Tropical and subtropical dry broadleaf forests

The tropical and subtropical dry broadleaf forest is a habitat type defined by the World 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 centimeters of rain per year, they have long dry seasons which last several months and vary with geographic location. These seasonal droughts 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 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. Trees on moister sites and those with access to ground water tend to be evergreen. Infertile sites also tend to support evergreen trees. Three tropical dry broadleaf forest ecoregions, the East Deccan dry evergreen forests, the Sri Lanka dry-zone dry evergreen forests, and the Southeastern Indochina dry evergreen forests, are characterized by evergreen trees.[1]

Though less biologically diverse than rainforests, tropical dry forests are home to a wide variety of wildlife including monkeys, deer, large cats, parrots, various rodents, and ground dwelling birds. Mammalian biomass tends to be higher in dry forests than in rain forests, especially in Asian and African dry forests. Many of these species display extraordinary adaptations to the difficult climate.[1]

This biome is alternately known as the tropical bane forest biome or the tropical and subtropical deciduous forest biome.

Biome map 02
Extent of dry forest regions.

Geographical variation

Chacachacare dry forest 3
Trinidad and Tobago dry forest on Chacachacare showing the dry-season deciduous nature of the vegetation

Dry forests tend to exist in the drier areas north and south of the tropical rainforest belt, south or north of the subtropical deserts, generally in two bands: one between 10° and 20°N latitude and the other between 10° and 20°S latitude. The most diverse dry forests in the world occur in southern Mexico and in the Bolivian lowlands.[2] The dry forests of the Pacific Coast of northwestern South America support a wealth of unique species due to their dry climate. The Maputaland-Pondoland bushland and thickets along the east coast of South Africa are diverse and support many endemic species. The dry forests of central India and Indochina are notable for their diverse large vertebrate faunas. Madagascar dry deciduous forests and New Caledonia dry forests are also highly distinctive (pronounced endemism and a large number of relictual taxa) for a wide range of taxa and at higher taxonomic levels.[1] Trees use underground water during the dry seasons.

Biodiversity patterns and requirements

Subtropical semi-evergreen seasonal forest in Northern Thailand
Subtropical semi-evergreen seasonal forest in Doi Inthanon National Park, Northern Thailand, at the end of the dry season.

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.[1]

Effective conservation of dry broadleaf forests requires the preservation of large and continuous areas of forest. Large natural areas are required to maintain larger predators and other vertebrates, and to buffer sensitive species from hunting pressure. The persistence of riparian forests and water sources is critical for many dry forest species. Large swathes of intact forest are required to allow species to recover from occasional large events, like forest fires.[1]

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, particularly if degradation has been intense and persistent.[1]

See also


  1. ^ a b c d e f g  This article incorporates text available under the CC BY-SA 3.0 license. World Wide Fund for Nature. "Tropical and Subtropical Dry Broadleaf Forest Ecoregions". Archived from the original on 2012-04-25. Retrieved 2012-09-25.
  2. ^ Gentry, A (1993). "Diversity and floristic composition of Neotropical dry forests". In Mooney, H; Bullock, S; Medina, E (eds.). Tropical deciduous forest ecosystems. Cambridge, UK: Cambridge University Press. pp. 146–194.

External links

Central Indochina dry forests

The Central Indochina dry forests are a large tropical and subtropical dry broadleaf forests ecoregion in Southeast Asia.

Frank Sound Forest

Frank Sound Forest lies near the southern coast of the East End distinct of Grand Cayman, one of the Cayman Islands, a British Overseas Territory in the Caribbean Sea. It is one of the territory’s Important Bird Areas (IBAs).

Hawaiian tropical dry forests

The Hawaiian tropical dry forests are a tropical dry broadleaf forest ecoregion in the Hawaiian Islands. They cover an area of 6,600 km2 (2,500 sq mi) on the leeward side of the main islands and the summits of Niʻihau and Kahoʻolawe. These forests are either seasonal or sclerophyllous. Annual rainfall is less than 127 cm (50 in) and may be as low as 25 cm (9.8 in); the rainy season lasts from November to March. Dominant tree species include koa (Acacia koa), koaiʻa (A. koaia), ʻakoko (Euphorbia spp.), ʻōhiʻa lehua (Metrosideros polymorpha), lonomea (Sapindus oahuensis), māmane (Sophora chrysophylla), loulu (Pritchardia spp.), lama (Diospyros sandwicensis), olopua (Nestegis sandwicensis), wiliwili (Erythrina sandwicensis), and ʻiliahi (Santalum spp.). Endemic plant species in the dry forests include hau heleʻula (Kokia cookei), uhiuhi (Caesalpinia kavaiensis), and Gouania spp. The palila (Loxioides bailleui), a Hawaiian honeycreeper, is restricted to this type of habitat.

List of ecoregions in Angola

The following is a list of ecoregions in Angola, according to the Worldwide Fund for Nature (WWF).

List of ecoregions in Cambodia

The following is a list of ecoregions in Cambodia.

List of ecoregions in India

The Himalaya, which runs across India's northern tier, is the boundary between two of the Earth's great ecozones — the Palearctic, which covers most of temperate-to-arctic Eurasia, and Indomalaya, which covers most of the Indian subcontinent and extends into Indochina, Sundaland (Malaysia and western Indonesia) and the Philippines.

List of ecoregions in Laos

The following is a list of ecoregions in Laos.

List of ecoregions in Thailand

The following is a list of ecoregions in Thailand.

List of ecoregions in Vietnam

The following is a list of ecoregions in Vietnam.

List of terrestrial ecoregions (WWF)

This is a list of terrestrial ecoregions as compiled by the World Wildlife Fund (WWF). The WWF identifies terrestrial, freshwater, and marine ecoregions.

The terrestrial scheme divides the Earth's land surface into 8 terrestrial ecozones, containing 867 smaller ecoregions. Each ecoregion is classified into one of 14 major habitat types, or biomes.

Additional ecoregions for Antarctic Realm are currently being incorporated (based on Terauds et al. 2012).

Antarctic Realm - Tundra Biome:

1 North-east Antarctic Peninsula;

2 South Orkney Islands;

3 North-west Antarctic Peninsula;

4 Central south Antarctic Peninsula;

5 Enderby Land;

6 Dronning Maud Land;

7 East Antarctica;

8 North Victoria Land;

9 South Victoria Land;

10 Transantarctic Mountains;

11 Ellsworth Mountains;

12 Marie Byrd Land;

13 Adelie Land;

14 Ellsworth Land;

15 South Antarctic Peninsula.

Terauds, A, SL Chown, F Morgan, HJ Peat, DJ Watts, H Keys, P Convey, DM Bergstrom. 2012. Conservation biogeography of the Antarctic. Diversity and Distributions 1–16. DOI: 10.1111/j.1472-4642.2012.00925.x

Northern dry deciduous forests

The Northern dry deciduous forests is a tropical dry broadleaf forest ecoregion of east-central India. It covers an area of 58,300 square kilometers (22,500 sq mi), extending across portions of Andhra Pradesh, Chhattisgarh, Orissa, and Jharkhand states. The region extends north and south in the dry western rain shadow of the Eastern Ghats range, which block the moisture-laden monsoon winds from the Bay of Bengal to the east. It is surrounded by the more humid Eastern Highlands moist deciduous forests ecoregion.

Sonoran-Sinaloan transition subtropical dry forest

The Sonoran-Sinaloan transition subtropical dry forest is a tropical dry broadleaf forest ecoregion in northwestern Mexico.

South Deccan Plateau dry deciduous forests

The South Deccan Plateau dry deciduous forests receive most of their rainfall with the June–September southwest monsoon, and are characterized by tall trees that drop their leaves during the dry winter and spring months. Much of the forest has been degraded through over-use, and thorn forests and shrub thickets are common. To the north and east, the dry deciduous forests transition to the Deccan thorn scrub forests.

Southeastern Indochina dry evergreen forests

The Southeastern Indochina dry evergreen forests are a tropical dry broadleaf forest ecoregion of Indochina.

Southern African Sand Forest

Southern African Sand Forest is a sand forest, or a subtropical forest ecoregion of the Tropical and subtropical dry broadleaf forests Biome. It grows on ancient sand dunes in northern KwaZulu-Natal and southern Mozambique. In South Africa these forests are known simply as Sand Forest, while in Mozambique they are known as Licuati Forest.

Sri Lanka dry-zone dry evergreen forests

The Sri Lanka dry-zone dry evergreen forests are a tropical dry broadleaf forest ecoregion of the island of Sri Lanka. The ecoregion covers an area of 48,400 square kilometers (18,700 sq mi), which includes most of the island of Sri Lanka, with the exception of the islands' southwestern corner and central highlands, home to the Sri Lanka lowland rain forests and Sri Lanka montane rain forests ecoregions, respectively, and the northern Jaffna Peninsula, part of the Deccan thorn scrub forests ecoregion.

The Sri Lanka dry-zone dry evergreen forests are made up mostly of evergreen trees, which distinguish them from the deciduous trees that characterize most other tropical dry broadleaf forest ecoregions. The dry-zone dry evergreen forests most closely resemble the East Deccan dry evergreen forests of India's southeast coast.

Zambezian cryptosepalum dry forest

Zambezian cryptosepalum dry forest is a tropical dry broadleaf forest ecoregion of Southern Africa. It consists of several areas of thick forest in western Zambia and adjacent Angola. It is one of the largest areas of tropical evergreen forest outside the equatorial zone.

See also

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