CRB: Conservation Genetics of Tropical Forest Trees

点击翻译按钮获取中文摘要

9400147 Bawa The overall aim of this proposal is the examine the effect of deforestation and forest fragmentation on genetic diversity, gene dispersal, and mating patterns in tropical lowland rain forests of Costa Rica. The specific goals are to: (1) measure the amount of genetic differentiation in tropical tree populations over relatively small spatial scales, (2) ascertain if a matrix of fragmented populations possesses the same level of genetic diversity as a large forest area of equal size, (3) calculate the levels of gene flow in a large contiguous forest, among small fragments, and between fragments and large forest reserves, (4) assess the level of inbreeding for trees in small fragments and compare this to trees in large contiguous forests, and (5) determine if a decline in outbreeding is associated with inbreeding depression. Genetic variation will be studies using a variety of genetic markers and morphological traits. Simple Sequence Repeats (SSR's) that have been developed by the PI for tropical tree species will be used to estimate levels of gene flow and inbreeding. SSR's loci are highly variable with a tremendous discriminatory power, but have not been used in the study of natural populations of plants. %%% Deforestation and forest fragmentation are ubiquitous in the tropics and are presumed to result in loss of biodiversity, including genetic diversity within species. However, there are no estimates of loss of genetic diversity within species of tropical forest trees. One reason for this lack of knowledge is that the population genetics of tropical trees is poorly understood. Moreover, the genetic consequences of forest fragmentation depend on the levels of gene exchange among fragments and between fragments and large continuous tracts of forest. The information attained from this research will be useful in assessing the impact of deforestation on genetic diversity. This research will also provide information about the comparative utility of various markers for estimating pop ulation genetic parameters.