with metrics and their development is where to obtain the information or data to parameterize or determine the values of the metrics. Information can be gathered in several ways. First, scientists can collect their own data by measuring the system directly. For example, data for estimating the survival rate of individuals within a population can be measured using radio-telemetry tags that alert the scientist to mortality events. Remote sensing techniques are an invaluable resource for measuring landscape level factors such as land cover, human infrastructure (e.g. roads), plant phenology and productivity, and climate and weather (Neumann et al., 2015). Key parameters rates (survival, immigration, emigration, reproduction, etc.) are also available in the published literature for many systems (or from similar systems) and can be used to begin assessing metrics to assess healthy versus unhealthy states for the system. Expert knowledge and opinion can also be informative, particularly when other sources of information are lacking. Experts may include noted scientists, natural historians and agency personnel, as well as non-scientific experts such as indigenous people, who have a long and rich connection to the natural system. We can also look to novel data streams arising from technological advancements. Web-based acquisition of information based on reports from citizen scientists or the general public may prove useful, particularly for large spatial or temporal scales, and may also help describe the social landscape of the system. Similarly, documenting human use of web-based services and searches may help in understanding and quantifying human beliefs, values or expectations of a system, as well as help inform impacts to human health of system processes. Most health assessments will need to avail themselves of many different sources of information to adequately measure the various features of the system map.
Mobilizing knowledge to action
Measuring the health status of a wild population or ecosystem has its own merits but without moving this knowledge into action, little will come of it. The gaps between knowing what to do to promote health across people, animals and environments and doing it can be wide and difficult to breach. Evidence can be used to change outcomes, but only if people apply it in practice and policy.
One Health practitioners can benefit from models of individual and social change that are found in the health promotion, marketing and business literature. The Health Belief Model, for example, is one of the most widely used conceptual frameworks for guiding human health interventions. The model contains several concepts that predict why people will take a health-promoting action, including perceived susceptibility to harm, benefits and barriers to change, cues to action and self-efficacy (Champion and Skinner, 2008). The Theory of Reasoned Action and the Theory of Planned Behaviour focus on individual motivational factors as determinants of the likelihood of performing a specific action (Ajzen, 1991). They focus on how attitudes, subjective norms and perceived control influence health behaviours. Theories and models such as these can help target interventions designed to encourage the adoption of health-protecting measures on an individual or collective level.
Multiple theories of change have been developed (Mitchell, 2013) and can be used to build a bridge between what we know, what we want to achieve, and the activities it will take to get us from mapping and measuring a system’s health to mobilizing what we learn into action. Given the complexity of ecosystem health, most actions will require involvement of researchers, local knowledge creators, managers, planners, beneficiaries and stakeholders at the start to develop consensus on the shared goals by explicitly documenting different views and assumptions and by helping people see how sharing their knowledge contributes to long-term positive impacts.
Knowledge mobilization is an active process of creating linkages between creators and users of information to produce value-added outcomes. The Knowledge to Action Framework was developed to help create and sustain evidence-based actions (Field et al., 2014). This framework, based on commonalities of over 30 planned-action theories, follows the premise that knowledge is best co-created by researchers and those who need to use the knowledge and includes both a knowledge creation and an action cycle as transdisciplinary research (Hirsch Hadorn et al., 2008; Berger-González et al., Chapter 6, this volume). The framework provides a series of steps to help mobilize available research into action while accounting for local context and explicit assessment of barriers and facilitators to use of the knowledge for creating changes to actions. Regardless of the type of knowledge user, knowledge mobilization requires a relentless dedication to understanding that user’s needs, and creating strategies and tools to engage, inform and motivate them under a variety of circumstances. A clear plan that outlines roles, responsibilities and authority to support action as well as secure the partnership and resources needed to sustain change are as essential as the efforts used to measure the health of people, animals or their shared ecosystems.
Ecosystem Health is Human Health
The connection between ecosystem health and human health is evident in the history of human morbidity and mortality, whose causes parallel land use, from mortality due primarily to predation, famine and vector-borne diseases in pre-modern societies, to the rise of infectious and waterborne diseases associated with agrarian settlements and industrial cities, and finally modern-day illnesses of sedentary lifestyles or those related to poor air quality (Rapport and Maffi, 2011). Today, increasingly rapid ecosystem degradation compounds these health effects through declines in basic ecosystem services such as provision of food and water (IPBES, 2019).
In addition to human population health, human cultural health is intimately tied to the ecosystems in which those cultures arose. Loss of biodiversity and ecosystem integrity is mirrored by loss of cultural diversity caused by similar anthropogenic pressures, including land-use change, exploitation or over-harvesting of resources, environmental contamination and introduction of non-native species (Rapport and Maffi, 2011). New fields of study concerned with cultural and linguistic conservation have developed in parallel with those of ecological conservation, pointing to what has been termed a ‘converging extinction crisis’ of social and ecological systems across the world (Harmon, 2002).
As the One Health community has highlighted in its work with emerging zoonoses of wildlife origin, and as the risk to humans from loss of ecosystem services confirms, the health of wild populations and wild places is of importance to more than just wildlife. By conveying the importance of environmental health as a source of human determinants of health (e.g. clean water and air), actions can be promoted that contribute to conservation goals as well as human health and prosperity (Wood and DeClerk, 2015). The challenge before us is to achieve a degree of consensus among various stakeholders about what health means for a given population or system, how it can be assessed, and how it can be promoted (Berger-González et al., Chapter 6, this volume).
There is no single answer to the question ‘What is health?’ for ecosystems or their various components, be it wildlife, cattle or humans. Nevertheless, health is at the very heart of One Health, and it is an important question to ask and answer as the One Health framework continues to evolve. Without an explicit definition of the desired state that resonates across all pillars of One Health, metrics for evaluating progress towards that state, and commitment to working towards that state for all stakeholders, and addressing how an added value of cooperation between human and animal health, environment and conservation sciences can be created, there can be no true progress.
