One of Australia's most serious weeds, Chrysanthemoides monilifera subsp. rotundata (bitou bush) was recently found for the first time in Western Australia as a well established population in Kwinana, a major port and industrial area south of Perth, the State's capital. This population is remote from other bitou bush infestations in Australia and had escaped detection despite extensive surveys in the same State for the other subspecies that is present in Australia, Chrysanthemoides monilifera subsp. monilifera (boneseed). The main reasons it went undetected are thought to be the tightly controlled access to this area because of mineral processing and port activities, the unusual invasion route via a heavy industrial area and the morphological similarity to a native species when it is not flowering. Two surveys defined the core population of 1038 plants that are spread along the coast over a 25-ha semi-circle with about a 500-m (1640 ft) diameter. Subsequent surveys of first a 500 m buffer zone and later a 1-km (0.621 mi) buffer found four additional plants, indicating that there is considerable potential for dispersal. We concluded that the survey has not delimited the distribution because of the potential and evidence for long distance dispersal. Cooperation by the various land managers has led to all plants being killed, as an initial step to management of this species. Other steps to be undertaken include an awareness campaign in the area that would need to be surveyed for delimitation of the spatial distribution and seed bank assessment to measure potential dispersal both in space and through time. It remains to be determined what is the best strategic response: eradication or containment.

Alligatorweed, waterhyacinth, and hydrilla are three nonnative aquatic species of concern in the Ross Barnett Reservoir near Jackson, MS. Point-intercept surveys were conducted on the reservoir from 2005 to 2010 to monitor native and nonnative species' distributions and assess herbicide treatment efficacy across the reservoir. Foliar applications of 2,4-D, glyphosate, imazapyr, and diquat were made during summer months for emergent and free-floating vegetation, whereas submersed applications of liquid copper and granular fluridone were applied in spring and late summer for subsurface hydrilla populations. American lotus is the native species that has been observed the most throughout the survey years, with occurrence frequencies averaging between 17 and 27%. Alligatorweed populations significantly decreased from 21% in 2005 to 4% in 2006; however, they consistently increased in the next 4 yr to 12% occurrence in 2010. Waterhyacinth occurrence has remained relatively constant over the study period, averaging below 10% occurrence. Hydrilla was discovered in the reservoir in late 2005 and has remained below 2% in frequency of occurrence since 2006. Suppression of these nonnative species has been attributed to rigorous monitoring and herbicide applications conducted on the reservoir since 2005. A logistic regression model indicated that as native species richness increased, the likelihood of a nonnative species occurring also increased.