Climatic Risk Atlas of European Butterflies

Abstract

Thymelicus sylvestris (PODA, 1761) – Small Skipper Full dispersal No dispersal 2050 SEDG -979 (-7.94%) -2907 (-23.58%) BAMBU -1880 (-15.25%) -3492 (-28.32%) GRAS -2283 (-18.52%) -4097 (-33.23%) 2080 SEDG -3060 (-24.82%) -4995 (-40.51%) BAMBU -4395 (-35.65%) -6533 (-52.99%) GRAS -5406 (-43.85%) -8045 (-65.25%) Changes in climatic niche distribution (in 10’×10’ grid cells; present niche space: 12329 cells) The Small Skipper occurs in all sorts of fl ower-rich places with tall grass, such as grasslands, road verges and edges of streams. The butterfl ies are fond of visiting thistles, knapweeds and other purple or pink fl owers for their nectar. The female deposits her eggs in batches of three to twenty in the leaf-sheaths of coarse-leaved grasses. Unlike the Essex Skipper, she only uses young, green leaves. After about three weeks, the eggs hatch and the small caterpillars begin spinning a shelter straightaway in which to hibernate. Only the next spring do they begin to feed and grow. At fi rst, they only feed during the day and later also at night. They pupate in a web of loosely spun white threads. The Small Skipper is single-brooded, but the butterfl ies emerge over a long period. Present distribution can be explained by climatic variables to only a limited extent (AUC = 0.72). Climate risk category: PR. © Chris van Swaay 93 2050 2080 SEDG (B1) BAMBU (A2) GRAS (A1FI) Thymelicus sylvestris (Hesperiidae) 94 Climatic Risk Atlas of European Butterfl ies Observed species distribution (50 × 50 km² UTM grid; black circles) and modelled actual distribution of climatic niche (orange areas) Multidimensional climatic niche. Occurrence probability defined by accumulated growing degree days until August (Gdd) and soil water content (Swc) for combinations of minimum, lower tercile, upper tercile and maximum values of annual temperature range and annual precipitation range. Climatic conditions: orange – unsuitable; green – hostile; black line – modelled threshold Thymelicus acteon (ROTTEMBURGER, 1775) – Lulworth Skipper Full dispersal No dispersal 2050 SEDG 222 (2.27%) -1744 (-17.79%) BAMBU -456 (-4.65%) -2089 (-21.31%) GRAS -445 (-4.54%) -2359 (-24.07%) 2080 SEDG -827 (-8.44%) -2875 (-29.33%) BAMBU -2148 (-21.92%) -4352 (-44.4%) GRAS -2860 (-29.18%) -5473 (-55.84%) Changes in climatic niche distribution (in 10’×10’ grid cells; present niche space: 9801 cells) The Lulworth Skipper can be found on warm, dry grassland, with bushes or scrub nearby, or at the edge of woodland. In the north of its range, it is mostly found on calcareous grassland. Eggs are laid on the withered leaves of many grasses. Directly after hatching, the small caterpillar spins itself a cocoon in which to hibernate. It does not begin to eat and grow until the following spring. It then builds itself a shelter by spinning blades of grass together, which it only leaves when looking for food. When fully grown, it pupates, changing into a green pupa suspended in the vegetation by a silken girdle. The Lulworth Skipper is mostly single-brooded. Present distribution can be explained by climatic variables to a moderate extent (AUC = 0.76). Climate risk category: R. © Albert Vliegenthart 95 2050 2080 SEDG (B1) BAMBU (A2) GRAS (A1FI) Thymelicus acteon (Hesperiidae) 96 Climatic Risk Atlas of European Butterfl ies Observed species distribution (50 × 50 km² UTM grid; black circles) and modelled actual distribution of climatic niche (orange areas) Multidimensional climatic niche. Occurrence probability defined by accumulated growing degree days until August (Gdd) and soil water content (Swc) for combinations of minimum, lower tercile, upper tercile and maximum values of annual temperature range and annual precipitation range. Climatic conditions: orange – unsuitable; green – hostile; black line – modelled threshold Hesperia comma (LINNAEUS, 1758) – Silver-spotted Skipper Full dispersal No dispersal 2050 SEDG -1980 (-16.77%) -3034 (-25.7%) BAMBU -2321 (-19.66%) -3408 (-28.87%) GRAS -2913 (-24.67%) -4003 (-33.91%) 2080 SEDG -4598 (-38.95%) -6026 (-51.04%) BAMBU -5466 (-46.3%) -7294 (-61.78%) GRAS -7069 (-59.88%) -9066 (-76.79%) Changes in climatic niche distribution (in 10’×10’ grid cells; present niche space: 11806 cells) The Silver-spotted Skipper occurs on open, poor grasslands, heathlands, and on sparsely covered blown sand. The habitat varies from dry to moist, but is never rich in nutrients. However, in their search for nectar, the skippers do visit nutrient-rich areas where fl owers are growing, usually not so far from their breeding ground. Eggs are laid on various fi ne-leaved grasses, passing the winter in this stage. In the spring, the caterpillars emerge and spin a shelter from blades of grass in which they spend most of their time, usually coming out to feed at night. When fully-grown, the caterpillar spins a cocoon of silk and grass blades near the ground in which it pupates. The Silver-spotted Skipper has one generation a year. Present distribution can be explained by climatic variables to a moderate extent (AUC = 0.77). Climate risk category: HR. © Chris van Swaay 97 2050 2080 SEDG (B1) BAMBU (A2) GRAS (A1FI) Hesperia comma (Hesperiidae) 98 Climatic Risk Atlas of European Butterfl ies Observed species distribution (50 × 50 km² UTM grid; black circles) and modelled actual distribution of climatic niche (orange areas) Multidimensional climatic niche. Occurrence probability defined by accumulated growing degree days until August (Gdd) and soil water content (Swc) for combinations of minimum, lower tercile, upper tercile and maximum values of annual temperature range and annual precipitation range. Climatic conditions: orange – unsuitable; green – hostile; black line – modelled threshold Ochlodes sylvanus (ESPER, 1777) – Large Skipper Full dispersal No dispersal 2050 SEDG -726 (-3.53%) -3276 (-15.94%) BAMBU -953 (-4.64%) -3309 (-16.1%) GRAS -1398 (-6.8%) -4058 (-19.74%) 2080 SEDG -750 (-3.65%) -4881 (-23.75%) BAMBU -2082 (-10.13%) -6893 (-33.54%) GRAS -3892 (-18.94%) -9349 (-45.49%) Changes in climatic niche distribution (in 10’×10’ grid cells; present niche space: 20554 cells) The Large Skipper is found on sunny, grassy vegetation in or near woods and scrub. It often visits fl owers, and the development of some rough vegetation close to the breeding ground is thus favourable. They are especially fond of bramble blossom for nectar. The female deposits her eggs onto the blades of coarse-leaved grasses one by one. The caterpillars make a shelter by spinning blades of grass together, and pass the winter in the third larval instar. When fully grown, they also spin leaves and silk together, to form a tube-like shelter in which to pupate. The Large Skipper is single-brooded. Present distribution can be explained by climatic variables to only a limited extent (AUC = 0.75). Climate risk category: PR. © Peter Ginzinger 99 2050 2080 SEDG (B1) BAMBU (A2) GRAS (A1FI) Ochlodes sylvanus (Hesperiidae) 100 Climatic Risk Atlas of European Butterfl ies Observed species distribution (50 × 50 km² UTM grid; black circles) and modelled actual distribution of climatic niche (orange areas) Multidimensional climatic niche. Occurrence probability defined by accumulated growing degree days until August (Gdd) and soil water content (Swc) for combinations of minimum, lower tercile, upper tercile and maximum values of annual temperature range and annual precipitation range. Climatic conditions: orange – unsuitable; green – hostile; black line – modelled threshold Gegenes pumilio (HOFFMANSEGG, 1804) – Pigmy Skipper Full dispersal No dispersal 2050 SEDG -11 (-2.1%) 195 (-37.14%) BAMBU -15 (-2.86%) -201 (-38.29%) GRAS -39 (-7.43%) -239 (-45.52%) 2080 SEDG 90 (17.14%) -220 (-41.9%) BAMBU -123 (-23.43%) -342 (-65.14%) GRAS -223 (-42.48%) -420 (-80%) Changes in climatic niche distribution (in 10’×10’ grid cells; present niche space: 525 cells) The Pigmy Skipper occurs in the same types of habitat as the Mediterranean Skipper (Gegenes nostrodamus). Dry gullies, rocky slopes, sandy or stony riverbanks with sparse vegetation, dry grassland and low scrub near the coast are all places where these butterfl ies can be seen, often basking in the sun on stones and bare soil. In spring, there are fewer butterfl ies than in the summer and autumn. The larvae feed on the grasses Hyparrhenia hirta and Sorghum halepensis. The Pigmy Skipper has two to three generations a year. Present distribution can be very well explained by climatic variables (AUC = 0.96). Climate risk category: HR. © Albert Vliegenthart 101 2050 2080 SEDG (B1) BAMBU (A2) GRAS (A1FI) Gegenes pumilio (Hesperiidae) 102 Climatic Risk Atlas of European Butterfl ies Observed species distribution (50 × 50 km² UTM grid; black circles) and modelled actual distribution of climatic niche (orange areas) Multidimensional climatic niche. Occurrence probability defined by accumulated growing degree days until August (Gdd) and soil water content (Swc) for combinations of minimum, lower tercile, upper tercile and maximum values of annual temperature range and annual precipitation range. Climatic conditions: orange – unsuitable; green – hostile; black line – modelled threshold Gegenes nostrodamus (FABRICIUS, 1793) – Mediterranean Skipper Full dispersal No dispersal 2050 SEDG -628 (-51.27%) -805 (-65.71%) BAMBU -626 (-51.1%) -828 (-67.59%) GRAS -718 (-58.61%) -927 (-75.67%) 2080 SEDG -731 (-59.67%) -1005 (-82.04%) BAMBU -912 (-74.45%) -1142 (-93.22%) GRAS -1035 (-84.49%) -1216 (-99.27%) Changes in climatic niche distribution (in 10’×10’ grid cells; present niche space: 1225 cells) Like the Pigmy Skipper (G. pumilio), the Mediterranean Skipper can be found in rocky or stony places, such as dried-up riverbeds, on dry, grassy vegetation or in thickets, and low scrub along the coast. The males defend their territory perched on a stone or on the ground, returning to the same spot if disturbed. These butterfl ies fl y fast and close to the ground. The larvae feed