Abstract:
Why is biological diversity distributed in the way that it is?
This question has been central to ecology and biogeography for centuries
and is of great importance for pure and applied reasons. I use a
functional trait view of ecology to complement standard sampling
protocols to better understand the distribution and structure of ant
(Hymenoptera: Formicidae) diversity across mountains. I use a longterm
dataset of ant diversity and abundance, combined with a recently
collected morphological trait dataset to examine how the alpha
and beta diversity of ants responds to changes in temperature
along an extensive elevational gradient in southern Africa. In addition,
I link morphological thermoregulatory traits to each other and
to the environment with a new database of ant elevational abundances
from across the globe. Finally, I analyse how physiological
thermal tolerances vary and constrain foraging patterns in montane
ants. I find that temperature is a strong driver of both alpha and beta
diversity patterns. In addition, morphological traits such as colour
and body size are found to have a significant relationship to ambient
temperatures. This relationship also implies that the relative abundances
of different ant species change depending on their thermoregulatory
traits (colour and body size) and the surrounding thermal
environment. Furthermore, the critical thermal minimum (CTmin) of the ant species investigated and the lowest environmental
temperatures are found to be key in constraining foraging activity
patterns. The data presented here strengthen and link existing ideas
about how thermoregulation can influence ecological communities
and also suggests important ways in which diversity patterns may
change in the future.
