Genetic variability, management, and conservation implications of the critically endangered Brazilian pitviper Bothrops insularis

Information on demographic, genetic, and environmental parameters of wild
and captive animal populations has proven to be crucial to conservation
programs and strategies. Genetic approaches in conservation programs of
Brazilian snakes remain scarce despite their importance for critically
endangered species, such as Bothrops insularis, the golden lancehead,
which is endemic to Ilha da Queimada Grande, coast of São Paulo State,
Brazil. This study aims to (i) characterize the genetic diversity of
ex-situ and in-situ populations of B. insularis using heterologous
microsatellites; (ii) investigate genetic structure among and within these
populations; and (iii) provide data for the conservation program of the
species. Twelve informative microsatellites obtained from three species of
the B. neuwiedi group were used to access genetic diversity indexes of
ex-situ and in-situ populations. Low-to-medium genetic diversity
parameters were found. Both populations showed low — albeit significant —
values of system of mating inbreeding coefficient, whereas only the
in-situ population showed a significant value of pedigree inbreeding
coefficient. Significant values of genetic differentiation indexes suggest
a small differentiation between the two populations. Discriminant analysis
of principal components (DAPC) recovered five clusters. No geographic
relationship was found in the island, suggesting the occurrence of gene
flow. Also, our data allowed the establishment of six preferential
breeding couples, aiming to minimize inbreeding and elucidate uncertain
parental relationships in the captive population. In a conservation
perspective, continuous monitoring of both populations is demanded: it
involves the incorporation of new individuals from the island into the
captive population to avoid inbreeding and to achieve the recommended
allelic similarity between the two populations. At last, we recommend that
the genetic data support researches as a base to maintain a viable and
healthy captive population, highly genetically similar to the in-situ one,
which is crucial for considering a reintroduction process into the island.