Endemism
Endemism is an important concept in conservation biology for measuring biodiversity in a particular place and evaluating the risk of extinction for species.
[1] In isolated areas where there is little possibility for organisms to disperse to new places, or to receive new gene flow from outside, the rate of endemism is particularly high.
[14] Endemism can also be created in areas which act as refuges for species during times of climate change like ice ages.
Baas Becking in 1934, describes the theory that the distribution of organisms smaller than 2 mm is cosmopolitan where habitats occur that support their growth.
[10][21] Using this work, Ledyard Stebbins and Jack Major then introduced the concepts of neoendemics and paleoendemics in 1965 to describe the endemics of California.
Neoendemism refers to species that have recently arisen, such as through divergence and reproductive isolation[14] or through hybridization[citation needed] and polyploidy in plants,[23] and have not dispersed beyond a limited range.
Holoendemics is a concept introduced by Richardson in 1978 to describe taxa that have remained endemic to a restricted distribution for a very long time.
[19][25] Some environments are particularly conducive to the development of endemic species, either because they allow the persistence of relict taxa that were extirpated elsewhere, or because they provide mechanisms for isolation and opportunities to fill new niches.
[26][27] These soils are found in the Balkan Peninsula, Turkey, Alps, Cuba, New Caledonia, South Africa, Zimbabwe, the North American Appalachians, and scattered distribution in California, Oregon, and Washington and elsewhere.
The Devil's Hole pupfish, Cyprinodon diabolis, has its whole native population restricted to a spring that is 20 x 3 meters, in Nevada's Mojave Desert.
The Socotra Archipelago of Yemen, located in the Indian Ocean, has seen a new endemic species of parasitic leech, Myxobdella socotrensis, appear.
For example, in the Alpes-Maritimes department of France, Saxifraga florulenta is an endemic plant that may have evolved in the Late Miocene and could have once been widespread across the Mediterranean Basin.
Plants on volcanoes tend to fill a specialized ecological niche, with a very restrictive range, due to the unique environmental characteristics.
[37] This puts endemic plants and animals at greater risk than widespread species during the rapid climate change of this century.
[38][39] Some scientists claim that the presence of endemic species in an area is a good method to find geographical regions that can be considered priorities for conservation.
[41] The concept of finding endemic species that occur in the same region to designate 'endemism hotspots' was first proposed by Paul Müller in a 1973 book.
The Caparaó National Park was formed in the Atlantic Forest, a biodiversity hotspot located in Brazil, in order to help protect valuable and vulnerable species.
When using bird species as an example, it was found that only 2.5% of biodiversity hotspots correlate with endemism and the threatened nature of a geographic region.
[1][45] A similar pattern had been found regarding mammals, Lasioglossum bees, Plusiinae moths, and swallowtail butterflies in North America: these different groups of taxa did not correlate geographically with each other regarding endemism and species richness.
Especially using mammals as flagship species proved to be a poor system of identifying and protecting areas of high invertebrate biodiversity.
[41] Other conservation efforts for endemics include keeping captive and semi-captive populations in zoological parks and botanical gardens.
The use of such methods may not only offer refuge and protection for individuals of declining or vulnerable populations, but it may also allow biologists valuable opportunities to research them as well.
