projects in Kenya, Peru, Nepal, Canada and several other countries (see Fig. 4.2). AMESH is described in considerably more detail elsewhere (see Waltner-Toews et al., 2008). However, as applied to One Health outcomes, it may be summarized as follows:
Fig. 4.2. The Adaptive Methodology for Ecosystem Sustainability and Health (AMESH). GIS, geographic information system. From Waltner-Toews et al. (2004), reprinted with permission.
• The process begins when local people, researchers or some third-party agency perceive a health-related problem.
• The responders, who could be anyone from international agencies to university-based research scholars, describe the situation systemically, including as many different perspectives and scales as feasible.
• Local stakeholders, together with research scholars and government and non-government agencies identify alternative courses of action that can best accommodate known trade-offs and optimize the achievement of multiple goals.
• They then choose a course of action that can achieve some balance of those different goals, develop a plan that incorporates feedback from which the implementers can learn and adapt, begin implementation, and ensure that governing, monitoring and management co-evolve with the changing situation.
The process, which has been demonstrated to be quite robust, incorporates both conventional investigative scientific and modelling techniques and democratic social processes, and, unlike many scientific investigations, can be altered and adapted to deal with new information and/or changing contexts (e.g. unstable markets for animal products, disease epidemics and the like).
An Integrated and Transdisciplinary Conception of Health
Because ecohealth applications face the danger of exploding in multiple directions at once, practitioners and scholars in the field have developed a variety of ways to set reasonable boundaries and articulate key principles.
Health (good or bad) arises from multiple interrelationships among various human and natural components of social-ecological systems (Whittaker et al., Chapter 7, this volume). In systems terms, community, population or ecosystem health is an emergent property. That is, it is evident at the level of the system but not at the scale of individual components or smaller subsets of relationships. One cannot predict from the individuals what the community will be like. Thus, one way to bound ecohealth work is to find units that are simultaneously useful for study, for administration of programmes, and for investigation of dynamics. This is part of defining the ‘problemshed’ relevant to the situation. Some geographic constructs lend themselves to this application more than others. In environment-and-health situations, watersheds have proven to be such a unit (Davies and Mazumder, 2003; Venema and Bunch, 2011; Bunch et al., 2014; Morrison et al., 2017). Not only are they arranged in a hierarchical manner (with sets of larger encompassing catchments and smaller subwatersheds) that help to frame conversations about external driving forces and upstream/downstream relationships, but water is clearly of central importance to both ecological and human health (Falkenmark and Folke, 2002; Boelee et al., 2019; WHO, 2019).
There are several useful conceptual models of environment-and-health interrelationships and emergence, such as the butterfly model of health (VanLeeuwen et al., 1999), and the Millennium Ecosystem Assessment framework that connects ecosystem services to constituents of human well-being (Corvalan et al., 2005). One current model that we find particularly useful is the Watershed Governance Prism (Fig. 4.3; Parkes et al., 2008, 2010). The prism expresses the potential for relationships among social systems, ecosystems and health with watersheds as an organizing construct that highlights water–land interaction, settings for health and well-being, and scale at which important driving forces (such as climate change) manifest. Although the prism is labelled for ‘watershed’ governance, because watersheds represent a setting to understand social-ecological systems and driving forces acting up on them, this can be substituted for other settings.
Fig. 4.3. The Watershed Governance Prism. From Parkes et al. (2008), reprinted with permission.
The Watershed Governance Prism is useful as a heuristic device to conceive of and guide the search for important relationships in a complex and problematic situation (e.g. among social systems and health, watersheds and social systems; see Table 4.2). Not every axis of the prism will necessarily be identified as important in every situation, but in identifying the problemshed and developing a system description of the issue, the prism can inform our scan of the problem. Furthermore, sets of relationships can be built up to represent common perspectives (e.g. the faces of the prism correspond to common approaches such as: (i) water governance for sustainable development; (ii) water governance for ecosystems and well-being; (iii) water governance for social determinants of health; and (iv) water governance for social-ecological health promotion). The Watershed Governance Prism thus helps to promote the search for relationships corresponding to various prism axes that may exist in a problem context, and also point out what aspects may be missing or neglected. When a conceptual model of a problematic environment-and-health situation is developed, some axes might not appear, but this can be a deliberate and justified choice, avoiding an accidental omission that arises out of ignorance or a narrow perspective.
Table 4.2. Relationships corresponding to axes on the Watershed Governance Prism. Adapted from Parkes et al. (2010).
| Linear connections (prism ‘axes’) | Representative examples of features, issues and characteristics of linear connections’ link to prism diagram |
|---|---|
| Ecosystems–health/well-being | Traditional environmental health relationships linking ecosystems with human health and well-being, with a focus on contaminants, pathogens, disease vectors, toxic or therapeutic agents, extending to health implications of loss of biodiversity and/or ecosystem services. |
| Watersheds–ecosystems | Natural resource and ecosystem management (including land and water use) within the watershed, agroecosystem viability and food security; the protection of baseline or ‘environmental’ water flows, including wetlands; saltwater intrusion/salinization of soil. |
| Watersheds–health/well-being | Water-related services and infrastructure (including source water protection, wastewater, sanitation and hygiene services); direct effects of natural disasters such as flooding, drought, landslides; structural flood defences, drainage and irrigation systems. |
|
Watersheds–social
|
