Jonathan G. Lundgren & Scott W. Fausti
Lundgren and Fausti Sci. Adv. 2015;1:e1500558 31 July 2015

Abstract:
Recent shifts in agricultural practices have resulted in altered pesticide
use patterns, land use intensification, and land-scape 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
ec-ological community influence pest populations, but the nature of these
interactions remains poorly understood within realistic community
complexities and on operating farms. We examine how species diversity and
the topology of linkages in species’ abundances affect pest abundance on
maize farms across the Northern Great Plains. 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, for example, trophic interactions) can reveal key network
characteristics, especially the importance and nature of network
centrality, which aid in understanding how these communities function.

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