Seite - 71 - in Biodiversity and Health in the Face of Climate Change

71 development through direct medical costs and indirect costs such as loss of produc- tivity and tourism (Narrod et  al. 2012). Epidemiological dynamics of VBDs are complex interactions of the vector, the pathogen and the host (Fig.  4.2). VBDs are clearly highly intertwined with climatic change and the degree of biodiversity (Engering et  al. 2013). In addition to tempera- ture alterations and rainfall changes, among other factors, heterogeneity of landscapes (Chaves et  al. 2011), urbanisation (Wood et  al. 2017) and local forest degradation (Brownstein et  al. 2005) are extrinsic factors determining VBD risk or burden. In this chapter, we show how climate change impacts VBDs and what role biodi- versity (and its loss) plays for VBDs. (1) We show how climatic changes shape the distribution and abundance of disease vectors. To point out current triple vulnerabil- ities regarding climate change, biodiversity and VBDs, we selected ticks and mos- quitoes as examples. (2) We point out important knowledge gaps on VBDs and biodiversity, which make prognoses for climate change challenging. (3) We review policy options to manage VBDs under climate and biodiversity changes and related infrastructural responses. 4.2 Disease-Transmitting Mosquitoes and  Ticks Due to global change, vector species may expand their distributions (Ogden et  al. 2006; Gould and Higgs 2009) and shift their seasonal and spatial occurrences (Lafferty 2009), the latter particularly to higher latitudes and altitudes (Siraj et  al. 2014; Dhimal et  al. 2014a, b, 2015). This leads to increased species richness, e.g. a higher biodiversity of the vector species and pathogens at time of arrival in newly invaded regions. However, invasive species show a tendency to successfully estab- lish in a new environment and outcompete native species sharing the same ecologi- cal niche. Thus, biodiversity can even decrease rather than increase under certain ecological conditions. Fig. 4.2 Scheme of vector-host-pathogen interactions indicating the complex interplay of public health, biodiversity and global changes 4 Vector-Borne Diseases