ABSTRACT
Sustaining ecosystem services is not optional; it is absolutely necessary to sustain human life on this planet. As described in Chapters 5 and 6, the collapse of civilizations in Mesopotamia and Mesoamerica can be linked to anthropogenic deforestation that exacerbated the severity of drought effects on ecosystem services (Xue et al. 1990; Zheng and Eltahir 1998; Janssen et al. 2008; Lentz and Hockaday 2009; Briant et al. 2010; Cook et al. 2012). Human history is lled with examples of social unrest, population displacement, and war resulting from food or water shortages that often are caused by human alteration of environmental conditions, as well as by insects or other natural causes (Riley 1878; Bray 1996; Diamond 1999; Acuña-Soto et al. 2002; Smith 2007; Zhang et al. 2007; Perry et al. 2008; Bora et al. 2010; Hsiang et al. 2011; see Chapter 6). In the wake of social unrest or displacement come epidemics of crowd diseases, often vectored by insects (Bray 1996; Diamond 1999; AcuñaSoto et al. 2002; Therrell et al. 2004; Brouqui 2011).
