Using the response–effect trait framework to quantify the value of fallow patches in agricultural landscapes to pollinators

Questions
What is the role of managed fallow habitats in providing resources for pollination services in agricultural landscapes? How is resource provision affected by fallow management and landscape structure? Can the resulting variation in the value of fallows to pollinators be explained using the response‐and‐effect trait framework?

Location
Four semi‐arid Mediterranean agricultural regions (NE Iberian Peninsula).

Methods
Landscape complexity, fallow field age and management practices were identified as the explanatory factors that interact which each other and affect the provision of resource for pollination communities. A trait‐based approach was taken to model the system. Plant traits were selected on the basis of their response to abiotic factors (response traits) and those that influence the interaction with pollinators (effect traits). Plant community characterization was calculated based on both taxonomic and functional indices. The linkages between the selected plant traits on contrasting fallows were analysed using community‐weighted mean redundancy analysis (CWM‐RDA).

Results
The presence of semi‐natural areas in the landscape was shown to enhance the value of fallows for pollinators, providing a source of diverse flower forms. In contrast, we found that field edges act as a relatively poor reservoir for flowering plant species in these areas. Land‐use practices promoting mid‐successional plant communities that support the coexistence of diverse life forms with overlapping flowering periods and a range of flower morphologies had the greatest potential to support a diverse pollinator community.

Conclusions
Early herbicide application (Feb) combined with shredding were identified as the best fallow practices for enhancing resources for pollinators. The construction of our framework will help policy makers to identify management recommendations that will result in the most beneficial plant communities for pollinators in fallows.

Citing Literature