This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as
Extensive bushmeat hunting is a major threat to wildlife conservation worldwide, particularly whe... more Extensive bushmeat hunting is a major threat to wildlife conservation worldwide, particularly when unselective methods such as wire snares kill target and nontarget species (by-catch). Animals that escape from snares have injuries of varying severity, with effects on performance that are largely unknown, as most studies typically focus on immediate mortality caused by snaring. Here, we assessed the life-history costs of debilitating snare injuries in individually known female spotted hyenas Crocuta crocuta in three clans in the Serengeti National Park, Tanzania. This keystone predator is a regular by-catch of illegal bushmeat hunting of herbivores in the Serengeti ecosystem. We monitored individuals which escaped from snares between May 1987 and March 2020 and survived long enough to return to their clan territories from commuting trips in the park and surrounding protected areas. Snares that inflicted debilitating injuries on females did not reduce longevity but did delay age at first reproduction and reduced both litter size and offspring survival to the age of 1 year. This long-term decrease in reproductive performance likely resulted from increased inflammatory and immune responses to the snare injury and/or a decreased ability to travel the long distances necessary to feed on migratory herbivores. While our results are based on a relatively small sample of females with debilitating injuries, they suggest that the total population-level costs of wire snares in terrestrial by-catch species may be underestimated and that future studies may need to account for the potential reproductive costs of sublethal snare injuries.
The small (2-to 7-kg) leopard cat (Prionailurus bengalensis) is the most common cat species in As... more The small (2-to 7-kg) leopard cat (Prionailurus bengalensis) is the most common cat species in Asia. Although it occurs in a wide range of habitats and seems to adapt well to anthropogenic habitat changes, surprisingly little is known about this species in the wild. All studies have focused on protected areas, although a large proportion of Southeast Asian forests are timber concessions. During this study, we used large camera-trapping data sets (783 records of 124 individuals) from 3 commercially used forests to investigate consequences of different logging regimes on density and habitat associations of the leopard cat. We applied spatial capture-recapture models accounting for the location of camera-traps (on or off road) to obtain estimates of leopard cat density. Density was higher in the 2 more disturbed forest reserves (X ¼ 12.4 individuals/100 km 2 6 1.6 SE and 16.5 6 2 individuals/100 km 2) than in the sustainably managed forest (9.6 6 1.7 individuals/100 km 2). Encounter rates with off-road traps were only 3.6-9.1% of those for on-road traps. Occupancy models, which accounted for spatial autocorrelation between sampling sites by using a conditional autoregressive model, revealed that canopy closure and ratio of climax to pioneer trees had a significantly negative impact on leopard cat occurrence. Our results confirm that the leopard cat is doing well in modified landscapes and even seems to benefit from the opening of forests. With such flexibility the leopard cat is an exception among tropical rainforest carnivores.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-... more This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
A thorough knowledge of the ecology, behavior, and physiology of species under free-ranging condi... more A thorough knowledge of the ecology, behavior, and physiology of species under free-ranging conditions is essential to understand their environmental needs, life-history strategies and thus is the crucial basis for their protection and conservation (Kays, Crofoot, Jetz,
Assigning a certain trait to a particular population and generalizing it toward the species can c... more Assigning a certain trait to a particular population and generalizing it toward the species can cause oversimplification errors, especially in case of widespread species which experience substantial variation in environmental conditions and habitats (Putman & Flueck, 2011). Such generalizations may miss relevant variability in behavior, physiology and ecology between populations, particularly in taxa such as carnivores that show considerable interspecific and intraspecific variation (Lott, 1991; Moehlman & Hofer, 1997). These generalizations may become of practical relevance if conservation actions are built upon expectations derived from populations studied elsewhere, with the potential to fail if the biology of the local population is different, for instance because it is adapted to local and historical environmental conditions.
Twenty six African and/or Asian bovid species kept at Al Wabra Wildlife Preservation, Qatar (lati... more Twenty six African and/or Asian bovid species kept at Al Wabra Wildlife Preservation, Qatar (latitude 25 °N, longitude 51 °E, altitude < 100m above sea level) were evaluated for their birth seasonality. A broad range of breeding patterns could be observed, from breeding throughout the whole year (e.g. blackbuck, dorcas gazelle, idmi gazelle, Speke´s gazelle), to explicit seasonality (e.g. mouflon, nilgai, Nubian ibex, wild goat) in breeding patterns. In general, natural breeding patterns were preserved in captivity. In some species, deviations from patterns reported in the wild are evident, with longer birthing seasons in captivity, sometimes with calves being born the whole year round. This applies mainly for species where birthing correlates with the rainfall season in the wild (e.g. beira antelope, idmi gazelle). It can be speculated that when water, and subsequently food, is supplied constantly, breeding is no longer seasonally restricted, indicating that the respective speci...
Since 1999, a population of Speke’s gazelles (Gazella spekei) has been managed at Al Wabra Wildli... more Since 1999, a population of Speke’s gazelles (Gazella spekei) has been managed at Al Wabra Wildlife Preservation (AWWP) in Doha, State of Qatar. As the population at AWWP seems to have suffered unprecedented declines, as compared to other gazelles at AWWP, over the last few years, it was decided to retrospectively evaluate all 206 necropsy reports recorded between 2001 and 2007 to investigate the reasons behind the observed mortality. Postmortem findings indicating lung infections accounted for almost 30 % of all deaths, followed by traumatic injuries (17.9 %) and maternal neglect leading to starvation and death in neonatal animals (13.5 %). Animals between 10 days and 1 year of age showed a higher tendency toward problems with lung infections, whereas animals between 2 and 3 years of age died more often because of traumatic injuries. Individuals older than 3 years of age often suffer from lung infection but usually in combination with other illnesses, such as renal and gastrointest...
Studies on humans indicate that encountering multiple sources of adversity in childhood increases... more Studies on humans indicate that encountering multiple sources of adversity in childhood increases the risk of poor long‐term health and premature death. Far less is known about cumulative effects of adversity during early life in wildlife. Focusing on the spotted hyena Crocuta crocuta, a social mammal with small litters, extensive maternal care, slow development and access to resources determined by social rank, we determined the contribution of ecological, maternal, social and demographic factors during early life on performance and fitness, and tested whether the impact of early‐life adversity is cumulative. Using longitudinal data from 666 female hyenas in the Serengeti National Park, we determined the early growth rate, survival to adulthood, age at first reproduction (AFR), lifetime reproductive success (LRS) and longevity. We fitted multivariate models in which we tested the effects of environmental factors on these performance measures. We then constructed a cumulative adversity index and fitted models to test the effect of this index on each performance measure. Finally, the value of cumulative adversity models was tested by comparing them to multivariate and single‐effect models in which the effect of each environmental factor was considered separately. High maternal rank decreased the AFR of daughters. Singleton and dominant cubs had higher growth rate than subordinate cubs, and singletons also had a higher survival chance to adulthood than subordinates. Daughters of prime age mothers had a higher growth rate, longevity and LRS. Little and heavy rainfall decreased survival to adulthood. Increasing numbers of lactating female clan members decreased growth rate, survival to adulthood and LRS. Cumulative adversity negatively affected short‐term performance and LRS. Multivariate models outperformed cumulative adversity and single‐effect models for all measures except for AFR and longevity, for which single‐effect models performed better. Our results suggest that in some wildlife populations the combination of specific conditions in early life may matter more than the accumulation of adverse conditions as such.
Proceedings of the 12th International Symposium on Visual Information Communication and Interaction, 2019
Recent advances in tracking technology allow biologists to collect large amounts of movement data... more Recent advances in tracking technology allow biologists to collect large amounts of movement data for a variety of species. Analysis of the collected data supports research on animal behaviour, influence of impact factors such as climate change and human intervention, as well as conservation programs. Analysis of the movement data is difficult, due to the nature of the research questions and the complexity of the data sets. It requires both automated analysis, e.g. for the detection of behavioural patterns, and human inspection, e.g. for interpretation, inclusion of previous knowledge, and for conclusions on future actions and decision making. We present a concept and implementation for the visual analysis of cheetah movement data in a web-based fashion that allows usage both in the field and in office environments.
This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as
Extensive bushmeat hunting is a major threat to wildlife conservation worldwide, particularly whe... more Extensive bushmeat hunting is a major threat to wildlife conservation worldwide, particularly when unselective methods such as wire snares kill target and nontarget species (by-catch). Animals that escape from snares have injuries of varying severity, with effects on performance that are largely unknown, as most studies typically focus on immediate mortality caused by snaring. Here, we assessed the life-history costs of debilitating snare injuries in individually known female spotted hyenas Crocuta crocuta in three clans in the Serengeti National Park, Tanzania. This keystone predator is a regular by-catch of illegal bushmeat hunting of herbivores in the Serengeti ecosystem. We monitored individuals which escaped from snares between May 1987 and March 2020 and survived long enough to return to their clan territories from commuting trips in the park and surrounding protected areas. Snares that inflicted debilitating injuries on females did not reduce longevity but did delay age at first reproduction and reduced both litter size and offspring survival to the age of 1 year. This long-term decrease in reproductive performance likely resulted from increased inflammatory and immune responses to the snare injury and/or a decreased ability to travel the long distances necessary to feed on migratory herbivores. While our results are based on a relatively small sample of females with debilitating injuries, they suggest that the total population-level costs of wire snares in terrestrial by-catch species may be underestimated and that future studies may need to account for the potential reproductive costs of sublethal snare injuries.
The small (2-to 7-kg) leopard cat (Prionailurus bengalensis) is the most common cat species in As... more The small (2-to 7-kg) leopard cat (Prionailurus bengalensis) is the most common cat species in Asia. Although it occurs in a wide range of habitats and seems to adapt well to anthropogenic habitat changes, surprisingly little is known about this species in the wild. All studies have focused on protected areas, although a large proportion of Southeast Asian forests are timber concessions. During this study, we used large camera-trapping data sets (783 records of 124 individuals) from 3 commercially used forests to investigate consequences of different logging regimes on density and habitat associations of the leopard cat. We applied spatial capture-recapture models accounting for the location of camera-traps (on or off road) to obtain estimates of leopard cat density. Density was higher in the 2 more disturbed forest reserves (X ¼ 12.4 individuals/100 km 2 6 1.6 SE and 16.5 6 2 individuals/100 km 2) than in the sustainably managed forest (9.6 6 1.7 individuals/100 km 2). Encounter rates with off-road traps were only 3.6-9.1% of those for on-road traps. Occupancy models, which accounted for spatial autocorrelation between sampling sites by using a conditional autoregressive model, revealed that canopy closure and ratio of climax to pioneer trees had a significantly negative impact on leopard cat occurrence. Our results confirm that the leopard cat is doing well in modified landscapes and even seems to benefit from the opening of forests. With such flexibility the leopard cat is an exception among tropical rainforest carnivores.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-... more This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
A thorough knowledge of the ecology, behavior, and physiology of species under free-ranging condi... more A thorough knowledge of the ecology, behavior, and physiology of species under free-ranging conditions is essential to understand their environmental needs, life-history strategies and thus is the crucial basis for their protection and conservation (Kays, Crofoot, Jetz,
Assigning a certain trait to a particular population and generalizing it toward the species can c... more Assigning a certain trait to a particular population and generalizing it toward the species can cause oversimplification errors, especially in case of widespread species which experience substantial variation in environmental conditions and habitats (Putman & Flueck, 2011). Such generalizations may miss relevant variability in behavior, physiology and ecology between populations, particularly in taxa such as carnivores that show considerable interspecific and intraspecific variation (Lott, 1991; Moehlman & Hofer, 1997). These generalizations may become of practical relevance if conservation actions are built upon expectations derived from populations studied elsewhere, with the potential to fail if the biology of the local population is different, for instance because it is adapted to local and historical environmental conditions.
Twenty six African and/or Asian bovid species kept at Al Wabra Wildlife Preservation, Qatar (lati... more Twenty six African and/or Asian bovid species kept at Al Wabra Wildlife Preservation, Qatar (latitude 25 °N, longitude 51 °E, altitude < 100m above sea level) were evaluated for their birth seasonality. A broad range of breeding patterns could be observed, from breeding throughout the whole year (e.g. blackbuck, dorcas gazelle, idmi gazelle, Speke´s gazelle), to explicit seasonality (e.g. mouflon, nilgai, Nubian ibex, wild goat) in breeding patterns. In general, natural breeding patterns were preserved in captivity. In some species, deviations from patterns reported in the wild are evident, with longer birthing seasons in captivity, sometimes with calves being born the whole year round. This applies mainly for species where birthing correlates with the rainfall season in the wild (e.g. beira antelope, idmi gazelle). It can be speculated that when water, and subsequently food, is supplied constantly, breeding is no longer seasonally restricted, indicating that the respective speci...
Since 1999, a population of Speke’s gazelles (Gazella spekei) has been managed at Al Wabra Wildli... more Since 1999, a population of Speke’s gazelles (Gazella spekei) has been managed at Al Wabra Wildlife Preservation (AWWP) in Doha, State of Qatar. As the population at AWWP seems to have suffered unprecedented declines, as compared to other gazelles at AWWP, over the last few years, it was decided to retrospectively evaluate all 206 necropsy reports recorded between 2001 and 2007 to investigate the reasons behind the observed mortality. Postmortem findings indicating lung infections accounted for almost 30 % of all deaths, followed by traumatic injuries (17.9 %) and maternal neglect leading to starvation and death in neonatal animals (13.5 %). Animals between 10 days and 1 year of age showed a higher tendency toward problems with lung infections, whereas animals between 2 and 3 years of age died more often because of traumatic injuries. Individuals older than 3 years of age often suffer from lung infection but usually in combination with other illnesses, such as renal and gastrointest...
Studies on humans indicate that encountering multiple sources of adversity in childhood increases... more Studies on humans indicate that encountering multiple sources of adversity in childhood increases the risk of poor long‐term health and premature death. Far less is known about cumulative effects of adversity during early life in wildlife. Focusing on the spotted hyena Crocuta crocuta, a social mammal with small litters, extensive maternal care, slow development and access to resources determined by social rank, we determined the contribution of ecological, maternal, social and demographic factors during early life on performance and fitness, and tested whether the impact of early‐life adversity is cumulative. Using longitudinal data from 666 female hyenas in the Serengeti National Park, we determined the early growth rate, survival to adulthood, age at first reproduction (AFR), lifetime reproductive success (LRS) and longevity. We fitted multivariate models in which we tested the effects of environmental factors on these performance measures. We then constructed a cumulative adversity index and fitted models to test the effect of this index on each performance measure. Finally, the value of cumulative adversity models was tested by comparing them to multivariate and single‐effect models in which the effect of each environmental factor was considered separately. High maternal rank decreased the AFR of daughters. Singleton and dominant cubs had higher growth rate than subordinate cubs, and singletons also had a higher survival chance to adulthood than subordinates. Daughters of prime age mothers had a higher growth rate, longevity and LRS. Little and heavy rainfall decreased survival to adulthood. Increasing numbers of lactating female clan members decreased growth rate, survival to adulthood and LRS. Cumulative adversity negatively affected short‐term performance and LRS. Multivariate models outperformed cumulative adversity and single‐effect models for all measures except for AFR and longevity, for which single‐effect models performed better. Our results suggest that in some wildlife populations the combination of specific conditions in early life may matter more than the accumulation of adverse conditions as such.
Proceedings of the 12th International Symposium on Visual Information Communication and Interaction, 2019
Recent advances in tracking technology allow biologists to collect large amounts of movement data... more Recent advances in tracking technology allow biologists to collect large amounts of movement data for a variety of species. Analysis of the collected data supports research on animal behaviour, influence of impact factors such as climate change and human intervention, as well as conservation programs. Analysis of the movement data is difficult, due to the nature of the research questions and the complexity of the data sets. It requires both automated analysis, e.g. for the detection of behavioural patterns, and human inspection, e.g. for interpretation, inclusion of previous knowledge, and for conclusions on future actions and decision making. We present a concept and implementation for the visual analysis of cheetah movement data in a web-based fashion that allows usage both in the field and in office environments.
Uploads
Papers by Heribert Hofer