Sammanfattning

Assuming better colonization abilities of inferior competitors, the competition-colonization trade-off (CCTO) is one of the hypotheses that explains spatial variation of species composition in fragmented habitats. Whereas this mechanism may structure some plant and insect communities, ecologists have failed to document its operation in other natural systems, and its generality has been questioned. We combined fieldwork and published data to study the composition of a guild of passerines (Parus cristatus, Parus montanus, Parus ater and Regulus regulus) inhabiting 10 landscapes that differed in the amount of forest habitat. The species were ordered in a stable, well-defined competitive hierarchy, and the dispersal ability of each species was inversely correlated with its position in this hierarchy. In functionally continuous landscapes, superior competitors occupied most fragments and all guild members commonly occurred. The relative incidences of superior and inferior competitors were reversed, and differences amplified, in landscapes where patches were physically (distance) or functionally (matrix hardness) isolated. We found little support for two competing hypotheses, namely reduced habitat quality in isolated patches and lower abundance of a keystone predator (Glaucidium passerinum) in fragmented landscapes. We concluded that the CCTO offered the most probable explanation for variation in the composition of the Parus guild across landscapes

Publicerad i

Proceedings of the Royal Society B: Biological Sciences
2007, Volym: 274, nummer: 1616, sidor: 1403-1411
Utgivare: ROYAL SOCIETY

SLU författare

• Jansson, Gunnar

  • Institutionen för naturvårdsbiologi, Sveriges lantbruksuniversitet
    

• Andren, Henrik

  • Institutionen för naturvårdsbiologi, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Miljö- och naturvårdsvetenskap


Publikationens identifierare

DOI: https://doi.org/10.1098/rspb.2007.0104

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/15288