Skip to main content
Advanced Search

Filters: Tags: invasibility (X)

5 results (7ms)   

View Results as: JSON ATOM CSV
While there has been extensive interest in understanding the relationship between diversity and invasibility of communities, most studies have only focused on one component of diversity: species richness. Although the number of species can affect community invasibility, other aspects of diversity, including species identity and community evenness, may be equally important. While several field studies have examined how invasibility varies with diversity by manipulating species identity or evenness, the results are often confounded by resource heterogeneity, site history, or disturbance. We designed a mesocosm experiment to examine explicitly the role of dominant species identity and evenness on the invasibility of...
The invasion paradox describes the co-occurrence of independent lines of support for both a negative and a positive relationship between native biodiversity and the invasions of exotic species. The paradox leaves the implications of native?exotic species richness relationships open to debate: Are rich native communities more or less susceptible to invasion by exotic species? We reviewed the considerable observational, experimental, and theoretical evidence describing the paradox and sought generalizations concerning where and why the paradox occurs, its implications for community ecology and assembly processes, and its relevance for restoration, management, and policy associated with species invasions. The crux...
Increasing demands on arid and semiarid ecosystems, which comprise one-third of Earth's terrestrial environment, create an urgent need to understand their biodiversity, function, and mechanisms of change. Sagebrush (Artemisia) steppe, the largest semiarid vegetation type in North America, is endangered because of losses to agriculture, excessive grazing, and invasive species. Establishment in 1950 of what is now designated as the Idaho National Engineering and Environmental Laboratory (southeastern Idaho, USA) created the largest existing reserve of this extensive vegetation type. We used cover, density, and frequency data for vascular plants sampled on 79 permanent plots nine times during 45 years to (1) assess...
Cover and richness of a 5-year revegetation effort were studied with ,respect to small-scale disturbance and nutrient manipulations. The site, originally a relict tallgrass prairie mined for gravel, was replanted to native grasses using a seed mixture of tall-, mixed-, and short-grass species. Following one wet and three relatively dry years, a community emerged, dominated by species common in saline soils not found along the Colorado Front Range. A single species, Alkali sacaton (Sporobolus airoides), composed nearly 50% of relative vegetation cover in control plots exhibiting a negative relationship between cover and richness. Seeded species composed approximately 92% of vegetation cover. The remaining 8% was...
Ecosystem susceptibility to invasion by nonnative species is poorly understood, but evidence is increasing that spatial and temporal variability in resources has large-scale effects. We conducted a study in Artemisia tridentata ecosystems at two Great Basin locations examining differences in resource availability and invasibility of Bromus tectorum over elevation gradients and in response to direct and interacting effects of removal of perennial herbaceous vegetation and fire. We monitored environmental conditions, soil variables, and B. tectorum establishment and reproduction over two years. Soil water (measured as the number of days soil matric potential was >?1.5 MPa) and nitrate availability (measured as micromoles...