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1.
Zootaxa ; 4772(3): zootaxa.4772.3.5, 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-33055604

RESUMO

Despite Greece being a global hotspot of subterranean biodiversity, its hypogean fauna is largely neglected from both an ecological and conservational point of view. An overview of the Niphargidae occurring in Greece is presented as an annotated list of all available published records. These records have resulted in an updated species list reflecting taxonomic corrections and species distribution range in the Greek peninsula. A total of 23 species, attributed to 3 genera, is up to date known from Greece with a high rate of endemicity found particularly in Crete. The endemic species of Greece amount to 21 (91% of total species richness), with the remaining species distributing also in the Republic of North Macedonia. Currently, none of them is listed in the national, European or global IUCN Red Lists of Threatened Species. Considering the increasing habitat degradation due to anthropic pressure, groundwater harvesting and climate change we could lose rare and endemic species without even acknowledging their existence.


Assuntos
Anfípodes , Animais , Biodiversidade , Ecossistema , Espécies em Perigo de Extinção , Grécia
2.
Zootaxa ; 4860(2): zootaxa.4860.2.10, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33056169

RESUMO

We describe the tadpole of the Botsford's leaf-litter frog Leptobrachella botsfordi, a species endemic to Mount Fansipan in northwest Vietnam, for the first time. Tadpoles of this species were found in steep, fast-flowing streams at elevations between 2500-2600 m asl. We also report a previously unknown locality for this species on Mount Fansipan, which increases the species' known Extent of Occurrence from 8 km2 to 36 km2. Our findings will inform subsequent conservation initiatives for this poorly known and highly threatened species.


Assuntos
Anuros , Espécies em Perigo de Extinção , Animais , Larva , Rios
6.
PLoS One ; 15(10): e0234673, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33002006

RESUMO

While flow is known to be a major driver of estuarine ecosystems, targeted flow manipulations are rare because tidal systems are extremely variable in space and time, and because the necessary infrastructure is rarely available. In summer 2018 we used a unique water control structure in the San Francisco Estuary (SFE) to direct a managed flow pulse into Suisun Marsh, one of the largest contiguous tidal marshes on the west coast of the United States. The action was designed to increase habitat suitability for the endangered Delta Smelt Hypomesus transpacificus, a small osmerid fish endemic to the upper SFE. The approach was to operate the Suisun Marsh Salinity Control Gates (SMSCG) in conjunction with increased Sacramento River tributary inflow to direct an estimated 160 x 106 m3 pulse of low salinity water into Suisun Marsh during August, a critical time period for juvenile Delta Smelt rearing. Three-dimensional modeling showed that directing additional low salinity water into Suisun Marsh ("Flow Action") substantially increased the area of low salinity habitat for Delta Smelt that persisted beyond the period of SMSCG operations. Field monitoring showed that turbidity and chlorophyll were at higher levels in Suisun Marsh, representing better habitat conditions, than the upstream Sacramento River region throughout the study period. The Flow Action had no substantial effects on zooplankton abundance, nor did Suisun Marsh show enhanced levels of these prey species in comparison to the Sacramento River. Fish monitoring data suggested that small numbers of Delta Smelt colonized Suisun Marsh from the Sacramento River during the 2018 Flow Action. Comparison of the salinity effects of the Flow Action to historical catch data for Suisun Marsh further supported our hypothesis that the Flow Action would have some benefit for this rare species. Our study provides insight into both the potential use of targeted flow manipulations to support endangered fishes such as Delta Smelt, and into the general response of estuarine habitat to flow management.


Assuntos
Monitorização de Parâmetros Ecológicos , Estuários , Osmeriformes , Animais , Ecossistema , Espécies em Perigo de Extinção , Microcystis/crescimento & desenvolvimento , Osmeriformes/crescimento & desenvolvimento , Rios , Salinidade , São Francisco , Áreas Alagadas , Zooplâncton/crescimento & desenvolvimento
7.
PLoS One ; 15(10): e0230763, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33002022

RESUMO

Scalloped Hammerhead shark (Sphyrna lewini) is an endangered species which its populations have been declining globally including in Indonesia, the world's top shark fishing country. However, there is a lack of information on the recent population structure of this species to promote proper management and its conservation status. This study aimed to investigate the genetic diversity, population structure, and connectivity of the S. lewini population, in three major shark landing sites: Aceh (n = 41), Balikpapan (n = 30), and Lombok (n = 29). Meanwhile, additional sequences were retrieved from West Papua (n = 14) and the Western Indian Ocean (n = 65) populations. From the analyses of the mitochondrial CO1 gene, a total of 179 sequences of S. lewini, with an average size of 594 bp, and 40 polymorphic loci in four and eight haplotypes for the Indonesian population and the Western Indian Ocean population were identified. The overall values of genetic diversity were high (h = 0.717; π = 0.013), with the highest values recorded in Aceh (h = 0.668; π = 0.002) and the lowest in Papua (h = 0.143; π = 0.000). On the contrary, the overall value was fairly low in the Western Indian Ocean (h = 0.232; π = 0.001). Furthermore, AMOVA and FST showed three significant subdivisions in Indonesia (FST = 0.442; P < 0.001), with separated populations for Aceh and West Papua, and mixed between Balikpapan and Lombok (FST = 0.044; P = 0.091). In contrast, genetic homogeneity was observed within the population of the Western Indian Ocean (FST = -0.013; P = 0.612). The establishment of a haplotype network provided evidence of a significantly different population and a limited genetic distribution between the Indonesian and the Western Indian Ocean populations (FST = 0.740; P < 0.001). This study showed the presence of a complex population of S. lewini with limited connectivity only in Indonesia separated from the Western Indian Ocean and requiring specific management measures based on the population structure at the regional level.


Assuntos
Espécies em Perigo de Extinção , Tubarões/genética , Animais , DNA Mitocondrial/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Genética Populacional , Haplótipos , Oceano Índico , Indonésia , Oceanos e Mares
8.
PLoS One ; 15(10): e0230760, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33095793

RESUMO

The impact of a range of different threats has resulted in the listing of six out of seven sea turtle species on the IUCN Red List of endangered species. Disease risk analysis (DRA) tools are designed to provide objective, repeatable and documented assessment of the disease risks for a population and measures to reduce these risks through management options. To the best of our knowledge, DRAs have not previously been published for sea turtles, although disease is reported to contribute to sea turtle population decline. Here, a comprehensive list of health hazards is provided for all seven species of sea turtles. The possible risk these hazards pose to the health of sea turtles were assessed and "One Health" aspects of interacting with sea turtles were also investigated. The risk assessment was undertaken in collaboration with more than 30 experts in the field including veterinarians, microbiologists, social scientists, epidemiologists and stakeholders, in the form of two international workshops and one local workshop. The general finding of the DRA was the distinct lack of knowledge regarding a link between the presence of pathogens and diseases manifestation in sea turtles. A higher rate of disease in immunocompromised individuals was repeatedly reported and a possible link between immunosuppression and environmental contaminants as a result of anthropogenic influences was suggested. Society based conservation initiatives and as a result the cultural and social aspect of interacting with sea turtles appeared to need more attention and research. A risk management workshop was carried out to acquire the insights of local policy makers about management options for the risks relevant to Queensland and the options were evaluated considering their feasibility and effectiveness. The sea turtle DRA presented here, is a structured guide for future risk assessments to be used in specific scenarios such as translocation and head-starting programs.


Assuntos
Conservação dos Recursos Naturais/métodos , Tartarugas/fisiologia , Animais , Coleta de Dados , Espécies em Perigo de Extinção , Feminino , Imunossupressão , Masculino , Densidade Demográfica , Vigilância da População , Medição de Risco
9.
PLoS One ; 15(10): e0231069, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33119595

RESUMO

Detailed information on shark and ray fisheries in the Andaman and Nicobar Islands, India are limited, including information on the diversity and biological characteristics of these species. We carried out fish landing surveys in South Andamans from January 2017 to May 2018, a comprehensive and cost-effective way to fill this data gap. We sampled 5,742 individuals representing 57 shark and ray species landed from six types of fishing gears. Of the 36 species of sharks and 21 species of rays landed, six species of sharks (Loxodon macrorhinus, Carcharhinus amblyrhynchos, Sphyrna lewini, C. albimarginatus, C. brevipinna, and Paragaleus randalli) comprised 83.35% of shark landings, while three species of rays (Pateobatis jenkinsii, Himantura leoparda and H. tutul) comprised 48.82% of ray landings, suggesting a species dominance in the catch or fishing region. We provide insights into the biology of species with extensions in maximum size for seven shark species. Additionally, we document an increase in the known ray diversity for the islands and for India with three previously unreported ray species. We found that amongst sharks, mature individuals of small-bodied species (63.48% males of total landings of species less than 1.5 m total length when mature) and immature individuals of larger species (84.79% males of total landings of species larger than 1.5 m total length when mature) were mostly landed; whereas for rays, mature individuals were predominantly landed (80.71% males of total landings) likely reflecting differences in habitat preferences along life-history stages across species and fishing gear. The largest size range in sharks was recorded in landings from pelagic longlines and gillnets. Further, the study emphasizes the overlap between critical habitats and fishing grounds, where immature sharks and gravid females were landed in large quantities which might be unsustainable in the long-term. Landings were female-biased in C. amblyrhynchos, S. lewini and P. jenkinsii, and male-biased in L. macrorhinus and H. leoparda, indicating either spatio-temporal or gear-specific sexual segregation in these species. Understanding seasonal and biological variability in the shark and ray landings over a longer study period across different fisheries will inform future conservation and fishery management measures for these species in the Andaman and Nicobar Islands.


Assuntos
Tubarões/classificação , Tubarões/fisiologia , Rajidae/classificação , Rajidae/fisiologia , Animais , Biodiversidade , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Feminino , Pesqueiros , Índia , Masculino , Densidade Demográfica , Especificidade da Espécie
12.
PLoS One ; 15(10): e0239182, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33112860

RESUMO

The koala (Phascolarctos cinereus) is currently listed by both the IUCN and the Australian Governments' Threatened Species Scientific Committee as vulnerable to extinction with an overall decreasing population trend. It is unknown exactly how many koalas remain in the wild, but it is known that habitat fragmentation and bushfires have ultimately contributed to the decline of the koala all over Australia. This novel study is a retrospective analysis of data over a 29-year period (1989-2018) using records for 12,543 sightings and clinical care admissions for wild koalas from the major koala hot-spots (Port Stephens, port Macquarie and Lismore) in New South Wales, Australia. This study aims to understand the long-term patterns and trends of key stressors that are contributing to the decline of koalas in New South Wales, and the synergic interactions of factors such as rescue location, sex and age of the koala, and if their decline is influenced progressively by year. The main findings of this retrospective analysis indicated that between all 3 rescue sites, the most common prognosis was disease, the most common disease was signs of chlamydia, and the most common outcome was release. The location where the highest number of koalas were found prior to being reported as sighted or admitted into clinical care was within the regional area of Lismore. Furthermore, sex was not a discriminating factor when it came to prognosis or outcome, but age was significant. Finally, incidents of disease were found to increase over long-term, whereas release decreased over time and euthanasia increased. The wealth of data available to us and the retrospective analysis enabled us in a way to 'zoom out' and reveal how the key environmental stressors have fluctuated spatially and temporally. In conclusion, our data provides strong evidence of added pressures of increased human population growth in metropolitan zones, which increases risks of acute environmental trauma and proximate stressors such as vehicle collisions and dog-attacks as well as increased sightings of virtually healthy koalas found in exposed environments. Thus our 'zoom out' approach provides support that there is an urgent need to strengthen on-ground management, bushfire control regimes, environmental planning and governmental policy actions that should hopefully reduce the proximate environmental stressors in a step wise approach. This will ensure that in the next decade (beyond 2020), NSW koalas will hopefully start to show reversed trends and patterns in exposure to environmental trauma and disease, and population numbers will return towards recovery and stability.


Assuntos
Espécies em Perigo de Extinção , Phascolarctidae , Animais , Infecções por Chlamydia/veterinária , Conservação dos Recursos Naturais/história , Conservação dos Recursos Naturais/tendências , Demografia/história , Demografia/tendências , Ecossistema , Espécies em Perigo de Extinção/tendências , Feminino , História do Século XX , História do Século XXI , Masculino , New South Wales , Phascolarctidae/microbiologia , Prognóstico , Estudos Retrospectivos
13.
Zootaxa ; 4822(3): zootaxa.4822.3.9, 2020 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-33056283

RESUMO

Foam-nesting frogs of the genus Physalaemus Fitzinger, 1826 have been long known for their diverse acoustic patterns (e.g., Barrio 1965; Bokermann 1966). Of the 49 species, the vocalizations of only three remain unknown to date (see Table 1 of Hepp Pombal 2020): P. caete Pombal Madureira, 1997, P. deimaticus Sazima Caramaschi, 1988, and P. insperatus Cruz, Cassini Caramaschi, 2008. Physalaemus caete is rare and narrowly distributed in Brazil's northern Atlantic Forest (Santos et al. 2016; Bernardo et al. 2017; Haddad et al. 2018), and an explosive breeder (EMS pers. obs.). For those reasons the species is classified in the endangered category of Brazil's red list of threatened species (ICMBio, 2018). Physalaemus caete was described in the late 1990s from the coastal region of the Brazilian state of Alagoas (Passo do Camaragibe) and reported for a second locality in Alagoas (Murici; Pombal Madureira 1997). Recently, the distribution was extended to a third locality (Paulista, state of Pernambuco; Santos et al. 2016). The distribution range of P. caete coincides with the "Pernambuco endemism center", a biogeographic subregion of coastal Atlantic Forest north of the São Francisco River (sensu Silva Casteli 2003). Here we describe the advertisement call of the Pernambuco population of P. caete and make comparisons with calls of congeners.


Assuntos
Anuros , Espécies em Perigo de Extinção , Animais , Brasil , Florestas , Vocalização Animal
15.
PLoS One ; 15(9): e0239267, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32997690

RESUMO

Caribbean Acropora spp. corals have undergone a decline in cover since the second half of the twentieth century. Loss of these architecturally complex and fast-growing corals has resulted in significant, cascading changes to the character, diversity, and available eco-spaces of Caribbean reefs. Few thriving Acropora spp. populations exist today in the Caribbean and western North Atlantic seas, and our limited ability to access data from reefs assessed via long-term monitoring efforts means that reef scientists are challenged to determine resilience and longevity of existing Acropora spp. reefs. Here we used multiple dating methods to measure reef longevity and determine whether Coral Gardens Reef, Belize, is a refuge for Acropora cervicornis against the backdrop of wider Caribbean decline. We used a new genetic-aging technique to identify sample sites, and radiocarbon and high-precision uranium-thorium (U-Th) dating techniques to test whether one of the largest populations of extant A. cervicornis in the western Caribbean is newly established after the 1980s, or represents a longer-lived, stable population. We did so with respect for ethical sampling of a threatened species. Our data show corals ranging in age from 1910 (14C) or 1915 (230Th) to at least November 2019. While we cannot exclude the possibility of short gaps in the residence of A. cervicornis earlier in the record, the data show consistent and sustained living coral throughout the 1980s and up to at least 2019. We suggest that Coral Gardens has served as a refuge for A. cervicornis and that identifying other, similar sites may be critical to efforts to grow, preserve, conserve, and seed besieged Caribbean reefs.


Assuntos
Antozoários/fisiologia , Conservação dos Recursos Naturais , Recifes de Corais , Refúgio de Vida Selvagem , Animais , Belize , Região do Caribe , Espécies em Perigo de Extinção , Dinâmica Populacional
16.
PLoS One ; 15(9): e0238636, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32970696

RESUMO

Statistically robust monitoring of threatened populations is essential for effective conservation management because the population trend data that monitoring generates is often used to make decisions about when and how to take action. Despite representing the highest proportion of threatened animals globally, the development of best practice methods for monitoring populations of threatened insects is relatively uncommon. Traditionally, population trend data for the Nationally Endangered New Zealand grasshopper Brachaspis robustus has been determined by counting all adults and nymphs seen on a single ~1.5 km transect searched once annually. This method lacks spatial and temporal replication, both of which are essential to overcome detection errors in highly cryptic species like B. robustus. It also provides no information about changes in the grasshopper's distribution throughout its range. Here, we design and test new population density and site occupancy monitoring protocols by comparing a) comprehensive plot and transect searches at one site and b) transect searches at two sites representing two different habitats (gravel road and natural riverbed) occupied by the species across its remaining range. Using power analyses, we determined a) the number of transects, b) the number of repeated visits and c) the grasshopper demographic to count to accurately detect long term change in relative population density. To inform a monitoring protocol design to track trends in grasshopper distribution, we estimated the probability of detecting an individual with respect to a) search area, b) weather and c) the grasshopper demographic counted at each of the two sites. Density estimates from plots and transects did not differ significantly. Population density monitoring was found to be most informative when large adult females present in early summer were used to index population size. To detect a significant change in relative density with power > 0.8 at the gravel road habitat, at least seventeen spatial replicates (transects) and four temporal replicates (visits) were required. Density estimates at the natural braided river site performed poorly and likely require a much higher survey effort. Detection of grasshopper presence was highest (pg > 0.6) using a 100 m x 1 m transect at both sites in February under optimal (no cloud) conditions. At least three visits to a transect should be conducted per season for distribution monitoring. Monitoring protocols that inform the management of threatened species are crucial for better understanding and mitigation of the current global trends of insect decline. This study provides an exemplar of how appropriate monitoring protocols can be developed for threatened insect species.


Assuntos
Espécies em Perigo de Extinção , Monitoramento Ambiental/métodos , Voo Animal/fisiologia , Gafanhotos/crescimento & desenvolvimento , Animais , Feminino , Geografia , Nova Zelândia , Dinâmica Populacional , Probabilidade , Especificidade da Espécie
17.
PLoS One ; 15(9): e0238914, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32946472

RESUMO

The Atlantic Forest is considered the fourth most important biodiversity hotspot. Although almost 96% of its original area has been devastated, a large part of its remaining conserved area is inhabited by traditional communities. This research focused on two Quilombola communities who reside within the Núcleo Picinguaba of the Serra do Mar State Park, State of São Paulo, Brazil. The objective was to use a combination of ethnoecological and ecological approaches to select priority species for which to develop participatory conservation and sustainable management plans in protected areas in Brazil. We collaborated with community members to collect ethnobotanical and ethnoecological data and then measured the abundance of native species in local forests through phytosociological sampling. We used this information to assess the degree of threat to useful species using the Conservation Priority Index, adding an additional layer of analysis based on habitat successional categories. We then overlayed those useful species identified as highest risk locally with those federally listed as threatened or endangered. Based on this, we identified three species as priority for the development of sustainable management plans: Virola bicuhyba, Cedrella fissilis and Plinia edulis.


Assuntos
Conservação dos Recursos Naturais/métodos , Espécies em Perigo de Extinção/estatística & dados numéricos , Magnoliopsida/crescimento & desenvolvimento , Oceano Atlântico , Brasil/etnologia , Ecossistema , Etnobotânica , Florestas , Humanos , Magnoliopsida/classificação
18.
PLoS One ; 15(9): e0238886, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32997674

RESUMO

In 2015, the Pacific marine heat wave, low river flows, and record high water temperatures in the Columbia River Basin contributed to a near-complete failure of the adult migration of endangered Snake River sockeye salmon (Oncorhynchus nerka, NOAA Fisheries 2016). These extreme weather events may become the new normal due to anthropogenic climate change, with catastrophic consequences for endangered species. Existing anthropogenic pressures may amplify vulnerability to climate change, but these potential synergies have rarely been quantified. We examined factors affecting survival of endangered sockeye (Oncorhynchus nerka) and threatened Chinook salmon (O. tshawytscha) as they migrated upstream through eight dams and reservoirs to spawning areas in the Snake River Basin. Our extensive database included histories of 17,279 individual fish that migrated since 2004. A comparison between conditions in 2015 and daily temperatures and flows in a regulated basin forced by output from global climate models showed that 2015 did have many characteristics of projected future mean conditions. To evaluate potential salmon responses, we modeled migration timing and apparent survival under historical and future climate scenarios (2040s). For Chinook salmon, adult survival from the first dam encountered to spawning grounds dropped by 4-15%, depending on the climate scenario. For sockeye, survival dropped by ~80% from their already low levels. Through sensitivity analyses, we observed that the adult sockeye migration would need to shift more than 2 weeks earlier than predicted to maintain survival rates typical of those seen during 2008-2017. Overall, the greater impacts of climate change on adult sockeye compared with adult Chinook salmon reflected differences in life history and environmental sensitivities, which were compounded for sockeye by larger effect sizes from other anthropogenic factors. Compared with Chinook, sockeye was more negatively affected by a history of juvenile transportation and by similar temperatures and flows. The largest changes in temperature and flow were projected to be upstream from the hydrosystem, where direct mitigation through hydrosystem management is not an option. Unfortunately, Snake River sockeye have likely lost much of their adaptive capacity with the loss of the wild population. Further work exploring habitat restoration or additional mitigation actions is urgently needed.


Assuntos
Migração Animal/fisiologia , Oncorhynchus/classificação , Migração Animal/classificação , Animais , Mudança Climática , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Idaho , Oncorhynchus/crescimento & desenvolvimento , Oncorhynchus/fisiologia , Oregon , Rios , Washington
19.
PLoS One ; 15(9): e0238948, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32915925

RESUMO

Several equids have gone extinct and many extant equids are currently considered vulnerable to critically endangered. This work aimed to evaluate whether domestic horse oocytes support preimplantation development of zebra embryos obtained by intracytoplasmic sperm injection (ICSI, zebroid) and cloning, and to study the Hippo signaling pathway during the lineage specification of trophectoderm cells and inner cell mass cells. We first showed that zebra and horse sperm cells induce porcine oocyte activation and recruit maternal SMARCA4 during pronuclear formation. SMARCA4 recruitment showed to be independent of the genetic background of the injected sperm. No differences were found in blastocyst rate of ICSI hybrid (zebra spermatozoon into horse egg) embryos relative to the homospecific horse control group. Interestingly, zebra cloned blastocyst rate was significantly higher at day 8. Moreover, most ICSI and cloned horse and zebra blastocysts showed a similar expression pattern of SOX2 and nuclear YAP1 with the majority of the nuclei positive for YAP1, and most SOX2+ nuclei negative for YAP1. Here we demonstrated that horse oocytes support zebra preimplantation development of both, ICSI and cloned embryos, without compromising development to blastocyst, blastocyst cell number neither the expression of SOX2 and YAP1. Our results support the use of domestic horse oocytes as a model to study in vitro zebra embryos on behalf of preservation of valuable genetic.


Assuntos
Desenvolvimento Embrionário , Equidae/embriologia , Equidae/genética , Cavalos/fisiologia , Oócitos/fisiologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Núcleo Celular/fisiologia , Clonagem de Organismos/veterinária , Citoplasma/fisiologia , Técnicas de Cultura Embrionária/veterinária , Desenvolvimento Embrionário/genética , Desenvolvimento Embrionário/fisiologia , Espécies em Perigo de Extinção , Equidae/metabolismo , Feminino , Perfilação da Expressão Gênica , Cavalos/genética , Técnicas In Vitro , Masculino , Técnicas de Transferência Nuclear/veterinária , Fatores de Transcrição SOXB1/genética , Injeções de Esperma Intracitoplásmicas/veterinária , Sus scrofa
20.
BMC Evol Biol ; 20(1): 114, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32912143

RESUMO

BACKGROUND: Understanding the structure and variability of adaptive loci such as the major histocompatibility complex (MHC) genes is a primary research goal for evolutionary and conservation genetics. Typically, classical MHC genes show high polymorphism and are under strong balancing selection, as their products trigger the adaptive immune response in vertebrates. Here, we assess the allelic diversity and patterns of selection for MHC class I and class II loci in a threatened shorebird with highly flexible mating and parental care behaviour, the Snowy Plover (Charadrius nivosus) across its broad geographic range. RESULTS: We determined the allelic and nucleotide diversity for MHC class I and class II genes using samples of 250 individuals from eight breeding population of Snowy Plovers. We found 40 alleles at MHC class I and six alleles at MHC class II, with individuals carrying two to seven different alleles (mean 3.70) at MHC class I and up to two alleles (mean 1.45) at MHC class II. Diversity was higher in the peptide-binding region, which suggests balancing selection. The MHC class I locus showed stronger signatures of both positive and negative selection than the MHC class II locus. Most alleles were present in more than one population. If present, private alleles generally occurred at very low frequencies in each population, except for the private alleles of MHC class I in one island population (Puerto Rico, lineage tenuirostris). CONCLUSION: Snowy Plovers exhibited an intermediate level of diversity at the MHC, similar to that reported in other Charadriiformes. The differences found in the patterns of selection between the class I and II loci are consistent with the hypothesis that different mechanisms shape the sequence evolution of MHC class I and class II genes. The rarity of private alleles across populations is consistent with high natal and breeding dispersal and the low genetic structure previously observed at neutral genetic markers in this species.


Assuntos
Charadriiformes , Genética Populacional , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe I/genética , Seleção Genética , Alelos , Animais , Charadriiformes/genética , Espécies em Perigo de Extinção , Variação Genética , Filogenia
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