Effects of forest fragmentation on the spatial genetic structure of Acer saccharum Marsh. (sugar maple) populations

Abstract

To examine the effects of forest fragmentation on within-population genetic structure of Acer saccha rum, the spatial distributions of allozyme variation in the first-year seedling cohorts of four forest patch populations (patches) were compared with those of four populations within continuous forest (controls). Forest patch populations exhibited less spatial mixing of genotypes than controls at the smallest scale examined (10-14.1 m), possibly as a result of reduced overlap of seed shadows in patches, which generally had lower densities of reproductive trees. Patch populations exhibited greater mixing of genotypes than controls at the largest scale examined (113.1-141.4 m), possibly as a result of the incorporation of immigrant pollen pools into mating events at forest patch edges. This may extend the spatial range of patch population breeding associations which might otherwise be truncated owing to limited forest patch area. Overall, results suggest that mating events are probably the primary determinant of spatial genetic structure within these cohorts in both forest patch and control populations of A. saccharum and that forest fragmentation has affected genetic structure by changing patterns of gene flow within, and possibly among, forest patch populations.

Spatial structure of genetic variability in natural stands of Fagus sylvatica L. (beech) in Italy

“…In two French populations only five out of 35 and two out of 20 significant SNDs were found. Similar patterns have been found for the coniferous species Pinus contorta (Epperson & Allard, 1989), Picea mariana (Knowles, 1991), Picea abies (Leonardi et a!., 1996) and for the broadleaved species Acer saccharum (Perry & Knowles, 1991;Young & Merriam, 1994), Quercuspetraea and Q. robur (Bacilieri et al, 1994). In this study most genotypes were apparently randomly located within the population.…”

Joint analysis of spatial genetic structure and inbreeding in a managed population of Scots pine

“…Forest management practices have also been shown to increase genetic structure compared with natural forests, especially if the breeding practices imply drastic reduction of the effective population size (Young and Merriam, 1994;Finkeldey and Ziehe, 2004). Population size reduction could potentially increase the rate of selffertilization because of the reduction in number of local compatible mates.…”

Genetic Diversity and Structure of Natural Quercus variabilis Population in China as Revealed by Microsatellites Markers

“…In addition, human activities may also have an impact on the genetic structure of various species [65][66][67]. However, the results of the present study showed that among the 19 Q. variabilis populations, the population in the center of the distribution did not experience a bottleneck effect, whereas three populations at the periphery (FJ, PS, CZ) did, and three genetic lineages (cluster I,II and III) obtained from STRUCTURE showed distributions in every population (Figures 4 and 5).…”