Toward Understanding Patterns of Coastal Marine Invasions: A Prospectus

Abstract

Understanding invasion patterns and processes depends greatly upon empirical measures. Although observation and theory have resulted in a conceptual framework for invasion ecology, the empirical data needed to rigorously test many key hypotheses and develop robust predictions lag far behind. This gap is especially conspicuous for marine systems, existing both in the quality and quantity of descriptive data. At the present time, most analyses that evaluate patterns of invasion or test specific hypotheses derive data from the existing literature, which is extremely uneven in space and time. This “by-catch” approach to data collection can result in biases, creating apparent patterns that must be viewed with caution. Quantitative field surveys, which employ standardized and repeatable measures, can be used to remove such bias. We call for a concerted international effort to conduct quantitative surveys, designed explicitly to test a variety of hypotheses and to produce the high-quality empirical data that is now lacking. Without this information base, many fundamental questions in marine invasion ecology will remain unresolved, limiting advances for basic science as well as its ability to guide effective management and policy.