Livestock grazing effects on riparian bird breeding behaviour in agricultural landscapes
- Hansen, Birgita, Fraser, Hannah, Jones, Christopher
- Authors: Hansen, Birgita , Fraser, Hannah , Jones, Christopher
- Date: 2019
- Type: Text , Journal article
- Relation: Agriculture, Ecosystems and Environment Vol. 270-271, no. (2019), p. 93-102
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- Description: Globally, many bird species that rely on native woodland or forest environments are declining due to vegetation clearing for livestock pastures and cereal cropping. In many landscapes, woodland remnants are restricted to waterways and roadsides in narrow, sometimes degraded patches, and not all patches can necessarily provide the resources required to support bird populations. This study investigated the influence of livestock grazing and vegetation characteristics on bird breeding activity in riparian zones in northern Victoria, Australia, where much of the landscape is used for production and has experienced significant loss of woodland. Birds were broadly categorised as ‘woodland’ or ‘non-woodland’ species, based on dependency on woodlands for breeding. The majority of woodland species detected were relatively common, and where riparian zones were heavily grazed, there was significantly lower woodland bird breeding activity compared to non-woodland bird breeding activity (the latter increasing with grazing intensity). Woodland and non-woodland birds had consistently opposite responses to grazing intensity, vegetation and landscape characteristics, suggesting that the factors influencing breeding differ markedly between these two groups. Thus, where riparian zones are intensively grazed, the bird community shifts from predominantly woodland to largely non-woodland species. This has implications for the conservation of both rare and common woodland bird species in southern Australia. Simple changes in land management, for example, livestock exclusion from important breeding habitat, may confer large gains for population persistence of woodland bird species.
- Authors: Hansen, Birgita , Fraser, Hannah , Jones, Christopher
- Date: 2019
- Type: Text , Journal article
- Relation: Agriculture, Ecosystems and Environment Vol. 270-271, no. (2019), p. 93-102
- Full Text:
- Reviewed:
- Description: Globally, many bird species that rely on native woodland or forest environments are declining due to vegetation clearing for livestock pastures and cereal cropping. In many landscapes, woodland remnants are restricted to waterways and roadsides in narrow, sometimes degraded patches, and not all patches can necessarily provide the resources required to support bird populations. This study investigated the influence of livestock grazing and vegetation characteristics on bird breeding activity in riparian zones in northern Victoria, Australia, where much of the landscape is used for production and has experienced significant loss of woodland. Birds were broadly categorised as ‘woodland’ or ‘non-woodland’ species, based on dependency on woodlands for breeding. The majority of woodland species detected were relatively common, and where riparian zones were heavily grazed, there was significantly lower woodland bird breeding activity compared to non-woodland bird breeding activity (the latter increasing with grazing intensity). Woodland and non-woodland birds had consistently opposite responses to grazing intensity, vegetation and landscape characteristics, suggesting that the factors influencing breeding differ markedly between these two groups. Thus, where riparian zones are intensively grazed, the bird community shifts from predominantly woodland to largely non-woodland species. This has implications for the conservation of both rare and common woodland bird species in southern Australia. Simple changes in land management, for example, livestock exclusion from important breeding habitat, may confer large gains for population persistence of woodland bird species.
Continental-scale decreases in shorebird populations in Australia
- Clemens, Robert, Rogers, Danny, Hansen, Birgita, Gosbell, Ken, Minton, Clive, Straw, Phil, Bamford, Mike, Woehler, Eric, Milton, David, Weston, Michael, Venables, Bill, Weller, Dan, Hassell, Chris, Rutherford, Bill, Onton, Kimberly, Herrod, Ashley, Studds, Colin, Choi, Chi-Yeung, Dhanjal-Adams, Kiran, Murray, Nicholas, Skilleter, Gregory, Fuller, Richard
- Authors: Clemens, Robert , Rogers, Danny , Hansen, Birgita , Gosbell, Ken , Minton, Clive , Straw, Phil , Bamford, Mike , Woehler, Eric , Milton, David , Weston, Michael , Venables, Bill , Weller, Dan , Hassell, Chris , Rutherford, Bill , Onton, Kimberly , Herrod, Ashley , Studds, Colin , Choi, Chi-Yeung , Dhanjal-Adams, Kiran , Murray, Nicholas , Skilleter, Gregory , Fuller, Richard
- Date: 2016
- Type: Text , Journal article
- Relation: Emu Vol. 116, no. 2 (2016), p. 119-135
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- Description: Decreases in shorebird populations are increasingly evident worldwide, especially in the East Asian-Australasian Flyway (EAAF). To arrest these declines, it is important to understand the scale of both the problem and the solutions. We analysed an expansive Australian citizen-science dataset, spanning the period 1973 to 2014, to explore factors related to differences in trends among shorebird populations in wetlands throughout Australia. Of seven resident Australian shorebird species, the four inland species exhibited continental decreases, whereas the three coastal species did not. Decreases in inland resident shorebirds were related to changes in availability of water at non-tidal wetlands, suggesting that degradation of wetlands in Australia's interior is playing a role in these declines. For migratory shorebirds, the analyses revealed continental decreases in abundance in 12 of 19 species, and decreases in 17 of 19 in the southern half of Australia over the past 15 years. Many trends were strongly associated with continental gradients in latitude or longitude, suggesting some large-scale patterns in the decreases, with steeper declines often evident in southern Australia. After accounting for this effect, local variables did not explain variation in migratory shorebird trends between sites. Our results are consistent with other studies indicating that decreases in migratory shorebird populations in the EAAF are most likely being driven primarily by factors outside Australia. This reinforces the need for urgent overseas conservation actions. However, substantially heterogeneous trends within Australia, combined with declines of inland resident shorebirds indicate effective management of Australian shorebird habitat remains important. © BirdLife Australia 2016.
- Authors: Clemens, Robert , Rogers, Danny , Hansen, Birgita , Gosbell, Ken , Minton, Clive , Straw, Phil , Bamford, Mike , Woehler, Eric , Milton, David , Weston, Michael , Venables, Bill , Weller, Dan , Hassell, Chris , Rutherford, Bill , Onton, Kimberly , Herrod, Ashley , Studds, Colin , Choi, Chi-Yeung , Dhanjal-Adams, Kiran , Murray, Nicholas , Skilleter, Gregory , Fuller, Richard
- Date: 2016
- Type: Text , Journal article
- Relation: Emu Vol. 116, no. 2 (2016), p. 119-135
- Full Text:
- Reviewed:
- Description: Decreases in shorebird populations are increasingly evident worldwide, especially in the East Asian-Australasian Flyway (EAAF). To arrest these declines, it is important to understand the scale of both the problem and the solutions. We analysed an expansive Australian citizen-science dataset, spanning the period 1973 to 2014, to explore factors related to differences in trends among shorebird populations in wetlands throughout Australia. Of seven resident Australian shorebird species, the four inland species exhibited continental decreases, whereas the three coastal species did not. Decreases in inland resident shorebirds were related to changes in availability of water at non-tidal wetlands, suggesting that degradation of wetlands in Australia's interior is playing a role in these declines. For migratory shorebirds, the analyses revealed continental decreases in abundance in 12 of 19 species, and decreases in 17 of 19 in the southern half of Australia over the past 15 years. Many trends were strongly associated with continental gradients in latitude or longitude, suggesting some large-scale patterns in the decreases, with steeper declines often evident in southern Australia. After accounting for this effect, local variables did not explain variation in migratory shorebird trends between sites. Our results are consistent with other studies indicating that decreases in migratory shorebird populations in the EAAF are most likely being driven primarily by factors outside Australia. This reinforces the need for urgent overseas conservation actions. However, substantially heterogeneous trends within Australia, combined with declines of inland resident shorebirds indicate effective management of Australian shorebird habitat remains important. © BirdLife Australia 2016.
- Wilson, David, Hansen, Birgita, Honan, Jodie, Chamberlain, Richard
- Authors: Wilson, David , Hansen, Birgita , Honan, Jodie , Chamberlain, Richard
- Date: 2017
- Type: Text , Journal article
- Relation: Australian Field Ornithology Vol. 34, no. (2017), p. 76-79
- Full Text: false
- Reviewed:
- Description: An understanding of migration phenology is critical to the conservation of long-distance migrants. Latham's Snipe Gallinago hardwickii is a cryptic, dispersed migratory wader that breeds in northern Japan during the austral winter and migrates to Australia for the non-breeding period. Records of this species for New South Wales (NSW) and the Australian Capital Territory (ACT) were extracted from a range of data sources including hunting reports, the Atlas of Living Australia, eBird and citizen science records, generating a dataset of first-arrival dates for 170 years (1846-2016). The first record in each year, corresponding to the expected arrival period of Latham's Snipe on southward migration, was used to infer the date of first arrival. These dates were analysed using simple linear regression against Julian day to test the hypothesis that changes in climate (i.e. increasing mean annual temperature) might result in a corresponding shift in arrival dates. The mean Julian day of first arrivals in NSW and the ACT was 14 August ± 9 days, with no significant change over the 170-year span of records. This suggests that migration phenology of Latham's Snipe has not been strongly influenced by changing large-scale climatic conditions at either the breeding or non-breeding grounds.
Generating population estimates for migratory shorebird species in the world’s largest flyway
- Hansen, Birgita, Rogers, Danny, Watkins, Doug, Weller, Dan, Clemens, Robert, Newman, Mike, Woehler, Eric, Mundkur, Taej, Fuller, Richard
- Authors: Hansen, Birgita , Rogers, Danny , Watkins, Doug , Weller, Dan , Clemens, Robert , Newman, Mike , Woehler, Eric , Mundkur, Taej , Fuller, Richard
- Date: 2022
- Type: Text , Journal article
- Relation: Ibis Vol. 164, no. 3 (2022), p. 735-749
- Full Text:
- Reviewed:
- Description: Population estimates are widely used to underpin conservation decisions. However, determining accurate population estimates for migratory species is especially challenging, as they are often widespread and it is rarely possible to survey them throughout their full distribution. In the East Asian–Australasian Flyway (EAAF), this problem is compounded by its size (85 million square kilometres) and the number of migratory species it supports (nearly 500). Here, we provide analytical approaches for addressing this problem, presenting a revision of the EAAF population estimates for 37 migratory shorebird species protected under Australian national environmental legislation. Population estimates were generated by (1) summarizing existing count data in the non-breeding range, (2) spatially extrapolating across uncounted areas, and (3) modelling abundance on the basis of estimates of breeding range and density. Expert review was used to adjust modelled estimates, particularly in under-counted areas. There were many gaps in shorebird monitoring data, necessitating substantial use of extrapolation and expert review, the extent of which varied among species. Spatial extrapolation to under-counted areas often produced estimates that were much higher than the observed data, and expert review was used to cross-check and adjust these where necessary. Estimates of population size obtained through analyses of breeding ranges and density indicated that 18 species were poorly represented by counts in the non-breeding season. It was difficult to determine independently the robustness of these estimates, but these breeding ground estimates were considered the best available data for 10 species that mostly use poorly surveyed freshwater or pelagic habitats in the non-breeding season. We discuss the rationale and limitations of these approaches to population estimation, and how they could be modified for other applications. Data available for population estimates will vary in quality and extent among species, regions and migration stage, and approaches need to be flexible enough to provide useful information for conservation policy and planning. © 2021 British Ornithologists' Union.
- Authors: Hansen, Birgita , Rogers, Danny , Watkins, Doug , Weller, Dan , Clemens, Robert , Newman, Mike , Woehler, Eric , Mundkur, Taej , Fuller, Richard
- Date: 2022
- Type: Text , Journal article
- Relation: Ibis Vol. 164, no. 3 (2022), p. 735-749
- Full Text:
- Reviewed:
- Description: Population estimates are widely used to underpin conservation decisions. However, determining accurate population estimates for migratory species is especially challenging, as they are often widespread and it is rarely possible to survey them throughout their full distribution. In the East Asian–Australasian Flyway (EAAF), this problem is compounded by its size (85 million square kilometres) and the number of migratory species it supports (nearly 500). Here, we provide analytical approaches for addressing this problem, presenting a revision of the EAAF population estimates for 37 migratory shorebird species protected under Australian national environmental legislation. Population estimates were generated by (1) summarizing existing count data in the non-breeding range, (2) spatially extrapolating across uncounted areas, and (3) modelling abundance on the basis of estimates of breeding range and density. Expert review was used to adjust modelled estimates, particularly in under-counted areas. There were many gaps in shorebird monitoring data, necessitating substantial use of extrapolation and expert review, the extent of which varied among species. Spatial extrapolation to under-counted areas often produced estimates that were much higher than the observed data, and expert review was used to cross-check and adjust these where necessary. Estimates of population size obtained through analyses of breeding ranges and density indicated that 18 species were poorly represented by counts in the non-breeding season. It was difficult to determine independently the robustness of these estimates, but these breeding ground estimates were considered the best available data for 10 species that mostly use poorly surveyed freshwater or pelagic habitats in the non-breeding season. We discuss the rationale and limitations of these approaches to population estimation, and how they could be modified for other applications. Data available for population estimates will vary in quality and extent among species, regions and migration stage, and approaches need to be flexible enough to provide useful information for conservation policy and planning. © 2021 British Ornithologists' Union.
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