Terrestrial Ecosystems and Restoration

The objective of this interdisciplinary research effort is to 1) characterize agents of change important to land management decision makers on the Colorado Plateau; 2) identify and analyze relationships between agents of change and key landscape attributes and processes; 3) collectively assess the influence of agents of change and attributes and processes on the services provided by the ecosystem...

Although most introduced insects are relatively benign, some become high-impact pests causing widespread ecological and economic damage. Introduced insects that are specialists and feed on a single genus of plants can be high-impact as they can potentially eliminate an entire native plant genus over large areas. Luckily, most introduced insects with this feeding behavior do not become high-impact...

Introductions of bio-control beetles (genus Diorhabda) are causing defoliation and dieback of exotic Tamarix spp. in riparian zones across the western U.S., yet the factors that determine the plant communities that follow Tamarix decline are poorly understood. In particular, Tamarix-dominated soils are often higher in nutrients, organic matter, and salts than nearby soils, and these soil...

Concerns about energy security and rising greenhouse gas emissions have stimulated an unprecedented increase in the push for alternative energy use, including the use of plant biomass as a source of renewable energy (bioenergy). However, meeting alternative energy goals, while also meeting food demands and mitigating potential detrimental effects of industrialized agriculture, has emerged as a...

Dryland regions have been degraded by invasive species, wildfire, overgrazing, agricultural conversion, energy development, recreational activity, and urban growth. These disturbances and others are accelerated by one of the fastest growing human populations in the country and a pressing background of decreasing water availability due to drought and elevated temperatures that are projected to...

In the southwest US, monsoon precipitation increases sharply along a northwest to southeast gradient. Pleuraphis jamesii or galleta grass, is an important C4 grass species that spans across this large range in precipitation pattern. In this study we are assessing the ability of galleta grass to adapt to changes in the seasonality of rainfall (termed “plasticity”). In the fall of 2014, we...

Forests in the semiarid southwestern U.S. are expected to be highly vulnerable to increasing aridity anticipated with climate change. In particular, low elevation forests and the processes of tree regeneration and mortality are likely to be highly susceptible to climate change. This work seeks to characterize how, where and when forest ecosystems will change and identify management strategies to...

Drylands cover 40% of the global terrestrial surface and provide important ecosystem services. However, climate forecasts in most dryland regions, especially the southwest U.S., call for increasing aridity. Specifically, changing climate will alter soil water availability, which exerts dominant control over ecosystem structure and function in water-limited, dryland ecosystems. This research seeks...

Historic over-grazing of arid grasslands in the Intermountain West has led to widespread soil erosion, loss of plant diversity, and invasion by exotic species. Degraded grassland conditions can be very persistent, even after livestock use has ceased. For example, in national parks on the Colorado Plateau, livestock have been excluded for decades, but soil and native plants have not recovered on...

Although it is not listed on the Federal Endangered Species list, there is considerable concern over northern leopard frog declines in western North America. It is listed as a “special concern” species by some state wildlife agencies (e.g., Arizona Game and Fish Department 1996) and declines have been reported in Arizona, Colorado, New Mexico, and other areas across the west. Leopard frogs have...

The Island Night Lizard was removed from the Federal list of "Threatened" species in May 2014. This rare and unique species represents an ancient lineage whose members are now sparsely distributed across parts of the Southwest North America, south through Mexico to the New World Tropics. The Island Night Lizard has a very small world range, occurring only on three of the southern California...

Arizona is the home to at least 10 cacti that are listed as endangered, threatened, or under conservation agreement. Land use and management activities that occur on federal, and to some extent state, lands on which the cacti occur require consultation among the U.S. Fish and Wildlife Service (USFWS), the agency managing the land on which the cacti is growing, and the party proposing an activity...