The species-area relationship (SAR) is one of the most widely-studied patterns in ecology. Because of the scrutiny the SAR has received, there has been an evolution regarding several aspects of the SAR, including the best empirical formulation to describe the pattern and its application to conservation biology. One issue that is beginning to receive more attention is the idea that properties of the non-habitat portion of the landscape (the matrix) can determine the strength of the SAR. Here we ask how matrix structure influences species richness in terrestrial habitat fragments. We conducted a meta-analysis wherein we used satellite images of fragmented landscapes from published studies to generate quantitative indices for three landscape variables: matrix contrast, matrix heterogeneity, and habitat amount. We coupled z-scores from published SARs with the three landscape variables to understand how structural aspects of the landscape matrix may be contributing to the strength of the SAR in fragmented landscapes.
Results/Conclusions
We observed a significant, positive relationship between matrix contrast and z-score among all studies included in the analysis, indicating that increasing contrast between habitat and the matrix resulted in a strengthening of the species-area-relationship. This effect of matrix contrast on the SAR was particularly strong in landscapes where habitat amount did not exceed 15% of the total landscape area. Our work shows that the structural contrast between matrix and habitat may play an underappreciated role in determining the relationship between species richness and area.