Importance of riparian habitats for small mammal and herpetofaunal communities in agricultural landscapes of southern Quebec

The presence of adequate riparian strips in agricultural landscapes is gene rally recognized to contribute to the reduction of the impacts of agricultu ral practices on the water quality of streams, to regularize water temperat ure and to help in the creation of important wildlife habitats. This study aimed at determining the importance of riparian strips in agricultural land scapes of southern Quebec for small mammal and herpetofaunal communities, a nd verifying farmers' general belief that these habitats become shelters fo r species considered as agricultural pests. Abundance, composition and dive rsity of communities were compared between three types of riparian strips: herbaceous, shrubby and wooded. A total of 1460 small mammals belonging to 14 species and 329 amphibians and reptiles belonging to 11 species were cap tured with line trapping and drift fences. The generalist species Sorer cin ereus, Zapus hudsonius, Blarina brevicauda, and Bufo americanus were abunda nt in all three types of riparian strips. Peromyscus maniculatus, Sorex fum eus, Clethrionomys gapperi, and Rana pipiens were associated more closely t o wooded strips, whereas Rana sylvatica was captured mostly in shrubby stri ps. The abundance of small mammals and herpetofauna increased with complexi ty of vegetation structure. Small mammal diversity was higher in herbaceous and wooded riparian strips, whereas the herpetofaunal community was more d iverse in shrubby strips. Proportion and abundance of pest species diminish ed with complexity of vegetation structure, whereas insectivores increased in abundance. Maintaining woody vegetation in riparian strips should increa se abundance and diversity of wildlife within agricultural landscapes where increasing development pressure is presently contributing to the conversio n of such habitats to herbaceous strips. Such a management approach should also help reducing the risk of riparian strips becoming shelters for pest s pecies. (C) 2001 Elsevier Science B.V. All rights reserved.