Rangeland ecosystems form extensive wildland landscapes visually dominated by grassland, shrubland, and savanna vegetation. Two important natural processes that control the structure and function of these ecosystems are herbivory and fire. Successful restoration, conservation, and use of rangelands usually requires the use of fire and herbivory and an understanding of vegetation response. Mediterranean-type savanna ecosystems are found as five small pockets in California, Chile, South Africa, Australia, and the shores of the Mediterranean Sea. Each area has a distinctive biota which humans have systematically homogenized over the past few thousand years. The Mediterranean-type savanna is an ideal laboratory for examining the relationships among long-lived woody plants, usually native; short-lived herbs, usually non-native; and grazing animals, at different ecological scales. Because people have had highly variable effects on the different systems, usually by changing grazing and burning regimes, comparative study of different regions can yield important insights into how native species may be enhanced and protected in restoration or conservation programs. Current Projects , , We are conducting several field experiments testing the effects of controlled cattle grazing and burning on biomass productivity, vegetation spatial structure, and water quality. This project is designed to test several theories about how grazing and burning may have changed the original California savanna and point the way to successful methods for ecosystem restoration. Results from these studies have shown that livestock grazing and prescribed fire, when properly applied, can enhance native plant recovery, may be useful for modifying vegetation structure, and does not degrade water quality.
Research Expertise and Interest
plant ecology, grazing, biodiversity, grasslands, environmental science, rangelands, fire, mediterranean ecosystems