You are not currently logged in.
Access your personal account or get JSTOR access through your library or other institution:
Disjunct performance and distribution in the sedge Carex prasina
Kathryn M. Flinn, Marcia J. Waterway and Martin J. Lechowicz
Vol. 163, No. 1 (May 2010), pp. 119-126
Stable URL: http://www.jstor.org/stable/40606651
Page Count: 8
Preview not available
Efforts to understand species distributions and predict responses to environmental changes depend on specifying how the abiotic environment determines distributions. At landscape scales, it is critical to distinguish effects of environmental factors from other mechanisms such as competition and dispersal limitation. We examined how environmental factors affect the distribution and performance of the sedge Carex prasina across a 10-km² oldgrowth forest in southern Québec. We isolated the effects of soil characteristics by conducting a greenhouse experiment that assessed the performance of C. prasina on soils from a range of wetland habitats where it could potentially occur. This allowed us to compare how the species' performance and its distribution across the landscape relate to the same soil characteristics. In the experiment, the biomass and leaf chlorophyll content of C. prasina increased with increasing soil organic matter (OM). Across the landscape, however, the species' probability of occurrence and abundance decreased with increasing soil prasina had similar biomass on soils from sites where it did and did not occur, but it had higher leaf chlorophyll content on soils from sites where it did not occur. We found no evidence that differential performance across environments determines the distribution of this species, as C. prasina tended to occur on soils where it showed reduced performance. Rather, other processes such as competition or dispersal limitation likely override any direct effects of the soil environment on distribution. Our results caution against the common assumption that the environments where a species tends to occur or be most abundant are the environments where it performs best. prasina presents a clear example of a species whose performance, at least along edaphic gradients, cannot explain its distribution. This example highlights the importance of distinguishing the relative roles of biotic and abiotic factors that shape species distributions across landscapes.
Oecologia © 2010 Springer