PARENT SESSION
Tuesday, August 8, 8:00-11:30 am
COS 29 - Forest ecology I
L-3, Lobby Level, Cook Convention Center
Presiders: C Tripler and C Wayson
Species similarity decay in forest ecosystems of Europe: the role of regional heterogeneity and dispersal strategy.
Rocchini, Duccio*,1, Bacaro, Giovanni1, Heinken, Thilo2, Diekmann, Martin3, Gégout, Jean-Claude4, Chiarucci, Alessandro1, 1 University of Siena, Siena, Italy2 University of Potsdam, Potsdam, Germany3 University of Bremen, Bremen, Germany4 Ecole Nationale du Génie Rural, des Eaux et des Forêts, Nancy, France
ABSTRACT- Measuring ecosystem diversity should not, for many reasons, disregard the measure of spatial pattern. To date, efforts were made to demonstrate the effect of spatial distance on species similarity. Meanwhile, no studies have been performed at stand scale, i.e. on a finer grain. Our aim was to test the distance decay hypothesis at stand scale (i.e., at community level) for both vascular plants and bryophytes, in forest ecosystems located in different biogeographic regions. Plots of 20 m x 20 m were analysed in Central Italy, Eastern France and North Germany, considering their composition in both vascular plant and bryophyte species. Boundary line regression models were applied in order to examine the decay of maximum similarity with respect to spatial distance. Vascular plants showed a decay rate higher than bryophytes, which is explained by their different dispersal strategy. Considering both vascular plants and bryophytes the decay rate was higher for heterogeneous landscapes than for homogeneous one. It is well known that the decay of similarity in species composition arises from both (i) an increase of dissimilarity of ecological properties with distance, strictly related to regional heterogeneity, and (ii) barriers among habitats which create isolation by hampering species dispersal across landscapes. We demonstrated that distance decay of similarity describes in a straightforward manner the distribution of biological diversity over the landscape, even considering finer scales of analysis.
Key words: forest ecosystem of Europe, distance decay, boundary line regression models