How does a transforming landscape influence bird breeding success?

Context The conversion of agricultural landscapes to tree plantations is a major form of landscape transformation worldwide, but its effects on biodiversity, particularly key population processes like reproductive success, are poorly understood. Objectives We compared bird breeding success between woodland remnants surrounded by maturing stands of plantation Radiata Pine and a matched set of woodland remnants in semi-cleared grazing land. Methods Our study was conducted in the Nanangroe region in south-eastern New South Wales, Australia. Using repeated field measurements, we quantified bird breeding success in 23 woodland remnants; 13 surrounded by Radiata Pine plantations and 10 on farms where remnants were surrounded by semi-cleared grazing land. We matched the attributes of native remnant patches between two types of matrix. Results We found that: (1) rates of nesting success of smaller-bodied birds in woodland remnants surrounded by grazing land were significantly higher than in woodland remnants surrounded by pine plantations; and (2) taxa with domed nests were more successful at nesting than species that constructed open cup/bowl nests in woodland remnants within farmlands. Conclusions Our findings suggest that bird breeding success in remnant woodland patches is significantly diminished as a result of the conversion of semi-cleared grazing land to pine plantations.