Changes in woodland bird communities as replanted woodland matures

Abstract

Small patches of woodland were progressively established on degraded agricultural land near Gunnedah, northern New South Wales, on the heavily cleared Liverpool Plains. Birds were resurveyed in the plantings, and in agricultural fields (cropping and pasture) and remnant woodland, in 2011-12, 10 years after initial surveys in 2000-01. The plantings in the later survey were 60, 18, 16 and 13 years old, with a shrub layer included in the three youngest cohorts. The survey sites (total 14 ha planted, all within 200 m of remnant woodland) were paired 1-ha plots in each vegetation category. Birds were surveyed by 30-min area searches of each plot eight times over all seasons, using the same plots, procedure and observer as before. In all, 73 species were recorded in the later survey (versus 72 in the earlier survey), for a total of 87 species over both survey periods, with 58 species in 2011-12 (versus 54 in 2000-01) in the plantings; eight of 15 new species visited or colonised the maturing plantings. Avian species richness and abundance increased from the cleared agricultural plots through the progressively older plantings to resemble those in the remnant woodland. Between the first and second surveys, bird communities in the younger plantings converged with those in the older plantings and woodland. The nectar-feeding, foliage-feeding and ground-feeding insectivore guilds benefitted most, having increased in frequency in, or moved into, the younger cohorts of plantings (>13 years old), or both. Several threatened and other declining woodland birds visited, increased in or colonised the plantings. However, noisy miners (Manorina melanocephala) progressively occupied a few plots and excluded some other birds.