated the probability that the ranking of empirical habitat suitability measures was in agreement with IUCN's classification into suitable, marginal and unsuitable habitat types. Results IUCN habitat suitability data were in accordance with the GPS data (> 95% probability of agreement) for 33 out of 49 species based on proportional habitat use estimates and for 25 out of 49 species based on selection ratios. In addition, 37 and 34 species had a > 50% probability of agreement based on proportional habitat use and selection ratios, respectively. Main conclusions We show how GPS-tracking data can be used to evaluate IUCN habitat suitability data. Our findings indicate that for the majority of species included in this study, it is appropriate to use IUCN habitat suitability data in macroecological studies. Furthermore, we show that GPS-tracking data can be used to identify and prioritize species and habitat types for re-evaluation of IUCN habitat suitability data

    Behavioral responses of terrestrial mammals to COVID-19 lockdowns

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    COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions. However, under strict lockdowns 10-day 95th percentile displacements increased by 73%, suggesting increased landscape permeability. Animals' 1-hour 95th percentile displacements declined by 12% and animals were 36% closer to roads in areas of high human footprint, indicating reduced avoidance during lockdowns. Overall, lockdowns rapidly altered some spatial behaviors, highlighting variable but substantial impacts of human mobility on wildlife worldwide.acceptedVersio
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