Genetic patterns and conservation of the Scarlet Macaw (Ara macao) in Costa Rica

Abstract

Once widely distributed throughout the lowland forests of Costa Rica, scarlet macaws (Ara macao) have been reduced to two major, geographically separated, populations along the Pacific slope. Past demographic declines raise conservation concerns regarding the detrimental effects of population fragmentation. This investigation aimed to evaluate the current status of scarlet macaws along the Pacific slope by examining levels of genetic variation and patterns of genetic structure within and among remnant populations. Statistical analyses using multilocus genotypes revealed strong differentiation between Central and South Pacific populations, suggesting local geographic barriers have historically restricted gene flow between these localities. High genetic diversity suggests neither population suffers from genetic erosion, likely resulting from relatively large population sizes and high dispersal capacity and longevity. However, evidence of disequilibrium within the Central Pacific population infers anthropogenic threats have disrupted natural population dynamics. These results advocate on focusing available resources on habitat restoration and nest protection, as a means to assist in reestablishing demographic stability and maintain the genetic health of wild scarlet macaws in Costa Rica.

Fine-scale genetic structure in the critically endangered red-fronted macaw in the absence of geographic and ecological barriers

“…Depending on the magnitude of connectivity between populations and on the reproductive outcomes of dispersers, the genetic structure and diversity can be more or less pronounced. This variability can be further modulated by historical trends due to past and ongoing threats eroding the viability of isolated nuclei and of highly fragmented and small populations of threatened species [20][21][22] . The influence of isolation by social barriers on the genetic structure of threatened species has been generally overlooked, often through assumptions that connectivity is generally disrupted due to population fragmentation associated with habitat loss and population declines.…”

Current trends in the application of non-invasive genetic sampling to study Neotropical birds: Uses, goals, and conservation potential

“…52 Shed feathers collected from medium- and large-bodied Neotropical birds were used as source of DNA to isolate microsatellites, 32,44 assign parentage and relatedness, 9,32,39 perform molecular sexing, 32,47 assess levels of microsatellites’ variation, and describe phylogenetic patterns. 9,38,47 In addition, feather-derived DNA was used to assess population structure, 33,42,45,46,48 amplify major histocompatibility complex genes to help estimate minimum viable population sizes, 31 and molecularly identify species. 43,44…”

“…Feces, eggs, and carcasses were also used, although in a limited manner, in conservation genetic studies of Neotropical avifauna. We found only one study using feces as primary source of DNA, 42 despite the use of this sample type in genetic studies of temperate birds for more than 15 years. 53,54 Eggs were used as source of DNA for the molecular identification of three Neotropical parrot and one owl species victims of illegal traffic, 37 and to assess the genetic diversity of the critically endangered Brazilian Merganser ( Mergus octosetaceus ).…”

Conservación de la lapa roja (Ara macao) con manejo in situ en el Pacífico Central de Costa Rica

“…Los análisis de genotipos multilocus revelaron una fuerte diferenciación entre dichas poblaciones, sugiriendo que barreras geográficas locales, históricamente, interrumpieron el flujo genético entre localidades. Sin embargo, ambas tenían alta diversidad genética, lo cual indicaba que no sufrían erosión genética (Monge et al, 2016). Estos resultados señalaron la necesidad de restaurar el hábitat y proteger las aves, con el propósito de ayudar a mantener la estabilidad demográfica y su salud genética, descartando por completo el requerimiento de liberar lapas criadas en cautiverio para manejar la genética de esas poblaciones.…”