The Control of Biological Invasions in the World's Oceans

Abstract: The introduction of alien, or nonindigenous, animals and plants has been identified by scientists and policy makers as a major threat to biodiversity in marine ecosystems. Although government agencies have struggled to control alien species on land and freshwater for decades with mixed success, the control of alien marine species is in its infancy. Prevention of introduction and establishment must be the first priority, but many populations of alien marine species are already well established worldwide. National and international policies leave loopholes for additional invasions to occur and provide only general guidance on how to control alien species once they are established. To address this issue, a multinational group of 25 scientists and attorneys convened in 1998 to examine options for controlling established populations of alien marine species. The discussions resulted in a framework for control of alien marine species to provide decision-making guidance to policymakers, managers, scientists, and other stakeholders. The framework consists of seven basic steps: (1) establish the nature and magnitude of the problem, (2) set objectives, (3) consider the full range of alternatives, (4) determine risk, (5) reduce risk, (6) assess benefits versus risks, and ( 7) monitor the situation. This framework can provide guidance for control efforts under the existing patchwork of national laws and can help provide a foundation for international cooperation.     

常宁市林业有害生物发生现状和防控对策

结合常宁市林业有害生物普查工作,在实地调查全市林业有害生物发生种类和发生现状的基础上,通过分析常宁市林业有害生物发生特点和成灾原因,结合林业工作实际,提出了常宁市林业有害生物防控对策．参7．     

Effects of a Biological Control Introduction on Three Nontarget Native Species of Saturniid Moths

Abstract: Damage to nontarget (native) invertebrates from biological control introductions is rarely documented. We examined the nontarget effects of a generalist parasitoid fly , Compsilura concinnata ( Diptera: Tachinidae), that has been introduced repeatedly to North America from 1906 to 1986 as a biological control agent against 13 pest species. We tested the effect of previously established populations of this fly on two native, nontarget species of moths ( Lepidoptera: Saturniidae) , Hyalophora cecropia and Callosamia promethea , in Massachusetts forests. We estimated survivorship curves for newly hatched H. cecropia larvae (n = 500), placed five per tree in the field and found no survival beyond the fifth instar. We simultaneously deployed cohorts (n = 100) of each of the first three instars to measure the effect of parasitoids during each stage of development. C. concinnata was responsible for 81% of H. cecropia mortality in the first three instars. We deployed semigregarious C. promethea in aggregations of 1–100 larvae in the field and recorded high rates of parasitism by C. concinnata among C. promethea larvae exposed for 6 days (69.8%) and 8 days (65.6%). We discovered a wild population of a third species of silk moth, the state-listed (threatened) saturniid Hemileuca maia maia, and found that C. concinnata was responsible for 36% (n = 50) mortality in the third instar. Our results suggest that reported declines of silk moth populations in New England may be caused by the importation and introduction of C. concinnata .     

Monitoring of Biological Diversity: a Common-Ground Approach

Abstract:  Practical approaches to monitoring biological diversity vary widely among countries, and the accumulating data are frequently not generalizable at the international scale. Although many present monitoring schemes, especially in developed countries, produce highly complex data, there is often a lack of basic data about the level and spatial distribution of biodiversity. We augmented the general framework for improving biomonitoring, proposed by Green et al. (2005) , and identified its core tasks and attributes. The first priority for a more unified biodiversity monitoring is to agree on a minimum set of core tasks and attributes, which will make it possible to build a standardized biomonitoring system even in countries with few resources. Our scheme has two main organizational levels—taxa and ecosystems. The basic elements of the biomonitoring system proposed are recording of presence and absence of taxa and ecosystems in a target area, mapping of their distribution in space, and assessment of their status. All the elements have to be repeated over time. Although these tasks are fundamental, they are frequently not considered in currently functioning biomonitoring programs. The whole system has to be hierarchical and additive: if more resources are available, new activities may be added to the basic routine. Agreeing on a common standard will facilitate aggregating measures of biodiversity status and trends into regional and global indices. This information will relate directly to several Convention on Biological Diversity indicators for assessing progress toward the 2010 Biodiversity Target.     

Managing Invasive Aquatic Plants in a Changing System: Strategic Consideration of Ecosystem Services

Abstract:  Climate change is projected to increase stress for many coastal plant communities. Along large portions of the North American coast, habitat degradation from anthropogenic changes to the environment already threaten the community structure of tidal marshes and submerged aquatic grass beds. The potential loss of ecological services historically provided by these communities has been a long-standing rationale for aggressive control of invading plants such as Phragmites australis and Hydrilla verticillata . Increasing evidence of ecological services provided by invasive species such as P. australis and H. verticillata suggest that, in the face of increasing stress, it may be prudent to take a more pragmatic approach regarding the effect of these species on coastal ecosystems. The notable resilience of these species to control efforts and their competitive success and comparative vigor in stressed systems and capacity to provide at least some beneficial services combine to suggest some invasive species may have a useful role in managed coastal ecosystems.