Response of semi-desert grasslands invaded by non-native grasses to altered disturbance regimes
نویسندگان
چکیده
Similar to other biomes across the globe, grasslands in the American Southwest have experienced significant changes to their historic composition and processes (Bahre, 1991; McPherson & Weltzin, 2000). Plant communities have been shaped by disturbances such as fire, grazing, and their interactions with climate. ‘Disturbance is a change in physical or biological factors that ultimately affects the structure and function of plant communities’ (McPherson & Weltzin, 2000). Different processes come into play over long time-scales, therefore altered disturbance regimes, compared with individual disturbance events, may have novel influences on vegetation (Clark, 1996). During the last several hundred years, most grasslands of the American Southwest experienced a novel disturbance type when cattle, coincident with the extirpation of prairie dogs, became a significant influence. Ecologists have argued about the detrimental effects of livestock grazing on plants (Belsky, 1986) vs. potential benefits to plant fitness (McNaughton, 1979) with evidence from systems that evolved with grazing by large herbivores. Grazing affects grasslands directly through the School of Natural Resources, University of Arizona, Tucson, AZ, USA
منابع مشابه
Invasive Plants and Wildlife Habitat Invasive Plants and Wildlife Habitat Effects of Plant Invasions on Wildlife in Desert Grasslands
Like all grasslands across North America, the distribution of desert grasslands has been reduced markedly, and remnants have been altered extensively by humans. In Arizona, NewMexico, Texas, USA, and in Mexico, desert grasslands have been invaded by dozens of non-native plants, especially perennial grasses that evolved in arid systems with similar climate and disturbance regimes. In desert gras...
متن کاملInvasive Plants and Wildlife Habitat Effects of Plant Invasions on Wildlife in Desert Grasslands
Like all grasslands across North America, the distribution of desert grasslands has been reduced markedly, and remnants have been altered extensively by humans. In Arizona, NewMexico, Texas, USA, and in Mexico, desert grasslands have been invaded by dozens of non-native plants, especially perennial grasses that evolved in arid systems with similar climate and disturbance regimes. In desert gras...
متن کاملInvasive Species and Fire in California Ecosystems
nvasive plant species occur throughout all floristic regions of California, but their spatial extent, diversity, and impacts within these regions vary considerably. Alterations of natural disturbance regimes have made communities more susceptible to these invasions (Brooks et al. 2004). Fire is a natural and chronic disturbance in many California plant communities and has been observed to promo...
متن کاملStability of exotic annual grasses following restoration efforts in southern California coastal sage scrub
1. Restoration of semi-arid shrub ecosystems often requires control of invasive grasses but the effects of these grass-control treatments on native and exotic forbs have not been investigated adequately to assess long-term stability. In southern California, coastal sage scrub (CSS) vegetation is one semi-arid shrub community that has been invaded extensively by both exotic grasses and exotic fo...
متن کاملPlant community response to loss of large herbivores differs between North American and South African savanna grasslands.
Herbivory and fire shape plant community structure in grass-dominated ecosystems, but these disturbance regimes are being altered around the world. To assess the consequences of such alterations, we excluded large herbivores for seven years from mesic savanna grasslands sites burned at different frequencies in North America (Konza Prairie Biological Station, Kansas, USA) and South Africa (Kruge...
متن کامل