“…Alternately, natural habitats can also have a negative impact on crop production (Zhang et al, 2007), for instance providing refugia for crop pests (Jeanneret, 2000;Roschewitz et al, 2005;Thies et al, 2005), promoting intra-guild predation amongst natural enemies (Gardiner et al, 2011), or reducing crop nutrient levels, vigor or yield (Marshall and Moonen, 2002;Kuemmel, 2003). Studies evaluating the influence of natural habitats on vineyard pest densities have shown both positive (Nicholls et al, 2001;Daane, 2010, 2011;Thomson and Hoffmann, 2013) and negative effects (Botero-Garcés and Isaacs, 2004;Sciarretta et al, 2008). While it is clear that biological control of pests is related to crop proximity to natural habitat (Kruess and Tscharntke, 1994;Bianchi et al, 2006;Chaplin-Kramer et al, 2011;Veres et al, 2013), outcomes are species specific and determined by various factors (Hunter, 2002;Fischer and Lindenmayer, 2007) including dispersal ability (Duelli and Obrist, 2003;Fahrig, 2007), functional guild (Straub and Snyder, 2006), spatial scale of analysis, , and patch size, isolation and density-area relationships (Hanski, 1998;Ricketts et al, 2001;Hambäck and Englund, 2005).…”