MEASURING INDIVIDUAL-LEVEL RESOURCE SPECIALIZATION

摘要: Many apparently generalized species are in fact composed of individual specialists that use a small subset the population's resource distribution. Niche variation is usually established by testing null hypothesis individuals draw from common This approach encourages publication bias which negative results rarely reported, and obscures degree specialization, limiting our ability to carry out comparative studies causes or consequences niche variation. To facilitate this paper outlines four quantitative indices intrapopulation use. Traditionally, such has been measured partitioning total width into within- between-individual, sex, phenotype components. We suggest two alternative measures quantify mean overlap between an its population, we discuss advantages disadvantages all measures. The utility depends on quality empirical data. If resources coarse-grained manner, may falsely appear generalized. Alternatively, specialization be overestimated cross-sectional sampling schemes where diet can reflect patchy environment. Isotope ratios, parasites, diet-morphology correlations complement data establish temporal consistency specialization.