Page - 458 - in Biodiversity and Health in the Face of Climate Change

458 described and its conceptualisation of biodiversity and mental well-being are detailed. Analysis of these frameworks found that no single framework details both biodiversity and mental well-being. As such, the author recommends that future researchers empirically test these frameworks using biodiversity indicators in order to further delineate which of these frameworks are ‘fit for purpose’ for describing the inter-relationships between biodiversity and mental well-being. Sjerp de Vries and Robbert Snep discuss methodological issues for consider- ation in future biodiversity–mental health research studies. The authors point out that within studies assessing relationships between biodiversity and mental health and well-being, the concept of biodiversity is frequently adapted from its original, ecological definition. To public health and psychology researchers, a focus on species richness may imply that having more species in a habitat is always better. However, to ecologists, this interpretation has little value as they are interested in the distinct assemblages of species, including functional characteristics, or if any key species are missing. Such adaptations to the ecological definition of biodiver- sity, the authors argue, could result in biodiversity  and mental health studies hav- ing relevance for public health and psychology, but not for nature conservation. Given that mental health promotion and nature conservation are two separate goals, the authors suggest that a more relevant research question is: can the same environment constitute a healthy, biodiverse ecosystem and enhance mental health at the same time? Suggestions are presented for future biodiversity and mental health research, with guidance for epidemiological studies assessing biodiversity in and around the residential environment on mental health and well-being. The authors recommend that future research studies should focus not on biodiversity per se, but on healthy biodiverse ecosystems that help keep people mentally healthy. Melissa Marselle and co-authors provide a comprehensive review of the scien- tific literature investigating the influence of biodiversity on mental health and well- being. The authors present a synthesis of 24 biodiversity and mental health and well-being studies. There is some evidence to suggest that biodiversity promotes better mental health and well-being, although more studies show a non-significant effect. Due to the heterogeneity in the studies, the authors examine the pattern of results in the 24 studies by level of biodiversity (from ecosystems/habitats to single species levels), which taxonomic groups are assessed (e.g. birds, trees) and mental health or well-being outcome variables. In this way, the authors identify at which level of biodiversity, group and outcome variable non-significant effects are found. Consistent non-significant relationships were only found at the ecosystem/habitat level with mental health outcomes, as most of the other results were mixed. Clear gaps in the research were also found, as none of the 24 studies investigated the effect of perceived species richness on mental health. The researchers make several rec- ommendations for future biodiversity and mental health and well-being studies with regard to improved, theoretically-grounded research designs, measurements of bio- diversity and mental health and well-being,  and investigation of mediators and dose-response relationships. M. R. Marselle et al.