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1.
Proc Natl Acad Sci U S A ; 118(28)2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34260383

RESUMO

A fundamental issue in migration biology is how birds decide when to start their journey, given that arriving too early or too late in a variable environment reduces individual fitness. Internal circannual regulation and predictable cues such as photoperiod prepare birds for migration, while variable external cues such as temperature and wind are thought to fine-tune departure times; however, this has not been demonstrated at the key point at which an individual animal decides to start migrating. In theory, environmental cues correlated between departure and arrival sites allow informed departure decisions. For 48 satellite-tracked Asian houbara Chlamydotis macqueenii, a medium-distance migrant with climatic connectivity between wintering and breeding areas, each tracked across multiple years, spring departure was under individually consistent temperature conditions, with greater individual repeatability than for photoperiod or wind. Individuals occupied a range of wintering sites latitudinally spanning 1,200 km but departed at lower temperatures from more northerly latitudes. These individual departure decisions produced earlier mean population-level departure and arrival dates in warmer springs. Phenological adjustments were fully compensatory, because individuals arrived on the breeding grounds under similar temperature conditions each year. Individuals' autumn departure decisions were also repeatable for temperature but less distinct than for spring, likely because of relaxed time constraints on leaving breeding grounds and the use of wind as a supplementary departure cue. We show that individual-level departure decisions informed by local temperatures can preadapt a population to adjust its population-level phenology in response to annual variability in spring temperatures without requiring genetic change in reaction thresholds.


Assuntos
Migração Animal/fisiologia , Sinais (Psicologia) , Aves Canoras/fisiologia , Temperatura , Animais , Reprodutibilidade dos Testes , Estações do Ano
2.
Mol Ecol ; 23(9): 2165-77, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24689851

RESUMO

Translocations are an increasingly common tool in conservation. The maintenance of genetic diversity through translocation is critical for both the short- and long-term persistence of populations and species. However, the relative spatio-temporal impacts of translocations on neutral and functional genetic diversity, and how this affects genetic structure among the conserved populations overall, have received little investigation. We compared the impact of translocating different numbers of founders on both microsatellite and major histocompatibility complex (MHC) class I diversity over a 23-year period in the Seychelles warbler (Acrocephalus sechellensis). We found low and stable microsatellite and MHC diversity in the source population and evidence for only a limited loss of either type of diversity in the four new populations. However, we found evidence of significant, but low to moderate, genetic differentiation between populations, with those populations established with fewer founders clustering separately. Stochastic genetic capture (as opposed to subsequent drift) was the main determinant of translocated population diversity. Furthermore, a strong correlation between microsatellite and MHC differentiation suggested that neutral processes outweighed selection in shaping MHC diversity in the new populations. These data provide important insights into how to optimize the use of translocation as a conservation tool.


Assuntos
Variação Genética , Genética Populacional , Aves Canoras/genética , Animais , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Efeito Fundador , Genótipo , Complexo Principal de Histocompatibilidade , Repetições de Microssatélites , Seleção Genética , Análise de Sequência de DNA , Seicheles
3.
Mol Phylogenet Evol ; 67(2): 468-83, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23438388

RESUMO

The hornbills comprise a group of morphologically and behaviorally distinct Palaeotropical bird species that feature prominently in studies of ecology and conservation biology. Although the monophyly of hornbills is well established, previous phylogenetic hypotheses were based solely on mtDNA and limited sampling of species diversity. We used parsimony, maximum likelihood and Bayesian methods to reconstruct relationships among all 61 extant hornbill species, based on nuclear and mtDNA gene sequences extracted largely from historical samples. The resulting phylogenetic trees closely match vocal variation across the family but conflict with current taxonomic treatments. In particular, they highlight a new arrangement for the six major clades of hornbills and reveal that three groups traditionally treated as genera (Tockus, Aceros, Penelopides) are non-monophyletic. In addition, two other genera (Anthracoceros, Ocyceros) were non-monophyletic in the mtDNA gene tree. Our findings resolve some longstanding problems in hornbill systematics, including the placement of 'Penelopides exharatus' (embedded in Aceros) and 'Tockus hartlaubi' (sister to Tropicranus albocristatus). We also confirm that an Asiatic lineage (Berenicornis) is sister to a trio of Afrotropical genera (Tropicranus [including 'Tockus hartlaubi'], Ceratogymna, Bycanistes). We present a summary phylogeny as a robust basis for further studies of hornbill ecology, evolution and historical biogeography.


Assuntos
Evolução Molecular , Proteínas Mitocondriais/genética , Proteínas Nucleares/genética , Filogenia , Animais , Teorema de Bayes , Aves , Proteínas Mitocondriais/classificação , Proteínas Nucleares/classificação , Análise de Sequência de DNA
4.
Environ Manage ; 51(6): 1236-46, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23640696

RESUMO

The lack of scientific baseline information hinders appropriate design and management of protected areas. To illustrate the value of science to management, we consider five scenarios for the 202.0 km² Puerto Princesa Subterranean River National Park, Philippines: (1) closure to human activities, (2) and (3) two levels of increase in unplanned human activities, (4) creation of a forest corridor and (5) additional allocation of land for permanent or shifting agriculture. We then use habitat-specific bird density estimates to simulate the net effect of each scenario on 18 focal bird populations. Closure has significant benefits-populations of five species are predicted to increase by >50 % and nine by >25 %, but two secondary forest flycatchers, including the endemic and 'Vulnerable' Palawan flycatcher, decline dramatically, while the creation of a 4.0 km² forest corridor yields average increases across species of 2 ± 4 % (SD). In contrast, heavier unplanned park usage produces declines in all but a few species, while the negative effects of an extra 2.0 km² of shifting cultivation are 3-5 times higher than for a similar area of permanent agriculture and affect species whose densities are highest in primary habitats. Relatively small changes within the park, especially those associated with agricultural expansion, has serious predicted implications for local bird populations. Our models do not take into account the full complexities of bird ecology at a site, but they do provide park managers with an evidence base from which to make better decisions relating to biodiversity conservation obligations which their parks are intended to meet.


Assuntos
Biodiversidade , Aves , Conservação dos Recursos Naturais , Animais , Filipinas , Densidade Demográfica , Árvores
5.
Zootaxa ; 5315(2): 122-130, 2023 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-37518613

RESUMO

The bustard genera Neotis and Ardeotis are generally considered to comprise four species each, but a 2002 molecular phylogeny found N. heuglinii interposed between two pairs of Ardeotis, with N. nuba basal to all seven others. In the absence of a new molecular study one approach to clarifying relationships in the Otididae is to examine the degree of difference in their self-advertisement displays (as performed solitarily, i.e., with no nearby conspecifics). In this regard N. nuba emerges as unique for possessing a strutting parade with its tail raised in a vertical fork, in complete contrast to the neck-inflation displays of other Neotis (which involve no use of the tail) and of all Ardeotis. The tail-fork in N. nuba, unknown in any other bustard, results from the outer rectrices being longer, stiffer and more pointed than the central ones. The species is also unique among bustards in its long broad sandy-rufous crown-stripe; and unlike all other Neotis the sexes are virtually alike in plumage. We consequently propose a new genus Nubotis for N. nuba. Furthermore, we suggest that confirmation of all components of the displays of N. heuglinii, N. denhami and N. ludwigii might precipitate a new genus for N. heuglinii. Fuller review of the distinctions between the Afrotropical A. arabs and A. kori on the one side and the non-Afrotropical A. nigriceps and A. australis on the other might also lead to the reinstatement of Austrotis for the latter two.


Assuntos
Aves , Animais , Filogenia
6.
PLoS One ; 16(5): e0249633, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34010302

RESUMO

Climate change is having profound effects on the distributions of species globally. Trait-based assessments predict that specialist and range-restricted species are among those most likely to be at risk of extinction from such changes. Understanding individual species' responses to climate change is therefore critical for informing conservation planning. We use an established Species Distribution Modelling (SDM) protocol to describe the curious range-restriction of the globally threatened White-tailed Swallow (Hirundo megaensis) to a small area in southern Ethiopia. We find that, across a range of modelling approaches, the distribution of this species is well described by two climatic variables, maximum temperature and dry season precipitation. These same two variables have been previously found to limit the distribution of the unrelated but closely sympatric Ethiopian Bush-crow (Zavattariornis stresemanni). We project the future climatic suitability for both species under a range of climate scenarios and modelling approaches. Both species are at severe risk of extinction within the next half century, as the climate in 68-84% (for the swallow) and 90-100% (for the bush-crow) of their current ranges is predicted to become unsuitable. Intensive conservation measures, such as assisted migration and captive-breeding, may be the only options available to safeguard these two species. Their projected disappearance in the wild offers an opportunity to test the reliability of SDMs for predicting the fate of wild species. Monitoring future changes in the distribution and abundance of the bush-crow is particularly tractable because its nests are conspicuous and visible over large distances.


Assuntos
Mudança Climática , Corvos/fisiologia , Espécies em Perigo de Extinção/tendências , Andorinhas/fisiologia , Distribuição Animal , Animais , Ecossistema , Etiópia , Modelos Estatísticos
7.
Zootaxa ; 4732(1): zootaxa.4732.1.2, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32230271

RESUMO

Based on molecular and morphological analyses, Irestedt et al. (2017) propose various taxonomic revisions for the genera Lophorina and Ptiloris (Paradisaeidae). Concerning Lophorina, which they recommend treating as three species rather than one, they hypothesize that the no longer extant type specimen of L. superba, heretofore believed to come from the Vogelkop in westernmost mainland New Guinea, in fact pertained to a different population (and different species, under their revised taxonomy), and they attempt to consolidate the nomenclatural repercussions of this by proposing a neotype for the name superba. However, the historical and specimen evidence fails to uphold their nomenclatural proposals, and the neotypification contains procedural errors. In particular, our examination of specimen material identifies nine points of conflict between what is clearly the most accurate contemporary illustration of the type and the plumage pattern and structure in the population to which Irestedt et al. assert it should be ascribed; we find not a single point in their favour. The only other relevant depiction of the type from the same period, while less accurate, also differs crucially from the population Irestedt et al. claim that it represents, especially in lacking black spots on the breast-shield. Furthermore, there is a strong historical rationale not only to believe that the type of superba was collected in the Vogelkop, as all contemporary commentators indicated, but also to regard the notion of tribespeople transporting it more than 600 km from its point of collection, as Irestedt et al. effectively suggest, as exceedingly unlikely. Consequently, with all this evidence against the proposed reidentification, the name L. s. superba should be maintained for populations of the Vogelkop, and the neotype designation rejected. The type locality reverts to the Vogelkop, but herein is further restricted to the Tamrau Mountains.


Assuntos
Passeriformes , Animais
8.
R Soc Open Sci ; 7(3): 200250, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32269827

RESUMO

Maintaining appropriate migratory strategies is important in conservation; however, translocations of migratory animals may alter locally evolved migration behaviours of recipient populations if these are different and heritable. We used satellite telemetry and experimental translocation to quantify differences and assess heritability in migration behaviours between three migratory Asian houbara (Chlamydotis macqueenii) breeding populations (640 km range across eastern, central and western Uzbekistan). Adults from the eastern population migrated twice as far (mean = 1184 km ± 44 s.e.) as the western population (656 km ± 183 s.e.) and showed significantly less variation in migration distance than the central population (1030 km ± 127 s.e.). The western and central populations wintered significantly further north (mean: +8.32° N ± 1.70 s.e. and +4.19° N ± 1.16 s.e., respectively) and the central population further west (-3.47° E ± 1.46 s.e.) than individuals from the eastern population. These differences could arise from a differing innate drive, or through learnt facultative responses to topography, filtered by survival. Translocated birds from the eastern population (wild-laid and captive-reared, n = 5) migrated further than adults from either western or central recipient populations, particularly in their second migration year. Translocated birds continued migrating south past suitable wintering grounds used by the recipient populations despite having to negotiate mountain obstacles. Together, this suggests a considerable conserved heritable migratory component with local adaptation at a fine geographic scale. Surviving translocated individuals returned to their release site, suggesting that continued translocations would lead to introgression of the heritable component and risk altering recipient migration patterns. Conservation biologists considering translocation interventions for migratory populations should evaluate potential genetic components of migratory behaviour.

9.
Conserv Biol ; 23(2): 433-9, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19016820

RESUMO

Predictive models can help clarify the distribution of poorly known species but should display strong transferability when applied to independent data. Nevertheless, model transferability for threatened tropical species is poorly studied. We built models predicting the incidence of the critically endangered Bengal Florican (Houbaropsis bengalensis) within the Tonle Sap (TLS) floodplain, Cambodia. Separate models were constructed with soil, land-use, and landscape data and species incidence sampled over the entire floodplain (12,000 km(2)) and from the Kompong Thom (KT) province (4000 km(2)). In each case, the probability of Bengal Florican presence within randomly selected 1 x 1 km squares was modeled by binary logistic regression with multimodel inference. We assessed the transferability of the KT model by comparing predictions with observed incidence elsewhere in the floodplain. In terms of standard model-validation statistics, the KT model showed good spatial transferability. Nevertheless, it overpredicted florican presence outside the KT calibration region, classifying 491 km(2) as suitable habitat compared with 237 km(2) predicted as suitable by the TLS model. This resulted from higher species incidence within the calibration region, probably owing to a program of conservation education and enforcement that has reduced persecution there. Because both research and conservation activity frequently focus on areas with higher density, such effects could be widespread, reducing transferability of predictive distribution models.


Assuntos
Aves/fisiologia , Conservação dos Recursos Naturais/métodos , Modelos Biológicos , Animais , Camboja , Demografia , Ecossistema
11.
Conserv Biol ; 22(6): 1424-42, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18847444

RESUMO

The International Union for Conservation of Nature (IUCN) Red List of Threatened Species was increasingly used during the 1980s to assess the conservation status of species for policy and planning purposes. This use stimulated the development of a new set of quantitative criteria for listing species in the categories of threat: critically endangered, endangered, and vulnerable. These criteria, which were intended to be applicable to all species except microorganisms, were part of a broader system for classifying threatened species and were fully implemented by IUCN in 2000. The system and the criteria have been widely used by conservation practitioners and scientists and now underpin one indicator being used to assess the Convention on Biological Diversity 2010 biodiversity target. We describe the process and the technical background to the IUCN Red List system. The criteria refer to fundamental biological processes underlying population decline and extinction. But given major differences between species, the threatening processes affecting them, and the paucity of knowledge relating to most species, the IUCN system had to be both broad and flexible to be applicable to the majority of described species. The system was designed to measure the symptoms of extinction risk, and uses 5 independent criteria relating to aspects of population loss and decline of range size. A species is assigned to a threat category if it meets the quantitative threshold for at least one criterion. The criteria and the accompanying rules and guidelines used by IUCN are intended to increase the consistency, transparency, and validity of its categorization system, but it necessitates some compromises that affect the applicability of the system and the species lists that result. In particular, choices were made over the assessment of uncertainty, poorly known species, depleted species, population decline, restricted ranges, and rarity; all of these affect the way red lists should be viewed and used. Processes related to priority setting and the development of national red lists need to take account of some assumptions in the formulation of the criteria.


Assuntos
Classificação/métodos , Conservação dos Recursos Naturais/métodos , Extinção Biológica , Ecossistema , Dinâmica Populacional , Medição de Risco/métodos , Especificidade da Espécie
12.
Data Brief ; 21: 1848-1852, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30519605

RESUMO

The data shown in this article are the number and proportion of deaths attributable to hunting/trapping, powerline collisions and natural causes in migratory Asian houbara Chlamydotis macqueenii originating from a breeding population in Uzbekistan. For wild adult and juvenile Asian houbara wintering in Central Asia during the period 2011-2018, 53.9% and 52.9%, respectively, of mortality was due to hunting/trapping, while in contrast most mortality in captive-bred released birds was natural with only 23.3% attributable to hunting/trapping. In winter, only one instance of powerline mortality was confirmed (6.0%). For wild adults, 23.0% of mortality during the summer was due to hunting/trapping, while 30.7% was due to powerline collisions. This data article is related to the publication "Captive breeding cannot sustain migratory Asian houbara Chlamydotis macqueenii without hunting controls" (Dolman et al., 2018) where further interpretation of the population-level consequences of these mortality causes can be found.

13.
Zootaxa ; 4189(2): zootaxa.4189.2.2, 2016 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-27988731

RESUMO

The hummingbird Amazilia alfaroana is known from a single specimen, collected on the Volcán de Miravalles, in north-west Costa Rica, in September 1895. Since the early 20th century, the taxon has been almost always been treated as a subspecies of Indigo-capped Hummingbird A. cyanifrons, which is otherwise endemic to Colombia, although it has also been tentatively suggested that the holotype might represent a hybrid between two unnamed species of trochilids. Our detailed analysis of the specimen reveals species-level differences between A. alfaroana and A. cyanifrons, and no evidence of characters that might suggest a hybrid between two species known to occur in the relevant region. Until molecular techniques have been brought to bear, we believe that A. alfaroana is best treated as a possibly now extinct species.


Assuntos
Aves/classificação , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Aves/anatomia & histologia , Aves/crescimento & desenvolvimento , Tamanho Corporal , Costa Rica , Ecossistema , Feminino , Masculino , Tamanho do Órgão
14.
Ambio ; 45(3): 313-22, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26666956

RESUMO

Aichi Target 11 of the Convention on Biological Diversity urges, inter alia, that nations protect at least 17 % of their land, and that protection is effective and targets areas of importance for biodiversity. Five years before reporting on Aichi targets is due, we assessed the Philippines' current protected area system for biodiversity coverage, appropriateness of management regimes and capacity to deliver protection. Although protected estate already covers 11 % of the Philippines' land area, 64 % of its key biodiversity areas (KBAs) remain unprotected. Few protected areas have appropriate management and governance infrastructures, funding streams, management plans and capacity, and a serious mismatch exists between protected area land zonation regimes and conservation needs of key species. For the Philippines to meet the biodiversity coverage and management effectiveness elements of Aichi Target 11, protected area and KBA boundaries should be aligned, management systems reformed to pursue biodiversity-led targets and effective management capacity created.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Animais , Aves , Orçamentos , Conservação dos Recursos Naturais/economia , Filipinas
15.
Evol Appl ; 7(9): 1134-43, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25553073

RESUMO

The importance of evolutionary conservation - how understanding evolutionary forces can help guide conservation decisions - is widely recognized. However, the historical demography of many endangered species is unknown, despite the fact that this can have important implications for contemporary ecological processes and for extinction risk. Here, we reconstruct the population history of the Seychelles warbler (Acrocephalus sechellensis) - an ecological model species. By the 1960s, this species was on the brink of extinction, but its previous history is unknown. We used DNA samples from contemporary and museum specimens spanning 140 years to reconstruct bottleneck history. We found a 25% reduction in genetic diversity between museum and contemporary populations, and strong genetic structure. Simulations indicate that the Seychelles warbler was bottlenecked from a large population, with an ancestral N e of several thousands falling to <50 within the last century. Such a rapid decline, due to anthropogenic factors, has important implications for extinction risk in the Seychelles warbler, and our results will inform conservation practices. Reconstructing the population history of this species also allows us to better understand patterns of genetic diversity, inbreeding and promiscuity in the contemporary populations. Our approaches can be applied across species to test ecological hypotheses and inform conservation.

16.
Science ; 330(6010): 1503-9, 2010 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-20978281

RESUMO

Using data for 25,780 species categorized on the International Union for Conservation of Nature Red List, we present an assessment of the status of the world's vertebrates. One-fifth of species are classified as Threatened, and we show that this figure is increasing: On average, 52 species of mammals, birds, and amphibians move one category closer to extinction each year. However, this overall pattern conceals the impact of conservation successes, and we show that the rate of deterioration would have been at least one-fifth again as much in the absence of these. Nonetheless, current conservation efforts remain insufficient to offset the main drivers of biodiversity loss in these groups: agricultural expansion, logging, overexploitation, and invasive alien species.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Ecossistema , Vertebrados , Anfíbios , Animais , Aves , Espécies em Perigo de Extinção/estatística & dados numéricos , Espécies em Perigo de Extinção/tendências , Extinção Biológica , Espécies Introduzidas , Mamíferos , Dinâmica Populacional
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