Endemism

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The orange-breasted sunbird (Nectarinia violacea) is exclusively found in South African fynbos vegetation. Orange-breasted Sunbird (Nectarinia violacea).jpg
The orange-breasted sunbird (Nectarinia violacea) is exclusively found in South African fynbos vegetation.
Bicolored frog (Clinotarsus curtipes) is endemic to the Western Ghats of India Bicolored Frog ( Clinotarsus curtipes ).jpg
Bicolored frog (Clinotarsus curtipes) is endemic to the Western Ghats of India

Endemism is the ecological state of a species being unique to a defined geographic location, such as an island, nation, country or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. Charles Darwin's study of endemic species in locations such as the Galápagos Islands helped form his ideas of Evolution. The extreme opposite of endemism is cosmopolitan distribution. An alternative term for a species that is endemic is precinctive, which applies to species (and subspecific categories) that are restricted to a defined geographical area.

Contents

Etymology

The word endemic is from New Latin endēmicus, from Greek ενδήμος, endēmos, "native". Endēmos is formed of en meaning "in", and dēmos meaning "the people". [1] The term "precinctive" has been suggested by some scientists as the equivalent of "endemism", [lower-alpha 1] and was first used in botany by MacCaughey in 1917. [2] Precinction was perhaps first used by Frank and McCoy. [3] [4] Precinctive seems to have been coined by David Sharp when describing the Hawaiian fauna in 1900: [5] "I use the word precinctive in the sense of 'confined to the area under discussion' ... 'precinctive forms' means those forms that are confined to the area specified." That definition excludes artificial confinement of examples by humans in far-off botanical gardens or zoological parks.

Overview

Amphipsalta zelandica, a species endemic to New Zealand Chorus cicada.jpg
Amphipsalta zelandica , a species endemic to New Zealand

Physical, climatic and biological factors can contribute to endemism. The orange-breasted sunbird is exclusively found in the fynbos vegetation zone of southwestern South Africa. The glacier bear is found only in limited places in Southeast Alaska. Political factors can play a part if a species is protected, or actively hunted, in one jurisdiction but not another.[ citation needed ]

There are two subcategories of endemism: paleoendemism and neoendemism. Paleoendemism refers to species that were formerly widespread but are now restricted to a smaller area. Neoendemism refers to species that have recently arisen, such as through divergence and reproductive isolation or through hybridization and polyploidy in plants.

Endemic types or species are especially likely to develop on geographically and biologically isolated areas such as islands and remote island groups, such as Hawaii, the Galápagos Islands and Socotra; they can equally develop in biologically isolated areas such as the highlands of Ethiopia, or large bodies of water far from other lakes, like Lake Baikal. Hydrangea hirta is an example of an endemic species found in Japan.

Endemic species can easily become endangered or extinct if their restricted habitat changes, particularly—but not only—due to human actions, including the introduction of new organisms. There were millions of both Bermuda petrels and Bermuda cedars in Bermuda when it was settled at the start of the seventeenth century. By the end of the century, the petrels were thought extinct. Cedars, already ravaged by centuries of shipbuilding, were driven nearly to extinction in the twentieth century by the introduction of a parasite. Bermuda petrels and cedars are now rare, as are other species endemic to Bermuda.

Threats to highly endemistic regions

Principal causes of habitat degradation and loss in highly endemistic ecosystems include agriculture, urban growth, surface mining, mineral extraction, logging operations [6] [7] and slash-and-burn agriculture.

Notes

  1. Precinctivity

Related Research Articles

Adaptive radiation A process in which organisms diversify rapidly from an ancestral species

In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches. Starting with a recent single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits. The prototypical example of adaptive radiation is finch speciation on the Galapagos, but examples are known from around the world.

Heard Island and McDonald Islands Australian external territory and volcanic group of barren Antarctic islands

The Territory of Heard Island and McDonald Islands (HIMI) is an Australian external territory comprising a volcanic group of barren Antarctic islands, about two-thirds of the way from Madagascar to Antarctica. The group's overall size is 372 km2 (144 sq mi) in area and it has 101.9 km (63 mi) of coastline. Discovered in the mid-19th century, the islands have been an Australian territory since 1947 and contain the country's two only active volcanoes. The summit of one, Mawson Peak, is higher than any mountain on the Australian mainland. The islands lie on the Kerguelen Plateau in the Indian Ocean.

Ecotone transition area between two biomes

An ecotone is a transition area between two biomes. It is where two communities meet and integrate. It may be narrow or wide, and it may be local or regional. An ecotone may appear on the ground as a gradual blending of the two communities across a broad area, or it may manifest itself as a sharp boundary line.

A biodiversity hotspot is a biogeographic region with significant levels of biodiversity that is threatened by human habitation.

Bermuda petrel species of bird

The Bermuda petrel is a gadfly petrel. Commonly known in Bermuda as the cahow, a name derived from its eerie cries, this nocturnal ground-nesting seabird is the national bird of Bermuda and can be found pictured on Bermudian currency. It is the second rarest seabird on the planet and a symbol of hope for nature conservation. They are known for their medium-sized body and long wings. The Bermuda petrel has a greyish-black crown and collar, dark grey upper-wings and tail, white upper-tail coverts and white under-wings edged with black, and the underparts are completely white.

Wildlife of Bermuda

The flora and fauna of Bermuda form part of a unique ecosystem due to Bermuda's isolation from the mainland of North America. The wide range of endemic species and the islands form a distinct ecoregion, the Bermuda subtropical conifer forests.

An Endemic Bird Area (EBA) is an area of land identified by BirdLife International as being important for habitat-based bird conservation because it contains the habitats of restricted-range bird species, which are thereby endemic to them. An EBA is formed where the distributions of two or more such restricted-range species overlap. Using this guideline, 218 EBAs were identified when Birdlife International established their Biodiversity project in 1987. A secondary EBA comprises the range of only one restricted-range species.

The ecological restoration of islands, or island restoration, is the application of the principles of ecological restoration to islands and island groups. Islands, due to their isolation, are home to many of the world's endemic species, as well as important breeding grounds for seabirds and some marine mammals. Their ecosystems are also very vulnerable to human disturbance and particularly to introduced species, due to their small size. Island groups such as New Zealand and Hawaii have undergone substantial extinctions and losses of habitat. Since the 1950s several organisations and government agencies around the world have worked to restore islands to their original states; New Zealand has used them to hold natural populations of species that would otherwise be unable to survive in the wild. The principal components of island restoration are the removal of introduced species and the reintroduction of native species.

<i>Tapinoma melanocephalum</i> Species of ant

Tapinoma melanocephalum is a species of ant that goes by the common name ghost ant. They are recognised by their dark head and pale or translucent legs and gaster (abdomen). This colouring makes this tiny ant seem even smaller.

Galápagos petrel species of bird

The Galápagos petrel is one of the six endemic seabirds of the Galápagos. Its scientific name derives from Ancient Greek: Pterodroma originates from pteron and dromos, meaning "wing" and "runner", and phaeopygia comes from phaios and pugios, meaning "dusky" and "rump". Members of Pterodroma genus are also called the gadfly petrels because their erratic twisting and turning in flight resemble that of gadflies.

Hawaiian petrel species of bird

The Hawaiian petrel or ʻuaʻu is a large, dark grey-brown and white petrel that is endemic to Hawaiʻi.

Calcareous glade

A calcareous glade is an ecological community that is found in the central eastern United States. Calcareous glades occur where bedrock such as limestone occurs near or at the surface, and have very shallow and little soil development. Because of the shallow soil and the extreme conditions created by it, trees are often unable to grow in the glades. This creates a habitat that is usually sunny, dry, and hot. Calcareous glade vegetation is more similar to that of a desert habitat than a grassland, being dominated by small spring annuals with occasional geophytic or succulent perennials.

Fauna of Puerto Rico Animals found in the United States Territory of Puerto Rico

The fauna of Puerto Rico is similar to other island archipelago faunas, with high endemism, and low, skewed taxonomic diversity. Bats are the only extant native terrestrial mammals in Puerto Rico. All other terrestrial mammals in the area were introduced by humans, and include species such as cats, goats, sheep, the small Asian mongoose, and escaped monkeys. Marine mammals include dolphins, manatees, and whales. Of the 349 bird species, about 120 breed in the archipelago, and 47.5% are accidental or rare.

Fauna of Ghana

The wildlife of Ghana is composed of its biodiversity of flora and fauna.

Electric ant Species of ant

The electric ant, also known as the little fire ant, is a small, light to golden brown (ginger) social ant native to Central and South America, now spread to parts of Africa, North America, Puerto Rico, Israel, Cuba, and six Pacific Island groups plus north-eastern Australia (Cairns).

In ecology, species homogeneity is a lack of biodiversity. Species richness is the fundamental unit in which to assess the homogeneity of an environment. Therefore, any reduction in species richness, especially endemic species, could be argued as advocating the production of a homogenous environment.

Short-range endemic (SRE) invertebrates are animals that display restricted geographic distributions, nominally less than 10,000 km2, that may also be disjunct and highly localised. The most appropriate analogy is that of an island, where the movement of fauna is restricted by the surrounding marine waters, therefore isolating the fauna from other terrestrial populations. Isolating mechanisms and features such as roads, urban infrastructure, large creek lines and ridges can act to prevent the dispersal and gene flow of the less mobile invertebrate species. Subterranean fauna, which include stygofauna and troglofauna, typically comprise short-range endemics.

Paleoendemism along with neoendemism is one of two sub-categories of endemism. Paleoendemism refers to species that were formerly widespread but are now restricted to a smaller area. Neoendemism refers to species that have recently arisen, such as through divergence and reproductive isolation or through hybridization and polyploidy in plants.

In biogeography and paleontology a relict is a population or taxon of organisms that was more widespread or more diverse in the past. A relictual population is a population that presently occurs in a restricted area, but whose original range was far wider during a previous geologic epoch. Similarly, a relictual taxon is a taxon that is the sole surviving representative of a formerly diverse group.

Flora of Madagascar

The flora of Madagascar consists of more than 12,000 species of vascular and non-vascular plants. Although fungus, lichens and algae are no longer included in the Plant Kingdom, they are discussed here as well. Around 83% of Madagascar's vascular plants are found only on the island. These endemics include five plant families, 85% of the over 900 orchid species, around 200 species of palms, and such emblematic species as the traveller's tree, six species of baobab and the Madagascar periwinkle. The high degree of endemism is due to Madagascar's long isolation following its separation from the African and Indian landmasses in the Mesozoic, 150–160 and 84–91 million years ago, respectively. However, few plant lineages remain from the ancient Gondwanan flora; most extant plant groups immigrated via across-ocean dispersal well after continental break-up.

References

  1. "Endemic". Reference.com. Retrieved 6 December 2014.
  2. MacCaughey, Vaughan (August 1917). "A survey of the Hawaiian land flora". Botanical Gazette. LXIV (2): 92. doi:10.1086/332097.
  3. Frank, J. H.; McCoy, E. D. (March 1990). "Endemics and epidemics of shibboleths and other things causing chaos". Florida Entomologist. 73 (1): 1–9. JSTOR   3495327.
  4. Frank, J. H.; McCoy, E. D. (March 1995). "Precinctive insect species in Florida". Florida Entomologist. 78 (1): 21–35. doi:10.2307/3495663. JSTOR   3495663. [also uses word precinction]
  5. Sharp, D. 1900. Coleoptera. I. Coleoptera Phytophaga, pp. 91–116 in D. Sharp [ed.]. Fauna Hawaiiensis, Being the Land-Fauna of the Hawaiian Islands. Cambridge Univ. Press; Cambridge, vol. 2 part 3 [see p. 91].
  6. Smiet, Fred (June 1982). "Threats to the Spice Islands". Oryx. 16 (4): 323–328. doi:10.1017/S0030605300017774.
  7. Foley, Jonathan A.; et al. (February 2007). "Amazonia revealed: forest degradation and loss of ecosystem goods and services in the Amazon Basin". Frontiers in Ecology and the Environment. Ecological Society of America. 5 (1): 25–32. doi:10.1890/1540-9295(2007)5[25:ARFDAL]2.0.CO;2.

Further reading