Invertebrate Invaders Share Common Characteristics
Successful invasive species may share certain characteristics, which could help scientists predict and control non-native species that are introduced to an environment.
That was the initial finding of research conducted by Alexander Y. Karatayev, director of Buffalo State’s Great Lakes Center, and Lyubov E. Burlakova, a research scientist with the center, and other scientists who collaborated to develop a preliminary profile of organisms most likely to succeed as freshwater, macroinvertebrate invasive species.
Karatayev and Burlakova worked with Sergey E. Mastitsky, recently of the center; Dianna K. Padilla, professor with the Department of Ecology and Evolution, Stony Brook University; and Sergej Olenin, professor with the Coastal Research and Planning Institute, Klaipeda University in Lithuania, to investigate whether freshwater, macroinvertebrate invaders were a random or selected group. The resulting paper, “Invaders are Not a Random Selection of Species,” was published in 2009 in Biological Invasions.
“The study grew out of a workshop we held in Ireland,” explained Karatayev. “We decided to see if we could make any generalizations about invasive species, with the hope that eventually it will be possible to predict and control potential problems.”
Before meeting, each scientist researched about 20 invasive species and brought information about specific characteristics such as reproduction, life cycle, and resistance to pollutants to the workshop. In “Invaders are not a random selection of species,” the team showed that successful freshwater invasive species are likely to be mollusks or crustaceans that are tolerant of at least some pollution. Additionally, Karatayev said, “They are not fussy eaters.”
For example, the zebra mussel, a well-known invasive species in the Great Lakes, is a filter-feeding mollusk; essentially, it strains its food out of the water. Macroinvertebrates with such feeding habits are far more likely to be successful invaders than macroinvertebrates that are predators.
To draw their conclusions, the researchers compared 119 invasive species to all native macroinvertebrate freshwater species in North American and Europe. Of the native species, about 35 percent can live only in water that is excellent or very good quality; they do not tolerate organic pollution. However, all the successful invaders tolerate at least some organic pollution—pollution that lowers the amount of dissolved oxygen in water.
Karatayev pointed out that many invasive species cannot survive their initial contact with a new environment. On the simplest level, for example, very few saltwater organisms can survive in fresh water. Those that survive must be able to establish a viable population—a population that can perpetuate itself, meaning that the invaders must be able to eat and reproduce.
One of the strongest arguments against the notion that invasive species are random is that the research demonstrated a significant difference between the make-up of native species and the make-up of successful invasive species. In North America, only 6.5 percent of native invertebrates are crustaceans; however, 38 percent of successful invasive species are crustaceans.
“Certain processes seem to be very similar in North America and Europe,” said Karatayev. “It’s certainly possible that these patterns are common all around the world.”