Vegetation-based Ecological Functions Sustainability Index (VEFSI) for optimizing ecosystem services in orchards

Abstract

CONTEXT

The need to quantify sustainability in agriculture and the ecosystem services it provides is increasingly felt by the sector. Indicators and indices are useful tools for this purpose, but are currently scarce in the specialized fruit-growing sector. In addition, there is a need for a more holistic view of the orchard system, which also considers unproductive spaces, such as the inter-row, where techniques can be implemented to improve adaptation to climate change.

OBJECTIVES

To help filling this gap, we developed VEFSI (Vegetation-based Ecological Functions Sustainability Index), a multifunctional index that can be used by technicians, researchers and farmers to establish the quality of grass cover in the orchard's inter-row in order to increase the ecosystem services performed by this.

METHODS

A dataset of field observation was collected during the year 2022–2023 in orchards located in South-West Piedmont (Northern Italy). Each record included observations on species richness, total vegetation cover and relative cover of each detected species. VEFSI was designed to include different ecological functions, such as nitrogen fixation, mechanical action performed by fascicled roots, soil cover performed by perennial organs, pollination service of the fruit crop and melliferous species for pollinator attraction. The index was calculated as a sum of scores attributed to single functions on the basis of the relative abundance of plants characterized by the corresponding functional traits.

RESULTS AND CONCLUSION

A positive relation has been found among VEFSI, vegetation cover (R² = 0.419; P < 0.001) and number of species (R² = 0.53; P < 0.001). Within the tested dataset the maximum theoretical value of 125 has not been reached, indicating trade-offs presence among functions. Despite this, the validation showed that VEFSI point out functional weaknesses and strengths of the vegetation covers, coherently with the real field situation. VEFSI proved to be a simple and reliable tool for estimating and evaluating ecological functions performed by orchard grassing.