Seite - 202 - in Biodiversity and Health in the Face of Climate Change

202 green spaces had a significant direct, and indirect, effect on general well-being. Individuals in the high biodiversity condition had greater general well-being scores than individuals in the low biodiversity condition, and perceived restorativeness mediated the relationship between biodiversity and well-being (Carrus et  al. 2015). Studies assessing ecosystems/habitats by Scania Green Score ‘lush, rich in species’ (Björk et  al. 2008; de Jong et  al. 2012; Grahn and Stigsdotter 2010), protected areas (Saw et  al. 2015) and green space types (Jorgensen et  al. 2010) on mental well- being  were all non-significant. Species Richness Ten studies examined the effect of species richness (Table  9.5). Three of these inves- tigated the influence of species richness on mental health, with mixed results. Huby et  al. (2006) found positive associations between mental health and greater bird species richness. Similarly, Wolf et  al.  (2017) found that participants in the high species rich conditions of trees and birds, reported less anxiety, compared to partici- pants in the low species rich conditions. However, Cox et  al. (2017) found no influ- ence of morning and afternoon bird species richness on depression, anxiety or stress. Across the 7 studies that measured mental well-being just over half of results (55%) were non-significant. Specifically, there was no difference in positive affect and arousal between low and high species richness conditions of fish/crustaceans (Cracknell et  al. 2016). Additionally, species richness of fish/crustaceans had no effect on happiness, when species abundance was held constant (Cracknell et  al. 2017). There was also no difference in vitality scores between the high and low spe- cies richness conditions of birds and trees (Wolf et  al. 2017). However, for positive affect, participants reported higher levels in the high species richness conditions of trees, and birds, compared to low species richness conditions (Wolf et  al. 2017). Bird species richness was positively associated with good health (Wheeler et  al. 2015). However, the negative association between bird species richness and poor health did not hold when accounting for covariates (Wheeler et  al. 2015). Butterfly species richness had no significant effect (Dallimer et  al. 2012; Fuller et  al. 2007), and plant species richness had a negative effect, on psychological  well-being (Dallimer et  al. 2012). Greater species richness of birds (Dallimer et  al. 2012; Fuller et  al. 2007; Luck et  al. 2011) and plants (Fuller et  al. 2007) were both associated with greater mental well-being. Perceived Species Richness No study investigated the effect of perceived richness on mental health (see Table  9.5). Four studies examined the influence of perceived species richness  on mental well-being. Just over half of the results (53%) demonstrated a positive effect. M. R. Marselle et al.