
Julián A. VelascoInstituto de Ciencias de la Atmósfera y Cambio Climático UNAM
Julián A. Velasco
Dr.
About
100
Publications
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Introduction
Climate change, macroecology, ecological modeling, spatial ecology, biodiversity
Additional affiliations
November 2018 - present
February 2017 - November 2018
May 2016 - January 2017
Centro Universitario de la Costa, Universidad de Guadalajara
Position
- PostDoc Position
Description
- Climatic niche evolution, Anolis, GIS, climate change, ecological niche modeling, macroecology
Education
August 2011
January 2004 - November 2008
August 1997 - November 2003
Publications
Publications (100)
Urbanization is a phenomenon where humans concentrate in high densities and consume more per capita energy than in rural areas, imposing high pressures on biodiversity and ecosystem services. Although Mexico is recognized as a megadiverse country and there is an understanding of ecological and evolutionary processes underlying this high diversity,...
Species abundance patterns are influenced by a myriad of factors, including habitat availability and ecological niche characteristics. However, the evidence concerning the specific impact factors such as niche position and niche breadth on mean and maximum abundances in vertebrates at a broad geographical scale remains inconclusive. In this study,...
¿Qué sabemos sobre el cambio climático en México?
Módulo 1. Biodiversidad y cambio climático
Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis ( Bd ), is a major driver of amphibian decline worldwide. The global presence of Bd is driven by a synergy of factors, such as climate, species life history, and amphibian host susceptibility. Here, using a Bayesian data‐mining approach, we modeled the epidemiological la...
Earth is home to millions of plant and animal species, with more than 40 thousand species facing extinction worldwide (Diaz et al. 2019). Species’ range size is particularly important in this context because it influences extinction risk (Purvis et al. 2000, Gaston & Fuller 2009), but the causes underlying the wide natural variation in range size r...
Mexico’s topographic and environmental heterogeneity, in combination with environmental fluctuations of the Neogene- Quaternary, has uniquely influenced the evolutionary history and distribution patterns of the region’s flora and fauna, sometimes causing closely related species to exhibit distinct climatic niches. Our study aimed to characterize th...
Advances in technology have equipped paleobiologists with new analytical tools to assess the fossil record. The functional traits of vertebrates have been used to infer paleoenvironmental conditions. In Quaternary deposits, birds are the second-most-studied group after mammals. They are considered a poor paleoambiental proxy because their high vagi...
Shifts between native and alien climatic niches pose a major challenge for predicting biological invasions. This is particularly true for insular species because geophysical barriers could constrain the realization of their fundamental niches, which may lead to underestimates of their invasion potential. To investigate this idea, we estimated the f...
Chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) is a major driver of amphibian decline worldwide. The global presence of Bd is driven by a synergy of factors, such as climate, species life history, and amphibian host susceptibility. Here, using a Bayesian data-mining approach, we modelled the epidemiological lands...
The collection of publicly available databases about climate change and its impacts on natural and human systems is unprecedented and ever-growing. However, the requirements of information can vary widely among users depending on their region, socioenvironmental context, and interests. Moreover, in the current era of active mitigation and adaptatio...
Centrándonos en la producción de maíz de temporal, evaluamos el riesgo socioecológico que enfrentan los municipios de México en la actualidad y cómo el
cambio climático podría modificar tal producción.
Aim: Our aim is to document the dimensions of current squamate reptile biodiversity in the Americas by integrating taxonomic, phylogenetic, and functional data, and assessing how this may vary across phylogenetic scales. We also explore the potential underlying mechanisms that may have originated the observed geographical diversity patterns.
Locat...
The intersection of macroecology and macroevolution is one of today’s most active research in biology. In the last decade, we have witnessed a steady increment of macroecological studies that use metrics attempting to capture macroevolutionary processes to explain present-day biodiversity patterns. Evolutionary explanations of current species richn...
Chagas disease, caused by the protozoa Trypanosoma cruzi, is an important yet neglected disease that represents a severe public health problem in the Americas. Although the alteration of natural habitats and climate change can favor the establishment of new transmission cycles for T. cruzi, the compound effect of human-modified landscapes and curre...
Empirical studies have shown that several taxa exhibit a decoupled relationship between lineage species diversification (the balance between speciation and extinction) and phenotypic diversification. This has been recognized by some authors as fundamental evidence for non-adaptive radiation. In the leaf-toed geckos Phyllodactylus of North America,...
Complex physical models are the most advanced tools available for producing realistic simulations of the climate system. However, such levels of realism imply high computational cost and restrictions on their use for policymaking and risk assessment. Two central characteristics of climate change are uncertainty and that it is a dynamic problem in w...
The formation of the Trans-Mexican Volcanic Belt (TMVB) and Pleistocene climatic fluctuations have been shown to influence the diversification of lineages and species distributed throughout central Mexico. In some taxa, however, evidence of lineage diversification is not easily recognized, as often is the case in reptiles. Here we present a phyloge...
The formation of the Trans-Mexican Volcanic Belt (TMVB) and Pleistocene climatic fluctuations have been shown to influence the diversification of lineages and species distributed throughout central Mexico. In some taxa, however, evidence of lineage diversification is not easily recognized, as often is the case in reptiles. Here we present a phyloge...
The cloud forest shows a great diversity of groups and has been considered as centers of high richness and endemism, throughout Asia, Africa and mainly in the Americas. To determine the specific and phylogenetic richness as well as the association in the composition of species of amphibians and reptiles in this environment in Mexico, using database...
Introduction:
Neotropical seasonally dry forest (NSDF) climatic constraints increased endemism, and phylogenetic niche conservatism in species that are restricted to this biome. NSDF have a large number of endemic Capparaceae taxa, but it is unknown if phylogenetic niche conservatism has played a role in this pattern.
Objective:
We carried out an...
We attempted to identify the factors influencing size and shape dimorphism between sexes, as well as among populations and species in the Sceloporus scalaris group (Sceloporus aeneus, S. scalaris, S. bicanthalis and S. subniger). Our analysis focused on five morphological characteristics: snout–vent length, head length, head width, forearm length a...
The spiny lizard genus Sceloporus was described by Wiegmann in 1828, with S. torquatus posteriorly designated as the type species. The taxonomic history of S. torquatus is complicated, as it has been confused with other taxa by numerous authors. Many modern systematics works have been published on Sceloporus , but none have included all five recogn...
Complex physical models are the most advanced tools available for producing realistic simulations of the climate system. However, such levels of realism imply high computational cost and restrictions on their use for policymaking and risk assessment. Two central characteristics of climate change are uncertainty and that it is a dynamic problem in w...
The jumping pitvipers of the genus Metlapilcoatlus are generally associated with montane environments and are widely distributed from central and southern Mexico to Panama. In this study, we analyzed the phylogenetic position and compared the morphology of a population from the Sierra Madre Oriental, within the Sierra Gorda Biosphere Reserve, to ot...
Evidence suggests that climate change could drastically reduce Mexico's agricultural productivity with severe socio-ecological consequences. Population growth and the increasing demand of resources will exacerbate these impacts. Focusing on rainfed maize production, we evaluate the socio-ecological risk that municipalities currently face and how cl...
Evidence suggests that climate change could drastically reduce Mexico's agricultural productivity with severe socio-ecological consequences. Population growth and the increasing demand of resources will exacerbate these impacts. Focusing on rainfed maize production, we evaluate the socio-ecological risk that municipalities currently face and how cl...
Continental mountain areas cover <15% of global land surface, yet these regions concentrate >80% of global terrestrial diversity. One prominent hypothesis to explain this pattern proposes that high mountain diversities could be explained by higher diversification rates in regions of high topographic complexity (HTC). While high speciation in mounta...
Impacts on ecosystems and biodiversity are a prominent area of research in climate change. However, little is known about the effects of abrupt climate change and climate catastrophes on them. The probability of occurrence of such events is largely unknown but the associated risks could be large enough to influence global climate policy. Amphibians...
Aim
To develop an updated distribution model and habitat suitability analysis for the Mexican wolf, to inform the recovery efforts in Mexico and the United States.
Location
Mexico and the southwestern United States.
Methods
We used an ensemble species distribution modelling (SDM) approach and a spatial analysis combining anthropogenic and ecologi...
Biological invasions are a big concern due to their potential to impact ecosystems, as well as local people. The hippo Hippopotamus amphibius, native to Africa, has invaded extensive areas of the Magdalena River basin (Colombia) over the past decades, and has been considered the largest invasive animal in the world. Here, we propose the use of two...
Aim
High levels of species richness in mountains are associated with their hypothetical roles as cradles and/or museums of diversity, but the generality of these roles remains unknown. To fill this gap, we tested these two hypotheses at a global scale and assessed the direct and indirect effects of abiotic regional features on the variation of mont...
En el año 2002, el entonces Centro de Control de Contaminación del Pacífico (CCCP) publicó el libro titulado COMPILACIÓN OCEANOGRÁFICA DE LA CUENCA PACÍFICA COLOMBIANA, lo que sería un referente bibliográfico de vital importancia para la caracterización de las zonas marino-costeras del Pacífico colombiano, abarcando un total de cinco capítulos en t...
Aim
The links between taxonomic, functional, and phylogenetic diversity and how these vary geographically are key to understanding how historical and contemporary processes have shaped communities at regional and local scales. Here, we evaluate the links between taxonomic, functional and phylogenetic diversity for the amphibians in the Continental...
The ecological and evolutionary factors underlying life history trait variation is one of the most interesting topics in biology. Although many studies have evaluated either macroevolutionary or macroecological patterns of life history traits across several taxonomic groups, only few studies have attempted to integrate both dimensions in a single a...
Extreme climate events such as droughts, cold snaps, and hurricanes can be powerful agents of natural selection, producing acute selective pressures very different from the everyday pressures acting on organisms. However, it remains unknown whether these infrequent but severe disruptions are quickly erased by quotidian selective forces, or whether...
The increasing demand for goods and services in cities around the world due to a rapidly growing urban population is pushing the socioecological systems that support them to their limits. The complexity of urban socioeconomic and environmental systems and their interactions generate a challenging multidimensional decision problem. In response, gove...
Body size is one of the most influential traits affecting many ecological and physiological processes across animal and plant taxa. Studies of the environmental factors shaping body size patterns may evaluate either temporal or spatial dimensions. Here, we analyzed body size evolution in the radiation of Anolis lizards across both geographical and...
Aim:
The effects of geographic and environmental variables on patterns of genetic and phenotypic differentiation have been thoroughly studied. Ecological speciation involves reproductive isolation due to divergent natural selection that can result in a positive correlation between genetic divergence and adaptive phenotypic divergence (isolation by...
The occurrence of the invasive Brown anole, Anolis sagrei from the Pacific coast of Mexico is confirmed based on squamation and the use of morphological characters. A PCA was performed to explore the morphological differences between the invasive anole and the native Clouded anole Anolis nebulosus. Some of the potential implications for dry tropica...
The mechanisms driving phenotypic evolution have been of interest to biologists since Darwin. Ecological release-wherein adaptive evolution occurs following relaxation of constraining selective pressures-and environmental filtering-wherein exaptive traits allow colonization of a new area-have been studied in several insular cases. Anolis lizards, w...
Model complexity in ecological niche modelling has been recently considered as an important issue that might affect model performance. New methodological developments have implemented the Akaike information criterion (AIC) to capture model complexity in the Maxent algorithm model. AIC is calculated based on the number of parameters and likelihoods...
Aim
We examined the geographical distribution of functional diversity for American amphibians and tested the relationship between functional diversity and environment. We also explored how the functional evenness of life‐history traits varies across biogeographical regions.
Location
Continental Americas.
Methods
We performed a trait classificati...
A new species of Anolis lizard from the Andean slopes of southwestern Colombia and northwestern Ecuador, from between 1187 and 2353 m in elevation, is described. The new species can be distinguished from other Anolis in squamation, cranial osteology, hemipenial morphology, and nuclear and mitochondrial DNA. The new species is sister to Anolisaequat...
Insular systems are usually characterized by have a high species diversity, endemism, and evolutionary uniqueness. Although ecological and evolutionary factors shaping insular diversity and endemism are relatively well established, there is a little understanding about climatic niche dynamics for many insular adaptive radiations. Here, we evaluate...
The Quimbaya toad, Atelopus quimbaya, is a small bufonid endemic to the Central Andes in Colombia and it is categorized as Critically Endangered by the International Union for Conservation of Nature-IUCN-. Here, we report historical sightings and recent extensive surveys conducted by us in three historical localities where the Quimbaya toad was rep...
Aim
Ecological niche modeling (ENM) is an approach used to estimate species‘ presence given its environmental preferences. Model complexity in ENMs has increasingly gained relevance in the last years. In particular, in Maxent algorithm is captured using the Akaike Information Criteria (AIC) based on the number of parameters and likelihoods of conti...
The Mexican wolf (Canis lupus baileyi) was included in the 1973 Endangered Species Act listing of the gray wolf (C. lupus), but then listed separately as a subspecies in 2015. Early accounts of its range included the Sierra Madre Occidental of Mexico, southeastern Arizona, southwestern New Mexico, and sometimes western Texas, supported by ecologica...
Adaptive radiation is a widely recognized pattern of evolution wherein substantial phenotypic change accompanies rapid speciation. Adaptive radiation may be triggered by environmental opportunities resulting from dispersal to new areas or via the evolution of traits, called key innovations, that allow for invasion of new niches. Species sampling is...
The intersection of macroecology and macroevolution is one of the most active research areas today. Macroecological studies are increasingly using phylogenetic diversification metrics to explore the role of evolutionary processes in shaping present-day patterns of biodiversity. Evolutionary explanations of species richness gradients are key for our...
Understanding the climatic and historical factors shaping species richness is a major goal of ecology and biogeography. Consensus on how climate affects species richness is still lacking, but four potential and non-exclusive explanations have emerged: water-energy, where diversity is determined by precipitation and/or temperature; seasonality, wher...
Anolis lizards (anoles) are textbook study organisms in evolution and ecology. Although several topics in evolutionary biology have been elucidated by the study of anoles, progress in some areas has been hampered by limited phylogenetic information on this group. Here we present a phylogenetic analysis of all 379 extant species of Anolis, with new...
We evaluated the tempo and mode of climatic niche evolution in the radiation of Caribbean Anolis lizards and the role of climate in shaping their exceptional insular endemism. Using phylogenetic comparative methods, climatic niche data and a calibrated phylogeny, we reconstructed climatic niche dynamics across time and space for Caribbean Anolis li...
Conservation status and priorities of amphibians from the Quindío Department, Colombia
We reviewed the conservation status and priorities for amphibians from the Quindío region of Colombia, with the purpose of proposing conservation actions. We modeled the potential distribution of threatened species using the maximum entropy algorithm in MaxEnt an...
We studied the phylogenetic status, morphological variation, dewlap color variation, and geographic distribution of four poorly known Anolis species nested in the Norops clade, particularly in the A. fuscoauratus group from the Andes of Colombia. In addition, we also describe a nomen nudum species based on morphological and molecular evidence. This...
IUCN Red Lists have been a valuable tool to prioritize conservation plans in endemic neo-tropical frogs. However, many areas in this region are poorly known in terms of their diversity and endemism. Based on examined museum specimens of the threatened species Pristimantis penelopus we revised its geographic distribution and determined the habitat s...
Caiman crocodilus apaporiensis has been considered by several authors as an extreme of morphological variation within the Caiman crocodilus complex. Here, we evaluate its position in the Caiman crocodilus complex morphospace using morphological traits from head shape. We examined the holotype and seventeen paratypes of Caiman crocodilus apaporiensi...
Aim The aim of this study was to test the link between climatic niche dynamics and species diversification in Anolis on islands and on the mainland. We tested the hypotheses that lineages in warmer climates and with narrow climate niches diversified more than lineages in cold climates and with broad climate niches. We also tested the hypothesis tha...
we observed a parrot snake predating an individual of bush anole. Furthermore, we report the first record of Polychrus gutturosus from Gorgona Island
We report the first records of Anolis ventrimaculatus for Ecuador based on twelve specimens from three localities: Chical (Provincia Carchi), El Cristal (Provincia Esmeraldas), and Lita (Provincia Imbabura). The locality in the Provincia Carchi lies approximately 16 km S from the nearest record (Ñambí, Department Nariño, Colombia). We also present...
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