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Titolo:
Measuring the ghost of competition: Insights from density-dependent habitat selection on the co-existence and dynamics of lemmings
Autore:
Morris, DW; Davidson, DL; Krebs, CJ;
Indirizzi:
Lakehead Univ, Dept Biol, Thunder Bay, ON P7B 5E1, Canada Lakehead Univ Thunder Bay ON Canada P7B 5E1 under Bay, ON P7B 5E1, Canada Lakehead Univ, Fac Forestry & Forest Environm, Thunder Bay, ON P7B 5E1, Canada Lakehead Univ Thunder Bay ON Canada P7B 5E1 under Bay, ON P7B 5E1, Canada Univ British Columbia, Dept Zool, Vancouver, BC V6T 1Z4, Canada Univ British Columbia Vancouver BC Canada V6T 1Z4 ver, BC V6T 1Z4, Canada
Titolo Testata:
EVOLUTIONARY ECOLOGY RESEARCH
fascicolo: 1, volume: 2, anno: 2000,
pagine: 41 - 67
SICI:
1522-0613(200001)2:1<41:MTGOCI>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
APPARENT COMPETITION; DICROSTONYX-GROENLANDICUS; NUTRITIONAL ECOLOGY; POPULATION-DYNAMICS; MICROTINE RODENTS; LEMMUS-SIBIRICUS; GERBIL ISOCLINE; DIET SELECTION; COMMUNITIES; ALASKA;
Keywords:
Arctic; co-existence; competition; density dependence; ghost of competition; habitat selection; isocline; isodar; isoleg; lemming;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
56
Recensione:
Indirizzi per estratti:
Indirizzo: Morris, DW Lakehead Univ, Dept Biol, Thunder Bay, ON P7B 5E1, Canada Lakehead Univ Thunder Bay ON Canada P7B 5E1 ON P7B 5E1, Canada
Citazione:
D.W. Morris et al., "Measuring the ghost of competition: Insights from density-dependent habitat selection on the co-existence and dynamics of lemmings", EVOL EC RES, 2(1), 2000, pp. 41-67

Abstract

When interspecific competitors resolve their co-existence by habitat segregation, their competition might, like a ghost, be invisible because the species occupy separate habitats. Population fluctuations should often bring the species into competition in jointly occupied habitats where their competition can be measured by habitat isodars (lines or planes of density where the expected fitness of individuals is the same in all occupied habitats). We tested the theory by calculating isodars for two species of lemmings with distinct habitat preferences When population densities are high, both habitats are occupied by both species But as densities decline, habitat isodars suggest that the joint dynamics of each species pass through a region where each occupies a separate habitat (the ghost of competition). the competition was asymmetrical. The density of collared lemmings in their preferred habitat was reduced as the density of brown lemmings increased in the same habitat. But collared lemmings had no direct competitive effect on brown lemmings. The interspecific effect from brown lemmings was comparable to - possibly even in excess of - intraspecific competition for habitat. The asymmetric competition for habitat yields spectacular new kinds of isolegs categorizing habitat competition between co-existing species. Although current evidence implicates competition, the patterns are also consistent with apparent competition driven by specialized predators. Regardless of whether lemming habitat use reflects true or apparent competition, the associated density dependent differences in habitat preference are likely to have major consequences for the nonstable dynamics of lemmings and non-linear lemming isoclines.

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Documento generato il 02/12/20 alle ore 05:03:31