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Foundation species influence trait‐based community assembly
Author(s) -
Schöb Christian,
Butterfield Bradley J.,
Pugnaire Francisco I.
Publication year - 2012
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2012.04306.x
Subject(s) - trait , facilitation , niche , intraspecific competition , ecology , context (archaeology) , biology , range (aeronautics) , ecological niche , environmental change , climate change , habitat , neuroscience , paleontology , materials science , computer science , composite material , programming language
Summary Here, we incorporate facilitation into trait‐based community assembly theory by testing two mutually compatible facilitative mechanisms: changes in the environmental filter, causing either an increase in the range of trait values (i.e. a range expansion effect) and/or a shift in trait distributions (i.e. a range shift effect); and changes in trait spacing, suggesting an effect on niche differentiation. We analyzed the distribution of three functional traits – leaf dry matter content, specific leaf area and lateral spread – of plant communities dominated by a cushion‐forming foundation species at four sites differing in elevation and aspect. We found support for environmental filtering and niche differentiation mechanisms by cushions, with filtering effects (in particular range shifts) increasing with environmental severity at higher elevation. The effect size of cushions on trait distribution was similar to that of environmental gradients caused by elevation and aspect. The consideration of intraspecific trait variability improved the detection of cushion effects on trait distributions. Our results highlight the importance of facilitation in the modification of taxonomic and functional diversity of ecological communities, and indicate that facilitation can occur through combined effects on environmental filtering and niche differentiation, with strong environmental context dependence of each mechanism.