Abstract

Although guanacos (Lama guanicoe) are widely distributed throughout much of their historic range, they are often restricted to small, isolated populations that are at risk of inbreeding and loss of genetic diversity. Here we assess a population inhabiting private ranches in the Bolivian Chaco threatened by hunting and habitat reduction. The region, once open grasslands, is dominated by dense shrubs from livestock grazing. The most-recent census identified only 74 individual and was designated as at “risk of extinction” by the Bolivian government. We assessed the population’s genetic health and uniqueness from the genetic patterns of 16 well-characterized microsatellite loci and the Hyper-variable Domain I of the mitochondrial Control Region with 29 fecal samples. Sex was determined amplifying a 162-bp fragment of the male SRY gene. We identified 19 male and 10 unique individuals. Microsatellite variation (Ho=0.64) was similar to larger, less-isolated populations. However, the estimated effective population size (Ne) of 34 individuals was low and indicated continuing loss of allelic variation. The two observed mtDNA haplotypes are common in other L. g. guanicoe populations. Although we documented moderate genetic diversity, gene flow among Bolivian and Paraguayan guanaco Chaco populations should be assessed and integrated into explicit conservation management plans.