5: Reader’s Choice Award runner-up for JEE: Ecology and economics of using native managed bees for almond pollination

Although evidence of the efficacy of alternative native managed bees in crop pollination is increasing, a broader ecological economic framework for evaluating their net benefits is missing. We conducted a cost-benefit analysis to show how management decisions regarding blue orchard bees might influence growers’ net profit in a California almond orchard. We studied how many bees, artificial nest sites (boxes), and nest cavities (tubes) influence net profit. To support grower’s decisions, we developed an ecological model of almond yield using published data and estimated net profit according to different management scenarios of the blue orchard bees. The model explained 17% of the variance of almond yields. Estimated annual net profit varied from $950 to $4,050 per acre depending on decisions of all the three management options. We predicted that increasing nest box density only increased average net profits by $1,600 per acre and attribute this to the short-foraging distance and nesting-search behavior of this managed bee. Adding more bees and tubes also increased the net profits, but not as much as nest box density. These results show that growers could increase benefit by providing more nest sites in orchards. If this simple management decision were implemented on one million acres of almond in California, then the increased net profit could be equivalent to 40% of annual gross value of California almond yield. Our ecological economic framework supports growers’ management decision-making process and suggest a broader ecological economic framework in integration of alternative native managed bees in orchard system.