Table S2. Coding and sources for biological traits of each taxonomic group Carabids Body size Activity length Data Continuous Ordinal, 3 Activity period Ordinal, 3 Spring breeding Nominal, 2 Carnivorous Herbivorous Omnivores Brachypterous Wing-dimorphic Nominal, 2 Nominal, 2 Nominal, 2 Nominal, 2 Nominal, 2 Macropterous Nominal, 2 Spiders Body size Activity length Data Continuous Ordinal, 3 Aridity score Continuous Shade score Continuous Ballooning Nominal, 2 Active hunter Running hunter Ambush hunter Stallking hunter Nominal, 2 Nominal, 2 Nominal, 2 Nominal, 2 Plants Height Primary life form Data Continuous Ordinal, 5 Life history Woodiness Light score Ordinal, 3 Nominal, 2 Ordinal, 6 Attribute Average body size in mm (Luff 2007) 1=short (1-3 months); 2=medium (4 months); 3=long (>5 months). Taken from Luff (2007) Main period when species is active, either foraging or breeding. 1=spring (early); 2=summer (mid); 3=autumn (late). Taken from Luff (2007) Either spring breeding or autumn breeding. Taken from Desender et al. (2010) and Ribera et al. (2001) 1=carnivore (Harvey et al. 2008; Ribera et al. 2001) 1=herbivore (Harvey et al. 2008; Ribera et al. 2001) 1=omnivore (Harvey et al. 2008; Ribera et al. 2001) 1=brachypterous species (Luff 2007, Lin et al. 2007) 1=wing dimorphic speices (Luff 2007, Lin et al. 2007) 1=macropterous species (Luff 2007, Lin et al. 2007) Attribute Female body size in mm (Roberts 1996) Number of months adult females active 1=short (35 months); 2=medium (6-7 months); 3=long (>7 months). Taken from Harvey et al. (2002) Standardised niche parameters between 0 and 1. Niche position is 0 for the species which prefer the moistest habitats and 1 for the species which prefer the driest habitats (Entling et al. 2007) Standardised niche parameters between 0 and 1. Niche position is 0 for the species which prefer the most open habitats and 1 for the species which prefer the most shaded habitats (Entling et al. 2007) 1=exact species is listed as ballooning in Bell et al. (2005) 1=active hunting strategy (Uetz et al. 1999) 1=running hunters (Uetz et al. 1999) 1=ambush hunters (Uetz et al. 1999) 1=stalking hunters (Uetz et al. 1999) Attribute Maximum plant height in cm (Hill et al. 2004) 1=Mega/meso/microphanerophyte; 2=Chamaephyte; 3=Hemicryptophyte; 4=Nonbulbous geophyte; 5=Therophyte. (Hill et al. 2004) 1=perennial; 2=biennial; 3=annual (Hill et al. 2004) 1=woody species (Hill et al. 2004) Ellenberg indicator (1-9). 1=most shade, 9=most open (Hill et al. 2004) Moisture score Ordinal, 7 Animal dispersed Wind dispersed Dispersule weight Nominal, 2 Nominal, 2 Ordinal, 7 Lateral spread Ordinal, 4 Seed bank Ordinal, 4 Ellenberg indicator (1-9). 1=most dry, 9= most wet. (Hill et al. 2004) 1=seeds dispersed by animals (Grime et al. 2007) 1=seeds dispersed by wind (Grime et al. 2007) 1=too small to be measured easily; 2=≤ 0.20 mg; 3=0.21-0.50 mg; 4=0.51-1.00 mg; 5=1.01-2.00 mg; 6=2.01-10.00 mg; 7=≥ 10 mg. (Grime et al. 2007) 1=little or no vegetative spread; 2=Tussock-forming graminoid, may slowly spread; 3=Rhizome shortly creeping; 4=Rhizome far-creeping. (Hill et al. 2004) 1=transient seed banks present during the summer and germinated synchronously in autumn; 2=transient seed banks present during winter and germinated synchronously in late winter or spring; 3=a small amount of seed persists in the soil, often for >5 years but concentrations of seed in the soil are only high after seed has just been shed; 4=there is a large bank of long persistent seeds in the soil throughout the year. (Grime et al. 2007) References Bell, J.R., Bohan, D.A., Shaw, E.M. & Weyman, G.S. (2005) Ballooning dispersal using silk: world fauna, phylogenies, genetics and models. Bulletin of Entomological Research 95, 69-114. Desender, K., Dekoninck, W., Dufrene, M. & Maes, D. (2010) Changes in the distribution of carabid beetles in Belgium revisited: Have we halted the diversity loss? Biological Conservation, 143, 1549-1557. Entling, W., Schmidt, M.H., Bacher, S., Brandl, R. & Nentwig, W. (2007) Niche properties of Central European spiders: shading, moisture and the evolution of the habitat niche. Global Ecology and Biogeography, 16, 440-448. Grime, J., Hodgson, J., Hunt, R., (2007) Comparative plant ecology: a functional approach to common British species. Castlepoint Press, Dalbeattie. Harvey, J.A., van der Putten, W.H., Turin, H., Wagenaar, R. & Bezemer, T.M. (2008) Effects of changes in plant species richness and community traits on carabid assemblages and feeding guilds. Agriculture Ecosystems & Environment, 127, 100-106. Harvey, P., Nellist, D., Telfer, M. (2002) Provisional Atlas of British Spiders (Arachnida, Araneae), vol. 1-2. Biological Records Centre, Abbots Ripton. Hill, M.O., Preston, C.D., Roy, D.B. (2004) PLANTATT - attributes of British and Irish plants: status, size, life-history, geography and habitats. Centre for Ecology & Hydrology, Abbotts Ripton. Lin, Y.C., James, R., Dolman, P.M. (2007) Conservation of heathland ground beetles (Coleoptera, Carabidae): the value of lowland coniferous plantations. Biodiversity and Conservation 16, 1337-1358. Luff, M.L. (2007) The Carabidae (Ground Beetles) of Britain and Ireland. Royal Entomological Society, St Albans. Ribera, I., Dolédec, S., Downie, I.S. & Foster, G.N. (2001) Effect of land disturbance and stress on species traits of ground beetle assemblages. Ecology, 82, 1112-1129. Roberts, M.J. (1996) Spiders of Britain and Northern Europe. HarperCollins Publishers Ltd, London. Uetz, G.W., Halaj, J., Cady, A.B. (1999) Guild structure of spiders in major crops. 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