The Hawaiian tropical high shrublands are a tropical savanna ecoregion in the Hawaiian Islands.
| Hawaiian tropical high shrublands | |
|---|---|
 | |
| Ecology | |
| Realm | Oceanian |
| Biome | Tropical and subtropical grasslands, savannas, and shrublands |
| Borders | |
| Geography | |
| Area | 1,900 km2 (730 sq mi) |
| Country | United States |
| State | Hawaii |
| Conservation | |
| Conservation status | Vulnerable [2] |
| Global 200 | No [3] |
The high shrublands ecoregion covers an area of 1,900 km2 (730 sq mi) on the upper slopes of the volcanoes Mauna Kea, Mauna Loa, Hualālai, and Haleakalā.
The plant communities include open shrublands, grasslands, and deserts. Shrubland species include ʻāheahea ( Chenopodium oahuense ), ʻōhelo ʻai ( Vaccinium reticulatum ), naʻenaʻe ( Dubautia menziesii ), and ʻiliahi ( Santalum haleakalae ). Alpine grasslands are dominated by tussock grasses, such as Deschampsia nubigena , Eragrostis atropioides , Panicum tenuifolium , and pili uka ( Trisetum glomeratum ). Deserts occur on the coldest and driest peaks, where only extremely hardy plants such as ʻāhinahina ( Argyroxiphium sandwicense ) and Dubautia species are able to grow.
The nēnē ( Branta sandvicensis ) is one of the few birds found in alpine shrublands, while ʻuaʻu ( Pterodroma sandwichensis ) nest in this ecoregion. [2]
A biome is a biogeographical unit consisting of a biological community that has formed in response to the physical environment in which they are found and a shared regional climate. Biomes may span more than one continent. Biome is a broader term than habitat and can comprise a variety of habitats.
The Global 200 is the list of ecoregions identified by the World Wide Fund for Nature (WWF), the global conservation organization, as priorities for conservation. According to WWF, an ecoregion is defined as a "relatively large unit of land or water containing a characteristic set of natural communities that share a large majority of their species dynamics, and environmental conditions". For example, based on their levels of endemism, Madagascar gets multiple listings, ancient Lake Baikal gets one, and the North American Great Lakes get none.
A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands. They cover 31–69% of the Earth's land area.
Deserts and xeric shrublands are a biome defined by the World Wide Fund for Nature. Deserts and xeric shrublands form the largest terrestrial biome, covering 19% of Earth's land surface area. Ecoregions in this habitat type vary greatly in the amount of annual rainfall they receive, usually less than 250 millimetres (10 in) annually except in the margins. Generally evaporation exceeds rainfall in these ecoregions. Temperature variability is also diverse in these lands. Many deserts, such as the Sahara, are hot year-round, but others, such as East Asia's Gobi, become quite cold during the winter.
The Oceanian realm is one of the World Wildlife Fund (WWF) biogeographic realms, and is unique in not including any continental land mass. It has the smallest land area of any of the WWF realms.
Montane grasslands and shrublands is a biome defined by the World Wildlife Fund. The biome includes high elevation grasslands and shrublands around the world. The term "montane" in the name of the biome refers to "high elevation", rather than the ecological term which denotes the region below treeline.
Argyroxiphium is a small genus of plants in the family Asteraceae. Its members are known by the common names silversword or greensword due to their long, narrow leaves and the silvery hairs on some species. The silverswords belong to a larger radiation of over 50 species, including the physically different genera Dubautia and Wilkesia. This grouping is often referred to as the silversword alliance. Botanist P. H. Raven referred to this radiation as "the best example of adaptive radiation in plants".
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.
Dubautia arborea, the tree dubautia or Mauna Kea dubautia, is a species of flowering plant in the family Asteraceae. A member of the silversword alliance, it is endemic to the island of Hawaiʻi. It is a shrub or small tree. It is an endangered species that is threatened by feral grazing animals.
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, koaiʻa, ʻakoko, ʻōhiʻa lehua, lonomea, māmane, loulu, lama, olopua, wiliwili, and ʻiliahi. Endemic plant species in the dry forests include hau heleʻula, uhiuhi, and Gouania spp. The palila, a Hawaiian honeycreeper, is restricted to this type of habitat.
The Hawaiian tropical low shrublands are a tropical savanna ecoregion in the Hawaiian Islands.
The Central Range sub-alpine grasslands is a montane grasslands and shrublands ecoregion on the island of New Guinea. The ecoregion covers the highest-elevation portions of the New Guinea Highlands, which extend along the spine of the island. The high elevations support rare tropical sub-alpine and alpine habitats, including many endemic plants and animals.
The Northwestern Himalayan alpine shrub and meadows is a montane grasslands and shrublands ecoregion of the elevations of the northwestern Himalaya of China, India, and Pakistan.
Mediterranean forests, woodlands, and scrub is a biome defined by the World Wide Fund for Nature. The biome is generally characterized by dry summers and rainy winters, although in some areas rainfall may be uniform. Summers are typically hot in low-lying inland locations but can be cool near colder seas. Winters are typically mild to cool in low-lying locations but can be cold in inland and higher locations. All these ecoregions are highly distinctive, collectively harboring 10% of the Earth's plant species.
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.
Biogeographic classification of India is the division of India according to biogeographic characteristics. Biogeography is the study of the distribution of species (biology), organisms, and ecosystems in geographic space and through geological time. India has a rich heritage of natural diversity. India ranks fourth in Asia and tenth in the world amongst the top 17 mega-diverse countries in the world. India harbours nearly 11% of the world's floral diversity comprising over 17500 documented flowering plants, 6200 endemic species, 7500 medicinal plants and 246 globally threatened species in only 2.4% of world's land area. India is also home to four biodiversity hotspots—Andaman & Nicobar Islands, Eastern Himalaya, Indo-Burma region, and the Western Ghats. Hence the importance of biogeographical study of India's natural heritage.
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.
The Altai alpine meadow and tundra ecoregion is a terrestrial ecoregion covering the higher elevation of the Altai Mountains at the center of the "X" formed by the borders separating Russia, Kazakhstan, China, and Mongolia. The mountain peaks are the farthest north in Central Asia, separating the plains of Siberia to the north from the hot, dry deserts to the south. Altitudes above 2,400 meters display characteristics of tundra, with patches of alpine meadows and some trees immediately below the treeline. The ecoregion is in the montane grasslands and shrublands biome, and the Palearctic realm, with a humid continental climate. It covers an area of 90,132 square kilometres (34,800 sq mi).
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