A survey method for evaluating drought-sensitive bryophytes in fragmented forests: A bryophyte life-form based approach

摘要

Drought-sensitive bryophytes are especially vulnerable to edge effects caused by forest fragmentation. Because of increased forest fragmentation, these bryophyte species are declining and are in need of conservation. Considering that a field survey including all bryophyte species is very time consuming, methods that make identification less difficult should be tested for their usefulness in conservation. This paper describes an alternative survey method that utilizes the correlation between bryophyte life-forms and microclimates for evaluating drought-sensitive bryophytes. This survey method was examined using epiphytic bryophyte flora on tree trunks in 27 fragmented forests of Kyoto city, in the western part of Japan. The usefulness of life-forms for this evaluation was discussed based on the correlation of life-forms with species richness and microclimates. The results indicated that, while life-from richness was considered to reflect the heterogeneity of moisture availability and light intensity in bryophyte habitats, a certain life-form category (for example, fans and dendroids) seemed to correlate with drought sensitivity of bryophytes. Considering this correlation, an alternative survey method was proposed that utilizes the richness of hygrophilous life-forms. This survey method seems to be more cost-effective than a traditional all-species survey, and provides an important step toward the conservation of drought-sensitive species.