Table 1.

Details of variables extracted from each article during the literature review

Variables extracted	Categories
Study area	Country(ies) where the study was located
Consideration of the drivers of ecosystem service relationships	Explicit: defined as identifying an ecosystem service relationship with potential drivers explicitly integrated into the assessment Implicit: defined as identifying an ecosystem service relationship, with potential drivers identified or discussed, but not explicitly incorporating it into the assessment No mention: defined as identifying an ecosystem service relationship, but not mentioning the driver or mechanisms leading to the synergy or trade-off
Driver identified	Categories adapted from drivers of change for ecosystem services identified in MA (2005): demographic (i.e. population size); socio-economic (i.e. average income); socio-political (i.e. type of governance); scientific and technological advances (i.e. advances in harvesting machinery); cultural and religious (i.e. religious values); policy instruments (i.e. incentives for behavioural change); land use/land cover change (i.e. decreased tree cover); species introductions/removals (i.e. the introduction of pest control species); natural resource management (i.e. fertiliser use); harvest and resource demand (i.e. meat consumption); climate change (i.e. increasing atmospheric temperatures); natural, physical and biological drivers (i.e. soil type)
Method used to calculate ecosystem service trade-offs and synergies	Correlation: measures the association between the supply of ecosystem services using correlation coefficients Overlap analysis: quantifies percentage of locations where two ecosystem services are provided at the same time. Trade-offs occur where one service is in high supply, and another is in low supply at different locations. Synergies occur where both service are simultaneously in high or low supply at different locations Ordination: multivariate analyses that order ecosystem service supply by values on multiple variables so that similar objects are near each other and dissimilar objects are farther from each other in ordination space ANOVA: tests whether there are statistical differences between the means of different ecosystem services Regression: quantifies how the supply of an ecosystem service changes when the supply of one or more other ecosystem services change. Regression methods include general linear models, logistic models, structural equation models and path analysis Scenario analysis: a systematic method for developing alternative futures about the supply of ecosystem services
Ecosystem services that were assessed	Categorised based on CICES V4.3 Ecosystem Service Classifications, group level (http://cices.eu/): biomass—nutrition (i.e. food production); water (for human consumption); biomass—materials (i.e. timber); water—materials (i.e. water used for industrial manufacturing); biomass-based energy sources (i.e. biofuel); mechanical energy (i.e. hydropower); mediation by biota (i.e. carbon storage and sequestration); mediation by ecosystems (i.e. mediation of noise or smells); mass flows (i.e. erosion control); liquid flows (i.e. flood mitigation); Gaseous/airflows (i.e. air ventilation); lifecycle maintenance, habitat and gene pool protection (i.e. pollination); Pest and disease control (i.e. pest regulation); soil formation and composition (i.e. soil fertility); water conditions (i.e. regulation of water quality); atmospheric composition and climate regulation (i.e. regulation of greenhouse gases); physical and experiential interactions (i.e. hiking); Intellectual and representative interactions (i.e. education); spiritual and/or emblematic (i.e. spiritual identity); other cultural outputs (such as enjoyment provided by existence of wild species) (Haines-Young and Potschin 2013)
Relationships identified between the ecosystem services	Trade-offs: one service increases, while the other decreases Synergy: two ecosystem services increase or decrease simultaneously