STRUCTURAL AND FLORISTIC TRAITS OF HABITATS WITH DIFFERING RELATIVE ABUNDANCE OF THE LEMURS MICROCEBUS MURINUS AND M. RAVELOBENSIS IN NORTHWESTERN MADAGASCAR

摘要

We analyzed the variations in several structural and floristic parameters in three habitats with differing relative abundance of two mouse lemur species, Microcebus murinus and M. ravehbensis, in order to explore possible functional links between thevegetation parameters and relative mouse lemur abundances. In the Ankarafantsika National Park the two species live in partial sympatry but occupy different parts of the forest in different relative abundances. Nine 50-m transects and nine sampling quadrats (900 m2 each) were installed for studying structural and schematic vegetation profiles and the spatial distribution of all woody plant individuals at the three sites. The lists of common plant species and plant species occurring along the profiles were compared with known lemur food plants. A cluster analysis based on 11 habitat characteristics revealed that the site with highest relative abundance of M. ravehbensis (JBB) was distinct from the two other sites (JBA/JBC). Compared with JBA/JBC, JBB comprised a relatively high forest with a higher proportion of large trees, a higher density of lianas, but a lower overall density of plant individuals. Moreover, it had lower richness in plant species and families and a floristic composition different from JBA/JBC. Finally, food plant species of both lemur species were not equally represented among the most frequent plant species. The differences in relative abundance of the two mouse lemur species may be functionally linked to structural and floristicdifferences in the vegetation, and these potential functional links are discussed. Accepted 23 October 2009.