scholarly journals Table scraps: inter-trophic food provisioning by pumas

2012 ◽  
Vol 8 (5) ◽  
pp. 776-779 ◽  
Author(s):  
L. Mark Elbroch ◽  
Heiko U. Wittmer

Large carnivores perform keystone ecological functions through direct predation, or indirectly, through food subsidies to scavengers or trophic cascades driven by their influence on the distributions of their prey. Pumas ( Puma concolor ) are an elusive, cryptic species difficult to study and little is known about their inter-trophic-level interactions in natural communities. Using new GPS technology, we discovered that pumas in Patagonia provided 232 ± 31 kg of edible meat/month/100 km 2 to near-threatened Andean condors ( Vultur gryphus ) and other members of a diverse scavenger community. This is up to 3.1 times the contributions by wolves ( Canis lupus ) to communities in Yellowstone National Park, USA, and highlights the keystone role large, solitary felids play in natural systems. These findings are more pertinent than ever, for managers increasingly advocate controlling pumas and other large felids to bolster prey populations and mitigate concerns over human and livestock safety, without a full understanding of the potential ecological consequences of their actions.

2012 ◽  
Vol 90 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Brian J. Miller ◽  
Henry J. Harlow ◽  
Tyler S. Harlow ◽  
Dean Biggins ◽  
William J. Ripple

When large carnivores are extirpated from ecosystems that evolved with apex predators, these systems can change at the herbivore and plant trophic levels. Such changes across trophic levels are called cascading effects and they are very important to conservation. Studies on the effects of reintroduced wolves in Yellowstone National Park have examined the interaction pathway of wolves ( Canis lupus L., 1758) to ungulates to plants. This study examines the interaction effects of wolves to coyotes to rodents (reversing mesopredator release in the absence of wolves). Coyotes ( Canis latrans Say, 1823) generally avoided areas near a wolf den. However, when in the proximity of a den, they used woody habitats (pine or sage) compared with herbaceous habitats (grass or forb or sedge)– when they were away from the wolf den. Our data suggested a significant increase in rodent numbers, particularly voles (genus Microtus Schrank, 1798), during the 3-year study on plots that were within 3 km of the wolf den, but we did not detect a significant change in rodent numbers over time for more distant plots. Predation by coyotes may have depressed numbers of small mammals in areas away from the wolf den. These factors indicate a top–down effect by wolves on coyotes and subsequently on the rodents of the area. Restoration of wolves could be a powerful tool for regulating predation at lower trophic levels.


2008 ◽  
Vol 122 (1) ◽  
pp. 76 ◽  
Author(s):  
Michael D. Jimenez ◽  
Valpa J. Asher ◽  
Carita Bergman ◽  
Edward E. Bangs ◽  
Susannah P. Woodruff

Four cases where large predators caused Grey Wolf (Canis lupus) mortality are recorded. We describe two incidents of Cougars (Puma concolar) killing Wolves in Montana and one incident of a Cougar killing a Wolf in Alberta. We report the first recorded incident of a Grizzly Bear (Ursus arctos) killing a Wolf in the western United States.


2021 ◽  
pp. 145-170
Author(s):  
Karen D. McCoy

An ecological community includes all individuals of all species that interact within a single patch or local area of habitat. Understanding the outcome of host–parasite interactions and predicting disease dynamics is particularly challenging at this biological scale because the different component species interact both directly and indirectly in complex ways. Current shifts in biodiversity due to global change, and its associated modifications to biological communities, will alter these interactions, including the probability of disease emergence, its dynamics over time, and its community-level consequences. Birds are integral component species of almost all natural communities. Due to their ubiquity and specific life history traits, they are defining actors in the ecology, evolution, and epidemiology of parasitic species. To better understand this role, this chapter examines the relative importance of birds and parasites in natural communities, revisiting basic notions in community ecology. The impact of changes in diversity for disease dynamics, including the debate surrounding dilution and amplification effects are specifically addressed. By considering the intrinsic complexities of natural communities, the importance of combining data from host and parasite communities to better understand how natural systems function over time and space is highlighted. The different elements in each section of the chapter are illustrated with brief, concrete examples from avian species, with a detailed example from marine bird communities in which Lyme disease bacteria circulate.


2011 ◽  
Vol 279 (1730) ◽  
pp. 910-915 ◽  
Author(s):  
Olof Liberg ◽  
Guillaume Chapron ◽  
Petter Wabakken ◽  
Hans Christian Pedersen ◽  
N. Thompson Hobbs ◽  
...  

Poaching is a widespread and well-appreciated problem for the conservation of many threatened species. Because poaching is illegal, there is strong incentive for poachers to conceal their activities, and consequently, little data on the effects of poaching on population dynamics are available. Quantifying poaching mortality should be a required knowledge when developing conservation plans for endangered species but is hampered by methodological challenges. We show that rigorous estimates of the effects of poaching relative to other sources of mortality can be obtained with a hierarchical state–space model combined with multiple sources of data. Using the Scandinavian wolf ( Canis lupus ) population as an illustrative example, we show that poaching accounted for approximately half of total mortality and more than two-thirds of total poaching remained undetected by conventional methods, a source of mortality we term as ‘cryptic poaching’. Our simulations suggest that without poaching during the past decade, the population would have been almost four times as large in 2009. Such a severe impact of poaching on population recovery may be widespread among large carnivores. We believe that conservation strategies for large carnivores considering only observed data may not be adequate and should be revised by including and quantifying cryptic poaching.


2003 ◽  
Vol 81 (6) ◽  
pp. 985-993 ◽  
Author(s):  
T Adam Switalski

Coyotes (Canis latrans) in Yellowstone National Park (YNP) have lived in the absence of wolves (Canis lupus) for over 60 years. I examined whether wolf reintroduction in 1995 and 1996 in YNP influenced coyote vigilance and foraging ecology. From December 1997 to July 2000, my co-workers and I collected 1708 h of coyote activity budgets. Once wolves became established in the Park, they once again provided a continuous source of carrion in the Lamar Valley and we found that coyotes began feeding on carcasses throughout the year. Although we documented that wolves killed coyotes, it also became clear that surviving coyotes quickly adjusted their behaviors when wolves were present. When coyotes were near wolves or in areas of high wolf use, they fed on carcasses much more; however, they increased the amount of time spent in vigilance activities and decreased rest. There appears to be a trade-off in which wolf kills provide a quick source of food that is energetically advantageous to coyotes; however, attendant costs included increased vigilance, decreased rest, and a higher risk of being killed. Changes in the behavior of coyotes in response to the reintroduction of this large carnivore may ultimately have wide-ranging cascading effects throughout the ecosystem.


2018 ◽  
Vol 131 (3) ◽  
pp. 252-253
Author(s):  
Thomas D. Gable ◽  
Steve K. Windels ◽  
Ian C. Rautio

Few accounts exist of Gray Wolves (Canis lupus) killing small sympatric mammalian predators. In January 2017, we observed a River Otter (Lontra canadensis) that had been killed by wolves on the ice in Voyageurs National Park, Minnesota. This is one of only a few documented instances of wolves killing otters.


1991 ◽  
Vol 18 (2) ◽  
pp. 119-130 ◽  
Author(s):  
David H.L. Thomas ◽  
Fethi Ayache ◽  
G. Edward Hollis

Non-use existence values are now widely considered to be an important justification for conservation in developed countries. Using the same approach to promote conservation in less-developed and developing countries, with their normally severe economic and social problems, is often wholly inappropriate, as existence values in less-developed and developing countries are usually very small. Conservation on grounds of ethics and aesthetics is a luxury which many of those latter countries do not feel able to afford, or often genuinely cannot.The establishment of the Ichkeul National Park in northern Tunisia was based primarily on non-use, existence values, but the survival of its wetlands is now threatened by a programme of dam construction. However, the Lake and marshes of Ichkeul have a number of important values and functions. These include livestock grazing on the marshes, the Lake's fisheries, the existing and potential value of the Park as a tourist resource, the role of the rivers in water-table recharge, and the function of the marshes in the ‘free’ treatment of sewage and purification of water. It can be shown that the economic gains from taking measures to prevent degradation of the wetland, namely by releases of water from the dams to maintain the marshes, would outweigh the economic benefits from the use of water in agricultural irrigation, and effectively maintain much of the international significance of the National Park and its surroundings.It is suggested that promotion of conservation in lessdeveloped countries is likely to meet with much greater success if economic arguments, based on a site's usevalues, are given priority in the approach of conservation organizations from developed countries. The significance of non-use values to nationals of the less-developed and many developing countries is still very minor, although, as their living standards improve, such prospects are likely to improve also. In many instances at least, by raising due awareness of the economic use-values of natural systems, it will be possible to provide a good case for a site's conservation.


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