Research
Research Overview
Natural and anthropogenic disturbances have shaped ecosystem structure and function for millennia. The role of humans as systems change agents in the Anthropocene is ever-increasing, and today, over 40% of our global land surface exists in a degraded state. We now see widespread and pervasive losses in the diversity, complexity, and function of natural systems because of the human fingerprint on planet Earth. Rapid transformations in natural ecosystems worldwide signal the urgent need for
1) establishing baselines for quantifying the impacts of disturbances on plant assemblages and post-disturbance recovery
2) building mechanistic understandings of the ecological responses of species to drivers of environmental change
3) evaluating the effectiveness of ecosystem restoration for bolstering the resilience of communities to disturbances
At the Forests and Global Change Lab, we address these needs by examining the impacts of natural and anthropogenic change on ecosystem community assembly and function. Over the last two decades, our analytical approach spans multiple ecological scales, focusing on spatial scales ranging from individual organisms to entire ecosystems, and time scales of hours to centuries. We integrate a wide range of methodologies at the lab including field measurements, dendrochronology, ecophysiology, multivariate statistical modeling, geographic information systems, and remote sensing.
Research at the lab focuses on two key questions:
1) How are forest ecosystems responding to shifting disturbance regimes in the Anthropocene?
2) How can people use applied science to maintain the integrity and resilience of human and natural systems in an era of rapid environmental change?
Current Projects
Fire ecology of Sky Island forests of the US-Mexico Borderlands
This long-term project focuses on examining the impacts of changing disturbance regimes on the high elevation forests of the US-Mexico Borderlands. These forests comprise an important regional conservation target because of their high biodiversity and endemism in a critically water-limited environment. At the Forests and Global Change Lab, we study the roles of wildfire, topography, and shifting land use in regulating forest community composition and diversity.
Biological monitoring is crucial for understanding impacts of contemporary wildfire behavior on community structure and function; to-date, I have established a network of monitoring plots spanning 34 priority conservation areas in Mexico, Arizona, and Texas, in which I have established more than 2100 vegetation transects. We continue to monitor these plots which serve as regional barometers of environmental change.
Mechanisms of post-disturbance plant community recovery
Mechanistic explanations are desperately needed for understanding how forests are responding to shifting disturbance regimes in the Anthropocene. Our plant ecophysiology research seeks to elucidate how physiological processes shape plant survival, regeneration, and growth responses to disturbance. We employ a range of methods for examining these phenomena, spanning from field and greenhouse ecophysiology experiments to landscape-scale water cycling analyses using remotely sensed imagery.
Best management practices for Northeastern barrens pollinator communities
Here in the Northeast, we are collaborating with land managers on a regional study to develop a set of best management practices for promoting pollinator diversity in Northeast barrens systems. Fire is an important driver of plant and pollinator species composition and diversity in these naturally dry, open habitats. Over the last century, fire, soil disturbances, and grazing have virtually ceased across most of these fire-adapted landscapes resulting in a major decrease in open habitats that serve as plant and pollinator biodiversity hotspots. We are working in a coordinated interagency effort with private and state practitioners who are experimenting with adaptive management at 20 sites, from Maine to Maryland, to identify successful management practices for promoting pollinator community abundance and diversity in Northeastern fire-adapted habitats.
Fescue Rescue: a bi-national project to recover Guadalupe fescue in the northern Sierra Madre Oriental
Guadalupe fescue (Festuca ligulata Swallen) is a US federally listed endangered grass known in just a few high elevation mountains that straddle the US-Mexico Border. The species is critically threatened by both climate change and recent wildfires within its restricted distribution. We are working in a bi-national collaboration to study the survival and regeneration requirements of this species through field surveys and greenhouse plant rearing experiments in the US and Mexico in a bi-national effort to save this species!
Invasive species and forest change
Invasive species comprise one of the greatest threats to forest health in the northeastern US. Students in the Forests and Global Change Lab are working on two projects on invasive species impacts on forest health here in Connecticut. First, we are working with collaborators at the Connecticut Agricultural Experiment Station to evaluate the impacts of recent emerald ash borer wasp parasitoid biocontrol releases are impacting the survival and regeneration capacity of white and green ash populations. Second, we are examining the spread vectors of beech leaf disease, a new invasive nematode (Litylenchus crenatae mccannii), which is now spreading into Connecticut’s beech forests.
Effects of forest management on forest drought resilience
We are studying how forest thinning, applied across millions of acres of northern Arizona, is influencing landscape water availability using evapotranspiration data from the ECOsystem Spaceborne Thermal Radiometer Experiment on the International Space Station (ECOSTRESS). The ultimate goals of this project are to 1) assess the accuracy of the ECOSTRESS sensor for quantifying adaptive management impacts on forest water relations, and 2) quantify the potential of different management practices for enhancing water supply for the entire state of Arizona. Such information is directly relevant for informing the development and implementation of local and state forest climate adaptation plans in Arizona and beyond, as both private and federal partners across the West allocate funding for implementing adaptive management programs for reducing wildfire risk and bolstering forest drought resiliency and water supply to downstream users.
