Effect of 'species weighting' on conservation status evaluation: a case study with light-traped adult caddisflies (Insecta: Trichoptera)

摘要

Wildlife conservation requires methods to express the conservation status of assemblages in order to identify those of importance. Expressions of diversity and a number of different conservation status indices are widely used techniques for assessing assemblages. Some of these indices are based on species lists, while others use abundances. In this study, the conservation statuses of 21 light-traped adult caddisfly assemblages were compared using species lists and abundance data. The results showed that the assessment based on species list provided a higher conservation status than that based on species abundances. Consequently, indices incorporating species abundances were not comparable with indices using only species lists. The difference between the two measures might be derived from the unequal weighting of species categories. In conclusion, incorporating species abundance reduces sampling method bias and increases the precision of the conservation status evaluation.