Are mesic communities less drought-resistant? A study on moisture relationships in dry sclerophyll forest at Inglewood, South Australia

Abstract

Soil moisture changes under two adjacent forest associations (Eucalyptus obliqua association in the more mesic environment, E. elaeophora association in the more xeric sites) were recorded in the Inglewood area of the Mount Lofty Ranges, South Australia.

The evidence indicated that the E. obliqua association had a higher index of evapotranspiration (I_tr = E_tr/E_w^0.75) over most of the range of available water (soil moisture + rainfall) than the E. elaeophora association. The more mesic association consequently completely exhausted the stored soil moisture during periods of low rainfall and had to survive a drought period every year.

The other association did not deplete the soil moisture reserves and in an average year, no drought occurred. Characteristic species of the more mesic association must be able to survive this drought period especially during the seedling stage.