Extensive loss and degradation of native vegetation in the agricultural landscape of inland south-eastern Australia has resulted in significant losses in bird diversity and abundance. Native vegetation continues to be lost through the attrition of paddock trees, which constitute a large component of the remaining vegetation. The planting of native trees and shrubs is being undertaken as a means of halting the loss of biodiversity. However, the effectiveness of revegetation activities is still being assessed. A study in the Wagga Wagga area of New South Wales was undertaken to examine the relative value of remnant vegetation, farm plantings, paddock trees, and pasture for bird diversity. Species richness was highest in remnant vegetation, and was similar in planted vegetation and paddock trees. Relative abundance was similar across these three vegetation types. Species composition differed among all vegetation types, with planted and paddock tree sites having predominantly different sub-sets of the bird assemblage characteristic of remnant vegetation. The protection of remnant vegetation is essential for the conservation of the region’s avifauna, but plantings and paddock trees also have important values for birds. However, plantings and paddock trees support different bird assemblages and complement each other. While important in their own right, the current plantings of native vegetation should not be considered as off-setting the continued loss of paddock trees. Retention of the avifauna of the Wagga Wagga area would be assisted if remnant vegetation and paddock trees were protected and integrated with appropriately designed revegetation.
Vegetation structure and composition during the pre‐ and early‐European period in Australia is often proposed as a benchmark against which to measure the effects of modern landscape management practices. However, little quantifiable information exists for that historical period. One potential source of information is the land survey record, used in this study to provide estimates of tree densities that existed during the period 1870 to 1900 in part of central New South Wales. Estimates were obtained for 23 parishes in the north Lachlan River valley, between the towns of Condobolin and Tottenham. Densities were calculated from portion corner to nearest tree data obtained from historical survey plans, using the plotless, closest individual method. Densities ranged from 6.0 to 31.4 trees per hectare for parishes with enough data points for reliable calculation. These figures would account for trees of a diameter large enough to be blazed with a survey mark. Any smaller trees would be additional and, although no quantitative data existed for this, qualitative evidence suggested that the figures obtained were more likely to be underestimates due to the presence of such small trees. The study area was predominantly covered by woodlands which varied in density across the landscape, in comparison to the modern landscape where much of the native vegetation has been cleared for agriculture. Although the tree density figures should be considered to be indicative rather than precise, they provide quantifiable historical figures for past conditions in an area where the historical record is otherwise sparse. Such information is valuable for interpreting ecological changes brought about by modern land management.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.