Distribution of genetic diversity among disjunct populations of the rare forest understory herb, Trillium reliquum

Abstract Background Asarum sieboldii Miq., a species of forest understory vegetation, is an herbaceous perennial belonging to the family Aristolochiaceae. The metapopulation of A. sieboldii is distributed sparsely and has a short seed dispersal distance by ants as their seed distributor. It is known that many flowers of A. sieboldii depend on self-fertilization. Because these characteristics can affect negatively in genetic structure, investigating habitat structure and assessment of genetic structure is needed. A total of 27 individuals in a valley were sampled for measuring genetic diversity, genetic distance, and genetic differentiation by RAPD-PCR. Results The habitat areas of A. sieboldii metapopulation were relatively small (3.78~33.60 m2) and population density was very low (five to seven individuals in 20×20 m quadrat). The habitat of A. sieboldii was a very shady (relative light intensity = 0.9%) and mature forest with a high evenness value (J = 0.81~0.99) and a low dominance value (D = 0.19~0.28). The total genetic diversity of A. sieboldii was quite high (h = 0.338, I = 0.506). A total of 33 band loci were observed in five selected primers, and 31 band loci (94%) were polymorphic. However, genetic differentiation along the valley was highly progressed (Gst = 0.548, Nm = 0.412). The average genetic distance between subpopulations was 0.387. The results of AMOVA showed 52.77% of variance occurs among populations, which is evidence of population structuring. Conclusions It is expected that a small-scale founder effect had occurred, an individual spread far from the original subpopulation formed a new subpopulation. However, geographical distance between individuals would have been far and genetic flow occurred only within each subpopulation because of the low density of population. This made significant genetic distance between the original and new population by distance. Although genetic diversity of A. sieboldii metapopulation is not as low as concerned, the subpopulation of A. sieboldii can disappear by stochastic events due to small subpopulation size and low density of population. To prevent genetic isolation and to enhance the stable population size, conservative efforts such as increasing the size of each subpopulation or the connection between subpopulations are needed.

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Risk of local extinction and genetic diversity of Melipona quadrifasciata (Apidae: Meliponini) in a possible Northeastern limit of its distribution in Brazil

Sociobiology ◽

10.13102/sociobiology.v63i2.946 ◽

2016 ◽

Vol 63 (2) ◽

pp. 804 ◽

Cited By ~ 3

Author(s):

Edilson D Araújo ◽

Rosane Gomes Oliveira ◽

Higor Cesar Meneses Calazans ◽

Carina Caroline Silva França ◽

Valdson SANTOS ◽

...

Keyword(s):

Genetic Diversity ◽

Molecular Analysis ◽

Local Population ◽

Rapid Loss ◽

Unique Haplotype ◽

Population Extinction ◽

Nesting Site ◽

Disjunct Populations ◽

Eusocial Bees ◽

Issr Primers

Rapid loss of genetic diversity among eusocial bees, and extinction of their local population has become a major world concern. Populations of M. quadrifasciata have increasingly declined due to predatory extractivism and destruction of their habitat. Knowledge of their local population could give insights on the strategies for monitoring and conservation of this species. In this study, initially, 14 colonies (140 workers) from the Northern limit of the Northeastern sandbank of the Atlantic Forest were analyzed employing geometric morphometrics techniques. Then the cytochrome b gene sequences and ISSR primers were utilized for molecular analysis. The results were compared with the results of 30 M. quadrifasciata colonies (300 workers) found in the semiarid Caatinga region. The morphometrics and the molecular analysis suggested the formation of disjunct populations between the studied geographical zones. All the 14 colonies analyzed from the river São Francisco region were found on the Southern margin of the river São Francisco and they all belonged to one single haplotype. No colonies were found on the Northern bank of the river. We suggest that the river São Francisco is an effective georgraphical barrier for the distribution of this species and propose an urgent need for the development of a conservation program for the population of M. quadrifasciata as it represents a unique haplotype in the region. Also their nesting habit exclusively in the diseased coconut trees which probably will be replaced by new trees, create the risk of population extinction due to the lack of nesting site.

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