Elevation use over time
All bumblebees tested for elevation shift over time have significantly
changed their altitude from a given year or time range. Bombus
alpinus, mendax and mucidus have uplifted since the ‘80s and
similarly B. konradini changed sometime between the 1960s and the
1980s considering that the data are unevenly distributed in time (Figure
2, Table 4). In B. alpinus, mendax and mucidus , the year of
record was a significant predictor in the most recent time interval, but
not in the older time interval and the slopes of the regression lines at
both sides were significantly different (Table 4). In B.
konradini , the records from the 60s were significantly different in
elevation from the more recent year groups, which were not different
from each other (Table 4). The estimated elevation uplift resulted large
in all species, between ca 325 and 535 m, but it is important to note
that occasional records were present also below the calculated elevation
range and that the estimate changes depending on the chosen quartile
(Supplementary table S3). Under future scenarios, the elevational shift
is predicted to continue considerably, based on the distribution of the
suitable patches (Supplementary table s4). Hypothesis H3 was therefore
fully confirmed by the observed and predicted shifts.