We aimed at assessing establishment risk for 25 arable weed species in a changing European climate for the period 2051-2080. An increase (0.3-46.7%) in the range size was projected for the 14 species and a decrease (1.2-67.4%) for the 11 species in a future climate. The inclusion of the land use data increased the explanatory power of the models. The greatest increases in range sizes were projected for Amaranthus retroflexus, Papaver hybridum and Fumaria parviflora, and declines for Sinapis arvensis, Cerastium semidecandrum and Chenopodium rubrum. Application of a more severe climate scenario (HadCM3A2) affected decline (0.5-18.5%) for 12 species and increase (2.2-31.5%) for 13 species in the range size projections compared with the less severe (HadCM3B2) scenario. Both model scenarios projected high percentage species loss in Mediterranean and temperate Europe, but high species gain in the Alps, Carpathians and in boreal Europe. The results suggest that even under moderate climate scenarios drastic changes in the weed establishment risk can be expected to take place in Europe in future.Key words: arable weed, climate change, climate envelope modelling, global warming
IntroductionAdaptation of agricultural production to climate change requires information on the future risks faced by production systems. One of the risks for cropping systems is a range expansion of arable weeds (e.g. Patterson 1995, McDonald et al. 2009). The first step in the risk assessment of weed range expansion is predicting the probability of successful establishment of weed species by matching climate data.The response of plants to climate change varies among species, depending on adaptation to specific climate conditions. Species adapted strictly to certain climate conditions may lose those conditions and face increase in extinction risk in a changing climate (Root et al. 2003, Thuiller et al. 2005. In contrast, species most likely to benefit from climate change in terms of extending range sizes are those with distributions independent of specific climate conditions and land use patterns (Hyvönen et al. 2011). Weed species are typically effective in dispersal and can maintain marginal populations outside their main ranges, i.e., they occur as casual aliens (see Richardson et al. 2000). Climate change could facilitate the establishment of such populations and thus extension of species range into new climate zones.The south-north climate gradient in Europe comprises the Mediterranean, temperate, boreal and arctic zones. Arable weed species richness declines from south to north along this gradient (Holzner and Immonen 1982, Glemnitz et al. 2006). The same pattern occurs for several noxious weed species (Schroeder et al. 1993, Milberg and Andersson 2006, Hyvönen et al. 2011, which are of particular interest from a weed management perspective, although the distribution of most harmful weed species is practically ubiquitous in Europe (Glemnitz et al. 2006). Projections for the range shifts of European plant species due to climate change have in...