Paleoendemism
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.
Etymology
[edit]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]
Causes
[edit]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]
Examples
[edit]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:
- Abies frasieri
- Asplenium scolopendrium var. americanum
- Franklinia alatahama
- Gaylussacia brachycera
- Gymnocladus dioicus
- Taxus floridana
- Torreya taxifolia
- Vandenboschia boschiana
Paleoendemism on islands
[edit]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.
See also
[edit]References
[edit]- ^ a b Stebbins, G. Ledyard; Major, Jack (1965). "Endemism and Speciation in the California Flora". Ecological Monographs. 35 (1): 2–35. Bibcode:1965EcoM...35....1S. doi:10.2307/1942216. JSTOR 1942216.
- ^ Vargas, Pablo (2007). "Are Macaronesian islands refugia of relict plant lineages?: A molecular survey". Phylogeography of Southern European Refugia. pp. 297–314. doi:10.1007/1-4020-4904-8_11. ISBN 978-1-4020-4903-3.
- ^ a b c Harrison, Susan; Noss, Reed (January 2017). "Endemism hotspots are linked to stable climatic refugia". Annals of Botany. 119 (2): 207–14. doi:10.1093/aob/mcw248. PMC 5321063. PMID 28064195.
- ^ Sandel, B.; Arge, L.; Dalsgaard, B.; Davies, R. G.; Gaston, K. J.; Sutherland, W. J.; Svenning, J.- C. (6 October 2011). "The Influence of Late Quaternary Climate-Change Velocity on Species Endemism". Science. 334 (6056): 660–4. Bibcode:2011Sci...334..660S. doi:10.1126/science.1210173. PMID 21979937.
- ^ Royer, Dana L.; Hickey, Leo J.; Wing, Scott L. (March 2003). "Ecological conservatism in the 'living fossil' Ginkgo". Paleobiology. 29 (1): 84–104. doi:10.1666/0094-8373(2003)029<0084:ECITLF>2.0.CO;2.
- ^ MacArthur, Robert H.; Wilson, Edward O. (2001-03-18). The Theory of Island Biogeography. Princeton University Press. ISBN 9780691088365. Retrieved 2019-03-06.