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24Some environmental variables and above-ground vegetation, seed rain, ant-borne seeds and 25 seed banks were studied on three abandoned fields, at the margins between these fields and a 26 remnant patch of a native steppe vegetation of a high value for nature and species 27 conservation. While the fields were the same size, were adjacent to the same patch of 28 remnant steppe and were cultivated with the same crop, site-specific environmental variables 29 contributed to 23% of the vegetation patterns; each site was characterised by its unique 30 historical trajectory and thus, by a particular set of species. Distance from boundaries 31 contributed to 10% of the vegetation patterns. Species characterising the surrounding steppe 32were found close to boundaries; species characterising abandoned fields were found further 33 away. Winter seed banks and summer deep seed bank did not contribute much to either effect 34 and were characterised by species dating back from past cultivation. Conversely, summer 35 surface seed bank greatly contributed to (83%) the differences in species composition 36 between the three fields. Seed rain contributed to differences in species composition between 37 fields (91%) and distance (76%). Ant-borne seeds largely contributed to the differences 38 between fields (87%).

Abstract. We present here a comparison between the outputs of a set of 25 climate models run for the mid-Holocene period (6 ka BP) with a set of palaeo-climate reconstructions from over 400 fossil pollen sequences distributed across the European continent. Three climate parameters were available (moisture availability, temperature of the coldest month and growing degree days), which were then grouped together using cluster analysis to provide regions of homogenous climate change. Each model was then investigated to see if it reproduced 1) the same directions of change and 2) the correct location of these regions. A fuzzy logic distance was used to compare the output of the model with the data, which allowed uncertainties from both the model and data to be taken into account. The initial comparison showed that the models were only capable of reproducing regions of little climate change, as the data-based reconstructions have a much larger range of changes due to their local nature. A correction for the model standard deviation was then applied to allow the comparison to proceed, and this second test shows that the majority of models simulate all the observed patterns of climatic change, although most do not simulate the observed magnitude of change. The models were then compared by distance to data, and by the amount of correction required. The majority of the models are grouped together both in distance and correction, suggesting that they are becoming more consistent. A test against a set of zero anomalies (no climate change) shows that, whilst the models are unable to reproduce the exact patterns of change, they all produce the correct direction of change for the mid-Holocene.

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