Intensive agriculture erodes β‐diversity at large scales

• DOI: 10.1111/j.1461-0248.2012.01815.x
• Publication Date: 2012-06-22T15:53:20Z
• Authors: Daniel S. Karp; Andrew J. Rominger; Jim Zook; Jai Ranganathan; Paul R. Ehrlich; Gretchen C. Daily
• Keywords: Costa Rica; 2. Zero hunger; 0106 biological sciences; Conservation of Natural Resources; Population Dynamics; Agriculture; Biodiversity; Plants; 15. Life on land; 01 natural sciences; Trees; Birds; Animals

AbstractBiodiversity is declining from unprecedented land conversions that replace diverse, low‐intensity agriculture with vast expanses under homogeneous, intensive production. Despite documented losses of species richness, consequences for β‐diversity, changes in community composition between sites, are largely unknown, especially in the tropics. Using a 10‐year data set on Costa Rican birds, we find that low‐intensity agriculture sustained β‐diversity across large scales on a par with forest. In high‐intensity agriculture, low local (α) diversity inflated β‐diversity as a statistical artefact. Therefore, at small spatial scales, intensive agriculture appeared to retain β‐diversity. Unlike in forest or low‐intensity systems, however, high‐intensity agriculture also homogenised vegetation structure over large distances, thereby decoupling the fundamental ecological pattern of bird communities changing with geographical distance. This ~40% decline in species turnover indicates a significant decline in β‐diversity at large spatial scales. These findings point the way towards multi‐functional agricultural systems that maintain agricultural productivity while simultaneously conserving biodiversity.