Ecosystem services in conventional farming systems. A review

Ecosystems worldwide are being disrupted under increased pressure from human activities. Nevertheless, most conservation studies and restoration efforts have so far focused on ecosystems of high heritage value related to their species diversity and/or the rarity of their habitats and/or species. However, “ordinary nature” (all the everyday, non-spectacular and non-protected landscapes, species and ecosystems) is also threatened by ecosystem disruption, which could affect major ecological functions and thus the supply of ecosystem services (ES). Conventional farming systems, which are mostly composed of agroecosystems characterised by ordinary nature, are already known to deliver some ES (e.g. pollination, carbon sequestration). Nevertheless, no systematic search has been done yet to determine which ES are identified and how there are studied in these conventional farming systems. We thus performed a first systematic evidence map (review of key articles to show, at a glance, the points that have been most studied, and highlight key gaps in the evidence base) to identify characterisation and measurement of ES provided by conventional agroecosystems from the review of 189 key international scientific articles. We excluded production for economic benefit, as this topic is already well documented in conventional agriculture systems. We found that most studies identified nutrient cycling (49.7%), carbon sequestration (46.6%), pest reduction (48.1%) or pollination (36.5%) as ES supplied by conventional agroecosystems. Correlations were also found between spatial scale and ES studied: for example, carbon storage was determined more at agricultural plot scale, while cultural services were determined more at landscape level. Our map also yielded 74 frequently used ES indicators, 50 of which are easily measurable and operational indicators of significant ES. Afterwards, one challenge that could be addressed in further studies is to determine for each indicator the range of measurement values that should be considered positive for ES provision, which is likely ecosystem-dependent.