<p> 1/40 1 Supplementary material Appendix A: characteristics of the sample sites</p><p>2 Elevation (in meters), GPS coordinates, pitfall activity (in days), year of sampling, mean canopy index (from 0 = absence to 2 = dense), </p><p>3 general exposure (F = Favorable, mostly southern exposure and U = Unfavorable, mostly northern exposure), annual mean temperature (°C), </p><p>4 annual precipitation (mm), main characteristics (vegetation, dominant species of shrubs or trees) and pictures illustrating some of the 20 sites in </p><p>5 the two Pyrenean valleys in which ants were sampled (9 sites in the Madriu valley and 11 sites in the Pique valley).</p><p>6 Annual mean temperature and annual precipitation were obtained from the WorldClim 1.4 database. </p><p>7 ABAL = Abies alba, ARUV = Arctostaphylos uva-ursi, BEPE = Betula pendula, COAV = Corylus avellana, FASY = Fagus sylvatica, PIMU = </p><p>8 Pinus mugo, PISY = Pinus sylvestris, RHFE = Rhododendron ferrugineum.</p><p>9</p><p>10 Valleys Alt. (m) GPS coordinates Pitfall activity Year Canopy index Exposure Temperature (°C) Precipitation (mm) Dominant vegetation 11 12 Madriu valley 1351 42° 30‘ 1” N, 1° 33‘ 1” E 7 2006 0.80 F 7.5 1037 Grassland with COAV and BEPE 13 1471 42° 29‘ 5” N, 1° 33‘ 3” E 7 2005 0.90 F 6.4 1102 Grassland with COAV 14 1612 42° 29‘ 4“ N, 1° 34‘ 1“ E 8 2005 0.00 F 5.7 1145 Grassland 15 1941 42° 29‘ 2“ N, 1° 35‘ 4“ E 6 2005 0.90 U 3.9 1263 Forest with BEPE and ABAL 16 2036 42° 29‘ 4“ N, 1° 35‘ 3“ E 6 2005 0.20 F 3.4 1294 Scree with ARUV, PIMU and PISY 17 2067 42° 29‘ 1“ N, 1° 34‘ 6“ E 6 2006 1.20 U 3.2 1308 Forest with RHFE, PIMU and ABAL 18 2280 42° 28‘ 5“ N, 1° 38‘ 2“ E 5 2005 0.35 F 2.6 1350 Grassland with RHFE and PIMU 19 2280 42° 28‘ 2“ N, 1° 34‘ 4“ E 5 2005 0.25 F 2.8 1334 Grassland with PIMU 20 2339 42° 29‘ 3“ N, 1° 34‘ 5“ E 5 2005 0.00 F 3.1 1318 Grassland with PIMU 21 22 23 Pique valley 1009 42° 44‘ 1" N, 0° 37‘ 2" E 7 2007 1.10 F 8.6 1027 Grassland with COAV 24 1044 42° 44‘ 4" N, 0° 37‘ 2" E 6 2007 1.85 U 8.6 1027 Forest with FASY and ABAL 25 1124 42° 44‘ 2" N, 0° 37‘ 1" E 6 2007 1.70 U 8.6 1027 Forest with FASY 26 1422 42° 43‘ 0" N, 0° 39‘ 0" E 6 2007 1.10 F 6.5 1124 Grassland with FASY and ABAL 27 1426 42° 43‘ 2" N, 0° 39‘ 1" E 6 2007 0.75 F 6.5 1124 Grassland with FASY and ABAL 28 1544 42° 43‘ 0" N, 0° 38‘ 2" E 6 2007 1.00 U 6.6 1114 Grassland with FASY and ABAL 29 1641 42° 44‘ 0" N, 0° 38‘ 3" E 6 2007 1.30 F 5.8 1159 Grassland with FASY and ABAL 30 1922 42° 42‘ 3" N, 0° 39‘ 3" E 6 2007 0.05 U 5.7 1165 Grassland with RHFE 31 1997 42° 43‘ 2" N, 0° 40‘ 2" E 7 2007 0.00 F 3.4 1294 Grassland 32 2283 42° 41‘ 3" N, 0° 39‘ 4" E 6 2007 0.00 F 2.7 1337 Grassland and scree 33 2299 42° 41‘ 3" N, 0° 40‘ 0" E 6 2007 0.00 F 2.5 1348 Grassland and scree 34 2/40 35 Madriu valley</p><p>36</p><p>37</p><p>38 Pique valley</p><p>39 3/40</p><p>40 Supplementary material Appendix B: Results obtained with the different sampling methods</p><p>41 Ant species richness (S), number of species occurrences, Simpson’s index of diversity (1-D) and </p><p>42 species richness estimators (ICE = Incidence-based coverage estimator, Chao2, Jack2 = 2nd order </p><p>43 jackknife) for both sampling methods used (pitfalls and hand collection) for the different transects of the</p><p>44 two Pyrenean valleys sampled. The means (±SD) correspond to the means of the three species richness </p><p>45 estimators with their standard deviation. The percentage indicates the percentage of ant species collected</p><p>46 (compared to the maximum number of species predicted by the 3 species richness estimators) in the </p><p>47 different transects.</p><p>48</p><p>49 50 Pitfalls 51 52 Valleys Alt. (m) S Occurrences 1-D ICE Chao2 ± SD Jack2 Mean ± SD % 53 54 Madriu valley 37 386 0.94 50.60 69.82 ± 26.35 59.82 60.08 ± 9.61 61.58 55 1351 21 85 0.91 32.27 32.40 ± 10.27 35.94 33.54 ± 2.08 62.62 56 1471 14 68 0.88 14.92 14.32 ± 0.89 15.99 15.08 ± 0.85 92.86 57 1612 11 73 0.84 13.28 12.43 ± 2.48 15.70 13.80 ± 1.70 79.69 58 1941 7 28 0.71 8.63 7.32 ± 0.89 8.99 8.31 ± 0.88 84.20 59 2036 10 33 0.76 17.71 13.17 ± 3.94 17.54 16.14 ± 2.57 61.96 60 2067 5 31 0.73 5.00 5.00 ± 0.10 4.15 4.72 ± 0.49 100.0 61 2280 6 38 0.75 6.46 6.00 ± 0.43 7.85 6.77 ± 0.96 88.63 62 2280 6 20 0.74 7.81 6.48 ± 1.24 8.85 7.71 ± 1.19 77.79 63 2339 1 10 0.00 1.00 1.00 ± 0.01 1.00 1.00 ± 0.00 100.0 64 65 66 Pique valley 25 256 0.91 26.54 25.60 ± 1.18 27.01 26.38 ± 0.72 94.76 67 1009 10 25 0.86 12.05 10.71 ± 1.37 12.99 11.92 ± 1.15 83.92 68 1044 3 7 0.57 3.73 3.00 ± 0.24 4.00 3.58 ± 0.52 83.88 69 1124 8 15 0.78 19.80 11.17 ± 3.94 15.54 15.50 ± 4.32 51.60 70 1422 9 19 0.86 10.69 9.95 ± 1.74 12.84 11.16 ± 1.50 80.65 71 1426 8 21 0.77 17.34 17.50 ± 9.63 17.25 17.36 ± 0.13 46.07 72 1544 6 16 0.78 7.16 6.95 ± 2.12 9.70 7.94 ± 1.53 75.60 73 1641 5 18 0.62 7.84 5.48 ± 1.24 7.85 7.06 ± 1.37 70.85 74 1922 9 48 0.84 9.89 9.95 ± 2.16 12.70 10.85 ± 1.61 82.97 75 1997 4 29 0.57 4.62 4.00 ± 0.41 5.85 4.82 ± 0.94 82.93 76 2283 6 30 0.64 10.75 8.85 ± 4.21 11.55 10.38 ± 1.39 57.78 77 2299 4 28 0.57 5.23 4.00 ± 0.24 5.00 4.74 ± 0.65 84.33 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 4/40</p><p>97 Hand collection 98 99 Valleys Alt. (m) S Occurrences 1-D ICE Chao2 ± SD Jack2 Mean ± SD % 100 101 Madriu valley 35 264 0.93 39.65 38.48 ± 3.65 43.97 40.70 ± 2.89 86.00 102 1351 23 63 0.92 33.82 27.89 ± 4.45 34.53 32.08 ± 3.65 71.70 103 1471 16 54 0.90 20.34 18.38 ± 3.02 22.69 20.47 ± 2.16 78.16 104 1612 9 40 0.78 11.50 10.43 ± 2.48 13.70 11.88 ± 1.67 75.78 105 1941 5 21 0.72 5.55 5.00 ± 0.24 6.00 5.52 ± 0.50 90.63 106 2036 7 22 0.71 11.74 7.95 ± 1.74 10.84 10.18 ± 1.98 68.78 107 2067 5 16 0.67 5.88 5.00 ± 0.16 5.14 5.34 ± 0.47 93.63 108 2280 5 18 0.74 5.45 5.00 ± 0.42 6.85 5.77 ± 0.96 86.71 109 2280 5 19 0.63 9.47 7.85 ± 4.18 10.55 9.29 ± 1.36 53.82 110 2339 2 11 0.16 3.10 2.00 ± 0.34 3.85 2.98 ± 0.93 67.04 111 112 113 Pique valley 26 240 0.91 30.4 33.47 ± 8.15 36.93 33.60 ± 3.27 77.38 114 1009 12 37 0.87 16.79 15.17 ± 3.94 19.54 17.17 ± 2.21 69.90 115 1044 5 10 0.72 9.29 7.85 ± 4.18 10.55 9.23 ± 1.35 54.17 116 1124 6 8 0.81 12.00 7.9 ± 2.76 11.69 10.53 ± 2.28 56.98 117 1422 8 20 0.84 9.09 8.32 ± 0.89 9.99 9.13 ± 0.84 87.59 118 1426 11 32 0.86 14.29 13.85 ± 3.99 17.55 15.23 ± 2.02 72.23 119 1544 6 12 0.79 7.39 6.24 ± 0.71 7.14 6.92 ± 0.60 86.66 120 1641 4 11 0.64 6.13 4.95 ± 2.07 7.70 6.26 ± 1.38 63.90 121 1922 9 47 0.78 16.61 11.85 ± 3.99 15.55 14.67 ± 2.50 61.35 122 1997 4 13 0.56 5.10 4.00 ± 0.16 4.14 4.41 ± 0.60 90.63 123 2283 5 29 0.63 5.50 5.00 ± 0.42 6.85 5.78 ± 0.96 86.46 124 2299 3 21 0.32 3.00 3.00 ± 0.05 1.29 2.43 ± 0.99 100.0 5/40 125 Supplementary material Appendix C: Sampling site dissimilarity matrix</p><p>126 Sampling site dissimilarity matrix computed with the Bray–Curtis distance index on the matrix of species presence/absence. The first </p><p>127 letter of the site label indicates the valley in which the transect was located (M for Madriu, P for Pique) and the four digits that follow the </p><p>128 elevation of the transect.</p><p>129 130 Sites M-1351 M-1471 M-1612 M-1941 M-2036 M-2067 M-2280 M-2280 M-2339 P-1009 P-1044 P-1124 P-1422 P-1426 P-1544 P-1641 P-1922 P-1997 P-2283 131 132 M-1471 0.37 133 134 M-1612 0.51 0.29 135 136 M-1941 0.81 0.83 0.79 137 138 M-2036 0.53 0.52 0.60 0.80 139 140 M-2067 0.87 1.00 1.00 0.33 0.78 141 142 M-2280 0.94 0.91 0.89 0.29 0.80 0.50 143 144 M-2280 0.81 0.91 0.89 0.43 0.60 0.33 0.29 145 146 M-2339 0.93 0.89 0.86 0.56 0.87 0.71 0.56 0.56 147 148 P-1009 0.49 0.47 0.62 0.90 0.56 1.00 0.90 0.90 0.88 149 150 P-1044 0.67 0.81 0.88 1.00 0.78 0.80 1.00 0.83 1.00 0.79 151 P-1124 0.65 0.76 0.81 0.88 0.73 0.86 0.88 0.88 1.00 0.48 0.57 152 P-1422 0.54 0.54 0.55 0.88 0.57 1.00 0.88 0.88 0.83 0.33 0.73 0.37 153 P-1426 0.53 0.59 0.68 0.80 0.62 0.89 0.80 0.80 0.87 0.41 0.67 0.550.39 154 P-1544 0.81 0.82 0.78 0.54 0.89 0.64 0.54 0.69 0.75 0.70 0.82 0.600.63 0.68 155 P-1641 0.67 0.71 0.65 0.83 0.78 0.80 1.00 0.83 1.00 0.68 0.60 0.710.60 0.67 0.45 156 P-1922 0.71 0.85 0.82 0.41 0.74 0.47 0.29 0.41 0.67 0.75 0.73 0.680.60 0.65 0.38 0.60 157 P-1997 0.93 0.90 0.88 0.45 0.88 0.56 0.27 0.45 0.33 0.89 1.00 1.000.86 0.88 0.80 1.00 0.57 158 P-2283 0.87 0.91 0.89 0.38 0.79 0.27 0.23 0.23 0.50 0.90 0.82 0.870.88 0.79 0.67 0.82 0.38 0.20 159 P-2299 0.93 1.00 1.00 0.64 0.88 0.33 0.45 0.45 0.67 1.00 0.78 1.001.00 0.88 0.80 0.78 0.57 0.25 0.20 160 6/40 161 Supplementary material Appendix D: Results of generalized linear models</p><p>162 Results of generalized linear models used to examine the relationships between ant species richness and temperature (T°C), exposure </p><p>163 (EFavorable/Unfavorable) and mean canopy index (MCI) in the two Pyrenean valleys (VMadriu/Pique) in which ants were sampled. These models were fitted </p><p>164 with a Poisson distribution. Five different candidate models, using different combinations of independent variables and interactions were tested </p><p>165 (for further details, see data analysis). For each model, the coefficients of each factor are reported in the table (coefficients in bold are significant </p><p>166 at P < 0.05). </p><p>167</p><p>Model 2 2 description Intercept (T°C) T°C EF MCI VP (T°C) x VP T°C x VP Species richness </p><p>1) T°C + V M/P 2.48 0.28 -0.54 -0.17 + T°C x VM/P 2) (T°C)2 + T°C + VM/P + 2 2.36 0.03 0.29 -0.32 -0.05 -0.14 (T°C) x VM/P + T°C x VM/P 3) E + MCI F/U 1.96 0.55 0.41 -0.36 + VM/P 4) T°C + EF/U + MCI + VM/P 2.22 0.29 0.26 -0.25 -0.49 -0.08 + T°C x VM/P 5) (T°C)2 + T°C + EF/U + MCI + VM/P + 2.11 0.03 0.30 0.24 -0.27 -0.28 -0.05 -0.05 2 (T°C) x VM/P + T°C x VM/P</p><p>168 7/40 169</p>