Animal-pollinated crops and cultivars-A quantitative assessment of pollinator dependence values and evaluation of methodological approaches

Crop pollinator dependence (PD) values are key when assessing a pollinator's contribution to agriculture, guiding management plans and policies for sustainable crop production. However, the available global compilations of crops PD are outdated and neglect variability between related crops and accessions (variety/cultivar), as well as pollen limitation (PL), that is the production lost due to inadequate pollen receipt. Here, we obtained quantitative PD values for animal-pollinated crops and their accessions, using data from available pollination experiments worldwide. We also tested pollination methodologies to assess their impact on PD values and to define suitable methodological guidelines for future pollination studies. We provide a list of continuous PD values for 141 crops, including 317 accessions and 37 crops not listed in previous assessments. We found that, globally, 74% of animal-pollinated crops are highly dependent on pollinators, and more than 40% of their production is associated with animal pollination. Pollen limitation was detected in 51% of the dataset entries, indicating that estimates calculated with open pollination studies underestimate crop pollinator dependence and, therefore, do not represent the true contribution of pollinators to food production. Synthesis and applications: Commonly applied methods for assessing PD values can lead to underestimations. Future studies evaluating pollinator dependence levels of crops and their accessions (i.e. potential pollinator contribution) should consider the possibility of pollen limitation in the study site, incorporating hand pollen supplementation (to open flower), open pollination, and pollinator exclusion treatments, preferably using the whole plant or branch as the unit of assessment. The PD values provided here, from studies that allow the incorporation of the concept of pollen limitation, enable more accurate quantifications of pollinator contribution to crop production. These PD values are an invaluable baseline and a requirement for future accurate evaluations of the value of pollinators for food security, supporting pollinator-friendly practices in agroecosystems. Commonly applied methods for assessing PD values can lead to underestimations. Future studies evaluating pollinator dependence levels of crops and their accessions (i.e. potential pollinator contribution) should consider the possibility of pollen limitation in the study site, incorporating hand pollen supplementation (to open flower), open pollination, and pollinator exclusion treatments, preferably using the whole plant or branch as the unit of assessment. The PD values provided here, from studies that allow the incorporation of the concept of pollen limitation, enable more accurate quantifications of pollinator contribution to crop production. These PD values are an invaluable baseline and a requirement for future accurate evaluations of the value of pollinators for food security, supporting pollinator-friendly practices in agroecosystems.image