When assessing the status of an endangered species, conservationists often take into account environmental factors, such as threats to habitat, and behavioral patterns of breeding and feeding. Increasingly, scientists also turn to genetic analysis to better understand threatened biodiversity. A recent study by Javier Gonzalez published in mongabay.com’s open-access journal, Tropical Conservation Science , explores the phylogenetic significance of the Masafuera Rayadito (Aphrastura masafuerae), Chile’s most endangered bird.
A member of the Furnariidae family, the small brown and beige bird possesses rusty “spine-like” tail feathers and inhabits densely vegetated areas. Scientists estimate the total population to range from 140 to 500 individuals. In 2012 the IUCN declared the Masafuera Rayadito to be a Critically Endangered species. With a distribution limited to a single island—Alejandro Selkirk—in the Juan Fernandez Archipelago off of Chile’s Pacific coast, the species is particularly vulnerable to extinction.
The Masafuera Rayadito (Aphrastura masafuerae) is endemic to Alejandro Slkirk Island, Chile. The IUCN lists the bird as Critically Endangered. Photo by: Javier Gonzalez.
While closely related taxa, including sister species, Thorn-tailed Rayadito (Aphrastura spinicauda), have previously undergone genetic study, Gonzalez conducts the first such investigation into the divergence of the Masafuera Rayadito from its mainland relatives.
The author extracted mitochondrial DNA from blood samples of two Masafuera Rayaditos and analyzed their nucleotide sequences.
The results of this study confirm that the Masafuera Rayadito and the thorn-tailed Rayadito are close relatives and estimate that the species diverged between 0.38 and 0.76 million years ago. These estimates are consistent with the geological age and origin of the Juan Fernandez Archipelago. “The level of genetic divergence between Aphrastura masafuerae and A. spinicuada supports a recent colonization of the Juan Fernandez Archipelago by the Masafuera Rayadito in the South Pacific Ocean, approximately 0.65 [million years] ago,” states Gonzalez in the study.
 Masafuera Rayadito habitat, Alejandro Selkirk Island, Archipelago de Juan Fernandez National Park, Chile. Photo by Javier Gonzalez. |
Due to its biogeographically remote location, Alejandro Selkirk Island harbors a notably high level of avian endemism—species found nowhere else in the world. In the case of the Masafuera Rayadito, uncertainty lingers about original colonization of the island. Gonzalez explains, “… [I]t remains unclear whether this avian species arrived at Alejandro Selkirk by a direct colonization from the mainland or from neighboring islands…”
According to Gonzalez’s study, the Masafuera Rayadito should remain a top conservation priority, as it represents a “taxonomically distinct” species and contributes critical phylogenetic diversity. Despite presumed population increases in the past decade, habitat loss by way of conversion to livestock grazing lands continues to threaten the existence of the Masafuera Rayadito. Increasing predator populations, natural—Masafuera Hawk—and invasive—feral cats and rats, also exert pressure on the Masafuera Rayadito.
Study area on Alejandro Selkirk Island, Archipelago de Juan Fernandez National Park, Chile. Map by: Javier Gonzalez
Gonzalez advises additional investigation of intraspecific genetic variability to understand how the founding population has survived in isolation for approximately 600,000 years.
Citations:
- Gonzalez, J. 2014. Phylogenetic position of the most endangered Chilean bird: the Masafuera Rayadito (Aphrastura masafuerae; Furnariidae). Tropical Conservation Science. 7(4): 677-689.
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