The role of permanent grasslands on ant community structure: Ants (Hymenoptera: Formicidae) as ecological indicators in the agro-ecosystems of the Taro River Regional Park (Italy)

Environmental stress, also associated with human land-use, induces a response in ecological indicators that can be measured and used to develop an effective land management policy. There are various reasons to usually exclude terrestrial invertebrates from land monitoring and assessment programmes. Ants are an exception and they are routinely used for biological monitoring in many Australian ecosystems. However, the value of ants as ecological indicators has been comparatively poorly studied in the Palaearctic region. This research is one of the first attempts to verify whether ants are eligible to become efficient ecological indicators in typical Mediterranean agro-ecosystems. The area of investigation has been selected in the Fluvial Regional Park of Taro River (Parma, Northern Italy). Since the reserve is located in the region that produces Parmigiano-Reggiano cheese, park management guidelines tend to match principles of environmental protection with human demands. In this framework, the fluvial park has developed a project for the preservation of Permanent Grasslands that are considered a valid alternative to monocultures for the production of cow fodder. In this work, sampling with pitfall traps was used to compare the presence and distribution of ant-fauna between Permanent Grasslands and Lucerne Monocultures. The results showed that the degree of invasiveness of agricultural practice has a meaningful impact on ant species composition: the reduction of environmental stress and disturbance produces variations in the ant community structure promoting especially Lasius niger (LINNAEUS, 1758). On the contrary, on such sites Messor cf. structor (LATREILLE, 1798) is present to a lesser extent. This research suggests that the study of ant communities is a promising method to evaluate the influence of different land management policies also in the agro-ecosystems of the Taro River Regional Park.