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Titolo:
A mammalian predator-prey imbalance: Grizzly bear and wolf extinction affect avian neotropical migrants
Autore:
Berger, J; Stacey, PB; Bellis, L; Johnson, MP;
Indirizzi:
Wildlife Conservat Soc, Moose, WY 83012 USA Wildlife Conservat Soc Moose WY USA 83012 servat Soc, Moose, WY 83012 USA Univ Nevada, Program Ecol Evolut & Conservat Biol, Reno, NV 89512 USA UnivNevada Reno NV USA 89512 Evolut & Conservat Biol, Reno, NV 89512 USA Univ New Mexico, Dept Biol, Albuquerque, NM 87131 USA Univ New Mexico Albuquerque NM USA 87131 Biol, Albuquerque, NM 87131 USA Univ Nevada, Dept Environm & Resource Sci, Reno, NV 89512 USA Univ NevadaReno NV USA 89512 Environm & Resource Sci, Reno, NV 89512 USA
Titolo Testata:
ECOLOGICAL APPLICATIONS
fascicolo: 4, volume: 11, anno: 2001,
pagine: 947 - 960
SICI:
1051-0761(200108)11:4<947:AMPIGB>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
WESTERN UNITED-STATES; NATIONAL-PARKS; TOP-DOWN; RIPARIAN ECOSYSTEMS; NATURAL REGULATION; NORTH-AMERICA; GREAT-BASIN; TAILED DEER; ISLE-ROYALE; LONG-TERM;
Keywords:
biodiversity; conservation; extinction; Grand Teton National Park; Greater Yellowstone Ecosystem; grizzly bears; moose; neotropical migrant birds; restoration ecology; riparian vegetation; trophic cascades; wolves;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
102
Recensione:
Indirizzi per estratti:
Indirizzo: Berger, J POB 340, Moose, WY 83012 USA POB 340 Moose WY USA 83012POB 340, Moose, WY 83012 USA
Citazione:
J. Berger et al., "A mammalian predator-prey imbalance: Grizzly bear and wolf extinction affect avian neotropical migrants", ECOL APPL, 11(4), 2001, pp. 947-960

Abstract

Because most large, terrestrial mammalian predators have already been lostfrom more than 95-99% of the contiguous United States and Mexico, many ecological communities are either missing dominant selective forces or have new ones dependent upon humans. Such large-scale manipulations of a key element of most ecosystems offer unique opportunities to investigate how the loss of large carnivores affects communities, including the extent, if any, ofinteractions at different trophic levels. Here, we demonstrate a cascade of ecological events that were triggered by the local extinction of grizzly bears (Ursus arctos) and wolves (Canis lupus) from the southern Greater Yellowstone Ecosystem. These include (1) the demographic eruption of a large, semi-obligate, riparian-dependent herbivore, the moose (Alces alces), during the past 150 yr; (2) the subsequent alteration of riparian vegetation structure and density by ungulate herbivory; and (3) the coincident reduction of avian neotropical migrants in the impacted willow communities. We contrasted three sites matched hydrologically and ecologically in Grand Teton National Park, Wyoming, USA, where grizzly bears and wolves had been eliminated 60-75 yr ago and moose densities were about five times higher, with thoseon national forest lands outside the park, where predation by the two large carnivores has been replaced by human hunting and moose densities were lower. Avian species richness and nesting density varied inversely with mooseabundance, and two riparian specialists, Gray Catbirds (Dumetella carolinensis) and MacGillivray's Warblers (Oporornis tolmiei), were absent from Park riparian systems where moose densities were high. Our findings not only offer empirical support for the top-down effect of large carnivores in terrestrial communities, but also provide a scientific rationale for restorationoptions to conserve biological diversity. To predict future impacts, whether overt or subtle, of past management, and to restore biodiversity, more must be known about ecological interactions, including the role of large carnivores. Restoration options with respect to the system that we studied in the southern Greater Yellowstone Ecosystem are simple: (1) do nothing and accept the erosion of biological diversity, (2) replace natural carnivores with human predation, or (3) allow continued dispersal of grizzly bears and wolves into previously occupied, but now vacant, habitat. Although additional science is required to further our understanding of this and other terrestrial systems, a larger conservation challenge remains: to develop public support for ecologically rational conservation options.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 20:55:45