Emeritus

Evolutionary biogeography; community and conservation ecology; human impact on native ecosystems; ecology, distribution, and systematics of mammals of western North America and Middle America; science in general education; history of biology, especially ecology & evolution.

Grassland ecology, fire ecology, ecology of birds, conservation biology related to the above topics.

The ecology and evolution of flowering plants in the Colorado Alpine and High Plains, and similar areas elsewhere in the Northern Hemisphere and the reproductive patterns of flowering plants.

Plant ecology, terrestrial ecosystem science.

Social behavior in insects, kin recognition system of honey bees, nest defense in honey bees, and social biology of the giant tropical ant.

Freshwater ecology and limnology.

Dynamics of evolutionary change in plants.

The genetic basis of evolutionary adaptation, and brain mechanisms underlying adaptive behaviors.

I teach and/or coordinate the labs for the following plant biology courses: EBIO 4500, Plant Biodiversity and Evolution; EBIO 4510, Plant Anatomy; and EBIO 4520, Plant Systematics.

My primary research interests focus on the evolutionary forces that influence genetic variation within and among populations.

Plant physiological ecology; forest-atmosphere exchanges of carbon dioxide, water vapor, ozone and energy; environmental and physiological control over the emission of isoprene and other biogenic volatile organic compounds (VOCs) from forest ecosystems and the relationship of VOC emissions to atmospheric chemistry; coupling of biogeochemical cycles, especially those involving water, carbon and nitrogen; the evolution of C4 photosynthesis in plants.

Paleo-ecology, arctic and alpine environments, and global change, with emphasis on pollen analysis (palynology) as a method of reconstructing past vegetation and climate to understand the present environment and to act as background for current environmental concerns.

Terrestrial ecosystem studies, including factors influencing biodiversity, productivity, soil carbon dynamics, decomposition and mineralization processes, and how these processes affect ecosystem services.

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.