Thetropical and subtropical dry broadleaf forest is ahabitat type defined by theWorld Wide Fund for Nature and is located at tropical and subtropical latitudes.[1] Though these forests occur in climates that are warm year-round, and may receive several hundred millimeters of rain per year, they have longdry seasons that last several months and vary with geographic location. These seasonaldroughts have great impact on all living things in the forest.
Deciduous trees predominate in most of these forests, and during the drought a leafless period occurs, which varies with species type. Because trees lose moisture through their leaves, the shedding of leaves allows trees such asteak andmountain ebony to conserve water during dry periods. The newly bare trees open up thecanopy layer, enablingsunlight to reach ground level and facilitate the growth of thickunderbrush. Trees on moister sites and those with access to ground water tend to beevergreen. Infertile sites also tend to support evergreen trees. Three tropical dry forest ecoregions, theEast Deccan dry evergreen forests, theSri Lanka dry-zone dry evergreen forests, and theSoutheastern Indochina dry evergreen forests, are characterized by evergreen trees.[1]
Though less biologically diverse thanrainforests, tropical dry forests are home to a wide variety of wildlife includingmonkeys,deer, largecats,parrots, variousrodents, and ground dwellingbirds. Mammalianbiomass tends to be higher in dry forests than in rain forests, especially in Asian and African dry forests. Many of thesespecies display extraordinary adaptations to the difficultclimate.[1]
This biome is alternately known as thetropical and subtropical dry forest biome or thetropical and subtropical deciduous forest biome.
Dry forests tend to exist in the drier areas north and south of thetropical rainforest belt, south or north of the subtropical deserts, generally in two bands: one between 10° and 20°Nlatitude and the other between 10° and 20°Slatitude. The most diverse dry forests in the world occur in western and southernMexico and in theBolivian lowlands.[2] The dry forests of thePacific Coast of northwesternSouth America support a wealth of unique species due to their dry climate. TheMaputaland-Pondoland bushland and thickets along the east coast ofSouth Africa are diverse and support manyendemic species. The dry forests of centralIndia andIndochina are notable for their diverse largevertebratefaunas.Madagascar dry deciduous forests andNew Caledonia dry forests are also highly distinctive (pronouncedendemism and a large number ofrelictual taxa) for a wide range of taxa and at highertaxonomic levels.[1] Trees use underground water during the dry seasons.
Species tend to have wider ranges thanmoist 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 andalpha diversity high but typically lower than adjacent moist forests.[1]
Effective conservation of dry broadleaf forests requires the preservation of large and continuous areas of forest. Large natural areas are required to maintain largerpredators and othervertebrates, and to buffer sensitive species fromhunting pressure. The persistence ofriparian forests and water sources is critical for many dry forest species. Large swathes ofintact forest are required to allow species to recover from occasional large events, like forest fires.[1]
Dry forests are highly sensitive to excessive burning anddeforestation;overgrazing andinvasive species can also quickly alter natural communities; restoration is possible but challenging, particularly if degradation has been intense and persistent.[1]
This article incorporates text available under theCC BY-SA 3.0 license.World Wide Fund for Nature."Tropical and Subtropical Dry Broadleaf Forest Ecoregions". Archived fromthe original on 2012-04-25. Retrieved2012-09-25.
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