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Estructura Genética de Poblaciones Fragmentadas de la Margarita Rutidosis leptorrhynchoides , Amenazada de Extinción
Author(s) -
Young A. G.,
Brown A. H. D.,
Zich F. A.
Publication year - 1999
Publication title -
conservation biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.2
H-Index - 222
eISSN - 1523-1739
pISSN - 0888-8892
DOI - 10.1046/j.1523-1739.1999.013002256.x
Subject(s) - biology , genetic diversity , genetic erosion , inbreeding depression , small population size , genetic structure , population , ecology , inbreeding , population fragmentation , habitat fragmentation , endangered species , population size , species richness , effective population size , genetic variation , conservation genetics , genetic divergence , range (aeronautics) , allele , habitat , microsatellite , genetics , demography , materials science , composite material , sociology , gene
The endangered grassland daisy Rutidosis leptorrhynchoides has been subject to severe habitat destruction and fragmentation over the past century. Using allozyme markers, we examined the genetic diversity and structure of 16 fragmented populations. The species had high genetic variation compared to other plant species, and both polymorphism and allelic richness showed strong positive relationships with log reproductive population size, reflecting a loss of rare alleles (frequency of q < 0.1) in smaller populations. Fixation coefficients were positively related to size, due either to a lack of rare homozygotes in small populations or to Wahlund effects (owing to spatial genetic structure) in large ones. Neither gene diversity nor heterozygosity was related to population size, and other population parameters such as density, spatial contagion, and isolation had no apparent effect on genetic variation. Genetic divergence among populations was low , despite a large north‐to‐south break in the species’ current distribution. To preserve maximum genetic variation, conservation strategies should aim to maintain the five populations larger than 5000 reproductive plants, all of which occur in the north of the range, as well as the largest southern population of 626 plants at Truganina. Only one of these is currently under formal protection. High heterozygosity in smaller populations suggests that they are unlikely to be suffering from inbreeding depression and so are also valuable for conservation. Erosion of allelic richness at self‐incompatibility loci, however, may limit the reproductive capacity of populations numbering less than 20 flowering plants.