Introduced Herbivores in Aspen Forests of Northern Arizona

Our work in Aspen montane forests of northern Arizona have focused on the ecological and evolutionary consequences of the interaction of fire and an introduced herbivore (elk). While fire promotes aspen regeneration, herbivory by elk virtually eliminates these young aspen, negatively affecting arthropod and bird diversity, food web structure, soil nutrient availability, microbial community composition, enzyme function. There are also cultural consequences of this herbivory in that elk alter plant community composition including ethnobotanical species.

 

Community and Ecosystem Genetics in Eucalyptus

Work in Eucalyptus globulus forests of Australia was focused on the additive genetic basis of soil nutrient availability. Using a world class provenance experimental design, soil nutreint availability was affected at two genetic levels: family and provenance. These results indicate that plant traits and their interactions with microbes which affect soil nutrient availability can be acted on by natural selection. They also suggest that evolutionary processes that resulted in population level differentiation of Eucalyptus globulus also have altered how those populations may acquire nutrients.

Community and Ecosystem Genetics in Populus

Work in Populus has been very diverse. From microbes to mammals, plant genetic factors have a strong effect on the structure of these systems. Much of our more recent work in these systems has focused on the genetic and environmental factors which affect community and ecosystem level processes.