Publication details
Soil matters: soil variables remarkably increase explained variation of tree beta diversity in forest dynamics plot
| Authors | |
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| Year of publication | 2013 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Variation partitioning of species composition into components explained by environmental and spatial variables is often used to identify a signature of niche- and dispersal-based processes in community assembly. Such interpretation, however, strongly depends on the quality of available environmental data. In recent studies conducted in forest dynamics plots, environment was represented only by readily available topographical variables. Using data from subtropical broad-leaved dynamics plot in Taiwan, we focus on the question whether topographical variables are sufficient to quantify environmental control imposed on vegetation, and how is it improved by including also soil variables. Our results based on variation partitioning among environmental variables and spatial descriptors (represented by PCNM axes) indicate that soil plays far more important role than topography, and that most of ecological information carried by topographical variables is redundant when soil variables are considered. To gain further insight, we introduced multiscale analysis of spatial structure not explained by environmental variables (component [c] in variation partitioning). Environmental variables are supposed to have broad-scaled spatial pattern, while dispersal processes are producing more fine-scale spatial signature in species composition, although this distinction is heavily dependent on the scale of the study. In our study, if only topography is included among explanatory variables, [c] is represented by substantial amount of broad-scaled spatial variation, indicating that yet other environmental variables were not considered. However, after including soil chemistry among explanatory variables, importance of broad-scaled spatial pattern in [c] decreased in favour of more fine-scale ones, eventually interpretable in the way that important environmental variables have been considered and what is left is signature of dispersal. We argue that topographical variables are not sufficient to reliably discern between niche- and dispersal-based processes in subtropical broad-leaved forest and that yet other variables, such as soil, need to be considered. Our results underpin the fact that interpretation of component [c] in variation partitioning as the signature of dispersal processes in community assembly is very sensitive to quality of available environmental data. |
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