Invasive Species

The spread of invasive species is, together with climate change, one of the most serious global environmental problems. These invaders are now present in all marine coastal habitats, often dominating these communities. In the past several decades at least 10 exotic species, including crabs, sea squirts, bryozoans, and shipworms, have invaded coastal habitats in southern New England . Little is known about the ecology of these species and how they are influencing the native fauna and flora. Some of our studies include:

  1. Determining the ability of invaders to compete with native fauna. We have found that alien and native species do not differ greatly in their competitive ability. However we have found that some invaders may reproduce earlier in the summer, allowing them to colonize new habitat before native species.
  2. Examining differences in the response of native predators to alien and native prey. We have found that predators eat both native and alien species, but that one or two alien species may be resistant to some predators, possibly as a consequence of chemical defense or unpalatability.

  3. Determining whether increased native community diversity confers any resistance to invasion. Our studies have shown that more diverse communities can occupy habitat space more consistently (if one species dies others quickly grow into the open space) and are more likely to prevent invasion by new species.

  4. Identifying the linkages between invasion success and climate change. Our research shows that subtle, climate-induced increases in water temperatures differentially affect native and non-native species, favoring species introductions and altering the composition of biological communities. We are now developing population models that link invasion success to climate and changes in land-use.