Fire

The saguaro cactus (Carnegiea gigantea) is a keystone species that grows only in the Sonoran Desert of northern Mexico and the southwestern United States. The USGS’ Southwest Biological Science Center is working to better understand the species’ biological features, its role as a keystone species that supports greater than 100 other plant and animal species, and its responses to climate change...

Biological soil crusts (biocrusts) are commonly found on the soil surface in arid and semi-arid ecosystems (collectively called drylands). Biocrusts can consist of mosses, cyanobacteria, lichens, algae, and microfungi, and they strongly interact with the soil. These organisms or consortium of disparate organisms, depending on the specific biocrust, are important to the functioning of ecosystems...

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...

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...

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...

The Restoration Assessment and Monitoring Program for the Southwest (RAMPS) seeks to assist U.S. Department of the Interior (DOI) and other land management agencies in developing successful techniques for improving land condition in dryland ecosystems of the southwestern United States. Invasion by non-native species, wildfire, drought, and other disturbances are growing rapidly in extent and...

Big sagebrush ecosystems are a major component of landscapes in the western U.S. and provide vital habitat to a wide array of wildlife species. However, big sagebrush ecosystems have been dramatically impacted by disturbances in the past several decades. This collaborative research between USGS and the University of Wyoming focuses on understanding how climatic and soil conditions influence big...

Agassiz’s desert tortoises (Gopherus agassizii) approach the southern edge of their mostly Mojave Desert range near Joshua Tree National Park. Modern desert tortoise research started in the Park in 1978 when the first tortoise population census was conducted on a one square mile area in the Pinto Basin known as the “Barrow Plot.” U.S. Geological Survey research began at the plot in 1997 and...