Do plant species interactions in the alpine zone? reflect abiotic gradients
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Do plant species interactions reflect abiotic gradients in the alpine zone? Simone Whitecloud Dartmouth College Abiotic gradients wind t precipitation t Abiotic gradients wind t precipitation t soil moisture t nutrients t Biotic response plant height t leaf size and shape t Biotic response plant height t leaf size and shape t species distribution t Alpine New England WIND Alpine New England WIND no snow accumulation t t snow accumulation Alpine New England WIND no snow accumulation t shorter stature plants t snow accumulation t taller stature plants t Alpine New England WIND no snow accumulation t shorter stature plants t no winter insulation t snow accumulation t taller stature plants t winter insulation t Abiotic terms stress = abiotic stress limits plants in acquire and exploit resources (Callaway 2007) t loss of existing tissue or limitation of photosynthesis (Korner 2003) t Biotic interactions facilitation plants beneļ¬t from the presence of their neighbors t nurse plants t +/+, +/0 t Biotic interactions competition reduced growth or reproduction from the presence of their neighbors t -/+, -/t Species interactions? Stress Gradient Hypothesis most stress more stress less stress less stress least stress Bertness et al. POSITIVE INTERACTIONS IN COMMUNITIES. Trends in Ecology & Evolution (1994) vol. 9 (5) pp. 191-193 Stress Gradient Hypothesis facilitation facilitation transition transition competition Bertness et al. POSITIVE INTERACTIONS IN COMMUNITIES. Trends in Ecology & Evolution (1994) vol. 9 (5) pp. 191-193 Alpine New England facilitation facilitation transition transition competition Research sites Katahdin Green Mountains White Mountains Research sites Katahdin Green Mountains White Mountains n=8 Study design WIND 20 m transects t 5 m apartt Data collection Findings 56 species t vascular plants t mosses t lichen t Diapensia lapponica Vaccinium vitis-ideae, V. uliginosum, Cetraria islandica Vaccinium vitis-ideae, V. uliginosum, Cetraria islandica PC2: + loadings on wind tolerant species PCA of Frequency is driven by wind PC1: + loadings on wind tolerant species, - loadings on plants needing shelter PC2: + loadings on wind tolerant species PCA of Frequency is driven by wind PC1: + loadings on wind tolerant species, - loadings on plants needing shelter Findings aspect effect t topographic effect t Cluster analysis of quadrats for a single PCA of Frequency is driven bypeak wind and grlowth form Cluster analysis of quadrats for a single PCA of Frequency is driven bypeak wind and grlowth form Cluster analysis of quadrats for a single PCA of Frequency is driven bypeak wind and grlowth form Cluster analysis of quadrats for a single PCA of Frequency is driven bypeak wind and grlowth form Cluster analysis of all ridge-shaped peaks Cluster analysis of all ridge-shaped peaks Cluster analysis of all ridge-shaped peaks Cluster analysis of all ridge-shaped peaks Findings community 1 community 2 community 1 community 2 pronounced cluster t community shifts t community 3 Simone Whitecloud t Dartmouth College t Future research Findings most severe less severe most severe less severe Simone Whitecloud t pronounced cluster t least severe Simone Whitecloud t Dartmouth College t Findings most severe less severe most severe less severe Simone Whitecloud t pronounced cluster t least severe Simone Whitecloud t Dartmouth College t Findings most severe less severe most severe less severe Simone Whitecloud t pronounced cluster t least severe Simone Whitecloud t Dartmouth College t Findings most severe less severe most severe less severe Simone Whitecloud t pronounced cluster t least severe Simone Whitecloud t Dartmouth College t Future research Future research
