Leaf phenological patterns of trees, shrubs and lianas in a dry semi-deciduous forest of north-western madagascar: functional types and adaptive significance

Plant phenology was studied in the dry semi-deciduous forest of Badrala (northwestern Madagascar). All categories of litterfall collected bi-weekly in 20 traps from the beginning of one year’s to the end of the next year’s dry season were separated, identified and weighed. The quantitative database on leaf litter production by different tree, shrub and liana species was supplemented by direct bi-weekly observations of their leaf flush, flowering and fruiting. Although distributed along a continuum, leaf-shedding rhythms of 36 species, out of about 90 species identified in leaf litterfall, could be classified into four categories (early deciduous, progressively deciduous, late deciduous, and evergreen) each having significantly different responses to variations of meteorological factors. The adaptation of the phenological responses, the complementary ecological role they played and the possible responses of the forest ecosystem to future climate changes are finally discussed.