For all researches, please visit our "Peer-reviewed publications" page.
Correa Ayram C, Mendoza M, Etter A, Pérez Salicrup D (2017)
Anthropogenic impact on habitat connectivity: A multidimensional human footprint index evaluated in a highly biodiverse landscape of Mexico
Ecological Indicators 72 895-909.
Evaluating the cumulative effects of the human footprint on landscape connectivity is crucial for implementing policies for the appropriate management and conservation of landscapes. We present an adjusted multidimensional spatial human footprint index (SHFI) to analyze the effects of landscape transformation on the remnant habitat connectivity for 40 terrestrial mammal species representative of the Trans-Mexican Volcanic System in Michoacán (TMVSMich), in western central Mexico. We adjusted the SHFI by adding fragmentation and habitat loss to its original three components: land use intensity, time of human landscape intervention, and biophysical vulnerability. The adjusted SHFI was applied to four scenarios: one grouping all species and three grouping several species by habitat spatial requirements. Using the SHFI as a dispersal resistance surface and applying a circuit theory based approach, we analyzed the effects of cumulative human impact on habitat connectivity in the different scenarios. For evaluating the relationship between habitat loss and connectivity, we applied graph theory-based equivalent connected area (ECA) index. Results show over 60% of the TMVSMich has high SHFI values, considerably lowering current flow for all species. Nevertheless, the effect on connectivity of human impact is higher for species with limited dispersal capacity (100–500m). Our approach provides a new form of evaluating human impact on habitat connectivity that can be applied to different scales and landscapes. Furthermore, the approach is useful for guiding discussions and implementing future biodiversity conservation initiatives that promote landscape connectivity as an adaptive strategy for climate change.
Keywords: Cumulative human impact, Habitat connectivity, Mexico, Multi-species
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
Cadena C, Pedraza C, Brumfield R (2016)
Climate, habitat associations and the potential distributions of Neotropical birds: Implications for diversification across the Andes
Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales 40(155) 275-287.
Contrary to the long-held view that the uplift of the Andes spurred biotic diversification by causing vicariance across multiple lineages with formerly continuous distributions, recent work suggests that dispersal across the Andes occurring after major uplift episodes was a major driver of speciation in Neotropical birds, with the ability of lineages to persist and disperse in the landscape being strong predictors of speciation. However, where and when dispersal events across the Andes occurred is unknown, and the role of climatic fluctuations and associated shifts in vegetation in promoting cross-Andes dispersal at different moments remains to be studied. We used models of species potential distributions based on contemporary and historical climatic data to examine scenarios of cross-Andes dispersal by 41 species of Neotropical lowland birds with varying habitat affinities. Our results indicate that ecological connectivity favoring cross-Andes dispersal at the present is higher in low-lying passes across the Andes of southern Ecuador and northern Peru than in passes in Colombia, and this spatial pattern appears to have been consistent at four different moments over the past 130,000 years. We also found that although some areas may be presently unsuitable for the dispersal of birds across the Andes, under past climatic conditions (i.e. during cooler and drier periods) they were substantially more likely to allow for ecological connectivity of populations across the cordillera. No consistent differences were found in ecological connectivity across the Andes in the present nor in the past for species occupying different habitat types. We suggest that valleys in the Andes are major drivers of evolutionary diversification not only by isolating populations of montane species, but also by allowing episodic dispersal of lowland species. Our models allow us to make predictions about gene flow which may be assessed in future studies examining fine-grain patterns of genetic exchange with landscape genetics tools. © Acad. Colomb. Cienc. Ex. Fis. Nat. 2016.
Keywords: Andean Uplift, Climatic Change, Isolation by Resistance, Lowland Forest, Speciation, Species Distribution Models.
Castañeda-Álvarez N, Khoury C, Achicanoy H, Bernau V, Dempewolf H, Eastwood R et al. (2016)
Nature Plants 2(4) 16022.
The wild relatives of domesticated crops possess genetic diversity useful for developing more productive, nutritious and resilient crop varieties. However, their conservation status and availability for utilization are a concern, and have not been quantified globally. Here, we model the global distribution of 1,076 taxa related to 81 crops, using occurrence information collected from biodiversity, herbarium and gene bank databases. We compare the potential geographic and ecological diversity encompassed in these distributions with that currently accessible in gene banks, as a means to estimate the comprehensiveness of the conservation of genetic diversity. Our results indicate that the diversity of crop wild relatives is poorly represented in gene banks. For 313 (29.1% of total) taxa associated with 63 crops, no germplasm accessions exist, and a further 257 (23.9%) are represented by fewer than ten accessions. Over 70% of taxa are identified as high priority for further collecting in order to improve their representation in gene banks, and over 95% are insufficiently represented in regard to the full range of geographic and ecological variation in their native distributions. The most critical collecting gaps occur in the Mediterranean and the Near East, western and southern Europe, Southeast and East Asia, and South America. We conclude that a systematic effort is needed to improve the conservation and availability of crop wild relatives for use in plant breeding.
Keywords: Andean Uplift, Climatic Change, Isolation by Resistance, Lowland Forest, Speciation, Species Distribution Models.
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
Gómez C, Tenorio E, Montoya P, Cadena C (2016)
Niche-tracking migrants and niche-switching residents: evolution of climatic niches in New World warblers (Parulidae).
Proceedings. Biological sciences / The Royal Society 283(1824) 20152458-.
Differences in life-history traits between tropical and temperate lineages are often attributed to differences in their climatic niche dynamics. For example, the more frequent appearance of migratory behaviour in temperate-breeding species than in species originally breeding in the tropics is believed to have resulted partly from tropical climatic stability and niche conservatism constraining tropical species from shifting their ranges. However, little is known about the patterns and processes underlying climatic niche evolution in migrant and resident animals. We evaluated the evolution of overlap in climatic niches between seasons and its relationship to migratory behaviour in the Parulidae, a family of New World passerine birds. We used ordination methods to measure seasonal niche overlap and niche breadth of 54 resident and 49 migrant species and used phylogenetic comparative methods to assess patterns of climatic niche evolution. We found that despite travelling thousands of kilometres, migrants tracked climatic conditions across the year to a greater extent than tropical residents. Migrant species had wider niches than resident species, although residents as a group occupied a wider climatic space and niches of migrants and residents overlapped extensively. Neither breeding latitude nor migratory distance explained variation among species in climatic niche overlap between seasons. Our findings support the notion that tropical species have narrower niches than temperate-breeders, but does not necessarily constrain their ability to shift or expand their geographical ranges and become migratory. Overall, the tropics may have been historically less likely to experience the suite of components that generate strong selection pressures for the evolution of migratory behaviour.
Keywords: evolution, migration, niche breadth, niche overlap
Jba H, Jos C, da SL G, Fs G, Fs G (2016)
Journal of Microbial & Biochemical Technology 08(06) 1-5.
Colombia is listed as the second largest country in plant diversity in the world, presenting more than 6000 species of endemic plants. The different genus and species of plants, as well as the various environments encountered in the country, are responsible for the countless amount of endophytic bacteria and fungi. So far, only a few endophytic microorganisms were isolated in Colombia, including the genera Pseudomonas, Burkholderia, Chromobacterium, Curtobacterium, Acremonium, Alternaria, Aspergillus and Fusarium, which have been isolated from rice, coffee, rose, grass and Espeletia plants. Fungi and bacteria isolated from these plants have great potential for use in biocontrol, bioremediation and in promoting plant growth. Colombia for its rich flora have become a promising country for finding new microorganisms associated with plants, especially those with potential for food industry, pharmaceuticals and agriculture.
Keywords: Bacteria and Colombia, Endophytic microorganisms, Fungi
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