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The Strange-tailed Tyrant Alectrurus risora (Aves: Tyrannidae) is an endemic species of southern South American grasslands that suffered a 90% reduction of its original distribution due to habitat transformation. This has led the species to be classified as globally Vulnerable. By the beginning of the last century, populations were partially migratory and moved south during the breeding season. Currently, the main breeding population inhabits the Ibera wetlands in the province of Corrientes, north-east Argentina, where it is resident all year round. There are two remaining small populations in the province of Formosa, north-east Argentina, and in southern Paraguay, which are separated from the main population by the Parana-Paraguay River and its continuous riverine forest habitat. The populations of Corrientes and Formosa are separated by 300 km and the grasslands between populations are non-continuous due to habitat transformation. We used mtDNA sequences and eight microsatellite loci to test if there were evidences of genetic isolation between Argentinean populations. We found no evidence of genetic structure between populations (Phi(ST) = 0.004, P = 0.32; Fst = 0.01, P = 0.06), which can be explained by either retained ancestral polymorphism or by dispersal between populations. We found no evidence for a recent demographic bottleneck in nuclear loci. Our results indicate that these populations could be managed as a single conservation unit on a regional scale. Conservation actions should be focused on preserving the remaining network of areas with natural grasslands to guarantee reproduction, dispersal and prevent further decline of populations.
A species of Galapagos tortoise endemic to Espanola Island was reduced to just 12 females and three males that have been bred in captivity since 1971 and have produced over 1700 offspring now repatriated to the island. Our molecular genetic analyses of juveniles repatriated to and surviving on the island indicate that none of the tortoises sampled in 1994 had hatched on the island versus 3% in 2004 and 24% in 2007, which demonstrates substantial and increasing reproduction in situ once again. This recovery occurred despite the parental population having an estimated effective population size <8 due to a combination of unequal reproductive success of the breeders and nonrandom mating in captivity. These results provide guidelines for adapting breeding regimes in the parental captive population and decreasing inbreeding in the repatriated population. Using simple morphological data scored on the sampled animals, we also show that a strongly heterogeneous distribution of tortoise sizes on Espanola Island observed today is due to a large variance in the number of animals included in yearly repatriation events performed in the last 40years. Our study reveals that, at least in the short run, some endangered species can recover dramatically despite a lack of genetic variation and irregular repatriation efforts.
Intraspecific genetic diversity and distribution of North African hedgehogs (Mammalia: Erinaceidae)
(2019)
Despite growing efforts to halt biodiversity loss, knowledge of species diversity and distribution is highly geographically biased, leaving some areas unexplored. Taxa distributed in remote, desert areas, such as hedgehogs (Mammalia; Eulipotyphla) in North Africa, are good examples of current knowledge gaps in systematics and biogeography. Here we studied the geographical distribution and intraspecific genetic diversity of hedgehogs in North Africa. Specimens belonging to North African and Eurasian species were analysed with mitochondrial (control region, CR) and nuclear (recombination activating gene 1, RAG1) gene fragments. This revealed a broader geographical distribution of Atelerix algirus in south-western Libya and of Paraechinus aethiopicus along the Atlantic Sahara. High intraspecific genetic differentiation was found in A. algirus and A. albiventris at the mitochondrial level, with nuclear haplotype sharing across their ranges. These findings suggest that biogeographical patterns of hedgehogs in North Africa are more complex than previously suggested, highlighting a need for further investigation in this remote and poorly known area.