Impacts of clearing, fragmentation and disturbance on the bird fauna of Eucalypt savanna woodlands in central Queensland, Australia (original) (raw)
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The clearance of woodlands and the simultaneous creation of alien environments have been identified as the primary reasons for the decline of many woodland birds in southeastern Australia. This study measured how the size of woodland remnants and habitat structural complexity affected bird composition and distribution in the northern Australian Capital Territory and bordering areas of New South Wales. Within this region only 8% of the original woodlands remain, embedded as patches in a matrix of pasture and suburbia.
Biological Conservation, 2009
The loss, fragmentation and degradation of native vegetation are major causes of loss of biodiversity globally. Extinction debt is the term used to describe the ongoing loss of species from fragmented landscapes long after the original loss and fragmentation of habitat. However, losses may also result from habitat changes that are unrelated to fragmentation, which reduce breeding success and recruitment. Many woodland birds have declined in fragmented landscapes in Australia, probably due to loss of small, isolated populations, though the ecological processes are poorly understood. We record the progressive regional loss of two ground-foraging, woodland birds, the Brown Treecreeper Climacteris picumnus and Hooded Robin Melanodryas cucullata, in northern New South Wales, over 30 years. This has happened despite most habitat loss occurring over 100 years ago, suggesting the payment of an extinction debt. Our observations suggest that several ecological processes, caused by habitat loss, fragmentation or degradation, and operating over different time scales, have led to both species' declines. Female Brown Treecreepers disperse poorly among vegetation remnants, leaving only males in isolated populations, which then go extinct. In contrast, Hooded Robins suffer high nest predation in fragmented landscapes, producing too few recruits to replace adult mortality. Foraging by both species may also be affected by regrowth of ground vegetation and shrubs. We found little support for a major role played by drought, climate change or aggressive Noisy Miners Manorina melanocephala. We propose that both extinction debt in the classical sense and ongoing habitat change frequently contribute to species' decline in modified landscapes. Management to arrest and reverse such declines needs to consider these multiple causes of decline. For instance, reconnecting isolated populations may be inadequate alone, and activities such as appropriate grazing, fires and the addition of woody debris may also be required.
Priorities for ecological restoration in the Western Woodlands Way
The biodiversity of Australia is undergoing serious and ongoing declines, resulting principally from loss and fragmentation of native vegetation through agricultural development. These problems are especially critical in areas such as the New South Wales tablelands, where clearance of native woodlands for agriculture has resulted in large population losses for many native species.
PLoS ONE, 2012
The value for biodiversity of large intact areas of native vegetation is well established. The biodiversity value of regrowth vegetation is also increasingly recognised worldwide. However, there can be different kinds of revegetation that have different origins. Are there differences in the richness and composition of biotic communities in different kinds of revegetation? The answer remains unknown or poorly known in many ecosystems. We examined the conservation value of different kinds of revegetation through a comparative study of birds in 193 sites surveyed over ten years in four growth types located in semi-cleared agricultural areas of south-eastern Australia. These growth types were resprout regrowth, seedling regrowth, plantings, and old growth. Our investigation produced several key findings: (1) Marked differences in the bird assemblages of plantings, resprout regrowth, seedling regrowth, and old growth.
Ecological Management & Restoration, 2021
Article type : Feature Article Research supporting restoration aiming to make a frag e ted la dscape fu ctio al for native wildlife Summary Temperate woodlands are among the most threatened ecosystems in Australia because the land on which they occur is highly suited to agriculture. Two hundred years of habitat loss and fragmentation in the Midlands agricultural region in Tasmania have led to widespread declines in native vertebrates and landscapes with populations of predators including feral Cat (Felis catus) and the native-invasive Noisy Miner (Manorina melanocephala). Ecologists at the University of Tasmania co-designed mechanistic animal-centric research on mammals and birds in the Midlands to inform vegetation restoration carried out by Greening Australia that would support the recovery of wildlife species. We used species-appropriate technologies to assess the decisions made by individual animals to find food and shelter and to disperse across this fragmented landscape, and linked these, together with patterns of occupancy, across multiple spatial and temporal scales. We focussed on a native (Spottedtailed Quoll, Dasyurus maculatus) and an invasive (Cat) carnivore, a woodland-specialist herbivore (Eastern Bettong, Bettongia gaimardi) and woodland birds including the nativeinvasive Noisy Miner. Our results, which show intense predatory and competitive pressure of Cat and Noisy Miners on native fauna, highlight how grounding restoration in the context of ecological
Conservation planning for species occupying fragmented landscapes: …
… . Conservation planning …
All Treesearch publications were written or produced by Forest Service personnel and are in the public domain. ... Source: Pages 424-450 in: Kareiva, PM; Kingsolver, JG; Huey, RB, comps., eds. Biotic Interactions and Global Change. Sunderland, Massachuseets: ...
Austral Ecology, 2007
Forestry operations in jarrah forests of southwestern Australia use two types of selective logging, gaps which remove 85-95% of basal area and shelterwoods which remove 40-60% of basal area.These operations create considerable lengths of forestry edge (edges between logged and unlogged forest) each year, but their impact on the avifauna of the jarrah forest is unknown. Changes in bird density were examined along edges created by forestry operations in jarrah forests using a BACI design experiment. Bird densities were estimated on 1-ha plots that were surveyed three times per season, in three seasons both before and after logging. There was no evidence of edge effects at the community level; overall bird density and species richness did not changes along forestry edges. Scarlet robin (Petroica multicolor) abundance increased significantly along both gap and shelterwood edges, relative to controls. Apart from a probably spurious increase in density along gap edges by red-winged fairy-wrens (Malurus elegans), no other species showed a significant change in density along edges. There was also no difference in responses to gap and shelterwood edges, despite gaps removing more basal area than shelterwoods, suggesting that response to forestry edges in the jarrah forest may be threshold dependent, rather than increasing with increasing intensity of logging operations. Comparisons with other studies examining density changes along forestry edges in southwestern Australia suggest that density changes observed in this study are short-term in nature. The limited density change in avifauna along forestry edges is probably because selective logging practices were examined instead of clear-felling. Studies in the literature indicate that this pattern is likely to be true for many forest ecosystems.