Much of the research conducted in our lab focuses on beneficial insects in agricultural landscapes. Specifically, we investigate how the type and configuration of natural habitat in agricultural landscapes influences beneficial insects and the services they provide (e.g., pest control). In general, the more natural habitat found in a landscape, the more beneficial insects and the higher the level of services will be found. Sometimes, however, more natural habitat does not lead to more beneficial insects and higher levels of services.
In a recent paper co-authored by Claudio and former lab member Tim Meehan, Tscharntke and collegues present five hypotheses for when and why more natural habitat does not always lead to more beneficial insects and reduced pest populations. The hypotheses are:
- Pest populations have no effective natural enemies in the region.
- Natural habitat is a greater source of pests than natural enemies.
- Crops provide more important resources for natural enemies that does natural habitat.
- Natural habitat is insufficient in amount, proximity, composition or configuration to provide large enough enemy populations for pest control.
- Agricultural practices counteract natural enemy establishment and biocontrol provided by natural habitat.
In these cases where biocontrol fails to control crop pests, the authors suggest several alternative management approaches including improved plant resistance, crop rotation, or crop diversification. Furthermore, the authors conclude that, rather than focusing on the scale of individual farms, conservation programs should consider and be applied at the landscape scale, as this scale is more relevant to the insects and services they provide.
By working together and taking a large-scale approach to conservation management, farmers have the potential to make a big difference in the future health and functioning of the environment.
Tscharntke, T., et al., When natural habitat fails to enhance biological pest control – Five hypotheses, Biological Conservaiton (2016), http://dx.doi.org/10.1016/j.biocon.2016.10.001