Page - 190 - in Biodiversity and Health in the Face of Climate Change

190 9.3.1.2 Participants The number of participants varied considerably among the recently published stud- ies: ranging from 35 (Johansson et  al. 2014) through to the millions (with the use of data from the national census, Wheeler et  al. 2015). Participant type also differed, including university students (Cracknell et  al. 2016, 2017; Saw et  al. 2015) and staff (Johansson et  al. 2014), adults participating over the internet (White et  al. 2017; Wolf et  al. 2017), group walkers over the age of 55 (Marselle et  al. 2015; Marselle et  al. 2016), park users (Carrus et  al. 2015), visitors to forests (Foo 2016), and resi- dents of specific countries or regions as previously detailed (Annerstedt van den Bosch 2015; Cox et  al. 2017; Duarte-Tagles et  al. 2015; Jones 2017; Rantakokko et  al. 2018; Wheeler et  al. 2015). 9.3.1.3 Theoretical Position Where articulated, the theoretical underpinnings largely reflected the dominant understandings of environment-health linkages (for further discussion on biodiver- sity and health theories, see Marselle Chap. 7, this volume). Specifically, 9 studies (Annerstedt van den Bosch, et  al. 2015; Cox et  al. 2017; Cracknell et  al. 2016, 2017; Foo 2016; Marselle et  al. 2015, 2016; Saw et  al. 2015; White et  al. 2017) used the Attention Restoration Theory (Kaplan and Kaplan 1989; Kaplan 1995) and the Stress Reduction Theory (Ulrich 1983; Ulrich et  al. 1991) to explain the effects of biodiversity on mental health and/or well-being. Additionally, the Biophilia hypoth- esis (Kellert and Wilson 1993) was also mentioned (Annerstedt van den Bosch et  al. Experimental Quasi-experimental Natural experiment Longitudinal (cohort) Repeated measures Cross-sectional 0 2 4 Number of studies 6 8 Fig. 9.2 Type of study design used to examine biodiversity and mental health and well-being relationships across the 16 studies published after 2012 M. R. Marselle et al.