Invasive species, management for conservation and remote sensing

Abstract

The paper chosen for the award by the Chief Editors of Applied Vegetation Science, from among those published in 2007 is that by Hartman & McCarthy (2007). Exotic (alien, non-indigenous) species are a concern for their impact on native communities, as well as fascinating probes into community structure: natural experiments. Recent research has tried to measure their impact by examining invaded and non-invaded sites. This approach has the flaw that the non-invaded sites may not have been invaded because they were different in the first place. Examining sites before and after an invasion is difficult because invasions are not normally noticed until after they have happened, and anyway there might have been an allogenic environmental change, or one caused by the reaction of the other species. The ideal would be to go backwards in time in both invaded and non-invaded sites. Impossible? But Hartman & McCarthy (2007) did this by dendrochronology. Working in deciduous hardwood forest in Ohio, USA, they shewed that the exotic understorey shrub Lonicera maackii (Rupr.) Herder reduced the growth of native trees in the overstorey.