Environmental challenges of intensive woody crops: The case of super high-density olive groves

Super high-density olive groves (>800 trees ha-1) are rapidly expanding in olive oil producer countries, which entails a strong modification of the olive growing system with important agronomic, economic, sociocultural, and environmental consequences. Among them, the latter is particularly unknown. The aim of this paper is to bring the attention on the environmental impacts of super high-density olive groves, by systematically reviewing the current evidence and identifying knowledge gaps yet to be filled. As a result, we can argue that new super highdensity olive plantations reduce habitat heterogeneity and complexity, and the younger trees of these plantations impoverish habitat quality for farmland biodiversity. In addition, the high input use (e.g. phytosanitary treatments, fertilisers and water supply) may entail ecological impacts as well. Therefore, we conclude that i) new highly intensive olive groves should be limited to areas with lower ecological value; ii) consumers should have more information concerning how is produced the olive oil they buy, including the environmental impacts produced; iii) agricultural policies should be reformulated following the provider-gets principle; iv) input use (fertilisers, pesticides, water, etc.) should be gradually optimised to reduce the environmental impact; and fi-nally, v) more research is necessary to foster decisions based on science. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Super high-density olive groves, with over 800 trees per hectare, are rapidly expanding in olive oil producer countries, resulting in significant modifications to the olive growing system with important implications for agronomy, economy, socioculture, and environment. The environmental impacts of these groves are relatively unknown, and this paper aims to raise awareness on the topic by reviewing current evidence and identifying knowledge gaps. The findings suggest that these new olive groves may reduce habitat heterogeneity and quality, and their high input use could have ecological consequences as well. Recommendations include limiting highly intensive plantations to areas with lower ecological value, providing consumers with more information on the environmental impacts of olive oil production, reformulating agricultural policies, optimizing input use, and conducting more research for science-based decision-making.