Organic farming, a low intensity system, may offer benefits for a range of taxa, but what affects the extent of those benefits is imperfectly understood. We explored the effects of organic farming and landscape on the activity density and species density of spiders and carabid beetles, using a large sample of paired organic and conventional farms in the UK. Spider activity density and species density were influenced by both farming system and surrounding landscape. Hunting spiders, which tend to have lower dispersal capabilities, had higher activity density, and more species were captured, on organic compared to conventional farms. There was also evidence for an interaction, as the farming system effect was particularly marked in the cropped area before harvest and was more pronounced in complex landscapes (those with little arable land). There was no evidence for any effect of farming system or landscape on web-building spiders (which include the linyphiids, many of which have high dispersal capabilities). For carabid beetles, the farming system effects were inconsistent. Before harvest, higher activity densities were observed in the crops on organic farms compared with conventional farms. After harvest, no difference was detected in the cropped area, but more carabids were captured on conventional compared to organic boundaries. Carabids were more species-dense in complex landscapes, and farming system did not affect this. There was little evidence that non-cropped habitat differences explained the farming system effects for either spiders or carabid beetles. For spiders, the farming system effects in the cropped area were probably largely attributable to differences in crop management; reduced inputs of pesticides (herbicides and insecticides) and fertilisers are possible influences, and there was some evidence for an effect of non-crop plant species richness on hunting spider activity density. The benefits of organic farming may be greatest for taxa with lower dispersal abilities generally. The evidence for interactions among landscape and farming system in their effects on spiders highlights the importance of developing strategies for managing farmland at the landscape-scale for most effective conservation of biodiversity.

Aim:To quantify avian distribution shifts and the extent of niche tracking in response to changing temperature and precipitation patterns. Location: Sweden. Methods: We used abundance monitoring data to quantify changes in bird species distributions between two time periods, 2000-02 and 2010-12. First we examined shifts at the level of whole distributions using population centroids in temperature, rainfall, altitude, latitude and longitude. We then characterized shifts in temperature and latitude at different parts of species ranges using species response curves (SRC). We accounted for yearly turnover in abundance and sampling effort, and compared the observed shifts with those expected under perfect niche tracking. Results: Most species demonstrated changes in their distributions over the last decade but not all were in response to weather. The degree to which species tracked their climatic niches and the dynamics driving these shifts varied considerably. Only 20% of species shifted in the direction expected given the temperature changes, while few showed a strong response to rainfall. Most shifts did not fully compensate for changes in temperature. Range changes were most evident at the leading edges, but there was some evidence for retractions of trailing edges. Amongst species that tracked temperature, those with southerly distributions were less successful at tracking changes than those in the north. Main conclusions: Swedish birds demonstrated highly dynamic distributions, with many rapid directional shifts occurring over the last decade. However, only a few species kept pace with observed climatic change. Species that did not track their climatic niche may be tolerant to ongoing climatic change or constrained by strong habitat requirements. We demonstrate that measuring range shifts along both environmental and geographic gradients can help disentangle drivers of distribution changes. Aim:To quantify avian distribution shifts and the extent of niche tracking in response to changing temperature and precipitation patterns. Location: Sweden. Methods: We used abundance monitoring data to quantify changes in bird species distributions between two time periods, 2000-02 and 2010-12. First we examined shifts at the level of whole distributions using population centroids in temperature, rainfall, altitude, latitude and longitude. We then characterized shifts in temperature and latitude at different parts of species ranges using species response curves (SRC). We accounted for yearly turnover in abundance and sampling effort, and compared the observed shifts with those expected under perfect niche tracking. Results: Most species demonstrated changes in their distributions over the last decade but not all were in response to weather. The degree to which species tracked their climatic niches and the dynamics driving these shifts varied considerably. Only 20% of species shifted in the direction expected given the temperature changes, while few showed a strong response to rainfall. Most shifts did not fully compensate for changes in temperature. Range changes were most evident at the leading edges, but there was some evidence for retractions of trailing edges. Amongst species that tracked temperature, those with southerly distributions were less successful at tracking changes than those in the north. Main conclusions: Swedish birds demonstrated highly dynamic distributions, with many rapid directional shifts occurring over the last decade. However, only a few species kept pace with observed climatic change. Species that did not track their climatic niche may be tolerant to ongoing climatic change or constrained by strong habitat requirements. We demonstrate that measuring range shifts along both environmental and geographic gradients can help disentangle drivers of distribution changes.