AFLP diversity and spatial structure of Calycophyllum candidissimum (Rubiaceae), a dominant tree species of Nicaragua’s critically endangered seasonally dry forest
| Autor: | Alberto Dávila-Lara, Matthias Affenzeller, V. Díaz, Andreas Tribsch, Hans-Peter Comes |
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| Rok vydání: | 2017 |
| Předmět: |
0106 biological sciences
0301 basic medicine Gene Flow Seed dispersal Population Endangered species Population genetics Nicaragua Rubiaceae Biology Forests 010603 evolutionary biology 01 natural sciences 03 medical and health sciences Genetics Amplified Fragment Length Polymorphism Analysis education Genetics (clinical) Isolation by distance education.field_of_study Genetic diversity Habitat fragmentation Models Genetic Ecology Endangered Species Genetic Variation Bayes Theorem South America 030104 developmental biology Genetics Population Biological dispersal Original Article Seasons |
| Zdroj: | Heredity |
| Popis: | The Central American seasonally dry tropical (SDT) forest biome is one of the worlds’ most endangered ecosystems, yet little is known about the genetic consequences of its recent fragmentation. A prominent constituent of this biome is Calycophyllum candidissimum, an insect-pollinated and wind-dispersed canopy tree of high socio-economic importance, particularly in Nicaragua. Here, we surveyed amplified fragment length polymorphisms across 13 populations of this species in Nicaragua to elucidate the relative roles of contemporary vs historical factors in shaping its genetic variation. Genetic diversity was low in all investigated populations (mean HE= 0.125), and negatively correlated with latitude. Overall population differentiation was moderate (ΦST =0.109, Po0.001), and Bayesian analysis of population structure revealed two major latitudinal clusters (I: ‘Pacific North’+’Central Highland’; II: ‘Pacific South’), along with a genetic cline between I and II. Population-based cluster analyses indicated a strong pattern of ‘isolation by distance’ as confirmed by Mantel’s test. Our results suggest that (1) the low genetic diversity of these populations reflects biogeographic/population history (colonisation from South America, Pleistocene range contractions) rather than recent human impact; whereas (2) the underlying process of their isolation by distance pattern, which is best explained by ‘isolation by dispersal limitation’, implies contemporary gene flow between neighbouring populations as likely facilitated by the species’ efficient seed dispersal capacity. Overall, these results underscore that even tree species from highly decimated forest regions may be genetically resilient to habitat fragmentation due to species-typical dispersal characteristics, the necessity of broad-scale measures for their conservation notwithstanding. |
| Databáze: | OpenAIRE |
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