Professors

We take an integrative approach to synthesize the ecology, physiology, and anatomy of plants in a comparative framework. We define our questions in the natural, changing environment and follow the answers to the molecular or ultra-structural level. A unifying theme of our studies is the question of how plants survive and thrive in their natural environment and what mechanisms are responsible for the acclimation and adaptation of plants to extreme environmental conditions. We identify the physiological and structural traits (and hopefully the associated genes) that protect plants, and particularly their ability to collect solar energy, perform photosynthesis, and distribute sugars throughout the plant. We compare these characteristics among plant species with contrasting growth patterns and acclimation strategies.

As an aridlands ecologist, my research mission is to better understand the impacts of changing climate and land use on plant communities and soil resources in dryland ecosystems; research that crosses the boundaries of community, ecosystem, and landscape ecology. In my research program, I employ a variety of techniques in the fields of terrestrial plant ecology, soil biogeochemistry, and dendrochronology to address questions that not only further our knowledge of the structure and function of dryland ecosystems, but also address contemporary issues in sustainable restoration and management of these ecosystems.

Research in my lab concentrates on the interactions between plants, herbivores and natural enemies. I combine both field, greenhouse and laboratory work to investigate the dynamics of these interactions from many perspectives, including behavior, evolution, ecology, physiology and plant and insect chemistry. This research has its roots and context in attempts to understand how plant-insect-natural enemy relationships evolve and are maintained.

Plant ecology, terrestrial ecosystem science. Major areas of research include the nutritional ecology of alpine plants, resource use by plant communities, abiotic and biotic constraints on primary production and nutrient fluxes in alpine ecosystems, and the role of competition/ facilitation in plant communities. Experimental approaches, both in the field and in laboratory growth chambers, are emphasized in addressing research goals.

Social behavior in insects, kin recognition system of honey bees, nest defense in honey bees, and social biology of the giant tropical ant. Kin recognition studies are designed to examine the various factors--queen, workers, nesting material, and food--that go into recognition of nestmates, to demonstrate how these factors are integrated, their fitness outcomes, and their genetic basis. Nest defense is an interesting but relatively unexplored issue in honey bee biology. Studies have focused on the role of the guard bees in initiating defense responses. The giant tropical ant is a good model for the adaptation of a social insect to its environment. These studies, conducted in Costa Rica, have dealt with division of labor and recruitment

As a biology education researcher, I investigate teaching and learning in biology with the aim of understanding what drives students to persist in biology research endeavors when they encounter setbacks and how students develop creativity as biology problem solvers. As the fields of Ecology and Evolution continue to develop, the problems we tackle will become more complex and challenging and require scientists to produce increasingly innovative solutions. To best instruct the next generation of scientists, we must understand why and how scientists make progress when challenges arise and the processes through which innovative solutions are constructed. My lab aims to characterize how students develop dispositions that help them to persist through difficulty and the skills that allow them to be more creative when engaging in biology research endeavors. We use our investigations to inform the design, implementation, and evaluation of new pedagogical innovations that support persistence and creativity in biology.

I study the persistence of species and communities in heterogeneous, fragmented, and disturbed landscapes; and what determines the diversity of communities in these landscapes. I use field surveys and experiments, laboratory experiments and theory. My current research is focused on 1) how environmental heterogeneity affects invasibility and extinction in communities, and 2) how landscape spatial structure and traits of species determine the structure and dynamics of communities.

1) Plant Physiological Ecology: We integrate the ecology, physiology, and anatomy of plants. A unifying theme of our studies is the question of how plants survive and thrive in their natural environment and what mechanisms and genes are responsible for the acclimation and adaptation of plants to extreme environmental conditions. We compare and contrast these characteristics among plant species with different growth patterns and acclimation strategies. One focus of our work is the role of plant carotenoids. 2) Human diet-gene interactions: I sponsor undergraduate independent literature research in this area that frequently leads to publication of student-authored comprehensive reviews for audiences of clinicians, nutritionists and/or teachers.

Research in my lab works at the nexus of population biology, community ecology, and evolutionary biology to understand how plants adapt and persist in a constantly changing world. Our current research projects are specifically focused on the evolution of dispersal, habitat specialization, and phenotypic plasticity in plants that occupy variable environments. We use field experiments, genetic tools, and comparative methods and work in variety of ecosystems, including vernal pool wetlands...

Lab Positions Open Dr. Evans is looking for talented and enthusiastic undergraduates, graduate students, and postdocs. Contact him if you are interested in joining his lab. Undergraduates interested in the EBIO honors program who are interested in statistical and quantitative genetics should contact Dr. Evans about possibilities. I am happy to work with undergraduates, graduates and postdocs to obtain funding as well. Some internal funding programs include: Summer Multicultural Access...

My work intersects the disciplines of microbial ecology and terrestrial ecosystem ecology. In particular, I am interested in understanding the role of microbial communities in terrestrial ecosystem processes. Recent research focuses on the biogeography of soil microbial communities, the impacts of global change factors (N deposition, climate change) on microbial communities/processes, and the assessment of microbial community structure (including archaea, fungi, bacteria, and viruses) in soil and other microbial habitats.

I use mathematical and simulation models to explore population genetics and the genomics of speciation.

My research focuses on two pervasive and inter-related forms of biological change: disease emergence and species invasions. Our group uses long-term data, ecological experiments and modeling approaches to examine the factors that drive disease emergence and biological invasions. We work on a wide range of organisms from diverse study systems, including zooplankton, amphibians, fishes, insects and humans.

My research is at the interface of quantitative genetics, population genomics and bioinformatics. I use these tools to address key ecological and evolutionary questions from multiple perspectives with a particular interest in domestication, adaptation, conservation, and speciation. Much of my work focuses on identifying the genetic changes that underlie the formation of new species or varieties, and more generally, the genetic basis of novel phenotypes. Currently, I am using sunflowers (Helianthus), mustard (Brassica) and chocolate (Theobroma) as model systems to pursue these research questions. In all three genera, I am examining how hybridization has shaped evolution, including the origin of new hybrid species, the breeding of modern lineages of domesticated plants, and the spread of invasive species.

Research Interests I am interested in the taxonomy, systematics and evolution of the diatoms. I also study biogeography, as well as applications of diatoms, such as water quality monitoring and biofuels. My current research is focused on freshwater diatoms of China, India, Russia as well as western North America. The development of internet-based research tools for diatom research is also one of my interests.

Freshwater ecology and limnology. Topics of special recent interest include (1) the systems ecology of tropical lakes and rivers; (2) adaptation and ecology of plankton, especially phytoplankton; (3) chemistry of atmospheric deposition, especially as it relates to nutrient mass balance in ecosystems; (4) the trophic ecology of lakes; and (5) water quality and limnology of lakes and streams in Colorado.

Research interests My research program focuses on understanding drivers and processes of biodiversification. I'm especially interested in the way symbiotic interactions affect distribution, ecology and evolution of invertebrates. Our lab mainly uses diverse mollusk groups (clams, cockles, snails, etc.) to address research questions, but other systems are also being explored (protists, algae, crustaceans, etc.). We adopt a combination of phylogenetic comparative methods, geometric morphometrics, molecular evolution and bioinformatic approaches to study biodiversification at species, population, and genomic levels.

Research projects include the landscape, phylo-, population or conservation genetics of a wide diversity of organisms focused mainly on understanding how individuals use the landscape, how to re-establish species extirpated from their native range, and how to use the principles of evolution to restore high fitness in populations that may harbor a high frequency of fixed or segregating deleterious alleles. In addition, we pursue discipline-based education research in biology.

I am interested in the mechanisms producing and maintaining patterns of species distribution, abundance, and diversity. To address these processes, I consider three levels of ecological organization to be equally important: species-level autecology, population-level dynamics, and community-level processes and interactions. My research so far has highlighted small mammal range dynamics, abundance patterns across altitudinal ranges, and species richness patterns along latitudinal and elevational gradients. I particularly exploit mountain systems as natural experiments to look at how evolutionary history, ecological processes, and future climate change influence species populations. My overarching goal is to strive for quantitative, general theories applicable to both the advancement of ecology and the improvement of our conservation strategies. I use multiple tools at various spatial scales to address research questions, including field studies, synthesis of collection and historical data, comparative analyses, null models, GIS, and simulation modeling.

My research interests combine the fields of parasitology, disease ecology, conservation biology, and herpetology. I work in a variety of places ranging from locally in Colorado to tropical rainforests. Many of my current projects involve fieldwork, labwork, meta-analyses, and applied conservation activities. Parasites and pathogens are ubiquitous and rival the diversity of free-living organisms on the planet. As global environments are changing rapidly, we are beginning to observe increases in infectious disease prevalence in both humans and wildlife. In order to understand patterns of emerging disease across the diverse spectrum of parasitic organisms, we must integrate several disciplines and ask questions at scales ranging from genetic and population levels to community and ecosystem levels. I am most interested in understanding the ways in which anthropogenic disturbances (e.g., land use, invasive species, wetland management) affect the parasites and pathogens of humans and wildlife. In the realm of conservation biology, the goal of my research is to identify key factors that lead to shifts in the abundance and distribution of parasites and pathogens in order to offer ecologically informed solutions to mitigate disease threats to vulnerable wildlife species.

In my lab, we are interested in understanding the developmental evolution of our own subphylum, the vertebrates. To do this, we study developmental gene expression, regulation, and function in three model organisms; lamprey, amphioxus, and zebrafish. Lamprey, a jawless vertebrate, is the most basal vertebrate amenable to experimental manipulation at embryonic stages. Amphioxus is the most basal extant chordate and is thought to closely resemble the invertebrate ancestor of the vertebrates. Zebrafish, a teleost, is one of the most experimentally tractable vertebrate model systems. By comparing lamprey and amphioxus development with that of zebrafish, and other vertebrates like frog and salamander, we aim to reconstruct the genetic and developmental changes underlying the earliest events in vertebrate evolution.

In my lab we use mathematics, computers, and data collected in the field or from experimental model systems to figure out why species go extinct, why invasive species are so bad, and how best to maintain biodiversity.

My primary research interests focus on the evolutionary forces that influence genetic variation within and among populations. DNA sequences of mitochondrial, chloroplast, and nuclear genes, and electrophoretic variation of proteins are used to characterize variation in populations of plants and animals. Phylogeographic studies are used to describe patterns of variation and to make historical inferences about glacial refugia and routes of migration. I am particularly interested in three unique opportunities afforded by organellar genomes: 1) contrasting patterns of mtDNA and cpDNA in conifers; mtDNA is maternally inherited, and short dispersal, while cpDNA is paternally inherited and has potentially very long dispersal; 2) marine and freshwater have two mitochondrial systems, one with maternal inhertance, one with paternal inheritance; 3) mistletoes, which are parasitic on conifers, have stolen some genes from their hosts, and incorporated it into their chloroplast genomes.

Research Interests I'm interested in all aspects of fungal biology. My research is focused on addressing three fundamental questions in mycology: (1) How do fungi evolve the ability to switch hosts or adapt to utilize various substrates? (2) How do fungi interact with other microorganisms? and (3) Where are potential unexplored habitats of novel fungal diversity? Genomics, metagenomics, transcriptomics, phylogenetics, and molecular community ecology are tools that I combine with...

The unifying theme of our lab's research is to understand how human stressors to the environment affect biodiversity and how to mitigate those impacts. These stressors include changes to landscapes, climate change, and species introductions. We often study spatial and temporal dynamics and use field studies at large spatial and long temporal scales to test theory and link ecological pattern with process. Areas of research include landscape connectivity/corridors, habitat fragmentation, plant-pollinator networks, insect community ecology, stable isotope ecology, and conservation biology. We work on a variety of taxa but have a particular fondness for insects. Settings for our field work include the longleaf pine ecosystem of the southeastern US and forests and meadows of the Rocky Mountains.

Ecological and Evolutionary Connections Between Animal Behavior and Population Biology. As a behavioral and evolutionary ecologist, I am fascinated by relationships among different scales of biological organization. Questions about individual variation (behavior, morphology, and physiology) and population patterns (social and genetic structure, population stability, species boundaries) are usually addressed in isolation from one another, but it is the relationship between these two levels that provides powerful predictive information about the causes and consequences of large scale patterns, such as the generation and loss of biodiversity. To make explicit links between behavioral ecology and population biology, I test theory-driven hypotheses related to both the function and proximate mechanisms that underlie individual behavior and use multi-level statistical models to explore the relationship between individual-level variation and larger-scale patterns within and among populations. I am currently most busy working on reproductive behavior and its consequences for population structure using the Hirundo rustica species complex as an interesting study system. This project is a large, international collaboration with many research opportunities for students at all stages of their careers.

Microbial ecology, biogeochemical cycles, and plant-microbe interactions. Theoretical (modeling) and experimental approaches are used to study the ecology of microorganisms in natural and disturbed systems. Active areas of research include: (1) microbial biogeochemistry of ecosystems in Colorado, Peru and Costa Rica, (2) the role of mycorrhizal fungi in the ecology of wild plants, and (3) biogeography and biodiversity of previously unknown microbial groups.

Terrestrial ecosystem studies, including factors influencing biodiversity, productivity, soil carbon dynamics, decomposition and mineralization processes, and how these processes affect ecosystem services. Most recently my research has involved studies of invasive plant species and invasibility of ecosystems within the context of other components of global change. Similarly, I'm keenly interested on how restoration can be conducted within an era of rapid environmental change.

Evolutionary genetics, molecular phylogenetics, plant-pollinator interactions, comparative methods. My lab studies the evolution and genetics of floral diversification, with a focus on the tomato family, Solanaceae. We use molecular phylogenies and statistical comparative methods to infer the evolutionary history of floral traits and to test ecological factors that may have shaped their evolution. We also employ molecular, genetic, and biochemical approaches to understand the mechanisms underlying floral trait differences across species. Recent work has focused on the evolution of flower color, as this trait has a relatively simple genetic basis and is ecologically important. Results of our studies suggest that flower color changes can involve a range of genetic mechanisms (e.g., gene deletion, changes in gene expression, functional evolution) and may often be driven by competition for pollinators among sympatric species.

Genetic basis of morphological evolution using the vertebrate dentition as a model system. Comparative analysis of gene action in tooth development of several species of teleost fishes (including the zebrafish) to investigate mechanisms of evolutionary change in tooth shape, location, and number. Additional interests include evolution of multi-gene families and phylogeny of fishes.

Plant Community Ecology; Restoration, Invasion biology, Environmental change, Conservation I am a plant community ecologist working at the interface of ecosystem, landscape and population biology. My goal is to apply cutting-edge “usable” science to the challenges of restoration, species invasion, and environmental change. My research group and I work with a range of conservation groups, government agencies and land managers to provide evidence-based solutions that take into account biodiversity, human well-being, and management opportunities. We employ a combination of long-term monitoring, modeling and experimental approaches in settings that range from alpine tundra to oak woodlands to grasslands. Common themes include plant-soil feedbacks, functional traits, species effects on ecosystem processes, and non-linear and threshold dynamics.

Hybridization, speciation, evolutionary ecology, and population genomics (primarily of birds). My research applies genomics and field experiments to natural hybrid zones and closely related taxa in order to investigate the architecture of reproductive isolation—the hallmark of speciation—and the genetic bases of traits relevant to speciation. This research also provides insight into the impacts of anthropogenic change, including climate change, on species distributions, interactions, and evolution. Selected Publications +Toews DPL, +Taylor...

Plant Systematics, Tropical Botany, Lichenology, Biodiversity Inventory, Molecular Genetics and Evolution, Taxonomy, Nomenclature, Pollination Biology. As a biologist, I am broadly interested in the ecology and evolution of all life on Earth, particularly how natural selection and contingency have shaped the evolution of millions of “endless forms most beautiful”. As a natural historian, I am interested in patterns and trends that characterize the histories of these endless forms. Knowledge of evolutionary history is empowering, has real-world applications, and predictive potential. In attempt to understand the evolution of biodiversity and the ecological functions that biodiversity sustains, I focus on macroevolutionary approaches at or above the species level. Most of my research emphasizes the species-rich (>4,000 taxa) and morphologically diverse tropical plant family Acanthaceae. More recently, I have advanced research in lichenology, particularly here in the United States where amazingly, some 230 years after Bartram first traversed the Southeast, we still know incredibly little about these organisms from taxonomic and biogeographic perspectives. In addition to biodiversity research on Acanths and lichens, I have maintained a long-term interest in the flora of the tepui highlands of northern South America, where I have participated in or co-led numerous plant collecting expeditions to remote locations in effort to provide baseline plant biodiversity information for these highly endemic ecosystems.

My research program seeks to gain insights on the understanding of feedback dynamics between ecosystem structure and function, and the influence of disturbance on trajectories of ecosystem processes. My approach involves field studies, remote sensing methodologies investigating temporal and spatial heterogeneity in ecosystem properties, and landscape and ecosystem modeling. My work incorporates theory in ecosystem and landscape ecology, with a recent emphasis on resilience and complex system theory. Current research projects include: biogeochemical dynamics of woody plant encroachment in the US Southwest, resilience of forest ecosystems under compound disturbance, and social-ecological systems in urban environments.