The recent find­ings by a team of North­eastern Uni­ver­sity ecol­o­gists studying plant life on the Boston Harbor Islands may advance soci­etal efforts to stem the damage caused by invading exotic species.

When these non-​​native species of plants gain a toe­hold and start col­o­nizing, they can cause tremen­dous eco­nomic and envi­ron­mental harm. For that reason, sci­en­tists con­tinue to try to iden­tify what fac­tors influ­ence the estab­lish­ment of exotic species in order to help pre­vent them from colonizing.

The North­eastern study, pub­lished in the journal Ecology, found that, con­trary to prior research, exotic plant species are more capable of col­o­nizing islands fur­ther away from the main­land than their native counterparts.

Our study shows how the pre­dic­tions of island bio­geog­raphy can pro­vide insight into the broad-​​scale fac­tors dri­ving the col­o­niza­tion and estab­lish­ment of exotic species on islands,” said Asso­ciate Pro­fessor of Biology Geof­frey C. Trussell, one of the lead researchers, and director of Northeastern’s Marine Sci­ence Center.

Funded by the Andrew W. Mellon Foun­da­tion and the National Sci­ence Foun­da­tion, this study is unique because it over­came issues that have lim­ited the con­clu­sions of pre­vious studies on the dis­tri­b­u­tion and abun­dance of exotic and native species on islands. Trussell, Marine Sci­ence Center post­doc­toral research asso­ciate Jeremy Long, and Ted Elliman of the New Eng­land Wild Flower Society, focused their study on a group of islands that were ideal in terms of their loca­tion and the number of exotic and native species col­o­nizing on them.

Trussell noted that, according to clas­sical island bio­geog­raphy theory, larger islands should have more species than smaller islands and islands located closer to the main­land should have more species than islands fur­ther away from the mainland.

The North­eastern study found that, con­sis­tent with theory, the larger harbor islands closer to the main­land have more native and exotic species than the smaller islands fur­ther away from the mainland.

How­ever, the greater rel­a­tive abun­dance of exotic species on the islands fur­ther away from the main­land sug­gests that native and exotic species are responding dif­fer­ently to island iso­la­tion and poten­tially other factors.

We hope that sim­ilar approaches by future researchers will pro­vide a better under­standing of exotic and native plant com­mu­ni­ties and the mech­a­nisms dri­ving their dynamics,”added Trussell.