Abstract:
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The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster
yields has emerged as an agroecological paradigm. However, while
noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous
across studies and effects on pests are inconclusive. The observed
heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and
biocontrol are measured. Here, we use a pest-control database
encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage
as a function of landscape composition. Our results showed that
although landscape composition explained significant variation
within studies, pest and enemy abundances, predation rates, crop
damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes
with more noncrop habitat but overall showing no consistent trend.
Thus, models that used landscape-composition variables to predict
pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our
work shows that surrounding noncrop habitat does not consistently
improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future
efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased
understanding of how landscape effects are modulated by local
farm management and the biology of pests and their enemies. Agroecology, biodiversity, biological control, ecosystem services, natural enemies |