A baseline survey of birds in native vegetation on cotton farms in inland Eastern Australia

Abstract

Context: The Australian cotton industry has committed to (1) understanding the biodiversity value of remnant native vegetation on cotton farms, (2) funding independent, evidence-based assessments of the industry’s sustainability and environmental performance, and (3) investing in research that reports against recognised sustainability indicators.

Aims: The present study reports the results of an industry-wide survey to benchmark bird diversity in native vegetation on cotton farms spanning a 1260-km north–south subcontinental gradient from Central Queensland (Qld) to Southern New South Wales (NSW).

Methods: Between September and November 2014, birds were sampled twice on separate days in 2-ha quadrats (20 min per census) in eight remnant vegetation types as well as in native revegetation at 197 sites on 60 cotton farms spread across the principal cotton-growing zones (Central Qld, Border Rivers, Macquarie and Southern NSW) in inland eastern Australia.

Key results: We recorded 185 bird species in remnant and planted native vegetation on cotton farms. Species richness of bird communities declined from north to south. Bird community composition was similar in the three southern zones, differing somewhat in the north. The most frequent species were large (>60 g), readily detected landbirds common in agricultural districts, but 26 of the 53 extant species of conservation concern in the study region were also recorded, including 16 species of declining woodland birds. Bird composition, abundance, richness and diversity differed among the nine native vegetation types, with maximal and minimal bird abundance and diversity metrics recorded in river red gum-dominated riparian vegetation and grassland respectively.

Conclusions: Each remnant vegetation community had a generally distinct bird assemblage, indicating that all vegetation types contribute to regional biodiversity in cotton-growing zones in inland eastern Australia. Appropriate on-farm management of all remnant and planted native vegetation will assist regional biodiversity conservation.

Implications: For the Australian cotton industry to meet its stated environmental responsibilities, growers should be encouraged to prioritise the conservation management of remnant, riparian and planted native vegetation on cotton farms and the monitoring of bird species as an indicator of regional biodiversity response.