TY - JOUR A1 - Tucker, Marlee A. A1 - Boehning-Gaese, Katrin A1 - Fagan, William F. A1 - Fryxell, John M. A1 - Van Moorter, Bram A1 - Alberts, Susan C. A1 - Ali, Abdullahi H. A1 - Allen, Andrew M. A1 - Attias, Nina A1 - Avgar, Tal A1 - Bartlam-Brooks, Hattie A1 - Bayarbaatar, Buuveibaatar A1 - Belant, Jerrold L. A1 - Bertassoni, Alessandra A1 - Beyer, Dean A1 - Bidner, Laura A1 - van Beest, Floris M. A1 - Blake, Stephen A1 - Blaum, Niels A1 - Bracis, Chloe A1 - Brown, Danielle A1 - de Bruyn, P. J. Nico A1 - Cagnacci, Francesca A1 - Calabrese, Justin M. A1 - Camilo-Alves, Constanca A1 - Chamaille-Jammes, Simon A1 - Chiaradia, Andre A1 - Davidson, Sarah C. A1 - Dennis, Todd A1 - DeStefano, Stephen A1 - Diefenbach, Duane A1 - Douglas-Hamilton, Iain A1 - Fennessy, Julian A1 - Fichtel, Claudia A1 - Fiedler, Wolfgang A1 - Fischer, Christina A1 - Fischhoff, Ilya A1 - Fleming, Christen H. A1 - Ford, Adam T. A1 - Fritz, Susanne A. A1 - Gehr, Benedikt A1 - Goheen, Jacob R. A1 - Gurarie, Eliezer A1 - Hebblewhite, Mark A1 - Heurich, Marco A1 - Hewison, A. J. Mark A1 - Hof, Christian A1 - Hurme, Edward A1 - Isbell, Lynne A. A1 - Janssen, Rene A1 - Jeltsch, Florian A1 - Kaczensky, Petra A1 - Kane, Adam A1 - Kappeler, Peter M. A1 - Kauffman, Matthew A1 - Kays, Roland A1 - Kimuyu, Duncan A1 - Koch, Flavia A1 - Kranstauber, Bart A1 - LaPoint, Scott A1 - Leimgruber, Peter A1 - Linnell, John D. C. A1 - Lopez-Lopez, Pascual A1 - Markham, A. Catherine A1 - Mattisson, Jenny A1 - Medici, Emilia Patricia A1 - Mellone, Ugo A1 - Merrill, Evelyn A1 - Mourao, Guilherme de Miranda A1 - Morato, Ronaldo G. A1 - Morellet, Nicolas A1 - Morrison, Thomas A. A1 - Diaz-Munoz, Samuel L. A1 - Mysterud, Atle A1 - Nandintsetseg, Dejid A1 - Nathan, Ran A1 - Niamir, Aidin A1 - Odden, John A1 - Oliveira-Santos, Luiz Gustavo R. A1 - Olson, Kirk A. A1 - Patterson, Bruce D. A1 - de Paula, Rogerio Cunha A1 - Pedrotti, Luca A1 - Reineking, Bjorn A1 - Rimmler, Martin A1 - Rogers, Tracey L. A1 - Rolandsen, Christer Moe A1 - Rosenberry, Christopher S. A1 - Rubenstein, Daniel I. A1 - Safi, Kamran A1 - Said, Sonia A1 - Sapir, Nir A1 - Sawyer, Hall A1 - Schmidt, Niels Martin A1 - Selva, Nuria A1 - Sergiel, Agnieszka A1 - Shiilegdamba, Enkhtuvshin A1 - Silva, Joao Paulo A1 - Singh, Navinder A1 - Solberg, Erling J. A1 - Spiegel, Orr A1 - Strand, Olav A1 - Sundaresan, Siva A1 - Ullmann, Wiebke A1 - Voigt, Ulrich A1 - Wall, Jake A1 - Wattles, David A1 - Wikelski, Martin A1 - Wilmers, Christopher C. A1 - Wilson, John W. A1 - Wittemyer, George A1 - Zieba, Filip A1 - Zwijacz-Kozica, Tomasz A1 - Mueller, Thomas T1 - Moving in the Anthropocene BT - global reductions in terrestrial mammalian movements JF - Science N2 - Animal movement is fundamental for ecosystem functioning and species survival, yet the effects of the anthropogenic footprint on animal movements have not been estimated across species. Using a unique GPS-tracking database of 803 individuals across 57 species, we found that movements of mammals in areas with a comparatively high human footprint were on average one-half to one-third the extent of their movements in areas with a low human footprint. We attribute this reduction to behavioral changes of individual animals and to the exclusion of species with long-range movements from areas with higher human impact. Global loss of vagility alters a key ecological trait of animals that affects not only population persistence but also ecosystem processes such as predator-prey interactions, nutrient cycling, and disease transmission. Y1 - 2018 U6 - https://doi.org/10.1126/science.aam9712 SN - 0036-8075 SN - 1095-9203 VL - 359 IS - 6374 SP - 466 EP - 469 PB - American Assoc. for the Advancement of Science CY - Washington ER - TY - JOUR A1 - Luft, Laura A1 - Neumann, C. A1 - Itzerott, S. A1 - Lausch, A. A1 - Doktor, D. A1 - Freude, M. A1 - Blaum, Niels A1 - Jeltsch, Florian T1 - Digital and real-habitat modeling of Hipparchia statilinus based on hyper spectral remote sensing data JF - International journal of environmental science and technology N2 - The abandonment of military areas leads to succession processes affecting valuable open-land habitats and is considered to be a major threat for European butterflies. We assessed the ability of hyper spectral remote sensing data to spatially predict the occurrence of one of the most endangered butterfly species (Hipparchia statilinus) in Brandenburg (Germany) on the basis of habitat characteristics at a former military training area. Presence-absence data were sampled on a total area of 36 km(2), and N = 65 adult individuals of Hipparchia statilinus could be detected. The floristic composition within the study area was modeled in a three-dimensional ordination space. Occurrence probabilities for the target species were predicted as niches between ordinated floristic gradients by using Regression Kriging of Indicators. Habitat variance could be explained by up to 81 % with spectral variables at a spatial resolution of 2 x 2 m by transferring PLSR models to imagery. Ordinated ecological niche of Hipparchia statilinus was tested against environmental predictor variables. N = 6 variables could be detected to be significantly correlated with habitat preferences of Hipparchia statilinus. They show that Hipparchia statilinus can serve as a valuable indicator for the evaluation of the conservation status of Natura 2000 habitat type 2330 (inland dunes with open Corynephorus and Agrostis grasslands) protected by the Habitat Directive (Council Directive 92/43/EEC). The authors of this approach, conducted in August 2013 at Doberitzer Heide Germany, aim to increase the value of remote sensing as an important tool for questions of biodiversity research and conservation. KW - Habitat gradients KW - Military areas KW - Natura 2000 KW - hyper spectral KW - Vegetation continuum KW - Kriging Y1 - 2016 U6 - https://doi.org/10.1007/s13762-015-0859-1 SN - 1735-1472 SN - 1735-2630 VL - 13 SP - 187 EP - 200 PB - Springer CY - New York ER - TY - JOUR A1 - Stiegler, Jonas A1 - Pahl, Janice A1 - Guillen, Rafael Arce A1 - Ullmann, Wiebke A1 - Blaum, Niels T1 - The heat is on BT - impacts of rising temperature on the activity of a common European mammal JF - Frontiers in Ecology and Evolution N2 - Climate conditions severely impact the activity and, consequently, the fitness of wildlife species across the globe. Wildlife can respond to new climatic conditions, but the pace of human-induced change limits opportunities for adaptation or migration. Thus, how these changes affect behavior, movement patterns, and activity levels remains unclear. In this study, we investigate how extreme weather conditions affect the activity of European hares (Lepus europaeus) during their peak reproduction period. When hares must additionally invest energy in mating, prevailing against competitors, or lactating, we investigated their sensitivities to rising temperatures, wind speed, and humidity. To quantify their activity, we used the overall dynamic body acceleration (ODBA) calculated from tri-axial acceleration measurements of 33 GPS-collared hares. Our analysis revealed that temperature, humidity, and wind speed are important in explaining changes in activity, with a strong response for high temperatures above 25 & DEG;C and the highest change in activity during temperature extremes of over 35 & DEG;C during their inactive period. Further, we found a non-linear relationship between temperature and activity and an interaction of activity changes between day and night. Activity increased at higher temperatures during the inactive period (day) and decreased during the active period (night). This decrease was strongest during hot tropical nights. At a stage of life when mammals such as hares must substantially invest in reproduction, the sensitivity of females to extreme temperatures was particularly pronounced. Similarly, both sexes increased their activity at high humidity levels during the day and low wind speeds, irrespective of the time of day, while the effect of humidity was stronger for males. Our findings highlight the importance of understanding the complex relationships between extreme weather conditions and mammal behavior, critical for conservation and management. With ongoing climate change, extreme weather events such as heat waves and heavy rainfall are predicted to occur more often and last longer. These events will directly impact the fitness of hares and other wildlife species and hence the population dynamics of already declining populations across Europe. KW - activity KW - ODBA KW - animal tracking KW - European hare KW - extreme weather events KW - climate change Y1 - 2023 U6 - https://doi.org/10.3389/fevo.2023.1193861 SN - 2296-701X VL - 11 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Geißler, Katja A1 - Heblack, Jessica A1 - Uugulu, Shoopala A1 - Wanke, Heike A1 - Blaum, Niels T1 - Partitioning of Water Between Differently Sized Shrubs and Potential Groundwater Recharge in a Semiarid Savanna in Namibia JF - Frontiers in Plant Science N2 - 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. d2H and d18O 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. KW - bush encroachment KW - groundwater recharge KW - rooting depth KW - Savannas KW - stable isotopes KW - shrub size KW - Acacia mellifera KW - rain event depth Y1 - 2019 U6 - https://doi.org/10.3389/fpls.2019.01411 SN - 1664-462X VL - 10 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Noonan, Michael J. A1 - Tucker, Marlee A. A1 - Fleming, Christen H. A1 - Akre, Thomas S. A1 - Alberts, Susan C. A1 - Ali, Abdullahi H. A1 - Altmann, Jeanne A1 - Antunes, Pamela Castro A1 - Belant, Jerrold L. A1 - Beyer, Dean A1 - Blaum, Niels A1 - Boehning-Gaese, Katrin A1 - Cullen Jr, Laury A1 - de Paula, Rogerio Cunha A1 - Dekker, Jasja A1 - Drescher-Lehman, Jonathan A1 - Farwig, Nina A1 - Fichtel, Claudia A1 - Fischer, Christina A1 - Ford, Adam T. A1 - Goheen, Jacob R. A1 - Janssen, Rene A1 - Jeltsch, Florian A1 - Kauffman, Matthew A1 - Kappeler, Peter M. A1 - Koch, Flavia A1 - LaPoint, Scott A1 - Markham, A. Catherine A1 - Medici, Emilia Patricia A1 - Morato, Ronaldo G. A1 - Nathan, Ran A1 - Oliveira-Santos, Luiz Gustavo R. A1 - Olson, Kirk A. A1 - Patterson, Bruce D. A1 - Paviolo, Agustin A1 - Ramalho, Emiliano Estero A1 - Rosner, Sascha A1 - Schabo, Dana G. A1 - Selva, Nuria A1 - Sergiel, Agnieszka A1 - da Silva, Marina Xavier A1 - Spiegel, Orr A1 - Thompson, Peter A1 - Ullmann, Wiebke A1 - Zieba, Filip A1 - Zwijacz-Kozica, Tomasz A1 - Fagan, William F. A1 - Mueller, Thomas A1 - Calabrese, Justin M. T1 - A comprehensive analysis of autocorrelation and bias in home range estimation JF - Ecological monographs : a publication of the Ecological Society of America. N2 - 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], Silverman's 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 ( N̂ area ) 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 N̂ area. To contextualize our empirical results, we performed a detailed simulation study to tease apart how sampling frequency, sampling duration, and the focal animal's 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 N̂ area. While 72% of the 369 empirical data sets had >1,000 total observations, only 4% had an N̂ area >1,000, where 30% had an N̂ area <30. In this frequently encountered scenario of small N̂ area, AKDE was the only estimator capable of producing an accurate home range estimate on autocorrelated data. KW - animal movement KW - kernel density estimation KW - local convex hull KW - minimum convex polygon KW - range distribution KW - space use KW - telemetry KW - tracking data Y1 - 2018 U6 - https://doi.org/10.1002/ecm.1344 SN - 0012-9615 SN - 1557-7015 VL - 89 IS - 2 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Kuechly, Helga Ursula A1 - Mueller, Julia Sophie A1 - Reinfelder, Vanessa Luisa A1 - Wiedemann, Stephan A1 - Blaum, Niels T1 - Rodent-mediated dispersal of Acacia seeds in Kalahari savannah rangelands - implications for bush encroachment JF - African journal of ecology Y1 - 2011 U6 - https://doi.org/10.1111/j.1365-2028.2010.01230.x SN - 0141-6707 VL - 49 IS - 1 SP - 119 EP - 121 PB - Wiley-Blackwell CY - Malden ER - TY - JOUR A1 - Thiele, T. A1 - Jeltsch, Florian A1 - Blaum, Niels T1 - Importance of woody vegetation for foraging site selection in the Southern Pied Babbler (Turdoides bicolor) under two different land use regimes Y1 - 2008 SN - 0140-1963 ER - TY - JOUR A1 - Tews, Jörg A1 - Blaum, Niels A1 - Jeltsch, Florian T1 - Structural and animal species diversity in arid and semi-arid savannas of the southern Kalahari Y1 - 2004 ER - TY - JOUR A1 - Blaum, Niels A1 - Engeman, Richard M. A1 - Wasiolka, Bernd A1 - Rossmanith, Eva T1 - Indexing small mammalian carnivores in the southern Kalahari, South Africa N2 - Monitoring animal populations in changing environments is crucial to wildlife conservation and management, but restrictions in resources are a recurring problem for wildlife managers and researchers throughout Africa. Land-use- induced shrub encroachment in Kalahari savannah rangelands has led to fragmentation of the landscape. Mammalian carnivores are particularly vulnerable to local extinction in fragmented landscapes, but their low numbers and their often nocturnal and secretive habits make them difficult to monitor. In this study, we tested the applicability of a passive tracking method and compared two measurement methods and index calculations for monitoring small carnivores across a grazing gradient in the southern Kalahari. During the four years of monitoring in a five-year period, we used the knowledge of indigenous Khoisan Bushmen for the identification of carnivore tracks on 640 sand transects (5 m x 250 m). Our results showed that this simple and inexpensive observation method enabled detailed monitoring of 10 small carnivore species across the grazing gradient. A binary index calculated an index based on presence/absence of a species' tracks on each transect, whereas the track intrusion index used the number of track intrusions to each transect for each species in its calculations. For less common species, the two indices were similar in trend and magnitude, because the number of intrusions to each transect was typically 1 or 0. Usually, the two indices showed relatively strong correlations. However, species with patchy distributions of higher numbers presented difficulties for the binary index to monitor trends, but not for the track intrusion index. Y1 - 2008 SN - 1035-3712 ER - TY - JOUR A1 - Popp, Alexander A1 - Domptail, Stephanie A1 - Blaum, Niels A1 - Jeltsch, Florian T1 - Landuse experience does not qualify for adaptation to climate change N2 - The need to implement sustainable resource management regimes for semi-arid and arid rangelands is acute as non- adapted grazing strategies lead to irreversible environmental problems such as desertification and associated loss of economic support to society. In these sensitive ecosystems, traditional sectoral, disciplinary approaches will not work to attain sustainability: achieving a collective vision of how to attain sustainability requires interactive efforts among disciplines in a more integrated approach. Therefore, we developed an integrated ecological-economic approach that consists of an ecological and an economic module and combines relevant processes on either level. Parameters for both modules are adjusted for an arid dwarf shrub savannah in southern Namibia. The economic module is used to analyse decisions of different virtual farmer types on annual stocking rates depending on their knowledge how the ecosystem works and climatic conditions. We used a dynamic linear optimisation model to simulate farm economics and livestock dynamics. The ecological module is used to simulate the impact of the farmers' land-use decision, derived by the economic module, on ecosystem dynamics and resulting carrying capacity of the system for livestock. Vegetation dynamics, based on the concept of State-and-transition models, and forage productivity for both modules is derived by a small- scale and spatially explicit vegetation model. This mechanistic approach guarantees that data collected and processes estimated at smaller scales are included in our application. Simulation results of the ecological module were successfully compared to simulation results of the optimisation model for a time series of 30 years. We revealed that sustainable management of semi-arid and arid rangelands relies strongly on rangeland managers' understanding of ecological processes. Furthermore, our simulation results demonstrate that the projected lower annual rainfall due to climate change adds an additional layer of risk to these ecosystems that are already prone to land degradation. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/03043800 U6 - https://doi.org/10.1016/j.ecolmodel.2008.11.015 SN - 0304-3800 ER -