Historical anthropogenic disturbances influence patterns of non-native earthworm and plant invasions in a temperate primary forest

Time lags are of potentially great importance during biological invasions. For example, significant delays can occur between the human activities permitting the arrival of an invader, the establishment of this new species, and the manifestation of its impacts. In this context, to assess the influence of anthropogenic disturbances, it may become necessary to include a historical perspective. In this study, we reconstructed the history of human activities in a temperate forest now protected as a nature reserve to evaluate the magnitude and duration of the impact of human disturbances (e.g. trails, old quarries), as well as environmental factors, in explaining the probability of occurrence and the intensity of invasion by non-native earthworms and plants. The present-day patterns of distribution and intensity of earthworms and plants were better explained by proximity to the oldest human disturbances (initiated more than a century ago) than by proximity to more recent disturbances or to all disturbances combined. We conclude that understanding present-day patterns of non-native species invasions may often require reconstructing the history of human disturbances that occurred decades or even centuries in the past.