Page - 236 - in Biodiversity and Health in the Face of Climate Change

236 takes the positivist stance that we can quantitatively measure exposure, moderators, mediators and outcomes in meaningful ways. Below we explain our decision- making in the development of the model. Exposure: Nature  – The exposure of interest is the natural environment, particu- larly as measured by biodiversity. The literature reinforces the need to also consider the composite type of environment (see Marselle et  al. 2013). Moderators: Personal Characteristics, Activity, Group  – The effects of any exposure or intervention will necessarily be moderated by the antecedent factors that the unique individuals bring to the situation. Socio-demographics are a well- known example in health literature, but Heintzman (2009, 2016) identifies addi- tional features that are relevant for spiritual outcomes, including motivation, history, current circumstances and spiritual beliefs/traditions. Heintzman (2009, 2016) and Yeh et  al. (2016), respectively writing in the leisure studies and sports medicine literature, identify various elements of the activity in nature as an impor- tant part of the exposure that will impact health. Additionally, Heintzman recog- nises that being alone or with a group, whether the group is structured or unstructured, and the type of group facilitation has a further impact on whether or not spiritual experiences are appreciated. Other authors have highlighted the impor- tance of intensity, duration and frequency of a nature-based activity as being of relevance (e.g. Marselle et  al. 2016). Mediators/Pathways: Mental, Emotional, Spiritual, Place, Social  – Hartig et  al. (2014) posited several mediators or pathways through which nature might affect health. Based on the literature around spiritual well-being as an outcome, we have made modifications to their model: excluding physical activity and air quality; pars- ing stress into subcomponents of mental restoration and positive emotions. This latter change enables greater specificity in accommodating aspects of the nature experience associated with spiritual well-being. Heintzman (2009) proposes spiri- tual experiences as a short-term outcome, but other authors suggest that these expe- riences are what produce spiritual well-being which has informed our placement of spiritual experiences as a mediator. Heintzman also identifies place processes as important; here we subsume them under sense of place, including identification with, and attachment to, special places but also the sacred dimension of place that is clearly relevant (see Sects. 10.3.1 and 10.3.2). Social aspects of nature experiences have also been recognised as important by many authors, however measurement of relevant constructs is complicated. Heintzman’s description of the literature and others’ qualitative findings suggest that social cohesion is potentially critical for the development of spiritual well-being. Outcome: Spiritual Well-being  – Here we follow the synthesis presented in Sect. 10.2 and Table  10.1 that someone who has spiritual well-being has significant ben- eficial relationships with self, others, the environment and some type of transcen- dent Other(s) that confer wholeness. In Fig.  10.2 we identify possible constructs to measure as part of spiritual well-being. In putting forth this model, we recognise that others may suggest placement of various constructs in different positions. We emphasise, however, that this model is a set of hypotheses to be tested. We also recognise that testing them all in one study K. N. Irvine et al.