For all researches, please visit our "Peer-reviewed publications" page.
Bush M, Correa-Metrio A, McMichael C, Sully S, Shadik C, Valencia B et al. (2016)
Quaternary Science Reviews 141 52-64.
A sedimentary record from the Peruvian Amazon provided evidence of climate and vegetation change for the last 6900 years. Piston cores collected from the center of Lake Sauce, a 20 m deep lake at 600 m elevation, were 19.7 m in length. The fossil pollen record showed a continuously forested catchment within the period of the record, although substantial changes in forest composition were apparent. Fossil charcoal, found throughout the record, was probably associated with humans setting fires. Two fires, at c. 6700 cal BP and 4270 cal BP, appear to have been stand-replacing events possibly associated with megadroughts. The fire event at 4270 cal BP followed a drought that caused lowered lake levels for several centuries. The successional trajectories of forest recovery following these large fires were prolonged by smaller fire events. Fossil pollen of Zea mays (cultivated maize) provided evidence of agricultural activity at the site since c. 6320 cal BP. About 5150 years ago, the lake deepened and started to deposit laminated sediments. Maize agriculture reached a peak of intensity between c. 3380 and 700 cal BP. Fossil diatom data provided a proxy for lake nutrient status and productivity, both of which peaked during the period of maize cultivation. A marked change in land use was evident after c. 700 cal BP when maize agriculture was apparently abandoned at this site. Iriartea, a hyperdominant of riparian settings in western Amazonia, increased in abundance within the last 1100 years, but declined markedly at c. 1070 cal BP and again between c. 80 and −10 cal BP.
Keywords: Agriculture, Forest enrichment, Fossil charcoal, Fossil diatoms, Fossil pollen, Human disturbance, Iriartea, Maize, Mauritia, Pre-Columbian
Carrillo-Angeles I, Suzán-Azpiri H, Mandujano M, Golubov J, Martínez-Ávalos J (2016)
Niche breadth and the implications of climate change in the conservation of the genus Astrophytum (Cactaceae)
Journal of Arid Environments 124 310-317.
The niche breadth of a species reflects its ability to inhabit different conditions, and to use different resources, hence, species with wider niche are expected to be more resilient to anthropogenic derived climate change. We estimated the niche breadth of all species of the genus Astrophytum from macro-environmental variables and measures of local habitat uses, in order to evaluate whether species having wider niche breadths are less prone to experience unsuitable conditions projected by the A1B and A2 scenarios of the IPCC for 2020 and 2050, and analyzed the implications of projections for the conservation of the genus Astrophytum. Our analysis suggests that most of populations of the four species will experience increasingly unsuitable conditions due to the increase of temperature and reduction in precipitation. The species less affected were those with wider niche breadth and situated in the middle of the latitudinal range and in the middle or lower extreme of the precipitation range for the genus (A. capricorne and A. myriostigma). Although the main threats for Astrophytum species come from the destruction of their habitats and activities as illegal extraction, climate change may reduce the chances for the regeneration of populations and the success of reintroduction programs.
Keywords: Bioclimatic variables, IPCC scenarios, MaxEnt, Threatened species
González-Santos R, Cadena-Íñiguez J, Morales-Flores F, Ruiz-Vera V, Pimentel-López J (2016)
Prediction of the effects of climate change on Sechium edule (Jacq.) Swartz varietal groups in Mexico
Genetic Resources and Crop Evolution.
Climate change has significant impacts on biodiversity and, particularly, on agriculture. In this study, the impact of climate change on five varietal groups of Sechium edule, up to the year 2050, was determined through the application of the HadGEM2-CC model based on bioclimate layers. The varietal groups, nigrum minor, albus dulcis and nigrum xalapensis, will lose more than 50 % of their potential current distribution due to a high impact in both the rcp 45 and the rcp 85 scenarios. These two varietal groups also have a limited distribution, which makes them highly susceptible. In the case of nigrum spinosum, a loss under 50 % is predicted with scenario rcp 45. The varietal group that increases its distribution in 11 % is virens levis. The model forecasts significant impacts up to the year 2050; however, the groups evaluated present high genetic diversity and phenotypic plasticity which allow adapting to new conditions that may contribute to mitigating the effects of climate change.
Keywords: Climate change, Sechium edule, Varietal groups
Martínez-Calderas J, Hernández-Saintmartín A, Rosas-Rosas O, Palacio-Núñez J, Villordo-Galván J, Olivera-Méndez A (2016)
THERYA 7(2) 241-255.
The margay (Leopardus wiedii, Schinz 1821) is a small Neotropical cat that is native with distribution from South America into Northeastern Mexico. This species is now threatened by illegal hunting and habitat destruction and, in Northeastern Mexico, their habitat has been fragmented and population sizes have been dramatically reduced. We use the MaxEnt algorithm to model the potential distribution of this elusive species, based on trustable presence records and information about their habitat condition. The aim of this study was to estimate the potential distribution of margays in Northeastern Mexico. We determined potential distribution in the physiographic subprovinces (PSP) of Llanuras y Lomerios, Gran Sierra Plegada and Carso Huasteco. A model was generated using recent and historical records through the MaxEnt algorithm. We used four records from online databases, 36 from literature and 13 from our own fieldwork, as well as 27 predictive variables: 19 associated with climate, two with land use and vegetation type, four associated with topography and two with anthropogenic effects. Seven variables contributed to over 90 % of the distribution model and were highly predictive (AUC = 0.964). The potential distribution of margay represents 9.0 % (7,607 km2) of the area, which is highly fragmented. The PSP Gran Sierra Plegada and Carso Huasteco showed the widest distribution range. The four most relevant variables were: precipitation of the most humid quarter, vegetation type, and both altitude and topographic indexes. We applied species distribution modeling by incorporating recent information collected through fieldwork and surveys as well as historical records in order to predict the margay’s potential distribution in Northeastern Mexico. We obtained a robust model based on the most relevant bioclimatic and landscape variables. The landscape in this region is highly fragmented and the largest continuous areas were located in the roughest and inaccessible landscape of the mountainous localities of Gran Sierra Plegada and Carso Huasteco, where an important portion of these PSP maintains continuity in the area of the potential distribution of the margay. Very little is known of the status and abundance of the margay and this study complements our current knowledge of this species in Northeastern Mexico and provides important information regarding the quality of the habitat in this portion of the country. There are several current threats that are being caused by changes in land use in Northeastern Mexico and other parts of their distribution, and this information is essential to establish conservation plans for this species and their habitat. More studies assessing potential distribution throughout their range are needed to support adequate conservation efforts.
Keywords: MaxEnt, Tropical habitats, Wild felids, connectivity, habitat fragmentation
Martínez-Méndez N, Aguirre-Planter E, Eguiarte L, Jaramillo-Correa J (2016)
Modelado de nicho ecológico de las especies del género Abies (Pinaceae) en México: Algunas implicaciones taxonómicas y para la conservación
Botanical Sciences 94(1) 5.
En Mesoamérica y el norte de México, los oyameles o abetos ( Abies , Pinaceae) presentan una distribución disyunta en áreas montañosas y templadas. En esta área se han reconocido entre seis y diez especies de Abies dependiendo de la propuesta taxonómica empleada; generalmente se considera que seis de éstas son endémicas a México y están incluidas en alguna categoría de riesgo. Dada esta incertidumbre taxonómica y la importancia económica del género ( Abies es el cuarto recurso maderable de México), se necesita tener información adicional que contribuya a su manejo sustentable. En este estudio se obtuvo los modelos de nicho ecológico para ocho de las especies y dos variedades de Abies reconocidas en México ( A. concolor , A. durangensis var. duragensis , A. durangensis var. coahuilensis , A. incki , A. guatemalensis , A. hickelii , A. jaliscana , A. religiosa y A. vejari ) a través del algoritmo de máxima entropía (Maxent) y utilizando variables bioclimáticas y topográficas provenientes de Worldclim, de Hydro k y datos depurados de presencia de diversas fuentes (CONABIO, GBIF, MEXU). Los resultados sugieren que A. concolor tiene el nicho ecológico más diferenciado con respecto a los demás abetos mexicanos. Asimismo, se observó que, con excepción de A. religiosa , el área de mayor idoneidad ambiental para todas las especies está fuera de la poligonal de algún área natural protegida ya sea federal o estatal, por lo que se proponen ampliar o crear nuevas áreas que protejan a estas especies.
Keywords: Abies, México, conservación, distribución geográfica, nicho ecológico.
Mendoza-González G, Martínez M, Rojas-Soto O, Téllez-Valdés O, Arias-Del Razo I (2016)
Journal for Nature Conservation.
We modeled the potential distribution of plant species that grow on the beaches and dunes of the Mexican Atlantic coast in order to identify areas of high biodiversity. We used environmental layers in combination with georeferenced data, utilizing the MaxEnt algorithm, and produced four regional consensus maps according to the geographic distribution of the species: along the entire Mexican Atlantic coast, the Gulf of Mexico; the Yucatan Peninsula and all species combined together on a single map. The largest number of widely distributed species in the Gulf of Mexico was concentrated in the northern and central regions, while biodiversity on the Yucatan Peninsula was likely to be concentrated in the north and on Cozumel island, which is the biggest island in the Mexican Caribbean. The map combining all species together revealed a potential concurrence of species in the Gulf of Mexico and Yucatan Peninsula transition, where climatic characteristics converge within a small geographic area. In order to conserve beach and coastal dune plant biodiversity, special attention must be paid to the management plans of established protected areas and to the promotion of new protected areas consistent with the areas reported in this study, particularly in the central Gulf of Mexico and northern Yucatan Peninsula, where areas under protection are currently scarce.
Keywords: Biodiversity, Coastal vegetation, Ecological niche modeling, Species distribution
Monroy-Vilchis O, Castillo-Huitrón N, Zarco-González M, Rodríguez-Soto C (2016)
Potential distribution of Ursus americanus in Mexico and its persistence: Implications for conservation
Journal for Nature Conservation 29 62-68.
The black bear Ursus americanus is an endangered species in Mexico. Its historical distribution has decreased by approximately 80% although its current distribution is not known with precision; it is only reported to be present in the mountains of Northern Mexico. This study proposes two ensemble models: Mexicós black bear (a) potential distribution compared with Natural Protected Areas (NPAs); and, (b) persistence areas for 2024. The current distribution variables are coniferous forest, elevation and dry forest. Suitable habitat for black bear (354,047km2, 18.07% of the country) was found mainly in the north of the Sonoran biogeographical zone, along the Sierra Madre Occidental, the center and south of the Sierra Madre Oriental and some northern regions of the Altiplano Norte. Comparing these areas with NPAs documented that only 12.41% of potential distribution coincided with current suitable habitat. There are unprotected areas in Sierra Madre Occidental center and central and southern of Sierra Madre Oriental. The model for 2024 indicates a reduction of suitable habitat of 64.5%, mainly in the northern Sonoran zone and the center Sierra Madre Occidental. On the other hand, areas that will persist (125,673km2) are located along the two main mountain ranges of Mexico. Identification of these sites will allow strengthening of long-term conservation strategies.
Keywords: Black bear, Conservation, Ensemble model, Future model, Habitat suitability, Mexico, Ursus americanus
Morales A, Villalobos F, Velazco P, Simmons N, Piñero D (2016)
Journal of Biogeography.
Aim To explore whether environmental factors are correlated with genetic and morphometric differences in the widely distributed bat species Tadarida brasiliensis. Location North America and Central America. Methods We used an extensive sampling comprising 131 localities that represent heterogeneous environments across the Nearctic and Neotropical regions. Museum specimens were examined and 25 craniodental characters were recorded. Individuals were genotyped at one mitochondrial locus (mtDNA) and nine nuclear loci (nDNA). Clustering and phylogenetic analyses were used to identify differentiated groups. Environmental variables and PCA-env approaches were used to determine the climatic niche and to measure the niche overlap, equivalence and similarity between groups. Mantel tests between genetic groupings and environmental variables, dispersal costs, Euclidean geographical distances and niche overlap were performed. Results We identified six genetic groups within Central and North American T. brasiliensis based on nDNA. The most strongly differentiated group, in both nDNA and mtDNA, was located in central Mexico. Morphometric data showed that individuals from populations in Florida are slightly larger than the others. Niche overlap was detected among Neotropical groups but not among Nearctic groups. The currently recognized subspecies were not recovered as distinct groups with either genetic or morphometric data. Main conclusions Our approaches suggest that environmental niche variation may help shape the distribution of genetic variation across heterogeneous landscapes, particularly in widely distributed species. Environmental niche analyses suggest that genetic differences between migratory and non-migratory groups of T. brasiliensis may be promoted by climatic variation throughout the Nearctic and Neotropical regions. In addition, genetic and morphometric analyses do not support the current subspecies classification of T. brasiliensis in North and Central America, which should be abandoned.
Keywords: Tadarida brasiliensis, ecological niche, genetic structure, morphometric, phylogeography, subspecies
Ornelas J, Gándara E, Vásquez-Aguilar A, Ramírez-Barahona S, Ortiz-Rodriguez A, González C et al. (2016)
A mistletoe tale: postglacial invasion of Psittacanthus schiedeanus (Loranthaceae) to Mesoamerican cloud forests revealed by molecular data and species distribution modeling.
BMC evolutionary biology 16(1) 78.
BACKGROUND: Ecological adaptation to host taxa is thought to result in mistletoe speciation via race formation. However, historical and ecological factors could also contribute to explain genetic structuring particularly when mistletoe host races are distributed allopatrically. Using sequence data from nuclear (ITS) and chloroplast (trnL-F) DNA, we investigate the genetic differentiation of 31 Psittacanthus schiedeanus (Loranthaceae) populations across the Mesoamerican species range. We conducted phylogenetic, population and spatial genetic analyses on 274 individuals of P. schiedeanus to gain insight of the evolutionary history of these populations. Species distribution modeling, isolation with migration and Bayesian inference methods were used to infer the evolutionary transition of mistletoe invasion, in which evolutionary scenarios were compared through posterior probabilities. RESULTS: Our analyses revealed shallow levels of population structure with three genetic groups present across the sample area. Nine haplotypes were identified after sequencing the trnL-F intergenic spacer. These haplotypes showed phylogeographic structure, with three groups with restricted gene flow corresponding to the distribution of individuals/populations separated by habitat (cloud forest localities from San Luis Potosí to northwestern Oaxaca and Chiapas, localities with xeric vegetation in central Oaxaca, and localities with tropical deciduous forests in Chiapas), with post-glacial population expansions and potentially corresponding to post-glacial invasion types. Similarly, 44 ITS ribotypes suggest phylogeographic structure, despite the fact that most frequent ribotypes are widespread indicating effective nuclear gene flow via pollen. Gene flow estimates, a significant genetic signal of demographic expansion, and range shifts under past climatic conditions predicted by species distribution modeling suggest post-glacial invasion of P. schiedeanus mistletoes to cloud forests. However, Approximate Bayesian Computation (ABC) analyses strongly supported a scenario of simultaneous divergence among the three groups isolated recently. CONCLUSIONS: Our results provide support for the predominant role of isolation and environmental factors in driving genetic differentiation of Mesoamerican parrot-flower mistletoes. The ABC results are consistent with a scenario of post-glacial mistletoe invasion, independent of host identity, and that habitat types recently isolated P. schiedeanus populations, accumulating slight phenotypic differences among genetic groups due to recent migration across habitats. Under this scenario, climatic fluctuations throughout the Pleistocene would have altered the distribution of suitable habitat for mistletoes throughout Mesoamerica leading to variation in population continuity and isolation. Our findings add to an understanding of the role of recent isolation and colonization in shaping cloud forest communities in the region.
Keywords: Animal Systematics/Taxonomy/Biogeography, Entomology, Evolutionary Biology, Genetics and Population Dynamics, Life Sciences, general
Ornelas J, González C, Hernández-Baños B, García-Moreno J (2016)
Molecular and iridescent feather reflectance data reveal recent genetic diversification and phenotypic differentiation in a cloud forest hummingbird
Ecology and Evolution.
The present day distribution and spatial genetic diversity of Mesoamerican biota reflects a long history of responses to habitat change. The hummingbird Lampornis amethystinus is distributed in northern Mesoamerica, with geographically disjunct populations. Based on sampling across the species range using mitochondrial DNA (mtDNA) sequences and nuclear microsatellites jointly analysed with phenotypic and climatic data, we (1) test whether the fragmented distribution is correlated with main evolutionary lineages, (2) assess body size and plumage color differentiation of populations in geographic isolation, and (3) evaluate a set of divergence scenarios and demographic patterns of the hummingbird populations. Analysis of genetic variation revealed four main groups: blue-throated populations (Sierra Madre del Sur); two groups of amethyst-throated populations (Trans-Mexican Volcanic Belt and Sierra Madre Oriental); and populations east of the Isthmus of Tehuantepec (IT) with males showing an amethyst throat. The most basal split is estimated to have originated in the Pleistocene, 2.39–0.57 million years ago (MYA), and corresponded to groups of populations separated by the IT. However, the estimated recent divergence time between blue- and amethyst-throated populations does not correspond to the 2-MY needed to be in isolation for substantial plumage divergence, likely because structurally iridescent colors are more malleable than others. Results of species distribution modeling and Approximate Bayesian Computation analysis fit a model of lineage divergence west of the Isthmus after the Last Glacial Maximum (LGM), and that the species’ suitable habitat was disjunct during past and current conditions. These results challenge the generality of the contraction/expansion glacial model to cloud forest-interior species and urges management of cloud forest, a highly vulnerable ecosystem to climate change and currently facing destruction, to prevent further loss of genetic diversity or extinction.
Keywords: Feather iridescence, Lampornis amethystinus, Mesoamerican highlands, glacial cycles