J. Retana et X. Cerda, Patterns of diversity and composition of Mediterranean ground ant communities tracking spatial and temporal variability in the thermal environment, OECOLOGIA, 123(3), 2000, pp. 436-444
The present study analyzed ant community structure and the factors affectin
g it in the Spanish Mediterranean area. The aim of this study was to test w
hether temperature controls the composition and diversity of the ground ant
fauna and the spatial and temporal distribution of dominance groups along
adjacent communities. The main descriptors of community structure (except p
erharps species richness) were found to vary along the gradient of vegetati
on cover: increased vegetation cover resulted in an increase in the relativ
e abundance of the most common species, which led to a significant decrease
in species evenness, together with a reduction in total ant density on the
ground. In open habitats, dominant and subordinate species were abundant d
uring different periods of the day, and this led to an increase in species
evenness. In areas with high vegetation cover, dominants benefited from the
lower temperatures by lengthening their periods of activity. This resulted
in a decrease in the abundance of subordinate species, and in lower evenne
ss. Seasonal patterns in community structure tracked temperature fluctuatio
ns and varied between habitat types. Evenness was similar in the two habita
t types in spring, but increased in grasslands and decreased in shrublands/
forests in summer. Species richness did not vary between seasons or habitat
types. The relative abundance of dominance groups in the two types of habi
tats showed a different pattern between seasons. In grasslands, subordinate
s increased and dominants decreased their relative abundance from spring to
summer, while in shrublands/forests, the opposite pattern was found. The o
verall conclusion from this study is that ground ant communities in open ar
eas are primarily regulated by temperature variations, while in shrublands
and forests, dominant species are more abundant, and competitive interactio
ns appear to be the major structuring force.