A number of hypotheses have been suggested to explain why invasive exotic plants dramatically increase their abundance upon transport to a new range. The novel weapons hypothesis argues that phytotoxins secreted by roots of an exotic plant are more effective against naïve resident competitors in the range being invaded. The common reed Phragmites australis has a diverse population structure inc...

The distribution and abundance of mosquito larvae in a freshwater marsh were determined during a low water period in the late summer. Culex tarsalis larval abundance was significantly associated with the percent cover by Typha spp. root masses and Typha spp. stem density in 1-m2 quadrants. Larval mosquito abundance was not significantly related to bulrush (Scirpus californicus) stem density, po...

Molecular investigation of the origin of colour vision has discovered five visual pigment (opsin) genes, all of which are expressed in an agnathan (jawless) fish, the lamprey Geotria australis. Lampreys are extant representatives of an ancient group of vertebrates whose origins are thought to date back to at least the early Cambrian, approximately 540 million years ago [1]. Phylogenetic analysi...

Agricultural pesticide use is necessary to help meet the increased demand for a safe and secure food supply for the United States, as well as the global community. Even with proper application and careful management, the possibility of pesticide leaching and detachment in runoff still exists following certain storm events. Several different management practices have been designed to reduce the ...

1 Determining the mechanisms by which invasive species exclude natives is critical for conserving and restoring native populations in impacted habitats. In recent decades the grass Phragmites australis has been aggressively invading coastal marshes of North America, with monocultures often replacing diverse assemblages of plants. 2 Our objective was to quantify how P. australis modifies the abi...

The invasive species Spartina alterniora Loisel was introduced to the eastern coast of China in the 1970s and 1980s for the purposes of land reclamation and the prevention of soil erosion. The resulting interspecific competition had an important influence on the distribution of native vegetation, which makes studying the patterns and mechanisms of the interactions between Spartina alterniora Lo...

As the human footprint expands, ecologists and resource managers are increasingly challenged to explain and manage abrupt ecosystem transformations (i.e., regime shifts). In this study, we investigated the role of a mechanical disturbance that has been used to restore and maintain local wetland diversity after a monotypic regime shift in northwestern Costa Rica [specifically, an abrupt landscap...