3.3. Sociality, tribes, and nesting guilds
The most predictive factors for solitary bee abundance were
percent canopy cover (site-stratified p-value = 0.039) and the number
of flowering herb species, while the most predictive factors for
social bee abundance were the number of tree species (site-stratified
p-value = 0.012), followed by the number of flowering tree
species (Fig. 6). For the tribe Halictini, the factors with the greatest
effect on bee abundance were the number of tree species in flower
(site-stratified p-value = 0.002) and the number of tree species. For
the tribe Augochlorini, the factors showing the greatest effect on
bee abundance were the number of tree species (site-stratified pvalue
= 0.021), followed by the percent canopy cover. For the tribe
Ceratinini, the traits that showed the greatest effect on bee abundance
were percent canopy cover (site-stratified p-value = 0.050)
and the number of herb species in flower (Fig. 7). The most predic-