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

AGUILAR RAMIRO; QUESADA MAURICIO; ASHWORTH LORENA; HERRERIAS-DIEGO YVONNE; LOBO JORGE

MOLECULAR ECOLOGY

Blackwell Publishing (Wiley Interscience)

Año: 2008 p. 5177 - 5188

0962-1083

Conservation of genetic diversity, one of the three main forms of biodiversity, is a fundamental concern in conservation biology as it provides the raw material for evolutionary change 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 diversity of plant populations and that certain plant’s life history and ecological traits can determine differential susceptibility to genetic erosion in fragmented habitats. Additionally, we assessed whether certain methodological approaches used by authors determine the ability of detecting fragmentation effects on plant genetic diversity. We found overall large and negative effects of fragmentation on genetic diversity and outcrossing rates but no effects on inbreeding coefficients. Significant increases on inbreeding coefficient in fragmented habitats were only observed in progenies. The mating system and the rarity status of plants explained the highest proportion of variation in the effect sizes among species. The time elapsed in fragmentation condition was also decisive in explaining variability among effect sizes: the larger the numbers of generations elapsed in fragmentation conditions the larger negative magnitude of effect sizes on Heterozygosity. Our results also suggest that fragmentation is affecting mating patterns towards increased selfing. We conclude that current conservation efforts in fragmented habitats should be focused on common or recently rare species and mainly outcrossing species and outline important issues that need to be addressed in future research on this area.