Biodiversity and multiple ecosystem functions in an organic farmscape

To increase ecosystem services provided by their lands, farmers in the United States are managing non-production areas to create a more biodiverse set of habitats and greater landscape heterogeneity. Relatively little is known, however, of the actual environmental outcomes of this practice, termed 'farmscaping'. We inventoried communities of plant and soil organisms and monitored indicators of ecosystem functions in six distinct habitats of an organic farm in California's Central Valley to better understand the ecological costs and benefits of farmscaping. A riparian corridor, hedgerows, a system of drainage ditches, and tailwater ponds supported different plant life history/functional groups and greater native plant diversity than the two production fields. Differences were less pronounced for belowground organisms, i.e., nematode functional groups, microbial communities (based on phospholipid fatty acid (PLFA) analysis) and earthworm taxa. Partial ordination analysis showed that environmental variables, rather than spatial location, explained much of the distribution of soil and plant taxa across the farmscape. Riparian and hedgerow habitats with woody vegetation stored 18% of the farmscape's total carbon (C), despite occupying only 6% of the total area. Infiltration rates in the riparian corridor were >230% higher than those observed in the production fields, and concentrations of dissolved organic carbon (DOC) in soil solution were as much as 65% higher. The tailwater pond reduced total suspended solids in irrigation runoff by 97%. Drainage ditches had the highest N2O-N emissions (mean values of 16.7 mu g m(-2) h(-1)) and nitrate (NO3--N) leaching (12.1 g m(-2) year(-1) at 75 cm depth). Emissions of N2O-N and leaching of NO3--N were, however, quite low for all the habitats. Non-production habitats increased biodiversity (particularly plants) and specific ecosystem functions (e.g. water regulation and carbon storage). Extrapolating relative tradeoffs to the entire farmscape showed that greater habitat enhancement through farmscaping could increase both biodiversity and multiple ecosystem functions of agricultural lands with minor loss of production area. (C) 2010 Elsevier B.V. All rights reserved.