Ecosystem services demand in social-ecological systems: towards a typology of assessment approaches

Assessing ecosystem service (ES) demand remains conceptually fragmented and methodologically inconsistent in social-ecological systems (SES) research due to the lack of a framework linking human preferences to benefits derived from ES fruition. This study develops a systematic typology of ES demand assessment based on an integrative review of empirical studies. We conceptualize demand as emerging from two competing modalities: the consumption of provisioning and cultural services, which may drive ecosystem depletion, and the need for risk reduction through regulating services, which supports ecosystem preservation. Building on this distinction, we identify five valuation approaches, two that directly translate ES value into realized benefits and three that infer demand indirectly through monetary estimation, expert knowledge, or threshold-based criteria. The framework clarifies how socio-economic variables represent human preferences and needs, revealing the diversity and underlying logic of current demand assessment practices. Limitations include the lack of analysis of interactions between demand modalities, the treatment of services in isolation rather than as interdependent bundles, and the neglect of temporal and spatial dimensions. By systematizing fragmented methodologies, the framework advances understanding of ES demand and provides a structured basis for selecting appropriate demand assessment approaches across diverse SES contexts.