The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Youhua Chen - One of the best experts on this subject based on the ideXlab platform.
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On the historical biogeography of global Galliformes: ancestral range and diversification patterns
Avian Research, 2014Co-Authors: Youhua ChenAbstract:In this study, the ancestral distributional ranges and the tempo of diversification patterns of global Galliformes were investigated. Different diversification models characterizing possible tempo patterns were fitted and compared onto the phylogenetic tree for the 197 Galliforme species, consisting of a constant-speciation and constant-extinction model (CONSTANT), a decreasing-speciation and constant-extinction model (SPVAR), a constant-speciation and increasing-extinction model (EXVAR) and a decreasing-speciation and increasing-extinction model (BOTHVAR). Ancestral range reconstruction was conducted using the dispersal-extinction-cladogenesis model. A constant-diversification-rate (CONSTANT) model best quantified the historical speciation patterns of this avian assemblage through model selection. Clade age and species richness are significantly and positively correlated. The most recent common ancestor for Galliformes species was originally found in the disjunctive regions between Southeast Asia and North America. High-frequency dispersal events were identified across the whole evolutionary time. The constant diversification rate for global Galliforme species implied that there were no diversification rate-shifting trends for Galliformes species. The present study may contribute to the understanding of the ecology and diversity patterns of Galliformes from the perspective of historical biogeography, although some limitations existed.
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On the historical biogeography of global Galliformes: ancestral range and diversification patterns
Avian Research, 2014Co-Authors: Youhua ChenAbstract:Background In this study, the ancestral distributional ranges and the tempo of diversification patterns of global Galliformes were investigated. Methods Different diversification models characterizing possible tempo patterns were fitted and compared onto the phylogenetic tree for the 197 Galliforme species, consisting of a constant-speciation and constant-extinction model (CONSTANT), a decreasing-speciation and constant-extinction model (SPVAR), a constant-speciation and increasing-extinction model (EXVAR) and a decreasing-speciation and increasing-extinction model (BOTHVAR). Ancestral range reconstruction was conducted using the dispersal-extinction-cladogenesis model. Results A constant-diversification-rate (CONSTANT) model best quantified the historical speciation patterns of this avian assemblage through model selection. Clade age and species richness are significantly and positively correlated. The most recent common ancestor for Galliformes species was originally found in the disjunctive regions between Southeast Asia and North America. High-frequency dispersal events were identified across the whole evolutionary time. Conclusions The constant diversification rate for global Galliforme species implied that there were no diversification rate-shifting trends for Galliformes species. The present study may contribute to the understanding of the ecology and diversity patterns of Galliformes from the perspective of historical biogeography, although some limitations existed.
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Conservation priority of global Galliformes species based on phylogenetic diversity.
Integrative zoology, 2014Co-Authors: Youhua ChenAbstract:In this study, based on phylogenetic diversity (PD), I develop a conservation strategy for Galliformes species around the world. A cladogram of 197 Galliformes species derived from a previous study was used for calculating PD metrics. Branch length is an important aspect of the phylogenetic information a tree can convey, but 2 traditionally-used metrics, the number of phylogenetic groups to which a taxon belongs (I) and the proportion that each taxon contributes to the total diversity of the group (W), are fully node-based and do not take branch length into account. Therefore, to measure PD more appropriately, I combined a branch-related metric, pendant edge (P), in addition to I and W. A final combined rank for Galliformes species was obtained by summing the ranks of the 3 metrics. My results showed that the 5% top priority species for conserving evolutionary potential were Galloperdix lunulata, Haematortyx sanguiniceps, Margaroperdix madagarensis, Syrmaticus soemmerringii, Coturnix pectoralis, Polyplectron napoleonis, Alectoris melanocephala, Xenoperdix udzungwensis, Afropavo congensis and Syrmaticus reevesii. The current species priority ranking based on pylogenetic diversity and the official International Union for Conservation of Nature (IUCN) ranking of Galliformes species was significantly correlated when considering the 5 categories of IUCN (critical endangered, endangered, vulnerable, near threatened and least concern). This indicated the feasibility of introducing the PD index into the network of IUCN regional Red List assessment. The 5% top priority countries selected using the complementarity principle possessing diversified Galliformes genetic resources were China, Indonesia, Mexico, India, Colombia, Australia, Brazil, Angola, Congo and Japan (in descending order). China, Indonesia, Mexico, Brazil, India and Colombia are consistently selected among the 4 top priority sets of richness, rarity, endemicity and PD. This result indicated that the priority result from PD is highly congruent with conventional measures. Along with other conventional ecological attributes, the alternative conservation scenario based on PD is reasonable and can be adopted in systematic conservation planning.
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Diversification rate-shifting patterns for global colour-polymorphic birds
Zoology and ecology, 2014Co-Authors: Youhua ChenAbstract:Diversification rate-shifting patterns for global colour-polymorphic birds were reported using both the piecewise Akaike information criterion (AIC) selection procedure and time-dependent rate-shifting continuous models. The phylogenies of five major orders of colour-polymorphic birds, obtained from a previous study, were considered for the present analysis, including Strigiformes, Caprimulgiformes, Falconidae, Accipitridae and Galliformes. The results showed that when using the MEDUSA piecewise method for the order Galliformes, a diversification-shifting event was found in the family of Cracidae. For the phylogeny of the order Accipitridae, twice rate-shifting patterns were identified over the phylogeny. For this bird order, the clades have accelerated diversification rates from low to high (0.0928 to 0.239 to 1.003) when the evolutionary history moves from the historical time to the contemporary time. At last, for other three orders, Falconidae, Caprimulgiformes and Strigiformes, no rate-shifting patter...
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SPECIES RICHNESS AND CO-OCCURRENCE PATTERNS OF Galliformes IN CHINA AT THREE LARGE SPATIAL SCALES: DOES SCALE SIZE MATTER?
2009Co-Authors: Youhua Chen, Luca LuiselliAbstract:Une analyse a ete conduite sur les Galliformes de Chine pour rechercher une structure de communaute a trois echelles spatiales. Les questions suivantes etaient posees: (1) la communaute des Galliformes de Chine montre-t-elle des patrons de structure non aleatoires a differentes echelles spatiales? (2) Si oui, quels sont-ils? (3) Les patrons observes sont-ils les memes a trois grands niveaux spatiaux differents? Nous avons utilise la richesse specifique (i. e. le nombre d'especes) dans chaque case de la grille d'analyse pour tester les patrons non aleatoires de co-occurrence d'especes a trois echelles spatiales: 1° x 1°, 5° x 5° et 10° x 10°. Nous avons etabli des matrices de presence / absence pour 51 especes de Galliformes existant en Chine, avec en lignes les especes et en colonnes les sites. Nous avons utilise le C-score comme indice quantitatif de co-occurrence et conduit une analyse de pseudo-communaute a l'aide de 30 000 simulations Monte Carlo afin de comparer les donnees reelles a des donnees aleatoires. Notre etude montre que les regions de plus grande richesse specifique se situent dans le SW de la Chine, provinces du Yunan et du Sichuan. Le patron de co-occurrence depend en partie de l'echelle d'analyse, avec des patrons non aleatoires se manifestant aux deux plus petites echelles. L'analyse des co-occurrences par guildes (basee sur les types de regime alimentaire et d'habitat) a suggere un assemblage des especes alea-toire pour la plupart des modeles nuls testes aux trois echelles spatiales etudiees. D'une maniere generale nos resultats indiquent que la competition interspecifique ne serait pas suffisante pour expliquer a elle seule le patron de distribution des Galliformes.
R. Will Stein - One of the best experts on this subject based on the ideXlab platform.
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Optimising different types of biodiversity coverage of protected areas with a case study using Himalayan Galliformes
Biological Conservation, 2016Co-Authors: Jonathon Dunn, R. Will Stein, Graeme M. Buchanan, Mark J. Whittingham, Philip J. K. McgowanAbstract:Abstract International targets have committed governments to expanding the global protected area (PA) network to 17% of the terrestrial surface by 2020. Optimising PA placement in the landscape is challenging due to a poor knowledge of biodiversity distribution and multiple definitions of conservation value. We explore these two issues using a case study of a highly threatened bird Order in a region of conservation concern where PA network effectiveness for biodiversity has not been formally explored previously. To determine if the existing PA network protects the most important areas for 24 species of Himalayan Galliformes, we use a novel method to compare the current network placement to results produced from Zonation prioritisation software and modelled species distributions. Specifically, we identify areas of high species richness and then weight maps by three different species specific conservation values. The current PA network captures ranges poorly. We found statistically significantly poorer fits between the optimal and the existing placement of the Himalayan PA network for Zonation results that were: (i) unweighted; (ii) weighted by Red List score; and (iii) weighted by endemism to the Himalaya. Across these and two other Zonation results, the placement of the optimal PA network covered 58% more of Galliformes distributions than the existing network. We advocate some refinements to the existing PA network to maximise Galliformes coverage and suggest that our method could be used to model the optimal PA network for a wide range of species and/or regions, something which will support the assessment and attainment of CBD targets.
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A molecular genetic time scale demonstrates Cretaceous origins and multiple diversification rate shifts within the order Galliformes (Aves).
Molecular phylogenetics and evolution, 2015Co-Authors: R. Will Stein, Joseph W. Brown, Arne Ø. MooersAbstract:Abstract The phylogeny of Galliformes (landfowl) has been studied extensively; however, the associated chronologies have been criticized recently due to misplaced or misidentified fossil calibrations. As a consequence, it is unclear whether any crown-group lineages arose in the Cretaceous and survived the Cretaceous–Paleogene (K–Pg; 65.5 Ma) mass extinction. Using Bayesian phylogenetic inference on an alignment spanning 14,539 bp of mitochondrial and nuclear DNA sequence data, four fossil calibrations, and a combination of uncorrelated lognormally distributed relaxed-clock and strict-clock models, we inferred a time-calibrated molecular phylogeny for 225 of the 291 extant Galliform taxa. These analyses suggest that crown Galliformes diversified in the Cretaceous and that three-stem lineages survived the K–Pg mass extinction. Ideally, characterizing the tempo and mode of diversification involves a taxonomically complete phylogenetic hypothesis. We used simple constraint structures to incorporate 66 data-deficient taxa and inferred the first taxon-complete phylogenetic hypothesis for the Galliformes. Diversification analyses conducted on 10,000 timetrees sampled from the posterior distribution of candidate trees show that the evolutionary history of the Galliformes is best explained by a rate-shift model including 1–3 clade-specific increases in diversification rate. We further show that the tempo and mode of diversification in the Galliformes conforms to a three-pulse model, with three-stem lineages arising in the Cretaceous and inter and intrafamilial diversification occurring after the K–Pg mass extinction, in the Paleocene–Eocene (65.5–33.9 Ma) or in association with the Eocene–Oligocene transition (33.9 Ma).
Philip J. K. Mcgowan - One of the best experts on this subject based on the ideXlab platform.
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What is the evidence available to support our knowledge about threats to the conservation of Galliformes in the Greater Himalaya
2021Co-Authors: Garima Gupta, Jonathon Dunn, M. Grainger, Roy A. Sanderson, Philip J. K. McgowanAbstract:1.Biodiversity is at a heightened risk of extinction and we are losing species faster than any other time. It is important to understand the threats that drive a species towards extinction in order to address those drivers. In this paper, we assess our knowledge of the threats faced by 24 Himalayan Galliformes species by undertaking a review to identify threats reported in the published literature and the supporting evidence that the threat is having an impact on the species population. Only 24 papers were deemed suitable to be included in the study. We found that biological resource use, agriculture and aquaculture are the predominant threats to the Galliformes in the Greater Himalaya but the evidence available in the studies is quite poor as only one paper quantified the impact on species. This study shows that major gaps exist in our understanding of threats to species and it is imperative to fill those gaps if we want to prevent species from going extinct.
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Optimising different types of biodiversity coverage of protected areas with a case study using Himalayan Galliformes
Biological Conservation, 2016Co-Authors: Jonathon Dunn, R. Will Stein, Graeme M. Buchanan, Mark J. Whittingham, Philip J. K. McgowanAbstract:Abstract International targets have committed governments to expanding the global protected area (PA) network to 17% of the terrestrial surface by 2020. Optimising PA placement in the landscape is challenging due to a poor knowledge of biodiversity distribution and multiple definitions of conservation value. We explore these two issues using a case study of a highly threatened bird Order in a region of conservation concern where PA network effectiveness for biodiversity has not been formally explored previously. To determine if the existing PA network protects the most important areas for 24 species of Himalayan Galliformes, we use a novel method to compare the current network placement to results produced from Zonation prioritisation software and modelled species distributions. Specifically, we identify areas of high species richness and then weight maps by three different species specific conservation values. The current PA network captures ranges poorly. We found statistically significantly poorer fits between the optimal and the existing placement of the Himalayan PA network for Zonation results that were: (i) unweighted; (ii) weighted by Red List score; and (iii) weighted by endemism to the Himalaya. Across these and two other Zonation results, the placement of the optimal PA network covered 58% more of Galliformes distributions than the existing network. We advocate some refinements to the existing PA network to maximise Galliformes coverage and suggest that our method could be used to model the optimal PA network for a wide range of species and/or regions, something which will support the assessment and attainment of CBD targets.
Anton F.‐j. Wroblewski - One of the best experts on this subject based on the ideXlab platform.
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a crown group galliform bird from the middle eocene bridger formation of wyoming
Palaeontology, 2003Co-Authors: Bonnie E Gulaswroblewski, Anton F.‐j. WroblewskiAbstract:Despite an extensive described fossil record of Galliformes (Aves: ‘landfowl’), very few specimens have been considered within a phylogenetic context. Here we present a cladistic analysis and description of a new, well-preserved and well-dated fossil specimen from the Middle Eocene Bridger Formation of Wyoming (c. 50 Ma). Amitabha urbsinterdictensis gen. et. sp. nov. is assigned to Galliformes on the basis of the presence of derived characters including double, and open, incisurae laterales on the sternum and an incisura capitis of the proximal humerus that is enclosed from the crus dorsale fossa by a distinct ridge. Amitabha is considered to be a member of the large and diverse ‘phasianoid’ clade of Galliformes (including, for example, the pheasants, peafowl and turkeys) owing to a lack of extensive pneumaticity in the sternal plate. The age of this avian taxon and degree of preservation allow for a discussion of the use of fossil birds for the calibration of ‘molecular clock’ hypotheses and dating divergences within Neornithes in general, and Galliformes in particular.
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A crown‐group galliform bird from the Middle Eocene Bridger Formation of Wyoming
Palaeontology, 2003Co-Authors: Bonnie E. Gulas‐wroblewski, Anton F.‐j. WroblewskiAbstract:Despite an extensive described fossil record of Galliformes (Aves: ‘landfowl’), very few specimens have been considered within a phylogenetic context. Here we present a cladistic analysis and description of a new, well-preserved and well-dated fossil specimen from the Middle Eocene Bridger Formation of Wyoming (c. 50 Ma). Amitabha urbsinterdictensis gen. et. sp. nov. is assigned to Galliformes on the basis of the presence of derived characters including double, and open, incisurae laterales on the sternum and an incisura capitis of the proximal humerus that is enclosed from the crus dorsale fossa by a distinct ridge. Amitabha is considered to be a member of the large and diverse ‘phasianoid’ clade of Galliformes (including, for example, the pheasants, peafowl and turkeys) owing to a lack of extensive pneumaticity in the sternal plate. The age of this avian taxon and degree of preservation allow for a discussion of the use of fossil birds for the calibration of ‘molecular clock’ hypotheses and dating divergences within Neornithes in general, and Galliformes in particular.
Huidong Tian - One of the best experts on this subject based on the ideXlab platform.
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Climate change induced range shifts of Galliformes in China.
Integrative zoology, 2010Co-Authors: Huidong TianAbstract:Climate change will cause range shifts of many species in the future. Galliformes might be particularly vulnerable to climate change, as they have low dispersal ability. Little is known about their possible responses to the future climate. We used a generalized additive model to predict the current and future ranges of all 63 Galliformes in China, based on a comprehensive species occurrence database and a combination of climate variables. Other environmental variables (e.g. elevation and human footprint index) were also considered, as well as the latitude and longitude of the occurrences. Principal component analysis was conducted to illustrate the association between environmental variables and Galliformes distributions. Using the Special Report on Emissions Scenarios (SRES) A2 climate change scenario for 2071-2100, we projected that 29 species would have range shifts over 50%, including 13 endemic species. Galliformes at higher elevation face greater range shifts. Northward shifts are greater than those in other directions. We suggest conservationists pay special attention to the 29 Galliformes that face extensive range shifts, especially the endemic species among them.
