scholarly journals Humans induce differential access to prey for large African carnivores

2020 ◽  
Author(s):  
Kirby L. Mills ◽  
Nyeema C. Harris
Keyword(s):  
Prey Selection ◽  
Diel Activity ◽  
Apex Predators ◽  
Ecological Processes ◽  
Predator Prey ◽  
Human Presence ◽  
Temporal Niche ◽  
Prey Resources ◽  
Trophic Responses ◽  
Induced Changes

AbstractWildlife adaptively respond to human presence by adjusting their temporal niche, possibly modifying encounter rates among species and trophic dynamics that structure communities. Here we show that these human-induced modifications to behaviours are prolific among species and alter apex predators’ access to prey resources. We assessed human-induced changes to wildlife diel activity and consequential changes in predator-prey overlap using 11,954 detections of three apex predators and 13 ungulates across 21,430 trap-nights in West Africa. Over two-thirds of species altered their diel use in response to human presence, and ungulate nocturnal activity increased by 6.8%. Rather than traditional pairwise predator-prey comparisons, we considered spatiotemporally explicit predator access to a suite of prey resources to evaluate community-level trophic responses to human presence. Although leopard prey access was not affected, lion and hyena access to 3 prey species significantly increased when prey increased their nocturnal temporal niche to avoid humans. Ultimately, humans considerably altered the composition of available prey, with implications for prey selection, demonstrating how humans perturb ecological processes via behavioural modifications.

scholarly journals Humans disrupt access to prey for large African carnivores

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Kirby L Mills ◽  
Nyeema C Harris
Keyword(s):  
Prey Species ◽  
Prey Selection ◽  
Diel Activity ◽  
Spotted Hyena ◽  
Nocturnal Activity ◽  
Ecological Processes ◽  
Predator Prey ◽  
Human Presence ◽  
Prey Resources ◽  
Trophic Responses

Wildlife respond to human presence by adjusting their temporal niche, possibly modifying encounter rates among species and trophic dynamics that structure communities. We assessed wildlife diel activity responses to human presence and consequential changes in predator-prey overlap using 11,111 detections of 3 large carnivores and 11 ungulates across 21,430 camera trap-nights in West Africa. Over two-thirds of species exhibited diel responses to mainly diurnal human presence, with ungulate nocturnal activity increasing by 7.1%. Rather than traditional pairwise predator-prey diel comparisons, we considered spatiotemporally explicit predator access to several prey resources to evaluate community-level trophic responses to human presence. Although leopard prey access was not affected by humans, lion and spotted hyena access to three prey species significantly increased when prey increased their nocturnal activity to avoid humans. Human presence considerably influenced the composition of available prey, with implications for prey selection, demonstrating how humans perturb ecological processes via behavioral modifications.

State-shifts of lion prey selection in the Kruger National Park

2017 ◽  
Vol 44 (1) ◽  
pp. 28 ◽  
Author(s):  
N. T. Maruping-Mzileni ◽  
P. J. Funston ◽  
S. M. Ferreira
Keyword(s):  
National Park ◽  
Prey Selection ◽  
Management Strategies ◽  
Stable State ◽  
Kruger National Park ◽  
Ecological Processes ◽  
Policy Makers ◽  
Predator Prey ◽  
Key Indicator ◽  
Management Interventions

Aims Indicators of pending state-shifts carry value for policy makers. Predator–prey relations reflect key ecological processes that shape ecosystems. Variance in predator–prey relations may serve as a key indicator of future state-shifts. Methods Lion (Panthera leo) diet in the Kruger National Park was evaluated as such an indicator. Over the three-decade time span reviewed, variance in diet in relation to rainfall, prey abundance, management strategies and disease emergence were reviewed. Key results Rainfall patterns, both seasonal and cyclical, were identified as key drivers of predator–prey selection. However, the intensity of management in the form of artificial waterpoints overrode and confounded natural process. The results suggest that savanna systems are stable and punctuated by climatic events in the form of extreme above-average rainfall that temporarily destabilises the system. However, droughts are a cyclical part of the savanna system. Conclusion Lion prey selection did fluctuate with changing environmental conditions. Abrupt state shifts did occur; however, the ecosystem returned to a stable state. Implications State shifts in ecosystems pose key challenges to conservation managers. State shifts appear to be primarily associated with management interventions and environmental factors.

Kalahari Cheetahs

2017 ◽  
Author(s):  
Gus Mills ◽  
Margaret Mills
Keyword(s):  
Reproductive Success ◽  
Spatial Ecology ◽  
Prey Selection ◽  
Arid Ecosystems ◽  
Foraging Success ◽  
Ecological Processes ◽  
Demographic Groups ◽  
Important Prey ◽  
Hunting Behaviour ◽  
The Impact

This book demonstrates how cheetahs are adapted to arid savannahs like the southern Kalahari, and makes comparisons with other areas, especially the Serengeti. Topics dealt with are: demography and genetic status; feeding ecology, i.e. methods used for studying diet, diets of different demographic groups, individual diet specializations of females, prey selection, the impact of cheetah predation on prey populations, activity regimes and distances travelled per day, hunting behaviour, foraging success and energetics; interspecific competition; spatial ecology; reproductive success and the mating system; and conservation. The major findings show that cheetahs are well adapted to arid ecosystems and are water independent. Cheetah density in the study area was stable at 0.7/100 km2 and the population was genetically diverse. Important prey were steenbok and springbok for females with cubs, gemsbok, and adult ostrich for coalition males, and steenbok, springhares, and hares for single animals. Cheetahs had a density-dependent regulatory effect on steenbok and springbok populations. Females with large cubs had the highest overall food intake. Cheetahs, especially males, were often active at night, and competition with other large carnivores, both by exploitation and interference, was slight. Although predation on small cubs was severe, cub survival to adolescence was six times higher than in the Serengeti. There was no difference in reproductive success between single and coalition males. The conservation priority for cheetahs should be to maintain protected areas over a spectrum of landscapes to allow ecological processes, of which the cheetah is an integral part, to proceed unhindered.

scholarly journals Long-term UVB exposure promotes predator-inspection behaviour in a fish

2017 ◽  
Vol 13 (12) ◽  
pp. 20170497 ◽  
Author(s):  
Simon Vitt ◽  
Janina E. Zierul ◽  
Theo C. M. Bakker ◽  
Ingolf P. Rick
Keyword(s):  
Gasterosteus Aculeatus ◽  
Stratospheric Ozone ◽  
Ultraviolet B ◽  
Antipredator Behaviour ◽  
Uvb Radiation ◽  
Ecological Processes ◽  
Predator Prey ◽  
Natural Sunlight ◽  
Predator Inspection

Ultraviolet-B radiation (UVB) reaching the earth's surface has increased due to human-caused stratospheric ozone depletion. Whereas the harmful effects of UVB on aquatic organisms are well studied at the molecular and cellular level, recent studies have also begun to address behavioural changes caused by sublethal amounts of UVB. However, the behavioural consequences of long-term exposure to ecologically relevant UVB levels over several life stages are virtually unknown, particularly with regard to predator–prey behaviour. We found increased predator-inspection behaviour together with a smaller body length in three-spined sticklebacks ( Gasterosteus aculeatus ) after fish were exposed for about seven months to natural sunlight conditions with enhanced UVB, compared with full siblings exposed to natural sunlight only. The observed change in antipredator behaviour may reflect a direct behavioural response mediated through UVB-induced oxidative stress during development. Alternatively, the smaller body size in UVB-exposed fish may result in an increased inspection effort allowing them to spend more time foraging. Our findings suggest that, within the scope of environmental change, UVB radiation constitutes an important stress factor by eliciting behavioural responses that influence crucial ecological processes, such as predator–prey interactions.

scholarly journals Effects of a New Pedestrian Pathway in Grand Teton National Park on Breeding Sagebrush Songbirds

2008 ◽  
Vol 31 ◽  
pp. 3-7
Author(s):  
Anna Chalfoun
Keyword(s):  
Perceived Risk ◽  
Breeding Habitat ◽  
Energy Budgets ◽  
Human Presence ◽  
Wildlife Species ◽  
Fitness Consequences ◽  
Risk Of Predation ◽  
Natural Landscapes ◽  
Wildlife Populations ◽  
Induced Changes

Human-induced changes to natural landscapes have become ubiquitous, resulting in exposure of wildlife populations to novel stressors (Munns 2006). While it is clear that changes such as habitat loss can directly impact wildlife species, less clear is the extent to which human presence itself functions as a disturbance that influences wildlife behaviors with important fitness consequences. Animals clearly respond to perceived risk of predation by natural predators via, for example, fleeing, or altering foraging and/or breeding habitat selection (Marzluff 1988, Hakkarainen et al. 2001, Frid and Dill2002, Blumstein 2006, Borkowski et al. 2006, Fontaine and Martin 2006). Such responses can alter access to important resources, energy budgets, and therefore attributes such as body condition (Bechet et al. 2004) with potential impacts to survival and reproductive output. Of critical importance to the management of wildlife populations is therefore to determine 1) whether wildlife species perceive human presence as predation risk, 2) how individuals respond to such risk, and 3) how such responses influence fitness consequences and therefore population dynamics and community structure.

Prey Selection, Vertical Migrations and the Impacts of Harvesting Upon the Population Dynamics of a Predator-Prey System

2007 ◽  
Vol 69 (6) ◽  
pp. 1827-1846 ◽  
Author(s):  
Helen J. Edwards ◽  
Calvin Dytham ◽  
Jonathan W. Pitchford ◽  
David Righton
Keyword(s):  
Population Dynamics ◽  
Prey Selection ◽  
Predator Prey ◽  
Prey System

Rewilding

Ecology ◽  
2019 ◽  
Author(s):  
Meredith Root-Bernstein
Keyword(s):  
The United States ◽  
Large Species ◽  
Large Carnivores ◽  
Apex Predators ◽  
Ecological Processes ◽  
Large Herbivore ◽  
Large Herbivores ◽  
True Nature ◽  
The Public ◽  
Wide Range

Rewilding is an increasingly recognized approach to conservation and restoration, among academics, land managers, and the public. Although a number of different definitions have been proposed for rewilding (see Definitions of Rewilding), most approaches called “rewilding” include ideas about restoring a habitat to a less-anthropogenic state, restoring ecological processes and allowing them to take their own course without managing for a target ecosystem condition and (re)-introducing missing (usually large) species as a way to restore those ecological processes. Conceptualizations of rewilding and actual rewilding projects draw on a wide range of cultural and ecological ideas and practical knowledge, which are detailed in this article. Several organizations now represent rewilding interests to policymakers and the public and set up or facilitate rewilding initiatives in Europe and the Americas. Much of their philosophies, practice, data, and outcomes are not published. The Wildland Research Institute is an influential source of research on wilderness mapping, rewilding, restoration, and policy analysis in Europe. The European Centre for Nature Conservation (ECNC) supports and facilitates the conservation of large herbivore populations and their habitats at large scales in Eurasia through its Large Herbivore Network. Rewilding Europe implements rewilding projects throughout Europe, bringing together financing for large herbivore reintroductions and luxury wilderness tourism. Their European Rewilding Network brings together rewilding-related services and knowledge exchange. Similarly, the True Nature Foundation is a European foundation that works to restore habitats, reintroduce primarily large herbivores, and create sustainable tourism in nature areas. Wild Europe seeks to promote and lobby for the protection of large, “wild” natural areas. Similarly, the European Wilderness Society is an advocacy organization that identifies and promotes the stewardship and protection of large wilderness areas. The Rewilding Foundation is an international organization promoting and working toward the conservation of large areas of habitat and corridors for large carnivores. The Wildlands Network is an American organization that similarly seeks to conserve and connect large habitat areas and reintroduce apex predators. The Rewilding Institute in the United States also promotes protecting large habitats and creating corridors for large carnivores. There are also numerous site-based rewilding projects, which largely preceded the consolidation of rewilding as a concept. Many of these, through their creative rethinking of ecological and paleo-ecological orthodoxy, have influenced the development of rewilding practice and theory.

Marine Parasites and Disease in the Era of Global Climate Change

2021 ◽  
Vol 13 (1) ◽  
pp. 397-420
Author(s):  
James E. Byers
Keyword(s):  
Climate Change ◽  
Current Knowledge ◽  
Global Climate ◽  
Ecological Communities ◽  
Vital Rates ◽  
Ecological Processes ◽  
Performance Curves ◽  
Temperature Climate ◽  
Induced Changes ◽  
Host Parasite

Climate change affects ecological processes and interactions, including parasitism. Because parasites are natural components of ecological systems, as well as agents of outbreak and disease-induced mortality, it is important to summarize current knowledge of the sensitivity of parasites to climate and identify how to better predict their responses to it. This need is particularly great in marine systems, where the responses of parasites to climate variables are less well studied than those in other biomes. As examples of climate's influence on parasitism increase, they enable generalizations of expected responses as well as insight into useful study approaches, such as thermal performance curves that compare the vital rates of hosts and parasites when exposed to several temperatures across a gradient. For parasites not killed by rising temperatures, some simple physiological rules, including the tendency of temperature to increase the metabolism of ectotherms and increase oxygen stress on hosts, suggest that parasites’ intensity and pathologies might increase. In addition to temperature, climate-induced changes in dissolved oxygen, ocean acidity, salinity, and host and parasite distributions also affect parasitism and disease, but these factors are much less studied. Finally, because parasites are constituents of ecological communities, we must consider indirect and secondary effects stemming from climate-induced changes in host–parasite interactions, which may not be evident if these interactions are studied in isolation.

Negative frequency-dependent prey selection by wolves and its implications on predator–prey dynamics

2021 ◽  
Vol 179 ◽  
pp. 247-265
Author(s):  
Sarah R. Hoy ◽  
Daniel R. MacNulty ◽  
Matthew C. Metz ◽  
Douglas W. Smith ◽  
Daniel R. Stahler ◽  
...  
Keyword(s):  
Prey Selection ◽  
Frequency Dependent ◽  
Predator Prey

Prey Selection by Freshwater Predators with Different Foraging Strategies

1985 ◽  
Vol 42 (11) ◽  
pp. 1720-1732 ◽  
Author(s):  
Scott D. Cooper ◽  
Daniel W. Smith ◽  
James R. Bence
Keyword(s):  
Prey Selection ◽  
Foraging Strategies ◽  
Foraging Mode ◽  
Encounter Rates ◽  
Predator Prey ◽  
Anax Junius ◽  
Odonate Larvae ◽  
Selection For ◽  
Predator Foraging ◽  
Pachydiplax Longipennis

We observed several freshwater predators, including the odonate larvae Pachydiplax longipennis and Anax junius, the hemipterans Notonecta unifasciata and Buenoa scimitra, the dytiscid larva Acilius semisulcatus, and juvenile Gambusia affinis, feeding on a variety of microcrustacean prey and determined the frequency of the component parts of predator–prey interactions (encounter, attack, capture, ingestion). Encounter rates were the most important determinant of predator selectivity when predators were presented with a variety of microcrustacean prey. When only copepod species were used as prey, however, both encounter rates and capture success were important in determining predator diets. We used our data to test hypotheses concerning relationships between predator foraging mode and patterns of prey selection: mobile predators exhibited stronger selection for sedentary prey than did sit-and-wait predators; our own and literature data also indicated that macroinvertebrate sit-and-wait predators are better able to capture, and have higher selectivity for evasive prey than do mobile predators. A predator's attack acceleration, however, may be a better predictor of its selectivity for evasive versus nonevasive prey than its mean swimming speed.

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