Trading biodiversity for pest problems

Authors: Lundgren, Jonathan; FAUSTI, SCOTT - South Dakota State University

Submitted to: Science Advances
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2015
Publication Date: 7/31/2015
Citation: Lundgren, J.G., Fausti, S.W. 2015. Trading biodiversity for pest problems. Science Advances. 1(6):e1500558. doi:10.1126/sciadv.1500558.

Interpretive Summary: Recent shifts in agricultural production have resulted in increased pesticide use, land use intensification, and landscape simplification, all of which threaten biodiversity in and near farms. Here, we show that weakening arthropod species networks on farms results in greater pest pressure. Decreasing species diversity, community evenness, and weakening linkage density and decentralized network topology within a community is associated with greater insect pest abundance on maize farms. The scale and context of this study (53 operating farms and complete bioinventories of foliar communities), novel application of network analysis, and strength of the conclusions represent major advances for food security and land management. They also provide further justification for diversifying farmland to improve its resiliency against stressors.

Technical Abstract: Recent shifts in agricultural practices have resulted in increased pesticide use, land use intensification, and landscape simplification, all of which threaten biodiversity in and near farms. Pests are major challenges to food security, and responses to pests can represent unintended socioeconomic and environmental costs. Characteristics of the ecological community influence pest populations, but the nature of these interactions remain poorly understood within realistic community complexities and on operating farms. Here we examine how species diversity and the topology of linkages in species’ abundances affect pest abundance on maize farms across a region. Our results show that increased species diversity, community evenness, and linkage strength and network centrality within a biological network all correlate with significantly reduced pest populations. This supports the assertion that reduced biological complexity on farms is associated with increased pest populations, and provides a further justification for diversification of agroecosystems to improve the profitability, safety, and sustainability of food production systems. Bioinventories as comprehensive as the one conducted here are conspicuously absent for most agroecosystems, but provide an important baseline for community and ecosystem ecology and the effects of food production on local biodiversity and ecosystem function. Network analyses of abundance correlations of entire communities (rather than focal interactions, e.g., trophic interactions) can reveal key network characteristics, especially the importance and nature of network centrality, which aid in understanding how these communities function.