INTENSITY OF AGRICULTURAL PRACTICES AND EFFECTS ON ADJACENT HABITATS

In intensive agricultural areas small woodlots and woody hedgerows constitute the only remnant of natural forested habitats. Because they are reduced in size and are surrounded by farmlands, remnant habitats may be impacted by several abiotic factors. The conservation value of these habitats, however, cannot be fully ascertained while plant species richness and composition remain unknown. We describe the vegetation composition of woodlot edges and hedgerows associated with agricultural fields of different farming intensities. We inventoried thirteen woodlot edges and hedgerows in each of three types of farming systems characterized mainly by different frequency of tillage and by different levels of herbicide and fertilizer use. The number and percentage cover of species present did not differ greatly between farming regimes whereas the species composition varied considerably. In habitats adjacent to intensively farmed fields, we found more short‐lived grassy‐type plants that were largely of introduced origin and of weedy propensity. Conversely, more species typical of the maple‐tree association were found in habitats abutting less intensively managed fields. Species composition and abundance also differed with distances into the woodlots and hedgerows. These effects were more noticeable in woodlot edges than in hedgerows. We discuss the results in relation to their conservation as well as their agronomic implications. We suggest that a buffer strip at the edge of cultivated fields may be sufficient for the protection of native plants in woodlots (and probably of other wildlife) and, to a lesser extent, of hedgerows. Furthermore, buffer strips may reduce weed interaction between crop and non‐crop habitats.