Natural ecosystems are fundamental to local water cycles and the water ecosystem services that humans enjoy, such as water provision, outdoor recreation, and flood protection. However, integrating ecosystem services into water resources management requires that they be acknowledged, quantified, and communicated to decision-makers. We present an indicator framework that incorporates the supply of, and demand for, water ecosystem services. This provides an initial diagnostic for water resource managers and a mechanism for evaluating tradeoffs through future scenarios. Building on a risk assessment framework, we present a three-tiered indicator for measuring where demand exceeds the supply of services, addressing the scope (spatial extent), frequency, and amplitude for which objectives (service delivery) are not met. The Ecosystem Service Indicator is measured on a 0–100 scale, which encompasses none to total service delivery. We demonstrate the framework and its applicability to a variety of services and data sources (e.g., monitoring stations, statistical yearbooks, modeled datasets) from case studies in China and Southeast Asia. We evaluate the sensitivity of the indicator scores to varying levels data and three methods of calculation using a simulated test dataset. Our indicator framework is conceptually simple, robust, and flexible enough to offer a starting point for decision-makers and to accommodate the evolution and expansion of tools, models and data sources used to measure and evaluate the value of water ecosystem services.

Sustainable water resource management is a wicked problem, fraught with uncertainties, an indeterminate scope, and divergent social values and interests among stakeholders. To facilitate better management of Southeast Asia’s transboundary Sesan, Sekong and Srepok (3S) River basin, we used the Freshwater Health Index (FHI) to diagnose the basin’s current and likely future level of freshwater health. We used the conditions for December 2016 as a baseline, where Ecosystem Vitality and Ecosystem Services scored 66 and 80, respectively, out of a possible 100, whilst Governance & Stakeholders scored 43. Thus, the 3S provided a range of desired ecosystem services, but there were signs of environmental stress as well as undeveloped water governance systems and limited stakeholder engagement. We also modelled four hydropower development scenarios and found that increasing development reduced the scores of a subset of indicators. This compromised the future ability of the 3S basin’s ecosystem to provide its current range of services. The FHI helped identify data deficiencies, illuminated important social dynamics, made ecosystem–human–water dynamics more understandable to stakeholders, and examined the long-term dynamics of the basin.

The Vulnerable fishing cat Prionailurus viverrinus faces a perilous future in South-east Asia. It was last sighted in Cambodia in 2003. We deployed 16 camera traps at four sites in southern Cambodia during January–May 2015 to determine if the fishing cat was still present in the country. Eight photograph/video captures of fishing cats were recorded from the mangroves in Peam Krasop Wildlife Sanctuary and one from Ream National Park, but there were no records from Botum Sakor National Park or Prey Nup. A number of other globally threatened species were also photographed in Peam Krasop Wildlife Sanctuary: the Sunda pangolin Manis javanica, the hog deer Axis porcinus and the large-spotted civet Viverra megaspila. We learnt of the killing of an alleged fishing cat at the Sanctuary in July 2015 in retaliation for raiding fishing nets. Illegal hunting and capture of fishing cats for the wildlife trade were reported by local informants at all sites. We provide photographic and video evidence of the fishing cats and highlight the importance of Cambodia's mangroves for threatened species conservation.