生態系可利用食性棲位之統計與幾何性質

Isotope niche is now commonly used in ecological studies such as niche-based community assembly dynamics. However, comparing consumer isotope niche across sites with different basal resource variation can be problematic without proper correction. This study investigates the quantitative relationship between isotope niche size of basal resources (i.e. plant isotope niche size) and that of consumers (i.e. small mammal niche size). I used isotope trophic niche of nine small mammal communities in Taiwan as the study system to test whether consumer niche size, both at population and community level, increase with plant niche size, and whether standardization of consumer values by the range of plant isotope values could remove the relationship and improve the accuracy of the comparison among consumers across sites. While small mammal niche size increased with plant niche size as expected, standardization reserved, rather than removed, the relationships. These results suggest that the standardization approach typically applied might introduce a bias of underestimating consumer niche size at sites with large basal resource variation. Future studies should perform analyses using both standardized and original consumer values for a more robust conclusion.