Our research often involves a combination of literature syntheses, field sampling and experimentation, monitoring, and greenhouse and laboratory projects.
Presently, one of our main research priorities is better understanding functional outcomes of restoration and conservation actions. We currently have ongoing projects in California, Nevada, Arizona, New Mexico, Texas, Ohio, Oregon, and North and South Carolina.
Pecos National Historical Park, NM: Exotic plant management and implications
Within Pecos National Historical Park (PECO), there are over 50 acres encompassing the Pueblo and Mission Ruins Trail that are currently infested with invasive exotic plants. Kochia (Bassia scoparia), an annual plant introduced to North America from Europe and Asia. This non-native species has formed a near monoculture in the main ruins area and also occurs elsewhere in the park, such as near the visitor center. In many of the large kochia patches, native plants are nearly absent, including around heavily visited cultural sites. In addition to kochia creating a situation of low native diversity in the ruins area, there is potential for the species to spread and invade other sites throughout the park. Untreated kochia is highly competitive with other species in disturbed soils because of its ability to germinate at low soil temperatures, emerge early and grow rapidly, and tolerate heat, drought, and salinity. Additionally, several studies indicate rapid herbicide-resistance, which makes developing management strategies difficult.
We are working with PECO land managers and the National Park Service Southwest Exotic Plant Management Team (SW EPMT) to develop treatment options for reducing kochia and its spread and reestablish native plant species.
Our main project goals include:
- maintain cultural preservation of site; preserve components that contribute to the cultural story of the area
- develop field and laboratory studies to assist with managing and restoring native and culturally significant landscapes
- demonstrate successful ecological restoration techniques
Guadalupe Mountains National Park, TX: Exotic Plant Management and Grassland Restoration
Guadalupe Mountains National Park (GUMO) is situated between El Paso, TX and Carlsbad, MN. The Park encompasses a range of ecological features, from lowland shrublands and grasslands and higher elevation conifer forests. We are working with GUMO land managers to develop an exotic plant management plan that emphasizes best management practices for use in park operations to prevent the introduction and spread of current and future invasive plants. This plan will encompass management with wilderness. We are also working with GUMO managers on a grassland restoration plan. It is believed that the Salt Basin section of GUMO since European colonization has transitioned from a Chihuahuan Desert grassland to shrubland due to landscape activities, such as grazing livestock. We are working with staff to review their current draft plan for restoring degraded grasslands and also to develop and test grassland ecological restoration research techniques.
Learn more about Guadalupe Mountains National Park
Restoration of Ecological Function of Soils and Vegetation in the Mojave and Sonoran Deserts (BLM-CA)
With the expansion of energy development in the Mojave and Sonoran Deserts, there is a significant increase in disturbance to these ecosystems. Implementation of utility scale solar energy and wind farms are increasing, with construction-related disturbance in need of restoration after project completion. Additionally, these facilities have an impact on native pollinators and other wildlife, including the Desert Tortoise.
Restoration in desert ecosystems is particularly challenging. Precipitation is low and variable, with long dry periods between rainfall events. Extremely high temperatures further exacerbate the problem, as they increase evaporation of already low soil moisture. Restoration is more difficult when the thin top layer of soils are removed, as topsoil contains the major pools of plant-available carbon and nutrients, as well as the microorganisms critical in making nutrients and water available to plants.
The purpose of the proposed research is to test restoration techniques and develop methods that restore ecological structure and function in areas cleared for energy development and also to develop mitigation techniques which can be implemented in existing disturbed areas to mitigate future impacts from desert energy development.
Long-term assessment of restoration activities in Joshua Tree National Park
Joshua Tree NP. Road repaving, such as that which occurred along Key’s View Road in Joshua Tree National Park, may result in a buffer of vegetation and soil disturbance along the roadsides. To restore and mask the disturbance, Joshua Tree NP planted perennial species salvaged from the path of destruction and applied salvaged topsoil along the disturbance corridor. Additionally, they also placed dead plants and branches (referred to as vertical mulch) to provide cover and habitat and promote natural revegetation. We monitored the restoration sites in 2009, 2010, 2011 and 2017 to assess outplanting survival, seed bank structure, and established plant community composition among the restoration treatments.
Conservation planning support for the Southern Blue Ridge: The Jocassee Gorges Ecosystem Monitoring Network
With its purchase by the South Carolina Department of Natural Resources (DNR) in 1998, Jocassee Gorges became among the most unique and significant protected-area additions in the eastern United States. However, like other protected areas, this southern Blue Ridge landscape is not impervious to damaging and altering agents. Two of the more significant are the introduced insect hemlock woolly adelgid and altered fire regimes and introduced pests in oak forests. On the other hand, the diversely aged forests across the landscape from past timber harvest represent opportunities to encourage development of mixtures of young and old forests now rare in the East.
Effective conservation planning and facilitated forest restoration hinge on a good understanding of the rate and trajectory of change in forest ecosystems. This is especially true during an area of global change, not only in climate, but also in biological invasions (such as hemlock woolly adelgid) and changing disturbance regimes (such as fire). Modern conservation measures must respond to these changes, even if an outcome is passive management and simply identifying current conditions as a benchmark for future changes. In Jocassee Gorges and similar Blue Ridge landscapes, how will forests recover following hemlock woolly adelgid invasion? What functions may “replacement” forests provide, such as affording wildlife habitat, protection of streams, biodiversity, and carbon storage? In oak forests, will current trajectories continue during an era of limited fire and climatic changes? These are among several interesting and important questions that can be addressed by building upon a unique and successful forest monitoring network.
Our goal is to remeasure the long-term Jocassee Gorges Ecosystem Monitoring Network, consisting of 48 old-forest plots and 63 young-forest plants developing after timber harvest in the decades preceding 1998. The plots are 0.1 hectares (0.25 acres) in size and include complete censuses of trees, understory plants, and soil and topographic properties. A subset of the plots also had complete inventories of bird species. We are first proposing to focus on the 48 old-forest plots that were established in 2001 by Scott Abella as part of his Masters thesis at Clemson University with Dr. Victor Shelburne and in collaboration with DNR. These 48 plots span a range of forests in Jocassee Gorges, including hemlock, mixed hemlock-white pine-hardwood, oak, and various mixed deciduous forests. The opportunity to understand 15 years of forest change, including a fortuitous before/after comparison of hemlock woolly adelgid, on permanent plots is extremely unique. We are seeking grant and donation support for remeasuring old-forest plots in 2016, and for broader conservation assessments of the Jocassee Gorges Ecosystem Monitoring Network of all plots for forest health, plant diversity, and birds in subsequent years.
Evaluating restoration activities in Ohio oak savannas
In collaboration with the Metroparks of the Toldeo Area, oak restoration plots were evaluated in 2002, 2004, and again in 2015. These fire-dependent communities were estimated to cover over 12 million hectares in the early 1800s, before Euro-American settlement and extensive clearing for agriculture, wood cutting, livestock grazing, causing hydrological alteration and curtailing of frequent fire and significant loss of habitat.
We are currently working with the Metroparks on additional remeasurements and publications.