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"Klenzendorf, Sybille"
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Tigers Need Cover: Multi-Scale Occupancy Study of the Big Cat in Sumatran Forest and Plantation Landscapes
The critically endangered Sumatran tiger (Panthera tigris sumatrae Pocock, 1929) is generally known as a forest-dependent animal. With large-scale conversion of forests into plantations, however, it is crucial for restoration efforts to understand to what extent tigers use modified habitats. We investigated tiger-habitat relationships at 2 spatial scales: occupancy across the landscape and habitat use within the home range. Across major landcover types in central Sumatra, we conducted systematic detection, non-detection sign surveys in 47, 17×17 km grid cells. Within each cell, we surveyed 40, 1-km transects and recorded tiger detections and habitat variables in 100 m segments totaling 1,857 km surveyed. We found that tigers strongly preferred forest and used plantations of acacia and oilpalm, far less than their availability. Tiger probability of occupancy covaried positively and strongly with altitude, positively with forest area, and negatively with distance-to-forest centroids. At the fine scale, probability of habitat use by tigers across landcover types covaried positively and strongly with understory cover and altitude, and negatively and strongly with human settlement. Within forest areas, tigers strongly preferred sites that are farther from water bodies, higher in altitude, farther from edge, and closer to centroid of large forest block; and strongly preferred sites with thicker understory cover, lower level of disturbance, higher altitude, and steeper slope. These results indicate that to thrive, tigers depend on the existence of large contiguous forest blocks, and that with adjustments in plantation management, tigers could use mosaics of plantations (as additional roaming zones), riparian forests (as corridors) and smaller forest patches (as stepping stones), potentially maintaining a metapopulation structure in fragmented landscapes. This study highlights the importance of a multi-spatial scale analysis and provides crucial information relevant to restoring tigers and other wildlife in forest and plantation landscapes through improvement in habitat extent, quality, and connectivity.
Journal Article
Threatened predator on the equator: multi-point abundance estimates of the tiger Panthera tigris in central Sumatra
Information on spatial and temporal variation in abundance is crucial for effective management of wildlife. Yet abundance estimates for the Critically Endangered Sumatran tiger Panthera tigris sumatrae are lacking from Riau, the province historically believed to hold the largest percentage of this subspecies. Recently, this area has had one of the highest global rates of deforestation. Using camera traps we investigated tiger abundance across peatland, flat lowland, and hilly lowland forest types in the province, and over time, in the newly established Tesso Nilo National Park, central Sumatra. We estimated densities using spatially explicit capture–recapture, calculated with DENSITY, and traditional capture–recapture models, calculated with CAPTURE. With spatially explicit capture–recapture the lowest tiger density (0.34 ± SE 0.24 per 100 km2) was estimated in the hilly lowland forest of Rimbang Baling and the highest (0.87 ± SE 0.33 per 100 km2) in the flat lowland forest of the Park. Repeated surveys in the Park documented densities of 0.63 ± SE 0.28 in 2005 to 0.87 ± SE 0.33 per 100 km2 in 2008. Compared to traditional capture–recapture the spatially explicit capture–recapture approach resulted in estimates 50% lower. Estimates of tiger density from this study were lower than most previous estimates in other parts of Sumatra. High levels of human activity in the area appear to limit tigers. The results of this study, which covered areas and habitat types not previously surveyed, are important for overall population estimates across the island, provide insight into the response of carnivores to habitat loss, and are relevant to the interventions needed to save the tiger.
Journal Article
The Fate of Wild Tigers
Wild tigers are in a precarious state. Habitat loss and intense poaching of tigers and their prey, coupled with inadequate government efforts to maintain tiger populations, have resulted in a dramatic range contraction in tiger populations. Tigers now occupy 7 percent of their historical range, and in the past decade, the area occupied by tigers has decreased by as much as 41 percent, according to some estimates. If tigers are to survive into the next century, all of the governments throughout the species' range must demonstrate greater resolve and lasting commitments to conserve tigers and their habitats, as well as to stop all trade in tiger products from wild and captive-bred sources. Where national governments, supported in part by NGOs (nongovernmental organizations), make a consistent and substantial commitment to tiger conservation, tigers do recover. We urge leaders of tiger-range countries to support and help stage a regional tiger summit for establishing collaborative conservation efforts to ensure that tigers and their habitats are protected in perpetuity.
Journal Article
C2C—conflict to coexistence: A global approach to manage human–wildlife conflict for coexistence
Human–wildlife conflict (HWC) presents a growing challenge to conservation and development worldwide. World Wide Fund for Nature (WWF) and experts on human–wildlife coexistence strategies have responded to this challenge by developing a holistic, globally applicable approach to HWC management that can be tailored to specific local, regional, or national contexts. Its framework addresses the complexity of essential HWC management and long‐term coexistence strategies and is implemented in a structured yet contextualized step‐by‐step sequence by a team of facilitators and multiple stakeholders. The C2C: Conflict to Coexistence Approach centers on four principles (tolerance is maintained, responsibility is shared, resilience is built, holism is fundamental), four outcomes (wildlife thrives alongside human presence, habitat sufficient to maintain viable wildlife populations, people able and willing to live alongside wildlife, livelihoods/assets secured against presence of wildlife), and six HWC management elements (policy and governance, understanding interactions, prevention, response, mitigation, monitoring) that are to be implemented in an integrated way. It is currently undergoing testing in diverse pilot sites across three continents and demonstrating positive initial results. Here, we share the framework and methodology of the approach and initial results and experiences from these pilot sites. We introduce the C2C:Conflict to Coexistence Approach, with its holistic and integrated framework and globally applicable methodology for the management of human–wildlife conflict (HWC) that can be tailored to specific local, regional, or national contexts. Its framework addresses the complexity of essential HWC management and long‐term coexistence strategies and is implemented in a structured yet contextualized step‐by‐step sequence by a team of process facilitators involving multiple stakeholders. The video summary is uploaded to our website on human‐wildlife conflict, which can be found here: Human Wildlife Conflict
Journal Article
An Overview of Brown Bear Management in Six European Countries
During 1995-96, we surveyed members of organizations and governmental agencies to construct an overview of brown bear (Ursus arctos) management in Austria, Italy, Norway, Romania, Slovenia, and Sweden. From the results, we summarized the extent of brown bear damage in each country, identified which organizations were involved in bear management, and which duties they fulfilled. We conducted 94 interviews using a standardized questionnaire. Bear damage in most countries was <20% of all reported wildlife damage and totaled
Journal Article
Den-Type Use and Fidelity of American Black Bears in Western Virginia
During winters 1995-2001, Cooperative Alleghany Bear Study (CABS) personnel handled 119 individual adult American black bears (Ursus americanus) and 322 cubs in 198 dens on 2 study areas in western Virginia. Our objective was to determine den-type use and den-type fidelity of adult black bears and their offspring. We located 215 dens of radiocollared bears; 68% were in trees. Ground dens used by bears included nests in laurel (Kalmia latifolia) thickets, excavations, brush piles, and rock cavities. Although the proportion of all bears using tree dens did not differ between our 2 study areas, females used tree dens (65%, n = 127) more often than males on the northern study area. Sex and age were significant factors in determining the type of den a bear selected. Older bears denned in rock cavities more often than expected. Of 66 individual bears handled for 2-6 consecutive years, 38% consistently used tree dens, 12% were faithful to rock cavities, and only 6% regularly used ground dens for denning. Over the 6-year period, 42% switched den types, primarily from tree dens to rock cavities. Rock cavities seemed readily available, yet 68% of marked bears used trees. Bears are hunted by hounds in Virginia during December and January and may use tree dens to reduce the likelihood of detection during the hunting season.
Journal Article
Population dynamics of Virginia's hunted black bear population
The Cooperative Alleghany Bear Study (CABS) was initiated in 1994 by the Virginia Department of Game and Inland Fisheries (VDGIF) and the Virginia Polytechnic Institute and State University (VPI&SU) to investigate population dynamics on Virginia's hunted bear population. CABS personnel handled 746 different bears (1.5M:1F) 1,368 times on its northern study area during June 1994 to September 2000. The sex ratio for summer captures was 1.5M:1F, which differed from 1:1 (n = 1,008, Z = 6.17, P < 0.0001). Sex ratios for the summer captures ranged considerably among years (χ2 = 23.92, df = 6, P = 0.0005) and among age classes (χ2 = 119.22, df = 4, P < 0.0001), with the largest discrepancy among yearlings (5.7M:1F). The sex ratio among captured adults favored females (0.6M:1.0F). Average age for all captured bears was 3.87 ± S.E. 0.12 years; females (n = 309) averaged 5.20 ± S.E. 0.16 and males (n = 402) averaged 2.84 ± S.E. 0.14 years (t = 10.92, df = 709, P < 0.001). Litter size averaged 2.35 cubs/litter over the 6-year period and sex ratio did not differ from 1:1 (n = 183, Z = 0.74, P = 0.461), but varied among years (χ2 = 16.61, df = 5; P = 0.005). Three-hundred-and-seventy-six (164M, 212F) of 746 captured individuals were equipped with radio-transmitters. The ratio of radio-collared bears fluctuated from 2.6 F:1M (1998) to 8.6F:1M. We tested a radio-collar effect on survival as a covariate and found a significantly higher survival for radio-collared adult and 3-year-old females in the first 3 years of the study (χ2 = 6.64, 1 df, P = 0.01). Estimates using the Kaplan-Meier staggered entry showed survival rates for females (adults = 0.993, subadults = 0.997) higher than for males (adults = 0.972, subadults = 0.917). Estimates using the mark-dead recoveries data showed survival rates of 0.840 for adult females (0.714 for 2-year-olds) and 0.769 for adult males (0.335 for 2-year-olds). We observed 34 mortalities of radio-collared bears for which hunting mortality accounted for 85%. Four natural mortalities included a 5-year-old female and a 2-year-old male that were killed by other bears, and a 14-year-old and 2-year-old female that died of unknown causes. Among the ear-tagged sample, 2-year-old males experienced the highest mean harvest rate of 45%, with a high of 65% mortality in 1996. Among females, 2-year-olds were most vulnerable with a harvest mortality rate of 22% a year. (Abstract shortened by UMI.)
Dissertation
The spatial distribution and temporal trends of livestock damages caused by wolves in Europe
Wolf populations are recovering and expanding across Europe, causing conflicts with livestock owners. To mitigate these conflicts and reduce livestock damages, authorities spend considerable resources to compensate damages, support damage prevention measures, and manage wolf populations. However, the effectiveness of these measures remains largely unknown, especially at larger geographic scales. Here we compiled incident-based livestock damage data across 21 countries for the years 2018, 2019 and 2020, during which 39,262 wolf-caused incidents were reported from 470 administrative regions. We found substantial regional variation in all aspects of the data, including the primary target species, the density of damages, their seasonal distribution, and their temporal trend. More than half of the variation in damage densities across regions is explained by the area of extensively cultivated habitats occupied by wolves, namely natural grasslands and broad-leaved forests. Regional variation in husbandry practices and damage prevention, while difficult to quantify at a continental scale, appear important factors to further modulate these incidents. As illustrated with detailed data from Germany, for instance, the relationship between the number of wolf units and damages is diminishing over time, suggesting some adaptation of livestock owners and local authorities to their presence, for example by increasing prevention efforts. As we argue, temporal trends of damage incidents, which are robust to variation in data collection across regions, are thus informative about the local intensity of the wolf-human conflict. We estimated increasing trends for the majority of regions, reflecting the current expansion of wolves across the continent. Nonetheless, many of these increases were moderate and for more than one third of all regions, trends were negative despite growing wolf populations, thus indicating that wolf-livestock conflicts can be successfully mitigated with proper management.Competing Interest StatementThe authors have declared no competing interest.Footnotes* We improved our modelling and now use Poisson linear regression and also added additional covariates. We further improved the writing for clarity by reordering some parts and adding technical details. The main message of our manuscript remains unchanged: There appears to be considerable regional variation in all aspects of the data, including the frequency of incidents, the primary target species, the seasonal distribution and the overall trend. With the improved models, about 60% of the variation in incident frequency can be explained with landscape features, primarily by the amount of extensively used habitats also occupied by wolves.* https://doi.org/10.5281/zenodo.6821814
Paper