Biodiversity and the mitigation of climate change through bioenergy: impacts of increased maize cultivation on farmland wildlife

Abstract

The public promotion of renewable energies is expected to increase the number of biogas plants and stimulate energy crops cultivation (e.g. maize) in Germany. In order to assess the indirect effects of the resulting land-use changes on biodiversity, we developed six land-use scenarios and simulated the responses of six farmland wildlife species with the spatially explicit agent-based model system ALMaSS. The scenarios differed in composition and spatial configuration of arable crops. We implemented scenarios where maize for energy production replaced 15% and 30% of the area covered by other cash crops. Biogas maize farms were either randomly distributed or located within small or large aggregation clusters. The animal species investigated were skylark (Alauda arvensis), grey partridge (Perdix perdix), European brown hare (Lepus europaeus), field vole (Microtus agrestis), a linyphiid spider (Erigone atra) and a carabid beetle (Bembidion lampros). The changes in crop composition had a negative effect on the population sizes of skylark, partridge and hare and a positive effect on the population sizes of spider and beetle and no effect on the population size of vole. An aggregated cultivation of maize amplified these effects for skylark. Species responses to changes in the crop composition were consistent across three differently structured landscapes. Our work suggests that with the compliance to some recommendations, negative effects of biogas-related land-use change on the populations of the six representative farmland species can largely be avoided.

To integrate or to segregate food crop and energy crop cultivation at the landscape scale? Perspectives on biodiversity conservation in agriculture in Europe

“…plant protection and fertilisation). Therefore, such systems do not improve the conditions for farmland biodiversity but could rather aggravate the situation with covering a high proportion of the UAA [17]. Oilseed rape, as a mass flowering crop, can provide food resources for pollinating insects but only during a limited period of the year [69].…”

“…[14,15]). A number of spatially explicit modelling studies have also emerged to evaluate the biodiversity responses from energy crop production at regional, national and pan-national scales, maize in particular [16][17][18][19], some of which considered land-use change scenarios involving energy crop cultivation on marginal land of high nature value [20,21]. In addition, many field-scale or empirical studies with a focus on a particular energy crop have been conducted to compare biodiversity impacts with those of row crops or grasslands [22][23][24].…”

Interpreting outputs of agent-based models using abundance–occupancy relationships

“…The underlying cause of the increase in skylark numbers with landscape fragmentation was the temporal variation in food availability. With small fields, there was a higher diversity of vegetation types within the home range of the skylarks, and hence better foraging opportunities for birds while incubating and raising chicks; but this is only the case, when a variety of crops are grown in the fields (Gevers et al, 2011;Topping and Odderskaer, 2004), hence the reversal of the effect of landscape structure with the CROP scenario. Such effects can also be seen in real world studies.…”

Modelling farmer decision-making to anticipate tradeoffs between provisioning ecosystem services and biodiversity

“…However, while the number of skylarks is the highest until 2035 compared with the other scenarios, a sharp decrease was observed afterwards that can be explained by the large expansion of bioenergy cropping occurring in this scenario. Other simulation studies based on LUCC scenarios have shown the negative impact of bioenergy crops on wildlife at different spatial levels (Eggers et al, 2009;Gevers et al, 2011). In the latter study, an individual based model of skylark was used and the effect of land use scenarios was analysed.…”