Landscape composition influences the stability of pest suppression services in annual and perennial habitats
Perennial grasslands generally support a higher diversity of beneficial insects and greater ecosystem services such as pest suppression, compared to annual crops such as corn and soybean. For mobile insects such as predatory ladybeetles and bees, the composition of the surrounding landscape has also been shown to influence local processes where habitats embedded within diverse landscapes tend to support a greater abundance and diversity of beneficial insects. However, it is unclear how the stability (1/CV) in the provisioning of ecosystem services is affected by habitat type and the composition of the surrounding landscape. In this study, we used removal rates of sentinel prey collected from multiple sites across WI and MI (20-40), and across multiple years (2011-2014) to ask whether the stability of pest suppression services varied with landscape composition (proportion of grassland, agriculture, and urban) and habitat type (soybean and grassland).
Our results show that perennial grasslands generally had a greater rate of prey removal compared to soybean. The stability (1/CV) of removal rates was also greater in grasslands compared to soybean. The surrounding landscape did not influence the mean removal rates of prey in both soybean or grasslands but the proportion of grassland in the surrounding landscape did influence the stability of predation rates in soybean. Interestingly, the stability of predation rates was lower in soybean fields that were surrounded by grasslands. These results suggest that not only do local processes influence the stability of ecosystem services but that the surrounding landscape can also offset the provisioning of ecosystem services.