Author : Calumba, Honey Jane A.

Summary : Fieldwork was conducted on Mt. Malindang range, Misamis Occidental, Philippines from January to July 2004 in five different vegetation types (mossy, montane, almaciga, dipterocarp and agroecosystem) at elevation between 980 to 2169 meters above sea level. To investigate the distribution of land snails and assess malacofaunal diversity, the study area was sampled using a combination of timed search and visual search methods. Twenty land snails were recorded to be present on Mt. Malindang. Seven of the species collected are endemic to the Philippines, four are indigenous and two are alien species. Canonical correspondence analysis (CCA) of their local distribution in relation to environmental variables showed 79.1% variance of species abundance and distribution. Furthermore, CCA reveals that their distribution is most strongly related to vegetation type and altitude. The unexplained variance is probably related to a range of other abiotic, biotic, stochastic and scale factors. The 20 species of land snails are not uniformly distributed in the study area, indicating occurrence of ecological specialist. Majority of the snails were found to be localized with low level of abundance. Fourteen species were confined to one vegetation type while six species were found widely dispersed in different vegetation types. Species diversity, richness and endemism were found to be high in the montane forest. Results imply that special conservation of this habitat is necessary for retention of the broadest molluscan diversity. The absence of live individuals of one rare Mt. Malindang endemic species Amphidromus malindangensis and the presence of a large number of empty shells of the Philippine endemic Helicostyla crpytica further suggests that conservation of the entire Mt. Malindang forest is very important for molluscan conservation.