The effects of geographic orientation on shrub microclimates related to Australian pipit nesting

Abstract

Refugia with mild microclimates are central for the survival of many alpine species. Alpine shrubs create microclimates with conditions that can benefit birds, such as the Australian pipit, Anthus novaeseelandiae (Gmelin, 1789). Pipit populations in harsh climates utilise specific behavioural techniques to increase their nesting success: the Snowy Mountains A. novaeseelandiae population nest underneath shrubs at orientations between NNE and SE as identified by Norment and Green (2004). We wanted to determine whether conditions were significantly milder under a shrub between 22° and 125° in orientation. Recordings of abiotic conditions were taken under shrubs in Kosciuszko National Park and then compared to ambient conditions. We found that alpine shrub microclimates are less extreme than ambient conditions, their stability is independent of their aspect and that the microclimate between 22° and 125° remains more humid as ambient conditions become drier. This could add to our understanding of alpine bird ecology and play a role in conservation.