Page - 203 - in Biodiversity and Health in the Face of Climate Change

203 White et  al. (2017) found that greater perceived species richness of animals/plants was associated with more positive mood, arousal and recovery. Dallimer et  al. (2012) found positive associations between perceived species richness of birds, but- terflies and plants/trees and psychological  well-being (measured as reflection, con- tinuity with the past and attachment). Using the same perceived species richness variables, Marselle et  al. (2015, 2016) found no associations between perceived plant/tree and butterfly species richness and emotional well-being; perceived bird species richness had no influence on positive affect and happiness but was associ- ated with an increase in negative affect (Marselle et  al. 2015). An indirect effect of perceived bird species richness on positive affect, happiness and negative affect through perceived restorativeness was also found (Marselle et  al. 2016). Bird biodi- versity was associated with greater perceived restorativeness, which was in turn associated with greater positive affect and happiness, and reduced negative affect. Abundance of  Specific Taxonomic Groups Abundance was investigated in 4 studies (see Table  9.5). One study examined the impact on mental health, with mixed results. Cox et  al. (2017) found that afternoon, but not morning, bird abundance was associated with less depression, anxiety and stress. The reason for this difference for mental health, according to Cox et  al. (2017), is that afternoon abundance is a measure of the number of birds that people are likely to experience, as opposed to a measure of the total number of birds that are actually there. Three studies investigated the influence of the abundance of spe- cific taxonomic groups on mental well-being, all with positive results. Bird abun- dance was positively associated with reflection, continuity with the past and attachment (Dallimer et  al. 2012) and life satisfaction (Luck et  al. 2011). Greater abundance of fish/crustaceans, viewed in photographs, was related to greater reported happiness, when species richness was held constant (Cracknell et  al. 2017). This suggests that it may be the quantity of fish/crustaceans, and not the number of species per se, that influences happiness. Single Species One study assessed the effect of biodiversity loss by investigating the decline of a single species, the North American ash tree following infestation by the invasive emerald ash borer, on mental health and well-being (Jones 2017). The loss of ash trees, 5  years after initial infestation, was associated with an increase in depression, as well as a decrease in life satisfaction. The results suggest the negative influence that biodiversity loss could have on mental health and well-being. 9 Review of  the  Mental Health and  Well-being Benefits of  Biodiversity