7 results on '"Laffan, Shawn"'
Search Results
2. Assessing Endemism at Multiple Spatial Scales, with an Example from the Australian Vascular Flora
- Author
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Laffan, Shawn W. and Crisp, Michael D.
- Published
- 2003
3. Patterns, biases and prospects in the distribution and diversity of Neotropical snakes
- Author
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Guedes, Thaís B., Sawaya, Ricardo J., Zizka, Alexander, Laffan, Shawn, Faurby, Søren, Pyron, R. Alexander, Bérnils, Renato S., Jansen, Martin, Passos, Paulo, Prudente, Ana L. C., Cisneros‐Heredia, Diego F., Braz, Henrique B., Nogueira, Cristiano de C., Antonelli, Alexandre, and Meiri, Shai
- Subjects
GBIF ,Serpentes ,sampling gaps ,conservation ,geographical distribution ,phylogenetic diversity ,species richness ,data availability ,Data Paper - Abstract
Motivation We generated a novel database of Neotropical snakes (one of the world's richest herpetofauna) combining the most comprehensive, manually compiled distribution dataset with publicly available data. We assess, for the first time, the diversity patterns for all Neotropical snakes as well as sampling density and sampling biases. Main types of variables contained We compiled three databases of species occurrences: a dataset downloaded from the Global Biodiversity Information Facility (GBIF), a verified dataset built through taxonomic work and specialized literature, and a combined dataset comprising a cleaned version of the GBIF dataset merged with the verified dataset. Spatial location and grain Neotropics, Behrmann projection equivalent to 1° × 1°. Time period Specimens housed in museums during the last 150 years. Major taxa studied Squamata: Serpentes. Software format Geographical information system (GIS). Results The combined dataset provides the most comprehensive distribution database for Neotropical snakes to date. It contains 147,515 records for 886 species across 12 families, representing 74% of all species of snakes, spanning 27 countries in the Americas. Species richness and phylogenetic diversity show overall similar patterns. Amazonia is the least sampled Neotropical region, whereas most well‐sampled sites are located near large universities and scientific collections. We provide a list and updated maps of geographical distribution of all snake species surveyed. Main conclusions The biodiversity metrics of Neotropical snakes reflect patterns previously documented for other vertebrates, suggesting that similar factors may determine the diversity of both ectothermic and endothermic animals. We suggest conservation strategies for high‐diversity areas and sampling efforts be directed towards Amazonia and poorly known species.
- Published
- 2017
4. Phylogenetic diversity and conservation of crop wild relatives in Colombia.
- Author
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González‐Orozco, Carlos E., Sosa, Chrystian C., Thornhill, Andrew H., and Laffan, Shawn W.
- Subjects
AGRICULTURAL resources ,GRID cells ,CROPS ,GRAND strategy (Political science) ,CACAO beans - Abstract
Crop wild relatives (CWR) are an important agricultural resource as they contain genetic traits not found in cultivated species due to localized adaptation to unique environmental and climatic conditions. Phylogenetic diversity (PD) measures the evolutionary relationship of species using the tree of life. Our knowledge of CWR PD in neotropical regions is in its infancy. We analysed the distribution of CWR PD across Colombia and assessed its conservation status. The areas with the largest concentration of PD were identified as being in the northern part of the central and western Andean mountain ranges and the Pacific region. These centres of high PD were comprised of predominantly short and closely related branches, mostly of species of wild tomatoes and black peppers. In contrast, the CWR PD in the lowland ecosystems of the Amazon and Orinoquia regions had deeply diverging clades predominantly represented by long and distantly related branches (i.e. tuberous roots, grains and cacao). We categorized 50 (52.6%) of the CWR species as 'high priority', 36 as 'medium priority' and nine as 'low priority' for further ex‐situ and in situ conservation actions. New areas of high PD and richness with large ex‐situ gap collections were identified mainly in the northern part of the Andes of Colombia. We found that 56% of the grid cells with the highest PD values were unprotected. These baseline data could be used to create a comprehensive national strategy of CWR conservation in Colombia. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
5. Patterns, biases and prospects in the distribution and diversity of Neotropical snakes
- Author
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Guedes, Thais, Sawaya, Ricardo J., Zizka, Alexander, Laffan, Shawn, Faurby, Søren, Pyron, R. Alexander, Bérnils, Renato S., Jansen, Martin, Passos, Paulo, Prudente, Ana L. C., Braz, Henrique B., C. Nogueira, Cristiano de, and Antonelli, Alexandre
- Subjects
GBIF ,sampling gaps ,conservation ,geographical distribution ,data availability ,species richness ,phylogenetic diversity ,Serpentes - Abstract
MOTIVATION: We generated a novel database of Neotropical snakes (one of the world's richest herpetofauna) combining the most comprehensive, manually compiled distribution dataset with publicly available data. We assess, for the first time, the diversity patterns for all Neotropical snakes as well as sampling density and sampling biases. MAIN TYPES OF VARIABLES CONTAINED: We compiled three databases of species occurrences: a dataset downloaded from the Global Biodiversity Information Facility (GBIF), a verified dataset built through taxonomic work and specialized literature, and a combined dataset comprising a cleaned version of the GBIF dataset merged with the verified dataset. SPATIAL LOCATION AND GRAIN: Neotropics, Behrmann projection equivalent to 1° × 1°. TIME PERIOD: Specimens housed in museums during the last 150 years. MAJOR TAXA STUDIED: Squamata: Serpentes. SOFTWARE FORMAT: Geographical information system (GIS). RESULTS: The combined dataset provides the most comprehensive distribution database for Neotropical snakes to date. It contains 147,515 records for 886 species across 12 families, representing 74% of all species of snakes, spanning 27 countries in the Americas. Species richness and phylogenetic diversity show overall similar patterns. Amazonia is the least sampled Neotropical region, whereas most well‐sampled sites are located near large universities and scientific collections. We provide a list and updated maps of geographical distribution of all snake species surveyed. MAIN CONCLUSIONS: The biodiversity metrics of Neotropical snakes reflect patterns previously documented for other vertebrates, suggesting that similar factors may determine the diversity of both ectothermic and endothermic animals. We suggest conservation strategies for high‐diversity areas and sampling efforts be directed towards Amazonia and poorly known species.
- Published
- 2017
6. Patterns, biases and prospects in the distribution and diversity of Neotropical snakes.
- Author
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Guedes, Thaís B., Sawaya, Ricardo J., Zizka, Alexander, Laffan, Shawn, Faurby, Søren, Pyron, R. Alexander, Bérnils, Renato S., Jansen, Martin, Passos, Paulo, Prudente, Ana L. C., Cisneros‐Heredia, Diego F., Braz, Henrique B., Nogueira, Cristiano de C., and Antonelli, Alexandre
- Subjects
REPTILE diversity ,SNAKE ecology ,GEOGRAPHIC information systems ,PHYLOGENY ,GEOGRAPHICAL distribution of reptiles ,SPECIES diversity - Abstract
Motivation We generated a novel database of Neotropical snakes (one of the world's richest herpetofauna) combining the most comprehensive, manually compiled distribution dataset with publicly available data. We assess, for the first time, the diversity patterns for all Neotropical snakes as well as sampling density and sampling biases. Main types of variables contained We compiled three databases of species occurrences: a dataset downloaded from the Global Biodiversity Information Facility (GBIF), a verified dataset built through taxonomic work and specialized literature, and a combined dataset comprising a cleaned version of the GBIF dataset merged with the verified dataset. Spatial location and grain Neotropics, Behrmann projection equivalent to 1° × 1°. Time period Specimens housed in museums during the last 150 years. Major taxa studied Squamata: Serpentes. Software format Geographical information system (GIS). Results The combined dataset provides the most comprehensive distribution database for Neotropical snakes to date. It contains 147,515 records for 886 species across 12 families, representing 74% of all species of snakes, spanning 27 countries in the Americas. Species richness and phylogenetic diversity show overall similar patterns. Amazonia is the least sampled Neotropical region, whereas most well-sampled sites are located near large universities and scientific collections. We provide a list and updated maps of geographical distribution of all snake species surveyed. Main conclusions The biodiversity metrics of Neotropical snakes reflect patterns previously documented for other vertebrates, suggesting that similar factors may determine the diversity of both ectothermic and endothermic animals. We suggest conservation strategies for high-diversity areas and sampling efforts be directed towards Amazonia and poorly known species. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
7. Biogeographical regions and phytogeography of the eucalypts.
- Author
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González‐Orozco, Carlos E., Thornhill, Andrew H., Knerr, Nunzio, Laffan, Shawn, Miller, Joseph T., and Richardson, David
- Subjects
BIOGEOGRAPHY ,PHYTOGEOGRAPHY ,EUCALYPTUS ,SPECIES diversity ,REGIONAL medical programs ,MULTIDIMENSIONAL scaling ,CLUSTER analysis (Statistics) - Abstract
Aim To map spatial patterns of species richness, species endemism and species turnover of the eucalypts; to propose a biogeographical regionalization of eucalypts based on species turnover; and to identify the environmental correlates of these patterns. Location Australia and Malesia. Methods We analysed 798 eucalypt species ( Angophora, Corymbia and Eucalyptus) with distributions across Australia and Malesia using square cells with a resolution of 100 × 100 km. Species richness, endemism and species turnover were calculated. Phytogeographical regions were identified using an agglomerative cluster analysis derived from a matrix of pairwise Simpson's beta (β
sim ) dissimilarity values. Eleven environmental variables were used to analyse the environmental correlates of species turnover. Non-metric multidimensional scaling ( NMDS) of the βsim , Getis- Ord Gi* hotspot spatial statistics and an ordination of the βsim - NMDS were used to investigate the environmental drivers at the continental level and for each of the phytogeographical regions. Results We identified three centres of species richness and fourteen of endemism, of which several are newly identified. The main centres of species richness agree with previous studies. Six major eucalypt phytogeographical regions are proposed based on the species turnover: monsoon, tropical/subtropical, south-east, south-west, Eremaean north and Eremaean south. These findings are supported by significant environmental differences of the NMDS vectors and the Gi* statistics. The environmental drivers of species turnover are broadly consistent with the continental patterns of summer and winter rainfall below and above the Tropic of Capricorn. Main conclusions The proposed phytogeographical regions are similar to the Australian biomes. Climate is the main driver of the phytogeographical regions, varying from region to region. Comprehensive bioregionalization frameworks and phytogeography updates, as proposed here, are fundamental for enhancing our understanding of the spatial distribution of biodiversity and therefore benefit global biogeography and help planners to identify regions of high conservation relevance. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
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