POLLINATORS POLLINATION AND FOOD PRODUCTION

THE ASSESSMENT REPORT ON POLLINATORS, POLLINATION AND FOOD PRODUCTION
FIGURE 2.6.1
Climate change risk categories of European bumble bees and butterflies (assuming full dispersal and no dispersal; see text in Box
2.6.1 for definition of categories and scenarios).
Under the extreme, no dispersal GRAS scenario for bumble bees and butterflies (years 2100 and 2080, respectively) 16% (9 species)
of the modelled European bumble bees and 24% (59 species) of the analysed butterflies are projected to be at an extremely high
climatic risk, 29% (16 spp.) and 16% (39 spp.) will be at very high risk, 46% (26 spp.) and 30% (74 spp.) are at high risk, 5% (3 spp.)
and 24% (58 spp.) are at risk, and only 2% (1 sp.) and 6% (14 spp.) are at low risk.
Because bumble bees are mainly better adapted to colder conditions, they show a higher degree of vulnerability to climate change
than butterflies: only 7% of bumble bees compared to 30% of butterflies were categorized as R or LR. In addition to the projections of
the modelled bumble bee and butterfly species, species that were not modelled due to data limitations are all very rare and localized
in distribution and so their ranges are very likely to shrink considerably in any global change situations. Only a limited number of
species are projected to benefit from climate change under a full dispersal assumption (and given there are adequate floral or larval
resources) and can potentially enlarge their current distributions in Europe: among the bumble bees there are only 7% (4 species),
including Bombus zonatus (see Figure 2.6.2), while 18% (43 species) of butterflies could potentially profit, including Apatura metis
(see Figure 2.6.2).
Note: Contrary to the mostly cold-adapted bumble bees, many more solitary bees might benefit in a way similar to B. zonatus, as they
are more frequently adapted to drier and warmer climates and thus show higher diversity in, for example, the Mediterranean regions.
As could be expected, the three scenarios considered provide considerably different projections for 2080 and 2100, respectively. While
under the moderate change scenario (SEDG) only 8 butterfly and no bumble bee species are projected to be at the verge of extinction,
26 butterflies and 6 bumble bees are at this particular high risk under the intermediate change scenario (BAMBU). Under the most
severe change scenario (GRAS) 59 butterflies and 9 bumble bees are projected to lose almost all of their climatically suitable area.
Full dispersal
No dispersal
(a) Bumble bees
(b) Butterflies
(c) Bumble bees
(d) Butterflies
1a 1.8
1b 2.5
1c 0.0
1d
3.3
0.0
3.6
1.6
2.9
10.9
5.5
9.8
10.7
12.7
30.3
25.5
34.6
(1) SEDG
42.6
14.3
58.2
52.1
47.3
29.9
2a 1.8
2b 3.3 2c 1.8
2d
4.5
7.3 7.3
4.1
10.9
10.7
18.0
20.5
9.1
10.9
30.9
13.1
16.0
(2) BAMBU
43.6
99
2. DRIVERS OF CHANGE OF POLLINATORS,
POLLINATION NETWORKS AND POLLINATION
43.6
57.0
32.7
37.7
15.2
(3) GRAS
3a 3.6
3b 3c 1.8
3d
1.6
3.6
7.3
5.7
7.3
5.5
17.6 6.2
16.4
23.8
21.8
22.5
5.7
24.2
47.3
29.1
16.0
56.4
46.3
30.3
HHHR: extremely high climate change 10 risk: loss of > 95% of grid cells
HHR: very high climate change risk: loss of > 85 to 95 % of grid cells
HR: high climate change risk: loss of > 70 up to 85 % of grid cells
R: climate change risk: loss of > 50 up12 to 70 % of grid cells
LR: lower climate change risk: loss of ≤ 50 % of grid cells
LR increasing: lower climate change risk with net gain of grid cells
under full dispersal