Deciduous trees predominate these forests, and during the drought a leafless period occurs, which varies with species type. Because trees lose moisture though their leaves, the shedding of leaves allows trees such as teak and mountain ebony to conserve water during dry periods.
The newly bare trees open up the canopy layer, enabling sunlight to reach ground level and facilitate the growth of thick underbrush. Though less biologically diverse than rainforests, tropical dry forests are still home to a wide variety of wildlife including monkeys, large cats, parrots, various rodents, and ground dwelling birds. Many of these species display extraordinary adaptations to the difficult climate.
The most diverse dry forests in the world occur in southern Mexico and in the Bolivian lowlands1). The dry forests of the Pacific Coast of northwestern South America support a wealth of unique species due to their isolation2). The subtropical forests of Maputoland-Pondoland in southeastern Africa are diverse and support many endemics3). The dry forests of central India and Indochina are notable for their diverse large vertebrate faunas4). Dry forests of Madagascar and New Caledonia are also highly distinctive (pronounced endemism and a large number of relictual taxa) for a wide range of taxa and at higher taxonomic levels5).
Species tend to have wider ranges than moist forest species, although in some regions many species do display highly restricted ranges; most dry forest species are restricted to tropical dry forests, particularly in plants; beta diversity and alpha diversity high but typically lower than adjacent moist forests.
Large natural areas are required to maintain larger predators and other vertebrates; large areas are also needed to buffer sensitive species from hunting pressure; the persistence of riparian forests and water sources is critical for many dry forest species; periodic fires require larger blocks of intact forest to be able to aborb occassional large events.
Sensitivity to Disturbance
Dry forests are highly sensitive to excessive burning and deforestation; overgrazing and exotic species can also quickly alter natural communities; restoration is possible but challenging, particulary if degradation has been intense and persistent.
In this habitat are the following ecoregions:
(51) Madagascar Dry Forests
(60) Hawaii's Dry Forests
1) Parker et al. 1993, Bullock et al. 1996, Gentry 1996
2) Parker & Carr 1992, WWF/IUCN 1994, Bullock et al. 1996
3) Cowling & Hilton-Taylor 1994, WWF/IUCN 1994
4) Corbett & Hill 1992, Stewart & Cox 1995
5) IUCN/UNEP/WWF 1987, Preston-Mafham 1991, WWF/IUCN 1994, Wikramanayake et al. in prep.