Figure 3. Heatmaps and scatter plots showing the horizontal and vertical
distributions of (A) air temperature, (B) relative humidity, (C)
photosynthetic photon flux density (PPFD), (D) total leaf area, (E) ant
species abundance (ln (x+1) transformed)), and (F) ant species
richness. Colors with higher saturation indicate higher values of the
variables. Plots with missing ant samples were highlighted by grey color
in (E) and (F).
Distribution of ant assemblages along vertical and horizontal
gradients
In total, 35,710 individual ants from 138 species in 31 genera were
sampled. Ant abundance decreased significantly with increasing height in
the canopy (ln (x+1) tranformed, R2 =
0.67, F 7, 59 = 16.68, P < 0.001)
from an average of 395 individuals per m2 at 5 m, to
101 individuals per m2 at 60 m. Ant species richness
also significantly decreased with height in the canopy
(R2 = 0.66, F 7, 59 =
16.65, P < 0.001), from an average of 12 species per
m2 at 5 m to an average of 3 species per
m2 at 60 m. Both ant abundance and richness also
significantly varied across transects (horizontal positions) (Table S3,
Fig. 3). Ant community assemblages showed significant differences in
species composition both vertically and horizontally ( (Fig. S1 and S2;
PERMANOVA analysis, vertical stratification: F = 1.8, P =
0.01, R2 = 0.09,; across transects: F =
6.4, P = 0.001, R2 = 0.39,).
We pooled data within the same transect or vertical stratum to examine
distance-decay patterns between transects/strata. This showed strong
effects of vertical distance on pairwise dissimilarity indexes between
vertical strata (MRM analyses: coefficient = 0.007, P = 0.001,R2 = 0.65, Fig. 4). In contrast, we found no
effects of horizontal distance on pairwise assemblage dissimilarity
between transects (MRM analyses: coefficient = 0.0003, P = 0.52,R2 = 0.02, Fig. 4). At distances of <
50 m vertically and horizontally, pairwise dissimilarity was
consistently higher horizontally than vertically (Fig. 4).