Genetic consequences of habitat fragmentation in plant populations: susceptible signals in plant traits and methodological approaches

AGUILAR, R., QUESADA, M., ASHWORTH, L., HERRERIAS-DIEGO, Y. & LOBO

MOLECULAR ECOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2008 vol. 17 p. 5177 - 5188

0962-1083

Conservation of genetic diversity, one of the three main forms of biodiversity, is a fundamentalconcern in conservation biology as it provides the raw material for evolutionarychange and thus the potential to adapt to changing environments. By means of meta-analyses,we tested the generality of the hypotheses that habitat fragmentation affects genetic diversityof plant populations and that certain life history and ecological traits of plants can determinedifferential susceptibility to genetic erosion in fragmented habitats. Additionally, weassessed whether certain methodological approaches used by authors influence the abilityto detect fragmentation effects on plant genetic diversity. We found overall large and negativeeffects of fragmentation on genetic diversity and outcrossing rates but no effects oninbreeding coefficients. Significant increases in inbreeding coefficient in fragmentedhabitats were only observed in studies analyzing progenies. The mating system and the raritystatus of plants explained the highest proportion of variation in the effect sizes amongspecies. The age of the fragment was also decisive in explaining variability among effectsizes: the larger the number of generations elapsed in fragmentation conditions, the largerthe negative magnitude of effect sizes on heterozygosity. Our results also suggest that fragmentation is shifting mating patterns towards increased selfing. We conclude that currentconservation efforts in fragmented habitats should be focused on common or recently rarespecies and mainly outcrossing species and outline important issues that need to beaddressed in future research on this area.