The effect of woody plant diversity and other stand and landscape factors on the diversity and abundance of birds using farm shelterbelts.

Abstract

Shelterbelts are common features of farm landscapes that provide shelter for livestock and crops and timber but may also benefit wildlife. The importance of shelterbelt plant diversity for birds was investigated by a survey of 62 sites in the Central West region of New South Wales, Australia. An area search technique was used to assess bird occurrence. An all subsets and exponential regression analysis approach explored the relationships between woody plant diversity and avifauna diversity (using Hill’s diversity index), whilst seasonal variations were analysed using restricted maximum likelihood. Sixty-six bird species, including many that are woodland-dependent, representing eight foraging guilds, were observed in the shelterbelts. More species of birds occurred and at higher density in more floristically diverse shelterbelts. Other factors found to influence avifaunal use of shelterbelts were woody plant density, shelterbelt width, structural complexity, tree height, crown cover index and elevation. Seasonal analysis confirmed the importance of these independent variables but also revealed the significance of shelterbelt’s proximity to water during summer for birds using this habitat. This study shows that floristic diversity, amongst other factors, is a significant predictor of avifauna diversity in shelterbelts and suggests that shelterbelts may be designed to optimize their wildlife habitat and biodiversity conservation values.