Biogeographic range

Example of geographical distribution area: Range area. (Acer)

The biogeographic area, geographic distribution or distribution area is the geographic space in which the populations of a species, a subspecies or another type of taxon. The specialty that within biogeography deals with the specific areas of taxa is called chorology. Within a certain area of biogeographic distribution, species can adopt different modes of distribution.

In ecology and biogeography the study of the characteristics of areas is an important chapter. The area is linked, for example, with demography and with the chances of survival of the taxa. The fragmentation of the area due to alteration due to economic development is one of the major issues in conservation biology.

The extension is one of the fundamental parameters, but not the only one. A species is cosmopolitan or ubiquitous when it finds and occupies suitable habitats on all continents or in all oceans. The human species is a perfect example, as are its companions, the cockroach, the house fly or the house sparrow.

At the opposite extreme, a species is endemic when it occurs in a very restricted area. An endemism may be found in the area where it originated, as is the case with many island species and other dispersed habitats (eg isolated mountains), in which case they may be said to be neoendemic. A paleoendemism is a species whose restricted distribution represents only a small part of a larger earlier one, generally far from the area in which it arose evolutionarily. It can be said in this case that the species occupies a relict area.

An important parameter of the area of a species is its continuous or discontinuous character (in chorology the term «disjoint area» is used). The distribution of an evolutionarily new species is naturally continuous, but the hazards of climate change, epidemics, or ecological competition can lead to its fragmentation. Once the area is divided into several separate ones, evolution can lead to different destinations for the populations of each area, interpreting that this is one of the most important mechanisms involved in the differentiation of new species (allopatric speciation).

Distribution of biomes

A related but distinct biogeographic issue is that of the distribution of biomes, assemblages of species, and communities that extend over an area that is climatically and historically (in the sense of biological, community history) homogeneous. originally). A biogeographic province, region or realm is a terrestrial or maritime area occupied by a characteristic biome (defined by the taxa and communities that comprise it).

The terms fauna province or zoogeographic region are used when only referring to the animal part of the biota, that is, the fauna; Similarly, it is said floral or phytogeographic kingdom when it refers to the flora, the part of the biota formed by plants.

Abiotic factors

Thaumetopoea pityocampa, expanded its distribution area to the north in France.

Gradients in climatic factors create physiological barriers to dispersal. All species have limits of tolerance to abiotic factors, which can reduce their survival and reproductive success and limit range expansion beyond the limit. Changes in temperature can cause a species to change its geographic range. With rising temperatures as a result of global warming, species in the Northern Hemisphere have been seen to expand their range northward due to increased survival and reproduction as a result of warming. Precipitation may also be a determinant. key to limiting the limits of the geographic distribution area of the species. This is often seen in organisms with high water demands, whose survival and reproduction would decrease beyond the edge due to dry conditions, limiting expansion. Soil or air moisture is also seen to limit area expansion. of distribution. In terms of soil moisture, limited range expansion is observed for species that feed on soil organisms or for species that reside in the soil and depend on it for nutrients. If moisture requirements are not met beyond the range of the species, they will not be able to expand due to resulting reductions in fitness. There are many other abiotic factors that can determine a species' range, including dissolved oxygen, canopy cover, conductivity, alkalinity, and pH.

Biotic factors

It has been determined that freshwater gastropod Lymnaea stagnalis It has a greater presence of trematodes parasites on the edge of its distribution area than in the center of it.

Interactions between species can cause limitations to the geographic range of a species. The most obvious interaction limiting range expansion is predation, where prey species do not move beyond their range to avoid predator attack and mortality. Geographic range boundaries they can also be determined by competition, where less competitive species are forced into suboptimal conditions within range to avoid stress from reduced food and habitat. The geographic range of one species may be linked to another, where the range of one species cannot extend independently of the other. This is seen in mutualistic relationships, where population fitness and growth are reduced outside the hosts' range where the symbiont is not present. Parasitism may also play a role in limiting species expansion outside of the hosts. its area of distribution. This occurs when there is a greater presence of infection at range boundaries which reduces population growth and survival, and ultimately reduces further expansion. A greater presence of parasites can occur when abiotic conditions are unfavorable at the edge, leading to lower species resistance to infection.

Anthropic factors

The red-eyed cowboy, Molothrus aeneus, continues to expand its biogeographic distribution area in New Mexico and Texas due to deforestation.

Humans are responsible for causing changes to the environment and habitat that plants and animals depend on for survival. These impacts have the potential to alter species behaviors, interactions, and distributions. Many areas are deforested to provide land for agricultural or industrial use. Deforestation can cause habitat loss for millions of species and can cause their biogeographic range to expand or contract. Species that prefer cleared land may expand into their range to take advantage of new habitat, however, species that require forests to survive, their biogeographic range may decline or change entirely. Global warming resulting from greenhouse gases emitted into the air has been observed to cause changes in the dispersal and biogeographic distribution of species. Due to rising temperatures, organisms move northward to reach slightly cooler temperatures. to seek out the environmental niche to which they are adapted. This allows them to continue stable survival and reproduction, and ultimately maintain their population. Humans have also initiated many range expansions by transporting species to new locations both intentionally and accidentally. These introduced species can survive and reproduce in these new locations and expand their geographic range whenever conditions are right. These species can also cause changes in the biogeographic range of native species that cannot tolerate competition from invasive species, which have novel ways of using resources.