Re: Nützlichkeit des Wolfs
Verfasst: 16. Mär 2019, 17:44
.... Für alle anderen Gelegenheitsleser: Grundsätzliches, das man zur Ökologie von stark anthropogen geprägten Landschaften geblättert haben sollte.
Dorresteijn et al. (2015): Incorporating anthropogenic effects into trophic ecology: predator–prey interactions in a human-dominated landscape. DOI: 10.1098/rspb.2015.1602.
Excerpt (Conclusion)
Kommentare zur Studie von Dorresteijn et al. (2015) und kritische Stimmen:
Kuijper et al.(2016): Multi-trophic interactions in anthropogenic landscapes: the devil is in the detail. DOI: 10.1098/rspb.2015.2375.
Excerpt
Kuijper et al. (2016): Paws without claws? Ecological effects of large carnivores in anthropogenic landscapes. DOI: 10.1098/rspb.2016.1625.
Abstract
Außerdem:
Dorresteijn et al. (2014): Human-carnivore coexistence in a traditional rural landscape. DOI: 10.1007/s10980-014-0048-5.
Abstract
Llaneza et al. (2016): Resting in risky environments: the importance of cover for wolves to cope with exposure risk in human-dominated landscapes. DOI: 10.1007/s10531-016-1134-6.
Abstract
Dorresteijn et al. (2015): Incorporating anthropogenic effects into trophic ecology: predator–prey interactions in a human-dominated landscape. DOI: 10.1098/rspb.2015.1602.
Excerpt (Conclusion)
To date, ecological theory on trophic cascades has not explicitly included human effects, despite humanity’s pervasive impacts on the globe [7]. Our study adds to a growing recognition that humans play vital roles in influencing ecosystems through mediating and altering trophic cascades, as well as through direct landscape modification. Apex predators maintained their ecological role by suppressing lower trophic levels in a human-dominated landscape, but the combined direct and indirect anthropogenic top-down effects dominated over natural processes. Improving our understanding of human impacts on trophic cascades in human-dominated landscapes is especially important because apex predators are declining rapidly in much of the world, but, just as importantly, they are also being encouraged to recover and are being reintroduced to other areas. There are ample possibilities for restoring ecosystems through rewilding efforts or carnivore reintroduction programmes, but, especially in this context, it is important to anticipate the implications of simultaneous effects of humans and apex predators on multiple trophic levels. Given the extent and speed of global anthropogenic environmental change, elucidating how humans directly and indirectly alter bottom-up and top-down processes should receive increased consideration by future studies.
Kommentare zur Studie von Dorresteijn et al. (2015) und kritische Stimmen:
Kuijper et al.(2016): Multi-trophic interactions in anthropogenic landscapes: the devil is in the detail. DOI: 10.1098/rspb.2015.2375.
Excerpt
We applaud Dorresteijn et al. [1] for highlighting that ecological effects of large carnivores may be quite different in human-modified landscapes. Unfortunately, we feel that there are crucial flaws with their study design, analyses and interpretation. These flaws seriously undermine the strong conclusions that they draw about the role of topdown and bottom-up processes in anthropogenic landscapes. Our main concerns include (i) lack of relevant bottom-up data, (ii) a camera trap design unsuitable for testing their hypotheses regarding community structure, and (iii) top-down and bottom-up processes that are studied at an inappropriate spatial scale.
Kuijper et al. (2016): Paws without claws? Ecological effects of large carnivores in anthropogenic landscapes. DOI: 10.1098/rspb.2016.1625.
Abstract
Large carnivores are frequently presented as saviours of biodiversity and ecosystem functioning through their creation of trophic cascades, an idea largely based on studies coming primarily out of relatively natural landscapes. However, in large parts of the world, particularly in Europe, large carnivores live in and are returning to strongly human-modified ecosystems. At present, we lack a coherent framework to predict the effects of large carnivores in these anthropogenic landscapes. We review how human actions influence the ecological roles of large carnivores by affecting their density or behaviour or those of mesopredators or prey species. We argue that the potential for density-mediated trophic cascades in anthropogenic landscapes is limited to unproductive areas where even low carnivore numbers may impact prey densities or to the limited parts of the landscape where carnivores are allowed to reach ecologically functional densities. The potential for behaviourally mediated trophic cascades may be larger and more widespread, because even low carnivore densities affect prey behaviour. We conclude that predator–prey interactions in anthropogenic landscapes will be highly context-dependent and human actions will often attenuate the ecological effects of large carnivores. We highlight the knowledge gaps and outline a new research avenue to study the role of carnivores in anthropogenic landscapes.
Außerdem:
Dorresteijn et al. (2014): Human-carnivore coexistence in a traditional rural landscape. DOI: 10.1007/s10980-014-0048-5.
Abstract
Facilitating human-carnivore coexistence is a major conservation concern in human-dominated landscapes worldwide. Useful insights could be gained by studying and understanding the dynamics of human-carnivore coexistence in landscapes in which carnivores and humans have coexisted for a long time. We used a two-pronged approach combining ecological and social data to study coexistence of the brown bear (Ursus arctos) and humans in Transylvania, Romania. First, we surveyed 554 km of walking transects to estimate activity via a bear sign index, namely the proportion of anthills disturbed by bears, and used spatially explicit predictive models to test which biophysical and anthropogenic variables influenced bear activity. Second, we interviewed 86 shepherds and 359 villagers and community representatives to assess conflicts with bears and attitudes of shepherds towards bears. Our interdisciplinary study showed that bears and humans coexisted relatively peacefully despite occasional conflicts. Coexistence appeared to be facilitated by: (1) the availability of large forest blocks that are connected to the source population of bears in the Carpathian Mountains; (2) the use of traditional livestock management to minimize damage from bears; and (3) some tolerance among shepherds to occasional conflict with bears. In contrast, bear activity was unrelated to human settlements, and compensation for livestock losses did not influence people’s attitudes toward bears. Our study shows that coexistence of humans and carnivores is possible, even without direct economic incentives. A key challenge for settings with a discontinuous history of human-carnivore coexistence is to reinstate both practices and attitudes that facilitate coexistence.
Llaneza et al. (2016): Resting in risky environments: the importance of cover for wolves to cope with exposure risk in human-dominated landscapes. DOI: 10.1007/s10531-016-1134-6.
Abstract
Centuries of persecution have influenced the behaviour of large carnivores. For those populations persisting in human-dominated landscapes, complete spatial segregation from humans is not always possible, as they are in close contact with people even when they are resting. The selection of resting sites is expected to be critical for large carnivore persistence in human-dominated landscapes, where resting sites must offer protection to counteract exposure risk. Using wolves (Canis lupus) as a model species, we hypothesised that selection of resting sites by large carnivores in human-dominated landscapes will be not only influenced by human activities, but also strongly determined by cover providing concealment. We studied the fine-scale attributes of 546 wolf resting sites and confronted them to 571 random points in NW Iberia. Half of resting sites (50.8 %) were found in forests (mainly forest plantations, 73.1 %), 43.4 % in scrublands, and only 5.8 % in croplands. Compared to random points, wolves located their resting sites far away from paved and large unpaved roads and from settlements, whereas they significantly selected areas with high availability of horizontal (refuge) and canopy cover. The importance of refuge was remarkably high, with its independent contribution alone being more important than the contribution of all the variables related to human pressure (distances) pooled (51.1 vs 42.8 %, respectively). The strength of refuge selection allowed wolves even to rest relatively close to manmade structures, such as roads and settlements (sometimes less than 200 m). Maintaining high-quality refuge areas becomes an important element to favour the persistence of large carnivores in human-dominated landscapes as well as human-carnivore coexistence, which can easily be integrated in landscape planning.