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Alimi T, Fuller D, Herrera S, Arevalo-Herrera M, Quinones M, Stoler J et al. (2016)
BMC public health 16(1) 221.
BACKGROUND: Malaria control in South America has vastly improved in the past decade, leading to a decrease in the malaria burden. Despite the progress, large parts of the continent continue to be at risk of malaria transmission, especially in northern South America. The objectives of this study were to assess the risk of malaria transmission and vector exposure in northern South America using multi-criteria decision analysis. METHODS: The risk of malaria transmission and vector exposure in northern South America was assessed using multi-criteria decision analysis, in which expert opinions were taken on the key environmental and population risk factors. RESULTS: Results from our risk maps indicated areas of moderate-to-high risk along rivers in the Amazon basin, along the coasts of the Guianas, the Pacific coast of Colombia and northern Colombia, in parts of Peru and Bolivia and within the Brazilian Amazon. When validated with occurrence records for malaria, An. darlingi, An. albimanus and An. nuneztovari s.l., t-test results indicated that risk scores at occurrence locations were significantly higher (p < 0.0001) than a control group of geographically random points. CONCLUSION: In this study, we produced risk maps based on expert opinion on the spatial representation of risk of potential vector exposure and malaria transmission. The findings provide information to the public health decision maker/policy makers to give additional attention to the spatial planning of effective vector control measures. Therefore, as the region tackles the challenge of malaria elimination, prioritizing areas for interventions by using spatially accurate, high-resolution (1 km or less) risk maps may guide targeted control and help reduce the disease burden in the region.
Keywords: Biostatistics, Environmental Health, Epidemiology, Medicine/Public Health, Public Health, Vaccine, general
Arias-Alzate A, González-Maya J, Arroyo-Cabrales J, Martínez-Meyer E (2016)
Wild Felid Range Shift Due to Climatic Constraints in the Americas: a Bottleneck Explanation for Extinct Felids?
Journal of Mammalian Evolution 1-12.
Theoretical and empirical evidence suggests that the ecological niche of species tends to be conservative over evolutionary time in many taxonomic groups, thus representing long-term stable constraints on species geographic distributions. Using an ecological niche modeling approach, we assessed the impact of climatic change on wild felid species potential range shifts over the last 130 K years in the Americas and the potential of such shifts as an extinction driver. We found a significant range shift for most species (both living and extinct) across their distributions driven by large-scale environmental changes. Proportionally, the most drastic range increase for all species occurred in the Last Glacial Maximum (LGM: 18 K years)–Current transition, while for the Last Inter-Glacial (LIG: 130 K years)–LGM transition an important range reduction occurred, which was larger for extinct North American species. In conclusion, the reduction of climatically suitable areas for many species in the transition LIG–LGM may have produced population reductions, which, in turn, may have played an important role in species’ extinction throughout the continent.
Keywords: Bottlenecks, Ecological niche, Extinction, Felidae, Late Pleistocene, Range shift
Bacon C, Look S, Gutiérrez-Pinto N, Antonelli A, Tan H, Kumar P et al. (2016)
Botanical Journal of the Linnean Society.
Four species are recognized in the understorey palm genus Johannesteijsmannia (Arecaceae), all of which occur in close geographical proximity in the Malay Peninsula. We hypothesize that overlapping distributions are maintained by a lack of gene flow among species and that segregation along morphological trait or environmental axes confers ecological divergence and, hence, defines species limits. Although some species have sympatric distributions, differentiation was detected among species in morphological and genetic data, corroborating current species delimitation. Differences in niche breadth were not found to explain the overlapping distribution and co-existence of Johannesteijsmannia spp. Four species formed over the last 3 Mya, showing that diversity accumulated within a short time frame and wide range expansion has not occurred, potentially due to a lack of time for dispersal or the evolution of traits to facilitate movement. An assessment of genetic diversity is presented and, as expected, the widest distribution in the genus harbours the highest genetic diversity.
Keywords: Malesia, Palmae, niche, phylogenetics, speciation
Fuchs J, Lemoine D, Parra J, Pons J, Raherilalao M, Prys-Jones R et al. (2016)
Long-distance dispersal and inter-island colonization across the western Malagasy Region explain diversification in brush-warblers (Passeriformes: Nesillas )
Biological Journal of the Linnean Society.
The present study examines the colonization history and phylogeography of the brush-warblers (Nesillas), a genus of passerines endemic to islands of the western Indian Ocean (Madagascar, Comoros, and Aldabra Atoll). The phylogeny of all recognized Nesillas taxa was reconstructed employing Bayesian phylogenetic methods and divergence times were estimated using a range of substitution rates and clock assumptions. Spatiotemporal patterns of population expansion were inferred and niches of different lineages were compared using ecological niche modelling. Our results indicate that taxa endemic to the Comoros are paraphyletic and that the two endemic species on Madagascar (Nesillas typica and Nesillas lantzii) are not sister taxa. The brush-warblers started to diversify approximately 1.6 Mya, commencing with the separation of the clade formed by two species endemic to the Comoros (Nesillas brevicaudata and Nesillas mariae) from the rest of the genus. The lineages leading to the two Malagasy species diverged approximately 0.9 Mya; each with significantly different modern ecological niches and the subject of separate demographic processes. Patterns of diversification and endemism in Nesillas were shaped by multiple long distance dispersal events and inter-island colonization, a recurring pattern for different lineages on western Indian Ocean islands. The diversification dynamics observed for Nesillas are also consistent with the taxon cycle hypothesis.
Keywords: MAXENT, demographic history, ecological niche modelling, island biogeography, mitochondrial sequence data, phylogenetic constraints, taxon cycle
Molina-Henao Y, Guerrero-Chacón A, Jaramillo M (2016)
Ecological and Geographic Dimensions of Diversification in Piper subgenus Ottonia: A Lineage of Neotropical Rainforest Shrubs
Systematic Botany 41(2) 253-262.
Abstract The Neotropics are home to incomparable plant diversity. To evaluate the potential roles of geography and ecology on speciation in Neotropical plants we selected a small, tractable lineage of shrubby angiosperms, Piper subgenus Ottonia. We reconstructed a molecular phylogeny and provided insights into the species divergence times based on fossil calibration of the molecular clock. We support the monophyly of Piper subg. Ottonia and the two main lineages: Amazonian and Atlantic Forest, the latter containing the non-Atlantic species pair P. darienense—P. piscatorum. We also propose the origin of Piper subg. Ottonia in the early Eocene and suggest that the diversification of Piper subg. Ottonia was influenced by geo-historical events such as the Paleocene-Eocene Thermal Maximum (PETM) and the uplift of the Andes in the Miocene, as is the case for other angiosperms. Furthermore, we combined our phylogeny with geographic and environmental data in order to evaluate geographical and ecological contexts ...
Keywords: Age-range correlation, Miocene, allopatry, environmental niche modeling, sympatry
Posso-Terranova A, Andrés J (2016)
Journal of Biogeography.
Aim Despite the incredible diversity of lowland tropical rain forests, we still have limited understanding of the drivers of speciation in these ecoregions. Here, we investigated the relative contribution of geographical and environmental factors to the diversification of a Neotropical genus of poison frogs (Oophaga). Location Central and South America, including regions from southern Nicaragua to northern Ecuador. Methods We generated gene genealogies (12S, 16S, COI, CytB and tRNA-val, SIAH1, H3 and Rag1) and used species phylogenetic methods (MDC and *beast) to generate a robust phylogeny of Oophaga frogs. Then, we combined the resulting phylogenetic hypothesis with detailed geographical data and environmental niche modelling (ENM) to test the role of geographical isolation, climatic niche divergence and altitudinal gradients. Results Gene genealogies were discordant and did not show exclusive genealogical patterns; however, species tree resolved the phylogenetic relationship among Oophaga species with strong node support (> 0.9 ML/BPP). Geographical ranges showed little overlap between distantly related species. However, within the South American and Central American clades, sister taxa showed substantially overlapping ranges. Analyses of ecological disparity (DTT) indicated a departure from a neutral (Brownian) model of evolution, and age-range correlations, predicted niche occupancy profiles, and Seeva analyses showed that different species tend to evolve under different potential climatic niches. Main conclusions Oophaga frogs originated in Central America and reached South America after the closure of the Panama Isthmus. The South- and Central-American clades of this genus have convergently evolved to similar patterns of geographical distribution and niche occupancy. Within clades, sister taxa showed parapatric distributions replacing each other along elevational gradients as predicted by the models of divergence along continuous ecological gradients. Accordingly, we found strong shifts in climatic niches throughout the history of these two clades. However, the largest niche shifts seem to post-date the final elevation of the Talamanca and northern Andes. Overall, our data suggest that speciation along climatic gradients on a structured landscape has been a major evolutionary force behind the diversification of Oophaga poison frogs.
Keywords: dendrobatids, ecological speciation, neotropics, niche divergence, niche modelling, phylogenetics
Sanín M, Kissling W, Bacon C, Borchsenius F, Galeano G, Svenning J et al. (2016)
The Neogene rise of the tropical Andes facilitated diversification of wax palms ( Ceroxylon : Arecaceae) through geographical colonization and climatic niche separation
Botanical Journal of the Linnean Society.
he tropical Andes are a biodiversity hotspot, partly due to their rich and complex floristic composition. A fundamental question regarding this outstanding biodiversity is what role the Andean orogeny has played in species diversification. Ceroxylon is a genus of endemic Andean palms that stands out in the palm family (Arecaceae) due to its adaptation to cold, mountainous environments. Here, we reconstruct the biogeography and climatic preference of this lineage to test the hypothesis that Andean uplift allowed diversification by providing suitable habitats along climatic and elevational gradients. Ancestral areas were reconstructed under a model allowing for founder-event speciation and climatic niches were inferred from climatic variables at present-day occurrences of all species. Niche evolution in a phylogenetic framework was evaluated by testing differences between the climatic niches of clades. Our analyses identified four main clades, with a general pattern of diversification through geographical colonization from south to north after the Pliocene uplift of the northern Andes. Adaptation to low temperatures was conserved at the generic level, with climatic niche differentiation among clades along elevational temperature gradients. We conclude that the Neogene Andean uplift has facilitated the diversification of this iconic plant group via opportunities for geographical migration and separation within its climatic niche
Keywords: Miocene, Neotropics, cold adaptation, niche shift, phylogenetic niche conservatism, range expansion
ter Steege H, Vaessen R, Cárdenas-López D, Sabatier D, Antonelli A, de Oliveira S et al. (2016)
Scientific Reports 6 29549.
Amazonia is the most biodiverse rainforest on Earth, and the debate over how many tree species grow there remains contentious. Here we provide a checklist of all tree species collected to date, and describe spatial and temporal trends in data accumulation. We report 530,025 unique collections of trees in Amazonia, dating between 1707 and 2015, for a total of 11,676 species in 1225 genera and 140 families. These figures support recent estimates of 16,000 total Amazonian tree species based on ecological plot data from the Amazonian Tree Diversity Network. Botanical collection in Amazonia is characterized by three major peaks, centred around 1840, 1920, and 1980, which are associated with flora projects and the establishment of inventory plots. Most collections were made in the 20th century. The number of collections has increased exponentially, but shows a slowdown in the last two decades. We find that a species’ range size is a better predictor of the number of times it has been collected than the species’ estimated basin-wide population size. Finding, describing, and documenting the distribution of the remaining species will require coordinated efforts at under-collected sites
Keywords: Miocene, Neotropics, cold adaptation, niche shift, phylogenetic niche conservatism, range expansion
Alimi T, Fuller D, Qualls W, Herrera S, Arevalo-Herrera M, Quinones M et al. (2015)
Predicting potential ranges of primary malaria vectors and malaria in northern South America based on projected changes in climate, land cover and human population.
Parasites & vectors 8 431.
BACKGROUND: Changes in land use and land cover (LULC) as well as climate are likely to affect the geographic distribution of malaria vectors and parasites in the coming decades. At present, malaria transmission is concentrated mainly in the Amazon basin where extensive agriculture, mining, and logging activities have resulted in changes to local and regional hydrology, massive loss of forest cover, and increased contact between malaria vectors and hosts. METHODS: Employing presence-only records, bioclimatic, topographic, hydrologic, LULC and human population data, we modeled the distribution of malaria and two of its dominant vectors, Anopheles darlingi, and Anopheles nuneztovari s.l. in northern South America using the species distribution modeling platform Maxent. RESULTS: Results from our land change modeling indicate that about 70,000 km(2) of forest land would be lost by 2050 and 78,000 km(2) by 2070 compared to 2010. The Maxent model predicted zones of relatively high habitat suitability for malaria and the vectors mainly within the Amazon and along coastlines. While areas with malaria are expected to decrease in line with current downward trends, both vectors are predicted to experience range expansions in the future. Elevation, annual precipitation and temperature were influential in all models both current and future. Human population mostly affected An. darlingi distribution while LULC changes influenced An. nuneztovari s.l. distribution. CONCLUSION: As the region tackles the challenge of malaria elimination, investigations such as this could be useful for planning and management purposes and aid in predicting and addressing potential impediments to elimination.
Keywords: An. darlingi, An. nuneztovari s.l, Climate, Land-use changes, Malaria, Maxent, Population expansion, South America, Species distribution models, change
Antonelli A, Zizka A, Silvestro D, Scharn R, Cascales-Miñana B, Bacon C (2015)
An engine for global plant diversity: highest evolutionary turnover and emigration in the American tropics.
Frontiers in genetics 6 130.
Understanding the processes that have generated the latitudinal biodiversity gradient and the continental differences in tropical biodiversity remains a major goal of evolutionary biology. Here we estimate the timing and direction of range shifts of extant flowering plants (angiosperms) between tropical and non-tropical zones, and into and out of the major tropical regions of the world. We then calculate rates of speciation and extinction taking into account incomplete taxonomic sampling. We use a recently published fossil calibrated phylogeny and apply novel bioinformatic tools to code species into user-defined polygons. We reconstruct biogeographic history using stochastic character mapping to compute relative numbers of range shifts in proportion to the number of available lineages through time. Our results, based on the analysis of c. 22,600 species and c. 20 million geo-referenced occurrence records, show no significant differences between the speciation and extinction of tropical and non-tropical angiosperms. This suggests that at least in plants, the latitudinal biodiversity gradient primarily derives from other factors than differential rates of diversification. In contrast, the outstanding species richness found today in the American tropics (the Neotropics), as compared to tropical Africa and tropical Asia, is associated with significantly higher speciation and extinction rates. This suggests an exceedingly rapid evolutionary turnover, i.e., Neotropical species being formed and replaced by one another at unparalleled rates. In addition, tropical America stands out from other continents by having "pumped out" more species than it received through most of the last 66 million years. These results imply that the Neotropics have acted as an engine for global plant diversity.
Keywords: Angiosperms, Latitudinal diversity gradient, biogeography, diversification rates, evolution, phylogenetics, tropical biodiversity