Agricultural landscape complexity and functional biodiversity is sustained by the exotic flora in the Rolling Pampa

POGGIO, SANTIAGO L.; MOLINA, GONZALO A. R.; WEYLAND, FEDERICO; GHERSA, CLAUDIO M.

Portland, Oregon

Congreso; 9th IALE World Congress - Crossing Scales, Crossing Borders: Global Approaches to Complex Challenges; 2015

International Association for Landscape Ecology

The Pampas were homogeneous treeless grasslands whose vegetation heterogeneity was determined by topographic and climate gradients. Agriculture created complex farmlands that altered the natural heterogeneity and introduced new organisms assembling novel ecosystems. Our aim is highlighting the contribution of the exotic flora occurring in anthropic elements to retain biodiversity and ecological functions in farmlands of the Rolling Pampa. While croplands occupy about 90% of the mosaic area, anthropic elements such as fencerows, roadsides, and woodlots, occupy the remaining surface, which sustain most of plant diversity in agro-ecosystems, particularly native plants. Woodlots, a novel elements in the Pampas, are important drivers of bird richness and abundance. Species richness and abundance of predator, parasitoid and pollinating arthropods are also greater in anthropic elements. Exotic flowering plants provide flower resources to native bees. There is evidence that dispersal from nearby habitats accounts for community assembly in croplands. Human activities have increased the abundance and frequency of anthropic elements sustaining biodiversity and ecosystem functions in farmlands. However, agricultural intensification is changing this trend by removing small landscape features retaining semi-natural habitats and impoverishing their habitat quality for wildlife. Initiatives to conserve biodiversity in the intensively managed agro-ecosystems prevailing in the Pampas should be focused on restoring and managing small uncropped landscape elements.