The Influence of Local and Landscape Agricultural Intensification on Within Farm Biodiversity

Land-use change is considered the strongest driver of biodiversity. Yet, some agricultural systems can maintain high levels of biodiversity. It is therefore essential to understand which components of these farms are essential for conservation. We conducted a meta-analysis of the literature to determine the importance of local and landscape factors in promoting within farm biodiversity. We included published studies that had manipulated local management factors (e.g. organic vs. conventional) and landscape level factors (e.g. % cropland), and measured biodiversity. We hypothesized that both local and landscape scale factors would have significant beneficial effects on biodiversity within agriculture.

Preliminary results suggest that the mean log response ratio of species richness was significantly greater than zero, indicating that overall richness was higher in less intensive (organic and extensive) compared to more intensive management (conventional) types (mean = 0.34, lower 95% CI = 0.19, upper 95% CI = 0.49). Additionally, landscape effects also had a significant effect on overall richness across studies. The mean correlation coefficient for the relationship between percent non-crop area (landscape variable) and richness was greater than zero (mean = 0.210, lower 95% CI = 0.097, upper 95% CI = 0.323). Local and landscape factor effects on abundance paralleled effects on species richness; both local and landscape had significant effects on abundance. These results suggest that both local and landscape level factors are important for the conservation of biodiversity within agricultural systems.