A biome is a distinct geographical region with specific climate, vegetation, and animal life. It consists of a biological community that has formed in response to its physical environment and regional climate. Biomes may span more than one continent. A biome encompasses multiple ecosystems within its boundaries. It can also comprise a variety of habitats.
A forest is an ecosystem characterized by a dense community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' Food and Agriculture Organization (FAO) defines a forest as, "Land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent, or trees able to reach these thresholds in situ. It does not include land that is predominantly under agricultural or urban use." Using this definition, Global Forest Resources Assessment 2020 found that forests covered 4.06 billion hectares, or approximately 31 percent of the world's land area in 2020.
Rainforests are forests characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropical rainforests or temperate rainforests, but other types have been described.
A savanna or savannah is a mixed woodland-grassland ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses. According to Britannica, there exists four savanna forms; savanna woodland where trees and shrubs form a light canopy, tree savanna with scattered trees and shrubs, shrub savanna with distributed shrubs, and grass savanna where trees and shrubs are mostly nonexistent.
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. Though these forests occur in climates that are warm year-round, and may receive several hundred millimeters of rain per year, they have long dry seasons that last several months and vary with geographic location. These seasonal droughts have great impact on all living things in the forest.
Tropical and subtropical moist broadleaf forests (TSMF), also known as tropical moist forest, is a subtropical and tropical forest habitat type defined by the World Wide Fund for Nature.
Tropical climate is the first of the five major climate groups in the Köppen climate classification identified with the letter A. Tropical climates are defined by a monthly average temperature of 18 °C (64.4 °F) or higher in the coolest month, and feature hot temperatures all year-round. Annual precipitation is often abundant in tropical climates, and shows a seasonal rhythm but may have seasonal dryness to varying degrees. There are normally only two seasons in tropical climates, a wet (rainy/monsoon) season and a dry season. The annual temperature range in tropical climates is normally very small. Sunlight is intense in these climates.
The Atlantic Forest is a South American forest that extends along the Atlantic coast of Brazil from Rio Grande do Norte state in the northeast to Rio Grande do Sul state in the south and inland as far as Paraguay and the Misiones Province of Argentina, where the region is known as Selva Misionera.
Tropical rainforests are dense and warm rainforests that occur in tropical rainforest climate where there is no dry season – all months have an average precipitation of at least 60 mm. True rainforests are typically found between 10 degrees north and south of the equator ; they are a subset of the tropical forest biome that occurs roughly within the 28-degree latitudes. Tropical rainforests are a type of tropical moist broadleaf forest, that includes the more extensive seasonal tropical forests.
Laurel forest, also called laurisilva or laurissilva, is a type of subtropical forest found in areas with high humidity and relatively stable, mild temperatures. The forest is characterized by broadleaf tree species with evergreen, glossy and elongated leaves, known as "laurophyll" or "lauroid". Plants from the laurel family (Lauraceae) may or may not be present, depending on the location.
The Hawaiian tropical rainforests are a tropical moist broadleaf forest ecoregion in the Hawaiian Islands. They cover an area of 6,700 km2 (2,600 sq mi) in the windward lowlands and montane regions of the islands. Coastal mesic forests are found at elevations from sea level to 300 m (980 ft). Mixed mesic forests occur at elevations of 750 to 1,250 m, while wet forests are found from 1,250 to 1,700 m. Moist bogs and shrublands exist on montane plateaus and depressions. For the 28 million years of existence of the Hawaiian Islands, they have been isolated from the rest of the world by vast stretches of the Pacific Ocean, and this isolation has resulted in the evolution of an incredible diversity of endemic species, including fungi, mosses, snails, birds, and other wildlife. In the lush, moist forests high in the mountains, trees are draped with vines, orchids, ferns, and mosses. This ecoregion includes one of the world's wettest places, the slopes of Mount Waiʻaleʻale, which average 373 in (9,500 mm) of rainfall per year.
The Nilgiri Biosphere Reserve is a biosphere reserve in the Nilgiri Mountains of the Western Ghats in South India. It is the largest protected forest area in India, spreading across Tamil Nadu, Karnataka and Kerala. It includes the protected areas Mudumalai National Park, Mukurthi National Park, Sathyamangalam Wildlife Sanctuary in Tamil Nadu; Nagarhole National Park, Bandipur National Park, both in Karnataka; Silent Valley National Park, Aralam Wildlife Sanctuary, Wayanad Wildlife Sanctuary, and Karimpuzha Wildlife Sanctuary in Kerala.
Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial factor in shaping plant community, biodiversity, metabolic processes and ecosystem dynamics for montane ecosystems. Dense montane forests are common at moderate elevations, due to moderate temperatures and high rainfall. At higher elevations, the climate is harsher, with lower temperatures and higher winds, preventing the growth of trees and causing the plant community to transition to montane grasslands and shrublands or alpine tundra. Due to the unique climate conditions of montane ecosystems, they contain increased numbers of endemic species. Montane ecosystems also exhibit variation in ecosystem services, which include carbon storage and water supply.
The Ethiopian montane forests is a tropical moist broadleaf forest ecoregion in eastern Africa. It covers the middle elevations of the Ethiopian Highlands in Ethiopia and extends into neighboring Eritrea, Sudan, Djibouti, and Somaliland. The ecoregion includes distinctive Afromontane forests, woodlands, grasslands, and shrublands. The ecoregion's biodiversity is threatened by deforestation, conversion to agriculture, and overgrazing.
Stratification in the field of ecology refers to the vertical layering of a habitat; the arrangement of vegetation in layers. It classifies the layers of vegetation largely according to the different heights to which their plants grow. The individual layers are inhabited by different animal and plant communities (stratozones).
Seasonal tropical forest, also known as moist deciduous, semi-evergreen seasonal, tropical mixed or monsoon forest, typically contains a range of tree species: only some of which drop some or all of their leaves during the dry season. This tropical forest is classified under the Walter system as (i) tropical climate with high overall rainfall and (ii) having a very distinct wet season with dry season. These forests represent a range of habitats influenced by monsoon (Am) or tropical wet savannah (Aw/As) climates. Drier forests in the Aw climate zone are typically deciduous and placed in the Tropical dry forest biome: with further transitional zones (ecotones) of savannah woodland then tropical and subtropical grasslands, savannas, and shrublands.
The Negro–Branco moist forests (NT0143) is an ecoregion of tropical moist broadleaf forest to the east of the Andes in southern Venezuela, eastern Colombia and northern Brazil, in the Amazon biome. It lies on the watershed between the Orinoco and Rio Negro basins. It includes both blackwater and whitewater rivers, creating different types of seasonally flooded forest. The vegetation is more typical of the Guiana region than the Amazon.
The Yap tropical dry forests is a tropical and subtropical dry broadleaf forests ecoregion in Micronesia. It includes the Yap Islands and neighboring atolls in the Federated States of Micronesia.
Sri Lanka exhibits a remarkable biological diversity and is considered to be the richest country in Asia in terms of species concentration.
Rainforests and vine thickets are a major vegetation group in Australia. It consists of temperate to tropical rainforests, monsoon forests, and vine thickets. Rainforests and vine thickets are generally found in small pockets across the eastern and northern portions of the continent, including western Tasmania, eastern New South Wales, eastern Queensland, the northern portion of the Northern Territory, and the Kimberley Region of northeastern Western Australia.
