Farming and the Fate of Wild Nature

Abstract

World food demand is expected to more than double by 2050. Decisions about how to meet this challenge will have profound effects on wild species and habitats. We show that farming is already the greatest extinction threat to birds (the best known taxon), and its adverse impacts look set to increase, especially in developing countries. Two competing solutions have been proposed: wildlife-friendly farming (which boosts densities of wild populations on farmland but may decrease agricultural yields) and land sparing (which minimizes demand for farmland by increasing yield). We present a model that identifies how to resolve the trade-off between these approaches. This shows that the best type of farming for species persistence depends on the demand for agricultural products and on how the population densities of different species on farmland change with agricultural yield. Empirical data on such density-yield functions are sparse, but evidence from a range of taxa in developing countries suggests that high-yield farming may allow more species to persist.

Understanding and monitoring the consequences of human impacts on intraspecific variation

“…Environmental change will often harm populations that are poorly suited to the new conditions, which can lead to population declines, extirpation, and extinction (e.g., Green, Cornell, Scharlemann, & Balmford, 2005; Pörtner & Knust, 2007; Thomas et al., 2004). These negative effects can be offset, in part, when diversity within and among populations can help to buffer these problems through the so‐called portfolio effect (Leimu, Vergeer, Angeloni, & Ouborg, 2010; Moore, Yeakel, Peard, Lough, & Beere, 2014; Schindler, Armstrong, & Reed, 2015; Schindler et al., 2010).…”

Problem formulation and hypothesis testing for environmental risk assessments of genetically modified crops

“…The observed reductions in arable weed populations in some GMHT crops were considered detrimental effects, because weeds were considered to be valuable biodiversity (e.g., Giles, 2003). However, weed control is an intended effect of agriculture, and under some scenarios it can increase biodiversity (Green et al, 2005) hence confusion over whether weed populations should be protected. A similar confusion occurs over whether the reduction of predators and parasitoids associated with the intended reduction in abundance of the target insect pests of GM crops should be regarded as harm (Groot and Dicke, 2001).…”

Trade-offs between pasture production and farmland bird conservation: exploration of options using a dynamic farm model

“…Green et al (2005) proposed a conceptual model focussed on the trade-off between production and biodiversity in agro-landscapes managed with different strategies of spatial allocation of land use. In their model, the performance of a landscape composed of two management regimes was the average of the two regimes, thus assuming a linear effect of the proportion of land use and the absence of interaction.…”