Challenges in applying scientific evidence to width recommendations for riparian management in agricultural Australia
- Authors: Hansen, Birgita , Reich, Paul , Cavagnaro, Timothy , Lake, Philip
- Date: 2015
- Type: Text , Journal article
- Relation: Ecological Management and Restoration Vol. 16, no. 1 (2015), p. 50-57
- Full Text: false
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- Description: Intact riparian zones maintain aquatic-terrestrial ecosystem function and ultimately, waterway health. Effective riparian management is a major step towards improving the condition of waterways and usually involves the creation of a 'buffer' by fencing off the stream and planting vegetation. Determination of buffer widths often reflects logistical constraints (e.g. private land ownership, existing infrastructure) of riparian and adjacent areas, rather than relying on rigorous science. We used published information to support riparian width recommendations for waterways in agricultural Victoria, Australia. We focused on different ecological management objectives (e.g. nutrient reduction or erosion control) and scrutinised the applicability of data across different environmental contexts (e.g. adjacent land use or geomorphology). Not surprisingly, the evidence supported variable 'effective' riparian widths, depending on the objective and environmental context. We used this information to develop a framework for determining riparian buffer widths to meet a variety of ecological objectives in south-east Australia. Widths for reducing nutrient inputs to waterways were most strongly supported with quantitative evidence and varied between 20 and 38 m depending on environmental context. The environmental context was inconsistently reported, making it difficult to recommend appropriate widths, under different land-use and physiographic scenarios. The evidence to guide width determination generally had high levels of uncertainty. Despite the considerable amount of published riparian research, there was insufficient evidence to demonstrate that implemented widths achieved ecological objectives. We emphasise the need for managers to clearly articulate the objectives of proposed riparian management and carefully consider the environmental context. Monitoring ecological responses associated with different riparian buffer widths is essential to support future management decisions.
Long-term declines in multiple waterbird species in a tidal embayment, south-east Australia
- Authors: Hansen, Birgita , Menkhorst, Peter , Moloney, Paul , Loyn, Richard
- Date: 2015
- Type: Text , Journal article
- Relation: Austral Ecology Vol. , no. (2015), p.
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- Description: Worldwide, local extinctions and severe declines in waterbird densities are being reported from many important waterbird sites. Waterbird sites often exist as a network, collectively providing crucial habitat for different life history stages of different species. Therefore, population changes at one site may strongly influence others. In Australia, many waterbird species are highly mobile, and move rapidly over long distances in response to rainfall. Large tidal wetlands often serve as drought refugia or alternative breeding habitat for these species. These sites are also the migration terminus of many species of shorebirds that spend their non-breeding season in Australia. One such site in south-eastern Australia is Western Port, a Ramsar-listed tidal embayment forming part of the East Asian-Australasian Shorebird Site Network. We measured waterbird population trends over nearly 40 years in Western Port to see whether changes showed consistent trends over time across multiple species. Thirty-nine species were recorded often enough to allow an analysis of trends over time using dynamic linear models and, where appropriate, piecewise linear regression. Twenty-two species had declined, including four species of duck, five species of fish-eating bird (cormorants, terns and pelicans), one species each of grebe, gull and heron, and 10 species of shorebird. Only two species (Australian pied oystercatcher Haematopus longirostris and straw-necked ibis Threskiornis spinicollis) increased significantly over the same time period. Patterns of decline in non-migratory waterbirds may reflect diminishing wetland availability, local reductions in fish prey, increased predation pressure and changes in inland wetland resources. Declines in migratory shorebirds are most likely related to loss of habitat elsewhere in their trans-equatorial migration routes. These trends in waterbirds that use Western Port reflect widespread impacts on populations elsewhere in Australia and overseas, necessitating more than simply local management of this tidal embayment.
The golf ball method for rapid assessment of grassland structure
- Authors: Schultz, Nick , Keatley, Marie , Antos, Mark , Wong, Nathan , Moxham, Claire , Farmilo, Brad , Morgan, John
- Date: 2017
- Type: Text , Journal article
- Relation: Ecological Management and Restoration Vol. 18, no. 2 (2017), p. 134-140
- Full Text: false
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- Description: A key task for native grassland managers is to assess when biomass reduction is necessary to maintain plant and animal diversity. This requires managers to monitor grassland structure. Parks Victoria and La Trobe University developed a method for rapid assessment of grassland structure using golf balls. Baker-Gabb et al. (Ecological Management & Restoration, 17, 2016, p235) provide an example of where the method has been used to manage grassland structure to favour an endangered bird, the Plains-wanderer (Pedionomus torquatus). In this study, we provide further critical analysis of the method using three data sets collected across different parts of Victoria that relate golf ball scores to various habitat attributes. We demonstrate how the golf ball score provides a good surrogate for key aspects of grassland structure. We show that the method does not provide a reliable surrogate for above-ground biomass or vegetation cover, although we discuss how biomass and cover are not particularly good indicators of grassland structure. We argue that elements of grassland structure may be better correlated with desired conservation outcomes (e.g. plant species diversity or the presence of a particular species) than biomass or cover alone. We discuss examples of how the golf ball method has been used, and how it can be improved. The method will be particularly useful where a link can be demonstrated between golf ball scores and desired conservation outcomes, such as in the case of the Plains-wanderer. © 2017 Ecological Society of Australia and John Wiley & Sons Australia, Ltd
A field trial to test effects of watering, seed addition and disturbance on perennial species recruitment in Belah woodland
- Authors: Callister, Katrina , Westbrooke, Martin
- Date: 2017
- Type: Text , Journal article
- Relation: Ecological Management and Restoration Vol. 18, no. 3 (2017), p. 246-249
- Full Text: false
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- Description: Failure of perennial species to regenerate is a significant threat to semi-arid woodlands across south-eastern Australia. High grazing pressure eliminates the recruitment of many perennial species in semi-arid woodlands, but little is known about requirements for regeneration under low grazing pressure. We tested the effects of addition of water (irrigation to match the largest rainfall events of the last century), seed, soil disturbance and fire within a grazing exclosure in Belah (Casuarina pauper) woodland in the Murray-Sunset National Park, Victoria. Recruitment was observed in 13 perennial species and was dominated by chenopods. Addition of water, seed and soil disturbance increased abundance of juvenile perennial species above the low-level background recruitment that occurred in the prevailing drought conditions. This supports the view that continuous recruitment occurs for many semi-arid perennials. Low seed availability and an inability to maintain soil moisture conditions matching that of regeneration events are likely factors in the lack of recruitment for tree species and limited response of shrubs in this experiment. © 2017 Ecological Society of Australia and John Wiley & Sons Australia, Ltd
Western myall groves (Acacia papyrocarpa) determine the fine-scale distribution of soil Collembola in semi-arid South Australia
- Authors: Kwok, Alan , Greenslade, Penelope
- Date: 2016
- Type: Text , Journal article
- Relation: Austral Ecology Vol. 41, no. 6 (2016), p. 613-621
- Full Text: false
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- Description: Vegetation can exert a strong influence on the distribution and activity of biotic communities across a broad range of spatial scales, especially in arid and semi-arid ecosystems. At fine spatial scales, patches created by individual plants can support different faunal and floral communities even at locations distant from the plant. These differences can have profound effects on a range of ecosystem processes, including seed dispersal, nutrient cycling and resource distribution. In semi-arid Australia, areas surrounding groves of western myall (Acacia papyrocarpa) trees are largely devoid of vegetation, being referred to as ‘halos’. Here, we investigate the soil-dwelling Collembola in groves of western myall trees, the surrounding halos and nearby chenopod shrubland. We also investigated whether the abundance of Collembola was influenced by soil depth (0–5 cm layer vs. 6–10 cm layer) in groves. We found that collembolan density was approximately nine times lower and taxonomic richness half that in a halo compared with the grove and chenopod vegetation. Furthermore, analyses at finer taxonomic levels indicate that vegetation patches differed in species composition, with some species restricted to or preferring particular patches. In the grove, we found a higher abundance of Collembola in the 0–5 cm soil layer compared with the 6–10 layer. Our results indicate vegetation patches strongly influence collembolan abundance and species composition in bare patches around western myall. As patches created by vegetation are a common feature of semi-arid and arid regions, we suspect that these effects are widespread although seldom reported. Furthermore, as Collembola are involved in the decomposition process, Acacia papyrocarpa patches will be influencing nutrient cycling through their effects on the soil biota. Our results also emphasize that comprehensive fauna survey and management of woodland ecosystems need to consider fine-scale processes.
An assessment of riparian restoration outcomes in two rural catchments in south-western Victoria : Focusing on tree and shrub species richness, structure and recruitment characteristics
- Authors: Wevill, Tricia , Florentine, Singarayer
- Date: 2014
- Type: Text , Journal article
- Relation: Ecological Management and Restoration Vol. 15, no. 2 (2014), p. 133-139
- Full Text: false
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- Description: Riparian ecosystems are among the most degraded systems in the landscape, and there has been substantial investment in their restoration. Consequently, monitoring restoration interventions offers opportunities to further develop the science of riparian restoration, particularly how to move from small-scale implementation to a broader landscape scale. Here, we report on a broad range of riparian revegetation projects in two regions of south-western Victoria, the Corangamite and Glenelg-Hopkins Catchment Management Areas. The objectives of restoration interventions in these regions have been stated quite broadly, for example, to reinstate terrestrial habitat and biodiversity, control erosion and improve water quality. This study reports on tree and shrub composition, structure and recruitment after restoration works compared with remnant vegetation found regionally. Within each catchment, a total of 57 sites from six subcatchments were identified, representing three age-classes: <4, 4-8 and >8-12 years after treatment, as well as untreated (control) sites. Treatments comprised fencing to exclude stock, spraying or slashing to reduce weed cover, followed by planting with tube stock. Across the six subcatchments, 12 reference (remnant) sites were used to provide a benchmark for species richness, structural and recruitment characteristics and to aid interpretation of the effects of the restoration intervention. Vegetation structure was well developed in the treated sites by 4-8 years after treatment. However, structural complexity was higher at remnant sites than at treated or untreated sites due to a higher richness of small shrubs. Tree and shrub recruitment occurred in all remnant sites and at 64% of sites treated >4 years ago. Most seedling recruitment at treatment sites was by Acacia spp. This assessment provides data on species richness, structure and recruitment characteristics following restoration interventions. Data from this study will contribute to longitudinal studies of vegetation processes in riparian landscapes of south-western Victoria. © 2014 Ecological Society of Australia and Wiley Publishing Asia Pty Ltd.
Identifying a surrogate metric for monitoring the population status of a secretive habitat specialist, the heath skink Liopholis multiscutata, in south-eastern Australia
- Authors: Brown, Geoff , Robertson, Peter , Fanson, Ben
- Date: 2020
- Type: Text , Journal article
- Relation: Austral Ecology Vol. 45, no. 2 (2020), p. 206-214
- Full Text: false
- Reviewed:
- Description: Threatened species that exist in small isolated populations are vulnerable to extinction processes, so effectively monitoring the trajectory of such populations will help determine the most appropriate management actions to combat extinction threats. In this study, we aimed to track the population status of the fossorial heath skink Liopholis multiscutata that is listed as threatened in Victoria, south-eastern Australia, and exists there as a few small and highly disjunct populations, by using an appropriate surrogate population monitoring metric. This secretive lizard is a habitat specialist, is highly localised in Victoria and lives in warrens in semi-arid heathland or mallee on large dunes. Survey data, which included every warren and their constituent burrows, as well as an assessment of whether each burrow was ‘active’, were collected for the four known Victorian populations in 2007 and annually during 2014–2018 inclusive. We compared five population indices per monitoring site: number of active warrens (NAW), number of active burrows (NAB), population area for 80% of active warrens (PA80), percentage of warrens that were active (PAW) and average number of active burrows per active warren. The heath skink currently occurs in small populations (8–46 active warrens) and these populations have typically declined over recent years. NAW was the most robust metric; NAB and PA80 did not reveal strong temporal trends. PAW indicated that inactive warrens and burrows persist less than a year and hence may provide information about recent (within months) population changes. It is imperative to establish a material link between the effective monitoring of small, vulnerable populations and the implementation of management actions that benefit such populations. Here, NAW could be used as a long-term monitoring tool to provide an estimate of the minimum population size of the heath skink at a site. Its use would also ensure continuity in monitoring approaches for the Victorian populations. © 2019 Ecological Society of Australia
Quantifying shifts in topic popularity over 44 years of austral ecology
- Authors: Westgate, Martin , Barton, Philip , Lindenmayer, David , Andrew, Nigel
- Date: 2020
- Type: Text , Journal article
- Relation: Austral Ecology Vol. 45, no. 6 (2020), p. 663-671
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- Description: The Ecological Society of Australia was founded in 1959, and the society’s journal was first published in 1976. To examine how research published in the society’s journal has changed over this time, we used text mining to quantify themes and trends in the body of work published by the Australian Journal of Ecology and Austral Ecology from 1976 to 2019. We used topic models to identify 30 ‘topics’ within 2778 full-text articles in 246 issues of the journal, followed by mixed modelling to identify topics with above-average or below-average popularity in terms of the number of publications or citations that they contain. We found high inter-decadal turnover in research topics, with an early emphasis on highly specific ecosystems or processes giving way to a modern emphasis on community, spatial and fire ecology, invasive species and statistical modelling. Despite an early focus on Australian research, papers discussing South American ecosystems are now among the fastest-growing and most frequently cited topics in the journal. Topics that were growing fastest in publication rates were not always the same as those with high citation rates. Our results provide a systematic breakdown of the topics that Austral Ecology authors and editors have chosen to research, publish and cite through time, providing a valuable window into the historical and emerging foci of the journal. © 2020 Ecological Society of Australia