Woodland fragmentation is causing the decline of species and functional groups of birds in southeastern Australia

2002 ◽  
Vol 8 (4) ◽  
pp. 261 ◽  
Author(s):  
James Watson ◽  
Alexander Watson ◽  
David Paull ◽  
David Freudenberger

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. Woodland birds were surveyed in 72 woodland remnants of different size and vegetation structural complexity. Avifaunal species richness was found to increase with remnant area and habitat complexity (p < 0.01). Of the 31 resident woodland bird species detected, 22 were significantly affected by woodland patch size reduction and 20 species were significantly affected by habitat complexity loss (p < 0.05). Of the species affected, 19 were affected by both reductions in patch size and vegetation complexity. Seven species (Weebill, Brown Thornbill, Buff-rumped Thornbill, Spotted Pardalote, Grey Shrike-thrush, Scarlet Robin and White-winged Chough) not previously identified as threatened by habitat fragmentation occurred significantly less often in small remnants with low habitat complexity. Assessment of avifaunal guilds based on body size and foraging behaviour showed that all large species (n = 4) and 85% (n = 17) of insectivorous species that foraged above the ground were statistically affected by patch size and/or loss of habitat complexity. The occurrence of three species (50%) of granivores was also significantly affected (p < 0.05) by patch size and/or habitat complexity reduction. These results show that the distribution of many bird species, including some considered "common" and "widespread", is affected by patch size and habitat complexity. There are few, large complex woodland remnants within the study area, which continue to reduce in size and complexity. It is therefore predicted that the decline of woodland bird species will continue unless appropriate habitat conservation strategies are applied.

2008 ◽  
Vol 14 (3) ◽  
pp. 185 ◽  
Author(s):  
S. J. S. Debus

This paper documents the bird community in a small (~15 ha) patch of remnant woodland New South Wales sheep? wheat belt (i) before Noisy Miners Manorina melanocephala were abundant in the patch (1972-79), (ii) after a dense miner colony became established (1980-1990), (iii) after the miners were removed (1991?92) and, subsequently, (iv) while extensive, dense plantings of native trees became established (1992-2006). Bird species richness in the patch was, respectively, 64, 18, 45 and 83 species in each time period. Totals for small (<120 g) bush birds, mostly insectivorous passerines, were 26, 0, 22 and 46 species in the respective time periods. Although this was an unofficial, unreplicated and uncontrolled activity, the results support those of previous similar studies that indicate that Noisy Miners are a major contributor to the local decline of many woodland birds. The results also affirm the value of a shrub layer to small birds.


2011 ◽  
Vol 17 (1) ◽  
pp. 22 ◽  
Author(s):  
R S Bonifacio ◽  
C M Kinross ◽  
G M Gurr ◽  
H Nicol

Shelterbelts are common features of farm landscapes that provide shelter for livestock and crops and timber but may also benefit wildlife. The importance of shelterbelt plant diversity for birds was investigated by a survey of 62 sites in the Central West region of New South Wales, Australia. An area search technique was used to assess bird occurrence. An all subsets and exponential regression analysis approach explored the relationships between woody plant diversity and avifauna diversity (using Hill’s diversity index), whilst seasonal variations were analysed using restricted maximum likelihood. Sixty-six bird species, including many that are woodland-dependent, representing eight foraging guilds, were observed in the shelterbelts. More species of birds occurred and at higher density in more floristically diverse shelterbelts. Other factors found to influence avifaunal use of shelterbelts were woody plant density, shelterbelt width, structural complexity, tree height, crown cover index and elevation. Seasonal analysis confirmed the importance of these independent variables but also revealed the significance of shelterbelt’s proximity to water during summer for birds using this habitat. This study shows that floristic diversity, amongst other factors, is a significant predictor of avifauna diversity in shelterbelts and suggests that shelterbelts may be designed to optimize their wildlife habitat and biodiversity conservation values.


2018 ◽  
Vol 45 (6) ◽  
pp. 473 ◽  
Author(s):  
Donna J. Belder ◽  
Jennifer C. Pierson ◽  
Karen Ikin ◽  
David B. Lindenmayer

Habitat loss as a result of land conversion for agriculture is a leading cause of global biodiversity loss and altered ecosystem processes. Restoration plantings are an increasingly common strategy to address habitat loss in fragmented agricultural landscapes. However, the capacity of restoration plantings to support reproducing populations of native plants and animals is rarely measured or monitored. This review focuses on avifaunal response to revegetation in Australian temperate woodlands, one of the world’s most heavily altered biomes. Woodland birds are a species assemblage of conservation concern, but only limited research to date has gone beyond pattern data and occupancy trends to examine whether they persist and breed in restoration plantings. Moreover, habitat quality and resource availability, including food, nesting sites and adequate protection from predation, remain largely unquantified. Several studies have found that some bird species, including species of conservation concern, will preferentially occupy restoration plantings relative to remnant woodland patches. However, detailed empirical research to verify long-term population growth, colonisation and extinction dynamics is lacking. If restoration plantings are preferentially occupied but fail to provide sufficient quality habitat for woodland birds to form breeding populations, they may act as ecological traps, exacerbating population declines. Monitoring breeding success and site fidelity are under-utilised pathways to understanding which, if any, bird species are being supported by restoration plantings in the long term. There has been limited research on these topics internationally, and almost none in Australian temperate woodland systems. Key knowledge gaps centre on provision of food resources, formation of optimal foraging patterns, nest-predation levels and the prevalence of primary predators, the role of brood parasitism, and the effects of patch size and isolation on resource availability and population dynamics in a restoration context. To ensure that restoration plantings benefit woodland birds and are cost-effective as conservation strategies, the knowledge gaps identified by this review should be investigated as priorities in future research.


2009 ◽  
Vol 20 (2) ◽  
pp. 200-213 ◽  
Author(s):  
STOYAN C. NIKOLOV

SummaryOver the past half century, grassland birds in Europe have declined dramatically and in order to maintain and restore their populations it is critical to understand how habitat structures and quality within pastures affect birds. This study investigated the effects of habitat structure and pasture abandonment on grassland birds in IBA Ponor, western Bulgaria. Birds were sampled using the point count method at 143 randomly located circular plots and a total of 1,401 observations of birds from 31 species were recorded. The results showed that habitat complexity, management and landscape position influenced bird community structure and species occurrence within the upland pastures. Extensively grazed pastures supported higher structural complexity of vegetation cover and higher bird-species richness and diversity compared with abandoned ones. Moreover, bird species with a preference for grazed rather than abandoned pastures had higher conservation status and most were associated with shrub cover. To maintain high levels of avian diversity, habitat complexity within pastures should be maintained through extensive grazing, to ensure availability of scrub vegetation wherever possible. Finally, this study provided evidence that agri-environmental schemes should not be directly extrapolated from one country or region to another without been tested first, because within the same management, differences in habitat structural characteristics may exist due to the landscape and socio-economic characteristics of the region.


2003 ◽  
Vol 9 (2) ◽  
pp. 95 ◽  
Author(s):  
J. A. Seddon ◽  
S. V Briggs ◽  
S. J. Doyle

This study investigated relationships between birds and characteristics of woodland remnants in the central wheat/sheep belt of New South Wales, in order to provide information for conservation management of woodland birds and their habitats in this region. Birds were surveyed in standard area plots in 36 woodland remnants, which ranged from 1 to 1 376 hectares in size, in the central Lachlan catchment in the wheat/sheep belt of New South Wales. Habitat (e.g., shrub cover) and landscape (measures of isolation) characteristics of the remnants were recorded also. Presence/absence occurrences of 20 or more bird species, mostly woodland birds, were positively related to remnant area, shrub cover, number of shrub species, pine cover, fallen logs and branches, and number of remnants within two and five kilometres of the survey remnant. Species of birds that are habitat generalists showed negative or no relationships with these habitat and landscape variables. Richness of all bird species was positively related to remnant area and shrub cover. Number of woodland bird species was positively related to remnant area, shrub cover and tree hollows. Lower species diversities in smaller remnants were most likely caused by lower chances of survival or of successful breeding in small remnants, effects of isolation on the ability of birds to recolonize smaller remnants, small remnants being of insufficient area for some species to form territories, and generally poor habitat quality in small remnants. Retention, management and enhancement of woodland remnants 10 to 20 hectares or larger in size with good understorey cover are necessary for the future viability of woodland birds in the wheat/sheep belt of New South Wales.


1999 ◽  
Vol 5 (3) ◽  
pp. 224 ◽  
Author(s):  
Damon L. Oliver ◽  
Andrew J. Ley ◽  
Hugh A. Ford ◽  
Beth Williams

Five types of woodland and forest in the Bundarra-Barraba region of northern New South Wales were surveyed for Regent Honeyeaters Xanthomyza phrygia and other birds over two years. Regent Honeyeaters were found in 24 of the 93 transects, at a density of 0.09 birds/ha. Most were found in box-ironbark woodland (34% of 62 sites), with single records from box-gum woodland, box-stringybark woodland and dry plateau complex woodland. No Regent Honeyeaters were found in riparian gallery forest during censuses, but they were found breeding there at other times. All habitats contained a high density of birds, compared to other wooded regions in southern Australia, with riparian gallery forest and box-ironbark woodland being particularly rich in species and numbers. These habitats had greater flowering indices, larger trees and more mistletoes than other habitats. Sites used by Regent Honeyeaters supported significantly more birds and bird species than unoccupied sites. The region supports a total of 193 species, four of which are nationally threatened and seven which are threatened in New South Wales. The richness of the bird community in the region is partly because it retains a higher proportion of native vegetation cover (43%) than many other parts of rural Australia. Protection and rehabilitation of box-ironbark woodland and riparian gallery forest is of high priority in a regional conservation plan. However, all habitats in the Bundarra-Barraba region should be protected from clearing and degradation, because they are also used at times by Regent Honeyeaters and support a wide range of bird species. Wise management should retain many sensitive bird species that have disappeared from or declined in other regions of southeastern Australia.


2008 ◽  
Vol 35 (1) ◽  
pp. 19 ◽  
Author(s):  
G. W. Barrett ◽  
D. Freudenberger ◽  
A. Drew ◽  
J. Stol ◽  
A. O. Nicholls ◽  
...  

Tree planting has become a cornerstone strategy for natural resource management in agricultural landscapes, yet its contribution as habitat for woodland birds has not been fully investigated. A case study from the Holbrook region in southern New South Wales was used to assess woodland birds in young plantings of native trees and shrubs. Ground-foraging insectivorous woodland birds were under-represented in the plantings, partly due to a lack of native forb diversity (wildflowers) and leaf litter. Of 69 woodland bird species recorded over a three-year period, 48 species (70%) occurred in planted sites, 59 species (86%) occurred in remnant woodland, and 34 species (49%) occurred in adjacent paddock sites. The greater diversity of birds in planted sites relative to paddock sites was mostly due to understorey birds. The proportion of mist-netted birds recaptured was similar in both planted (15%) and remnant woodland (16%) sites, suggesting that individual birds were staying in planted sites. The proportion of woodland birds showing breeding activity (as measured by the presence of a brood patch) was slightly lower in planted sites (24% of all woodland species) than in remnant woodland (29%). Birds such as the superb fairy-wren, red-browed finch and southern whiteface were more likely to occur in planted sites, suggesting that plantings provide unique, transitional-stage habitat within agricultural landscapes. Restoring native forbs, as part of a broader strategy of woodland management, will help to reverse the decline of ground-foraging insectivorous woodland birds in agricultural landscapes.


2020 ◽  
Vol 642 ◽  
pp. 163-177 ◽  
Author(s):  
Y Niella ◽  
AF Smoothey ◽  
V Peddemors ◽  
R Harcourt

In the face of accelerating climate change, conservation strategies will need to consider how marine animals deal with forecast environmental change as well as ongoing threats. We used 10 yr (2009-2018) of data from commercial fisheries and a bather protection program along the coast of New South Wales (NSW), southeastern Australia, to investigate (1) spatial and temporal patterns of occurrence in bull sharks and (2) environmental factors affecting bull shark occurrence along the coast of NSW. Predicted future distribution for this species was modelled for the forecast strengthening East Australian Current. Bull sharks were mostly harvested in small to larger estuaries, with average depth and rainfall responsible for contrasting patterns for each of the fisheries. There was an increase in the occurrence of bull sharks over the last decade, particularly among coastal setline fisheries, associated with seasonal availability of thermal gradients >22°C and both westward and southward coastal currents stronger than 0.15 and 0.60 m s-1, respectively, during the austral summer. Our model predicts a 3 mo increase in the availability of favourable water temperatures along the entire coast of NSW for bull sharks by 2030. This coastline provides a uniquely favourable topography for range expansion in the face of a southerly shift of warmer waters, and habitat is unlikely to be a limiting factor for bull sharks in the future. Such a southerly shift in distribution has implications for the management of bull sharks both in commercial fisheries and for mitigation of shark-human interactions.


2020 ◽  
pp. 1-10
Author(s):  
VOLKER SALEWSKI ◽  
LUIS SCHMIDT

Summary Identifying the fate of birds’ nests and the causes of breeding failure is often crucial for the development of conservation strategies for threatened species. However, collecting these data by repeatedly visiting nests might itself contribute to nest failure or bias. To solve this dilemma, automatic cameras have increasingly been used as a time-efficient means for nest monitoring. Here, we consider whether the use of cameras itself may influence hatching success of nests of the Black-tailed Godwit Limosa limosa at two long-term study sites in northern Germany. Annually between 2013 and 2019, cameras were used to monitor godwit nests. In 2014 and 2019, nests were randomly equipped with cameras or not, and nest survival checked independently of the cameras. Nest-survival models indicated that survival probabilities varied between years, sites and with time of the season, but were unaffected by the presence of cameras. Even though predation is the main cause of hatching failure in our study system, we conclude that predators did not learn to associate cameras with food either when the cameras were initially installed or after they had been used for several years. Cameras were thus an effective and non-deleterious tool to collect data for conservation in this case. As other bird species may react differently to cameras at their nests, and as other sets of predators may differ in their ability to associate cameras with food, the effect of cameras on breeding success should be carefully monitored when they are used in a new study system.


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