Effects of the Ecuadorian Andes on genetic structure of the spectacled bear with new genetic datasets

The Andes arguably contains the most important biodiversity hot spot (Tropical Andes) in the world and is home to the only extant bear (spectacled bear, Tremarctos ornatus), in South America. Two molecular population genetics studies of the spectacled bear were recently carried out in Ecuador. However, these studies had contradictory results, which could hinder the development of an adequate conservation program for this species. To resolve this issue, we analyzed three molecular data sets representing a broad geographical sampling effort. The sets included six mitochondrial (mt) genes of 127 specimens, complete mitogenomes of 43 specimens, and seven nuclear DNA microsatellites of 88 specimens. The main results were as follows. (1) The mt genetic diversity levels obtained for the six mt gene data set were high and identical to the estimates of the two previous studies regardless of whether specific mt primers for this species were used. (2) The analysis of the six mt genes and mitogenome data revealed genetic heterogeneity among the spectacled bear samples of different Ecuadorian provinces, including significant heterogeneity between the northernmost and southernmost Ecuadorian areas. However, this heterogeneity is relatively small. (3) The genetic diversity levels with heterologous microsatellites were undifferentiable from the genetic levels reported with homologous microsatellites in a previous study. (4) Analysis of the microsatellite data set indicated a more significant spatial structure than previously reported. Up to seven different genetic clusters were detected but mixed in different areas of Ecuador. However, when they were analyzed at the province level only one unique genetic cluster was supported. (5) Based on these data, we suggest a single management plan for the entire spectacled bear population in Ecuador rather than a different management plan for each small spectacled bear population as suggested elsewhere.