The effect of deforestation on the genetic diversity and structure in Acer saccharum (Marsh): Evidence for the loss and restructuring of genetic variation in a natural system

Abstract

The level and distribution of genetic diversity can be influenced by species life history traits and demographic factors, including perturbations that might produce population bottlenecks. Deforestation and forest fragmentation are common sources of population disturbance in contemporary populations of forest ecosystems. Although the genetic effects of forest fragmentation and deforestation have been examined by assessing levels of genetic variation in forest fragments that remain after logging, few considerations have been made of the populations that re-colonize once-cleared areas. Here we examine the effects of humanmediated population bottlenecks on the level and distribution of genetic diversity in natural populations of the long-lived forest tree species, Acer saccharum (sugar maple). We compared genetic variation and structure for populations of sugar maple found within old-growth forested area and in area that has recolonized since logging. In this study the percent polymorphic loci and allelic richness estimates were reduced in the logged populations compared to old-growth populations. Jackknifed estimates of population genetic differentiation showed significantly higher differentiation among logged populations, with this result being consistently seen when individuals within populations were grouped according to diameter at breast height. The result of decreased genetic variation and higher levels of genetic structure among logged populations suggests that even one extensive bout of logging can alter the level and distribution of genetic variation in this forest tree species.

Genetic variability of Italian southern Scots pine (Pinus sylvestris L.) populations: the rear edge of the range

“…SigniWcant eVects of fragmentation on genetic diVerentiation among populations have been conWrmed in several forest tree species (e.g. Bacles et al 2004;Persson et al 2004;Baucom et al 2005;Jump and Penuelas 2006;Arnaud-Haond et al 2006). In our study, the AMOVA based on nSSR data attributed all the among-population variability to the among-population within-region component (percentage of variance: 8%, P = 0.001), representing diVerentiation among the Apennine populations.…”

“…SigniWcant eVects of fragmentation on genetic diversity have been found in several forest tree species (e.g. Persson et al 2004;Rossetto et al 2004;Baucom et al 2005;Jump and Penuelas 2006;Arnaud-Haond et al 2006). However, most of the research on the eVects of fragmentation in forest trees has been conducted on tropical species, thought to be particularly vulnerable due to their demographic and reproductive characteristics.…”

Genetic effects of forest fragmentation in high-density Araucaria angustifolia populations in Southern Brazil

“…Effects of fragmentation on genetic diversity, as loss of alleles and increase in inbreeding coefficient, have been also reported in some animal-pollinated tropical tree species, for example, Eucalyptus albens (Prober and Brown 1994), Pithecellobium elegans (Hall et al 1996), Symphonia globulifera (Aldrich et al 1998), and Swietenia humiles (White et al 1999). Forest logging has been also reported to reduce percent of polymorphic loci and allelic richness in a logged population compared to old-growth populations of temperate Acer sacchatum (Baucom et al 2005).…”

Genetic diversity of Oreopanax xalapensis (Araliaceae) in the Highlands of Chiapas

“…Por otra parte, es probable que ocurra una incorporación constante de individuos, con genotipos distintos, mediante la reproducción in situ pero posiblemente es a través de la dispersión de semillas promovida por diversas especies de aves que conjuntamente contribuyen a un aporte constante de variantes genéticas como se ha observado en otras plantas tropicales (Hamrick y Loveless, 1986 No obstante el posible el flujo genético entre las subpoblaciones hay una diferenciación moderada entre ellas, revelada por el estadístico F ST (0.25) y por la heterogeneidad de las frecuencias alélicas, lo cual puede ser reflejo de la influencia de factores que moldean la diversidad genética (Neigel, 2002). Estos factores pueden estar asociados a eventos de selección o deriva genética y estos a su vez con la historia de uso del bosque (Lande, 1999;Vornam et al, 2004;Baucom et al, 2005). Sin embargo, no se encontró evidencia de una relación entre el grado de perturbación con la diversidad genética.…”