Paleoendemism along with neoendemism is a possible subcategory 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.
The first part of the word, paleo, comes from the Greek word palaiós, meaning "ancient". [1] The second part of the word, endemism is from Neo-Latin endēmicus, from Greek ενδήμος, endēmos, "native". Endēmos is formed of en meaning "in", and dēmos meaning "the people". [2]
Changes in climate are thought to be the driving force in creating paleoendemic species, generally due to habitat loss. Regions where the climate has remained relatively stable form refugia which are more likely to be endemic hotspots today. [3] This applies to both neoendemism and paleoendemism. However, paleoendemism differs as it does not require additional factors such as barriers and ecological opportunities as it does not rely on adaptive radiation like neoendemism does. [3] It instead relies on the instability of other regions' climate, which may limit the range of a species to a more stable region, thus turning that species paleoendemic. Limited ability for dispersal is also important in the creation of endemic species. [4] The two terms can essentially be defined as "cradles" of new species (neoendemism), or "museums" of old species (paleoendemism). [3]
It is not always clear whether a particular species is paleoendemic or neoendemic.
Ginkgos are a paleoendemic genus. From the Mesozoic to the mid-Cenozoic, these trees could be found throughout the world. However, today, they can only be found in China in the wild. [5]
Several examples occur in plants native to the southeastern United States:
Islands as harbors for endemic species are explained by the theory of island biogeography. [6] However, in order to be considered a paleoendemic on an island, the species must have had a widespread distribution previously, [1] thus eliminating newly formed islands as potential refuges of paleo-endemics.
An island or isle is a piece of subcontinental land completely surrounded by water. There are continental islands, which were formed by being split from a continent by plate tectonics, and oceanic islands, which have never been part of a continent. Oceanic islands can be formed from volcanic activity, grow into atolls from coral reefs, and form from sediment along shorelines, creating barrier islands. River islands can also form from sediment and debris in rivers. Artificial islands are those made by humans, including small rocky outcroppings built out of lagoons and large-scale land reclamation projects used for development.
Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, isolation and habitat area. Phytogeography is the branch of biogeography that studies the distribution of plants. Zoogeography is the branch that studies distribution of animals. Mycogeography is the branch that studies distribution of fungi, such as mushrooms.
Allopatric speciation – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow.
Zelkova is a genus of six species of deciduous trees in the elm family Ulmaceae, native to southern Europe, and southwest and eastern Asia. They vary in size from shrubs to large trees up to 35 m (115 ft) tall. The bark is smooth, dark brown. Unlike the elms, the branchlets are never corky or winged. The leaves are alternate, with serrated margins, and a symmetrical base to the leaf blade. The leaves are in two distinct rows; they have pinnate venation and each vein extends to the leaf margin, where it terminates in a tooth. There are two stipules at each node, though these are caducous, leaving a pair of scars at the leaf base. Zelkova is polygamous. Staminate flowers are clustered in the lower leaf axils of young branchlets; the perianth is campanulate, with four to six lobes, and the stamens are short. Pistillate and hermaphrodite flowers are solitary, or rarely in clusters of two to four, in the upper leaf axils of young branchlets. The fruit is a dry, nut-like drupe with a dorsal keel, produced singly in the leaf axils. The perianth and stigma are persistent.
The Atlantic Forest is a South American forest that extends along the Atlantic coast of Brazil from Rio Grande do Norte state in the northeast to Rio Grande do Sul state in the south and inland as far as Paraguay and the Misiones Province of Argentina, where the region is known as Selva Misionera.
A biodiversity hotspot is a biogeographic region with significant levels of biodiversity that is threatened by human habitation. Norman Myers wrote about the concept in two articles in The Environmentalist in 1988 and 1990, after which the concept was revised following thorough analysis by Myers and others into "Hotspots: Earth's Biologically Richest and Most Endangered Terrestrial Ecoregions" and a paper published in the journal Nature, both in 2000.
Endemism is the state of a species only being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be endemic to that particular part of the world. An endemic species can also be referred to as an endemism or, in scientific literature, as an endemite.. Similarly many species found in the Western ghats of India are examples of endemism.
The biodiversity of New Caledonia is of exceptional biological and paleoecological interest. It is frequently referred to as a biodiversity hotspot. The country is a large South Pacific archipelago with a total land area of more than 18,000 square kilometres (6,900 sq mi). The terrain includes a variety of reefs, atolls, small islands, and a variety of topographical and edaphic regions on the largest island, all of which promote the development of unusually concentrated biodiversity. The region's climate is oceanic and tropical.
In biology, a refugium is a location which supports an isolated or relict population of a once more widespread species. This isolation (allopatry) can be due to climatic changes, geography, or human activities such as deforestation and overhunting.
The Eastern Arc Mountains are a chain of mountains found in Kenya and Tanzania. The chain runs from northeast to southwest, with the Taita Hills being in Kenya and the other ranges being in Tanzania. They are delimited on the southwest by the fault complex represented by the Makambako Gap that separates them from the Kipengere Range. To the northeast, they are delimited by more recent volcanism represented by Mount Kilimanjaro. The chain is considered a tentative World Heritage Site.
Last Glacial Maximum refugia were places (refugia) in which humans and other species survived during the Last Glacial Period, around 25,000 to 18,000 years ago. Glacial refugia are areas that climate changes were not as severe, and where species could recolonize after deglaciation.
The Paleotropical Kingdom (Paleotropis) is a floristic kingdom composed of the tropical areas of Africa, Asia and Oceania, as proposed by Ronald Good and Armen Takhtajan. Part of its flora is inherited from the ancient supercontinent of Gondwana or exchanged later. These Gondwanan lineages are related to those in the Neotropical Kingdom, composed of the tropical areas of Central and South America. Flora from the Paleotropical Kingdom influenced the tropical flora of the Australian Kingdom. The kingdom is subdivided into five floristic subkingdoms according to Takhtajan and about 13 floristic regions. In this article the floristic subkingdoms and regions are given as delineated by Takhtajan.
The Carboniferous rainforest collapse (CRC) was a minor extinction event that occurred around 305 million years ago in the Carboniferous period. The event occurred at the end of the Moscovian and continued into the early Kasimovian stages of the Pennsylvanian.
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 currently inhabiting a restricted area whose range was far wider during a previous geologic epoch. Similarly, a relictual taxon is a taxon which is the sole surviving representative of a formerly diverse group.
A glacial refugium is a geographic region which made possible the survival of flora and fauna during ice ages and allowed for post-glacial re-colonization. Different types of glacial refugia can be distinguished, namely nunatak, peripheral, and lowland. Glacial refugia have been suggested as a major cause of floral and faunal distribution patterns in both temperate and tropical latitudes. With respect to disjunct populations of modern-day species, especially in birds, doubt has been cast on the validity of such inferences, as much of the differentiation between populations observed today may have occurred before or after their restriction to refugia. In contrast, isolated geographic locales that host one or more critically endangered species are generally uncontested as bona fide glacial refugia.
Neoendemism is one of two sub-categories of endemism, the ecological state of a species being unique to a defined geographic location. Specifically, neoendemic species are those that have recently arisen, through divergence and reproductive isolation or through hybridization and polyploidy in plants. Paleoendemism, the other sub-category, refers to species that were formerly widespread but are now restricted to a smaller area.
The vegetation in Tasmania's alpine environments is predominately woody and shrub-like. One vegetation type is coniferous shrubbery, characterised by the gymnosperm species Microcachrys tetragona, Pherosphaera hookeriana, Podocarpus lawrencei, and Diselma archeri. Distribution of these species is relevant with abiotic factors including edaphic conditions and fire frequency, and increasingly, the threat of climate change towards species survival exists. Conservation and management of coniferous shrubbery are necessary considering that the paleoendemic species, Microcachrys,Pherosphaera and Diselma, have persisted in western Tasmanian environments for millions of years.
A glacial relict is a population of a species previously common during a glacial period that retreated into refugia during interglacial periods. They are typically cold-adapted species with a distribution restricted to regions and microhabitats that allow them to survive despite climatic changes.
The Mediterranean Biogeographic Region is the biogeographic region around and including the Mediterranean Sea. The term is defined by the European Environment Agency as applying to the land areas of Europe that border on the Mediterranean Sea, and the corresponding territorial waters. The region is rich in biodiversity and has many endemic species. The term may also be used in the broader sense of all the lands of the Mediterranean Basin, or in the narrow sense of just the Mediterranean Sea.
The Biodiversity of South Africa is the variety of living organisms within the boundaries of South Africa and its exclusive economic zone. South Africa is a region of high biodiversity in the terrestrial and marine realms. The country is ranked sixth out of the world's seventeen megadiverse countries, and is rated among the top 10 for plant species diversity and third for marine endemism.