Reconciling Environment and Production in Managed Ecosystems: Is Ecological Intensification a Solution?

Abstract

The overall demand for both agricultural and forest goods and services has strongly increased and is likely to continue to rise in the future, leading to more intensive practices in many managed ecosystems with potential negative effects for biodiversity and the environment (Cassman 1999; Tilman et al. 2002; Brussaard et al. 2010; Verkerk et al. 2014). Regarding agriculture, the challenge is to feed increasing numbers of people (food security) as well as to contribute to the development of bioenergy (Valentine et al. 2012). In the same vein, more forest products are required to satisfy new ambitious energy and construction policies (Jonsson 2013). Meanwhile, the concept of ecosystem services (ESs) has emerged and has been established in the environmental research and public spheres, exemplifying the complexity of ecosystems and their multiple relationships with human needs, including provisioning and regulating as well as social and cultural services (Tilman et al. 2002; Messier et al. 2015). Although conflicts or trade-offs between ESs have often been emphasized, positive interactions between, for example, regulating and provisioning ESs have paved the way to designing new management systems promoting ecological processes and reducing practices based on heavy mechanical or chemical means (Gaba et al. 2015). Overall, this is creating possibilities to reconcile production and the environment through a new type of ecologically driven intensification. According to Dore et al. (2011), ecological intensification (EI) consists in reducing artificial inputs while maintaining high production levels through biological regulation. It can thus be related to all practices that consist in intensifying the use of natural functions provided by ecosystems to support production (Chevassus au Louis and Griffon 2008). By nature, EI is closely related to biodiversity, which can directly or indirectly support production and other ESs through functional processes (Bommarco et al. 2013; Gaba et al. 2014). Although to date it has for the most part been mentioned in discussions on crop systems in agriculture, with some adjustments it can be generalized to other managed ecosystems dedicated to production (Rey et al. 2015). For instance, in forest science, concepts such as close-to-nature forestry, which explicitly integrates the reduction of inputs using natural processes, can fall under EI (Bauhus et al. 2013). As highlighted by Tittonell (2014), EI must be considered as designing ecosystem-based ‘‘[...] multifunctional agroecosystems that are both sustained by nature and sustainable in their nature.’’ From all these principles, it appears that EI contains all the ingredients to reconcile production and the environment (Fig. 1): (1) it aims at supporting and maximizing production; (2) it promotes practices that are based on functional ecological processes and that favor synergies between ESs (especially between regulating and provisioning ESs); and (3) it aims at reducing negative impacts of intensive management practices designed to increase productivity. So far, some important steps have been taken toward EI in both forestry and agriculture. For instance, in forestry, favoring species mixture in planted or natural forest stands may increase ecosystem productivity through temporal and spatial species niche complementarities (Forrester 2014). Silviculture practices based on natural processes (natural & Thomas Cordonnier thomas.cordonnier@irstea.fr