Navegando por Assunto "Endangered species"

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Artigo
Don’t put all your eggs in one basket
(Biological Conservation, 2019-10) Eisemberg, Carla Camilo; Vogt, Richard Carl; Balestra, Rafael Antônio M.; Reynolds, Stephen J.; Christian, Keith A. A.
The Brazilian Government established the Amazon Turtle Project (Projeto Quelônios da Amazônia – PQA) in 1975 to monitor and protect the main nesting sites of Amazon River turtles. The PQA has become the largest-scale and longest-term wildlife conservation initiative in the Brazilian Amazon. We evaluated the outcomes of the PQA across 11 protected localities over 30 years (1977–2008). Inside the protected localities, one population of Podocnemis expansa has declined and four have seen an increase in numbers. The PQA conservation efforts for P. unifilis were not as successful as those of Podocnemis expansa, but were sufficient to stabilize or increase populations. These results suggest that there is a minimum effort necessary for positive conservation outcomes, which was not achieved for Podocnemis sextuberculata. Given the lack of correlation between initial nesting numbers and positive population trends, the current level of success in a given locality cannot be used as a tool to prioritize future protection efforts. We recommend that the PQA should maintain or increase its coverage due to the high levels of local unpredictability. If current harvest trends are maintained, it is likely the only surviving populations of P. expansa will be within protected areas. Considering the scope of the PQA and the period that it has been operational, it is surprising how little recognition it has received; the lack of national and international awareness of its achievements may be one of the main reasons behind the lack of support from the Brazilian Government. © 2019 Elsevier Ltd
Artigo
Genetic Connectivity of the West Indian Manatee in the Southern Range and Limited Evidence of Hybridization With Amazonian Manatees
(2021-01-06) Luna, Fábia de Oliveira; Beaver, Caitlin E.; Nourisson, Coralie; Bonde, Robert K.; Attademo, Fernanda L. N.; Miranda, Adriana Vieira; Torres-Florez, Juan Pablo; Sousa, Glaucia Pereira de; Passavante, José Zanon; Hunter, Margaret E.; Jeremy Kiszka
The Antillean subspecies of the West Indian manatee is classified as endangered by the International Union for the Conservation of Nature (IUCN) Red List. In Brazil, the manatee population is listed as endangered with an estimated population size of 500–1,000. Historic hunting, recent habitat degradation, and fisheries bycatch have decreased the population size. The Amazonian manatee is listed as vulnerable by the IUCN with unknown population sizes within Brazil. The Antillean manatee occurs in sympatry with the Amazonian manatee in Brazil and hybridization has been previously indicated. To provide information on the genetic structure, diversity, and degree of hybridization in the sympatric zone near the Amazon River mouth, the mitochondrial DNA control region and 13 nuclear microsatellite markers were assessed on the two species. Samples were analyzed from the Antillean subspecies across its distribution in Brazil (n = 78) and from the Amazonian species (n = 17) at the Amazon River mouth and inland mainstem river. To assess the previously defined evolutionary significant units of Antillean manatees in the area, an additional 11 samples from Venezuela and Guyana were included. The Antillean manatee was found to be a single population in Brazil and had lower than average number of alleles (3.00), expected heterozygosity (0.34), and haplotype diversity (0.15) when compared to many other manatee populations. The low values may be influenced by the small population size and extended pressures from anthropogenic threats. Gene flow was identified with Venezuela/Guyana in admixed Antillean Brazil samples, although the two populations were found to be moderately divergent. The nuclear loci in Venezuela/Guyana Antillean manatee samples indicated high differentiation from the samples collected in the Amazon River (FST = 0.35 and RST = 0.18, p = 0.0001). No indication of nuclear hybridization was found except for a single sample, “Poque” that had been identified previously. The distribution of Antillean manatees in Brazil is extensive and the areas with unique habitat and threats would benefit from independent management and conservation actions. Gene flow, resulting in genetic diversity and long-term population stability, could be improved in the southern range through habitat restoration, and the establishments of travel corridors and protected areas, which are particularly important for successful parturition and neonatal calf survival.
Artigo
Molecular delimitation of the seasonal killifishes of the Hypsolebias antenori species group (Cyprinodontiformes, Rivulidae), with description of two new species from the Caatinga coastal basins, northeastern Brazil
(2023-12-22) Abrantes, Yuri Gomes ; Ramos, Telton Pedro Anselmo ; Bento, Diego de Medeiros ; Lima, Sergio Maia Queiroz
Hypsolebia antenori is a seasonal killifish considered to be broadly distributed along the Caatinga’s basins of northeastern Brazil, with records in the coastal drainages of the rio Pacoti, rio Jaguaribe, córrego Virgílio and rio Apodi-Mossoró basins. Based on morphological characters and molecular phylogenetic reconstructions, it was possible to diagnose two new species and restrict H. antenori to the rio Jaguaribe basin. Hypsolebias gongobira new species is described from a temporary pool in the rio Pacoti basin in Ceará State, in syntopy with the species threatened H. longignatus. Hypsolebias bonita new species occurs in the floodplains of the rio Apodi-Mossoró basin and in the córrego Virgílio microbasin in the Furna Feia National Park, in Rio Grande do Norte State. We also discuss the conservation status of these new species and how the São Francisco Interbasin Water transfer, and the agricultural and urban expansion in the semiarid may be adversely affecting these seasonal killifishes.
Artigo
New records of the troglobitic Hyalella veredae Cardoso & Bueno, 2014 (Crustacea, Amphipoda, Hyalellidae) from Minas Gerais caves, southeast Brazil, with notes on its natural history
(2021-01-18) Elina Bichuette, Maria; A. P. Bueno, Alessandra; P. A. Resende, Leonardo; Zepon, Tamires
Since its description, the troglobitic amphipod Hyalella veredae Cardoso & Bueno, 2014 has been recorded only in its type locality, Vereda da Palha cave, in southeastern Brazil. We report this species from three other caves in the region, expanding its distribution by at least 20 km². Inter- and intra-population variability in eye size was observed. Two caves had larger populations, probably due to the presence of biofilm. The species was classified as Critically Endangered due to its restricted area of occurrence, and regional impacts and threats.
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New records of the troglobitic Hyalella veredae Cardoso & Bueno, 2014 (Crustacea, Amphipoda, Hyalellidae) from Minas Gerais caves, southeast Brazil, with notes on its natural history
(2021-01-18) Zepon, Tamires; Resende, Leonardo; Bueno, Alessandra Angélica de Pádua ; Bichuette, Maria Elina
Since its description, the troglobitic amphipod Hyalella veredae Cardoso & Bueno, 2014 has been recorded only in its type locality, Vereda da Palha cave, in southeastern Brazil. We report this species from three other caves in the region, expanding its distribution by at least 20 km². Inter- and intra-population variability in eye size was observed. Two caves had larger populations, probably due to the presence of biofilm. The species was classified as Critically Endangered due to its restricted area of occurrence, and regional impacts and threats.
Artigo
Playback point counts and N‐mixture models suggest higher than expected abundance of the critically endangered blond titi monkey in northeastern Brazil
(American Journal of Primatology, 2020-03-30) Coelho, Igor P. et al.
Effective management of threatened species requires accurate population size estimation and monitoring. However, reliable population size estimates are lacking for many endangered species. The critically endangered blond titi monkey (Callicebus barbarabrownae) is an endemic primate of the Caatinga biome in Northeastern Brazil. A previous assessment based on presence‐only data estimated a minimum population size of 260 mature individuals in 2,636 km2 , and studies based on visual records suggested very low local relative abundance. However, this cryptic species is known to be difficult to visually detect. We played back recordings of C. barbarabrownae loud calls to count the number of responding groups in 34 sampling sites during 9 consecutive days in a 221‐km2 study area. Repeated group counts at sites were used in N‐mixture models, which account for imperfect detection, to estimate the number of groups in relation to dry forest area and distance to villages. We estimated a total of 91 groups in the study area. Considering the mean number of adults per group as three, we estimated a population of 273 adult individuals, resulting in a density of 2.3 individuals/km2 in the dry forest habitat. Detection probability was four times higher for surveys conducted between sunrise to midmorning than between midmorning to sunset. We also found that C. barbarabrownae abundance increases with increasing dry forest area and increasing distance to the nearest village, indicating the need to promote dry forest restoration in the Caatinga. As our results suggest a larger population of C. barbarabrownae than had been previously estimated for its entire distribution, our results suggest a need for similar assessments in other areas to reliably estimate the total population size. This study demonstrates how playback surveys coupled with N‐mixture models can be used to estimate population sizes of acoustically‐responsive primates, and thus contribute to more effective conservation management.
Artigo
Reproductive success of Antillean manatees released in Brazil: implications for conservation
(2022-07-26) Attademo, Fernanda Loffler Niemeyer; Normande, Iran Campello; Sousa, Glaucia Pereira; Costa, Alexandra Fernandes; Borges, João Carlos Gomes; Alencar, Ana Emília Barbosa de; Foppel, Ernesto Frederico da Costa; Luna, Fábia de Oliveira
Actions to rescue, rehabilitate and release calves of manatees are the main initiatives and strategies for conservation of the species in Brazil. The survival rate of animals in a natural environment and the reproductive success, identified by birth records, are some of the indicators used to estimate the release success for manatees. This study evaluated the effectiveness of releases of West Indian manatees based on the reproductive success of rescued animals that were released back into the wild in Brazil. Twenty-two female manatees were released in the states of Alagoas (into an extinct area) and Paraíba (into an existent population) from 1994–2020. Six females gave birth to 13 calves, all in Alagoas State. The average age of the first calving event was 11.7 (±1.49) years and 8.0 (±1.41) years after release. Among the females that had more than one calving, the average was 3.6 (±1.18) years between each calving. All calves observed were born alive; nevertheless, three (23.1%) died a few weeks after birth. In general, females rehabilitated in captivity and released in the wild were able to reproduce, especially in protected areas. This study emphasizes the need to intensify actions for the conservation of manatees and their habitats in order to achieve healthier wild populations.