Evidence of time-lag in the provision of ecosystem services by tropical regenerating forests to coffee yields

Abstract

Restoration of native tropical forests is crucial for protecting biodiversity and ecosystem functions, such as carbon stock capacity. However, little is known about the contribution of early stages of forest regeneration to crop productivity through the enhancement of ecosystem services, such as crop pollination and pest control. Using data from 610 municipalities along the Brazilian Atlantic Forest (30 m spatial resolution), we evaluated if young regenerating forests (less than 20 years old) are positively associated with coffee yield and whether such a relationship depends on the amount of preserved forest in the surroundings of the coffee fields. We found that regenerating forest alone was not associated with variations in coffee yields. However, the presence of young regenerating forest (within a 500 m buffer) was positively related to higher coffee yields when the amount of preserved forest in a 2 km buffer is above a 20% threshold cover. These results further reinforce that regional coffee yields are influenced by changes in biodiversity-mediated ecosystem services, which are explained by the amount of mature forest in the surrounding of coffee fields. We argue that while regenerating fragments may contribute to increased connectivity between remnants of forest fragments and crop fields in landscapes with a minimum amount of forest (20%), older preserved forests (more than 20 years) are essential for sustaining pollinator and pest enemy’s populations. These results highlight the potential time lag of at least 20 years of regenerating forests’ in contributing to the provision of ecosystem services that affect coffee yields (e.g., pollination and pest control). We emphasize the need to implement public policies that promote ecosystem restoration and ensure the permanence of these new forests over time.

Key tropical crops at risk from pollinator loss due to climate change and land use

“…It is impossible to predict exactly how our estimates of production risk measure will translate into actual crop production losses. There are multiple uncertainties associated with predicting pollinator biodiversity changes and how this affects crop production, some of which we explore here (e.g., the relationship between pollinator abundance and crop production), but many of which we do not or cannot [e.g., the changing distribution of crops ( 60 ), the economic viability of hand pollination ( 61 ), the buffering effects of managed pollinators ( 62 ), the effects of climate change alone ( 63 ), the uncertainty over whether pollinator abundance is more important than other measures of pollinator diversity ( 34 , 64 ), the buffering or magnifying effects of landscape composition or agroforestry ( 65 , 66 ), and other technological solutions such as the breeding or engineering of pollinator-independent cultivars] ( 67 ). As one example, crops in which hand pollination is already widely practiced, particularly apple, tomato, kiwi, oil palm, and vanilla ( 61 ), will likely be more resilient than our models would predict.…”