For crop pollination, the maximum potential benefit is manifested by the total agricultural crop output that is dependent to some degree on insect pollination. For population exposed, we focus on “local” beneficiaries, populations whose aggregate dietary requirements exceed pollinator-independent production within 100 km. The potential benefit provided by nature is the yield or production attributable to pollination where it has been sufficiently delivered by pollinators from surrounding habitat, and nature’s contribution is represented by the proportion of total potential pollination-dependent crop output that is pollinated.
The potential benefits provided by nature, which are often called “ecosystem services” (but should be thought of as the potential supply of a service, and only truly becomes a service when combined with human demand for the service) may be measured in terms of total production value of the crop pollinated or number of people equivalents whose dietary requirements are met by pollination. We emphasize that a proportional representation of nature’s contribution to providing potential benefits is important to track differences or changes across space and time; as realized benefits provided by nature could increase alongside (or due to) increases in maximum potential benefits or population exposed, though nature’s contributions may remain the same. That is, if more pollination-dependent crops are grown, a constant proportional contribution of nature would result in higher levels of the corresponding realized benefits, in this case pollination, even if conditions for people (in terms of food security) deteriorate. The relative proportion of nature’s contribution, along with people’s needs, especially for the most vulnerable people, are more useful metrics than realized benefits alone when considering change across several variables at once (stressors, people, and nature), as they reveal where and when nature plays a key role in delivering benefits.
We also examine the benefits not provided by nature, or benefit gaps, people depend upon for their well-being (which could be filled to some extent by other forms of capital, e.g., the labor to hand-pollinate), and the populations exposed to changes in benefit gaps for each NCP in future scenarios. We use the amount of crop losses due to insufficiently pollinated crops as the measure of benefit gap for pollination. This benefit gap results in the outcomes people will actually face and perceive – potentially leading to food shortages in this case— and is what will determine people’s well-being, the visible component of NCP. It does not by itself, however, reveal the role nature plays in contributing to that well-being.