Genetic consequences of habitat fragmentation in plant populations: global and souther patterns

AGUILAR RAMIRO; QUESADA MAURICIO; ASHWORTH LORENA

Bariloche, Argentina

Simposio; VI Southern Connexion Congress; 2010

Southern Connexion Asociation

<!-- @page { margin: 2cm } P { margin-bottom: 0cm; text-align: justify } P.western { font-family: "Arial", sans-serif } P.cjk { font-family: "Arial", sans-serif } P.ctl { font-family: "Arial", sans-serif; font-size: 11pt } --> The loss and fragmentation of habitats by human activities are pervasive phenomena in terrestrial ecosystems and the main current driving forces behind biodiversity loss. Much research has been conducted worldwide to evaluate fragmentation effects on plant population genetic parameters. We quantitatively reviewed the results of fragmentation studies to test the general hypothesis that fragmentation affects the genetic diversity of plant populations. We also assessed whether fragmentation has differential effects depending on certain life history and ecological traits of plants, and tested whether particular methodological approaches influence the ability to detect genetic erosion in fragmentation studies. Overall, genetic diversity and outcrossing rates of plants decreased in fragmented habitats. Outcrossing and either common or recently rare plants showed strongest negative effects on their genetic diversity. Higher inbreeding coefficients were only observed in studies analyzing progenies in fragmented habitats. Finally, the time elapsed in fragmentation conditions significantly influenced the magnitude of effects. Results suggest that fragmentation is shifting mating patterns towards increased selfing. Remarkably, only 20% of the studies were conducted in the Southern Hemisphere (SH). Although main general response patterns remain similar within this set of studies, I will discuss some particular trends observed in species from the SH and compare them with global patterns.