Natural history collections

Natural history collections, including plant specimens kept in herbaria, are the primary data that we use to describe plant diversity and distributions. We use them to find, describe, categorize, and name new species (taxonomy); to refine our understanding of the evolutionary relationships among organisms (systematics); to build regional floras and dichotomous keys; and to discern macro-ecological patterns. Along with several colleagues, I contribute to strategically growing the vascular plant collection in the Kathryn Kalmbach Herbarium at Denver Botanic Gardens, for example by collecting in under-botanized areas on Colorado's Eastern Plains. Often we synthesize and interpret floristic inventory data (see example below) for various landowners. Our various research teams also make collections so that the ecological (transect- or plot-based) work that we do is verified by properly vouchered specimens. 

REad a floristic inventory

Ecological drivers of plant diversity and distributions

I have participated in many research projects that on the surface seem quite different, yet all address the same overarching question: how do different ecological drivers shape plant diversity and distributions? Some questions I (in collaboration with many colleagues) have explored over the years include:

• How does prairie dog grazing shape plant community diversity on Colorado's Eastern Plains?
• Do native ants recognize and potentially disperse the seeds of non-native thistles?
• How do introduced populations of a plant become evolutionarily differentiated from native populations? What is the role of release from insect herbivores? 
• How do native and non-native plant species respond to wildfire?
• How do two global change stressors--drought and invasion--interact to affect native longleaf pine survival and growth (this work was done while I was a post-doc in Luke Flory's lab at the University of Florida)?

I have used various approaches to answering such questions including observational and experimental fieldwork and greenhouse experiments.