The geographical area in which a species can be found

C Island biogeography

Ecologists have been intrigued at least since the time of Hooker (1847, 1853, 1860) by the presence of related organisms on widely separated oceanic islands. Darwin (1859) and Wallace (1911) later interpreted this phenomenon as evidence of natural selection and speciation of isolated populations following separation or colonization from distant population sources. Simberloff (1969), Simberloff and Wilson (1969), and Wilson and Simberloff (1969) found that many arthropod species were capable of rapid colonization of experimentally defaunated islands. Although the theory of island biogeography originally was developed to explain the patterns of equilibrium species richness among oceanic islands (MacArthur and Wilson, 1967), the same factors and processes that govern colonization of oceanic islands explain rates of species colonization and metapopulation dynamics (see Section II.B) among isolated landscape patches, especially in montane landscapes (Cronin, 2003; Hanski and Simberloff, 1997; Leisnham and Jamieson, 2002; Simberloff, 1974; Soulé and Simberloff, 1986). Critics of this approach have argued that oceanic islands clearly are surrounded by habitat unsuitable for terrestrial species, whereas terrestrial patches may be surrounded by relatively more suitable patches. Some terrestrial habitat patches may be more similar to oceanic islands than others, for example, alpine tundra on mountaintops may represent substantially isolated habitats (Leisnham and Jamieson, 2002) as do isolated wetlands in a terrestrial matrix (Batzer and Wissinger, 1996), whereas disturbed patches in grassland may be less distinct (but see Cronin, 2003). A second issue concerns the extent to which the isolated populations constitute distinct species or metapopulations of a single species (Hanski and Simberloff, 1997). The resolution of this issue depends on the degree of heterogeneity and isolation among landscape patches and genetic drift among isolated populations over time.

2.3 Island Biogeography

Ecologists have been intrigued at least since the time of Hooker (1847, 1853, 1860)Hooker, 1847Hooker, 1853Hooker, 1860 by the presence of related organisms on widely separated oceanic islands. Darwin (1859) and A. Wallace (1911) later interpreted this phenomenon as evidence of natural selection and speciation of isolated populations following separation or colonization from distant population sources. Simberloff (1969), Simberloff and Wilson (1969), and E. Wilson and Simberloff (1969) found that many arthropod species were capable of rapid colonization of experimentally defaunated islands. Although the theory of island biogeography originally was developed to explain patterns of equilibrium species richness among oceanic islands (MacArthur and Wilson, 1967), the same factors and processes that govern colonization of oceanic islands explain rates of species colonization and metapopulation dynamics (see Section 3.2) among isolated landscape patches (Cronin, 2003; Hanski and Simberloff, 1997; Leisnham and Jamieson, 2002; Simberloff, 1974; Soulé and Simberloff, 1986). Critics of this approach have argued that oceanic islands clearly are surrounded by habitat unsuitable for terrestrial species, whereas terrestrial patches may be surrounded by relatively more suitable patches. Some terrestrial habitat patches may be more similar to oceanic islands than others, for example, alpine tundra on mountaintops may represent substantially isolated habitats (Leisnham and Jamieson, 2002), as do isolated wetlands in a terrestrial matrix (Batzer and Wissinger, 1996), whereas disturbed patches in grassland may be less distinct (but see Cronin, 2003). A second issue concerns the extent to which the isolated populations constitute distinct species or metapopulations of a single species (Hanski and Simberloff, 1997). The resolution of this issue depends on the degree of heterogeneity and isolation among landscape patches and genetic drift among isolated populations over time.

Abstract

Vicariance biogeography emerged in the late 1970s from distinct traditions in historical biogeography: the phylogenetic systematics and the panbiogeography. Vicariance biogeography, in the strict sense, is the study of repeated patterns of disjunct distributions within many members of a biota that may be explained by vicariance (or splitting of areas). Since its origin to the 1990s, it became the most important method or discipline within historical biogeography, involving the study of life and Earth history using cladistic methods (cladistic biogeography). In fact, nowadays both names (vicariance and cladistic biogeography) are frequently treated as synonyms. Vicariance biogeography became a very important method to classify areas of endemism on a global, regional, and local scale in terms of their historical relationships. Since the late 1990s this method or discipline has been in disuse because of many inherent problems when there is not congruence between geography and the phylogenetic tree of the species (ie, sympatric speciation, species extinction or dispersal). The development of molecular phylogenetics and its approaches to infer ancestral areas and times of diversification has displaced the use of cladistics biogeography and/or vicariance biogeography.

Species Richness and Diversity

Biogeography fundamentally relies on the categorization and ordering of biodiversity into units that can be measured, compared, and contrasted. Biologists categorize and order the natural world to make meaning of biogeography. The concept of a species is the oldest, most popular, and most debated biological unit to describe biodiversity and biogeography. Since Aristotle through to the Middle Ages, the Enlightenment, and up to the present, the concept of a species has undergone countless transformations (Wilkins, 2009). In fact, an exact universal working definition is likely to never exist because of the growing number of organisms and populations that continue to defy all proposed taxonomic, reproductive, or genetic definitions. The “species problem“ is still stimulating to some, but ultimately trivial – with most fields of biology tailoring definitions for purposes of human understanding on a taxon-by-taxon case and using species or other taxonomic units when it makes sense (Ehrlich, 1997; Kelt and Brown, 2000). Unfortunately, this has been largely miscommunicated, leading to the misconception that biodiversity and species diversity are equivalents. This mishap has been described as “biology's biggest blunder” and has stunted clear understanding of the state of biodiversity and biogeography (Woodwell, 2010).

Despite the artificial difficulties with the species concept, quantifying biogeography using species as units is always the first tool ecologists turn to because of its efficiency – counting species is far faster and easier than identifying and tallying populations or piecing together interaction webs. The species concept is a particularly useful unit for countryside biogeographers who are largely interested in comparing biodiversity's responses to human influences. The first measure is usually species richness, or the number of different species in a given area, which is later followed by an index of species diversity, which incorporates species and their abundances within an area. Species richness and diversity are deployed first in countryside biogeography, but, ideally, countryside biogeography also measures biodiversity using ecosystem components that determine function.

What is the geographic distribution of species?

What are species called that are found in only one geographic location?

What does species mean in geography?

Is defined as a species within a specific geographic area?