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Tozer M.G.,New South Wales Office of Environment and Heritage | Ooi M.K.J.,University of Wollongong
Annals of Botany | Year: 2014

Background and aims Seed dormancy enhances fitness by preventing seeds from germinating when the probability of seedling survival and recruitment is low. The onset of physical dormancy is sensitive to humidity during ripening; however, the implications of this mechanism for seed bank dynamics have not been quantified. This study proposes a model that describes how humidity-regulated dormancy onset may control the accumulation of a dormant seed bank, and seed experiments are conducted to calibrate the model for an Australian Fabaceae, Acacia saligna. The model is used to investigate the impact of climate on seed dormancy and to forecast the ecological implications of human-induced climate change. Methods The relationship between relative humidity and dormancy onset was quantified under laboratory conditions by exposing freshly matured non-dormant seeds to constant humidity levels for fixed durations. The modelwas field-calibrated by measuring the response of seeds exposed to naturally fluctuating humidity. The modelwas applied to 3-hourly records of humidity spanning the period 1972-2007 in order to estimate both temporal variability in dormancy and spatial variability attributable to climatic differences among populations. Climate change models were used to project future changes in dormancy onset. Key Results A sigmoidal relationship exists between dormancy and humidity under both laboratory and field conditions. Seeds ripened under field conditions became dormant following very short exposure to low humidity (<20 %). Prolonged exposure at higher humidity did not increase dormancy significantly. It is predicted that populations growing in a temperate climate produce 33-55%fewer dormant seeds than those in a Mediterranean climate; however, dormancy in temperate populations is predicted to increase as a result of climate change. Conclusions Humidity-regulated dormancy onset may explain observed variation in physical dormancy. The model offers a systematic approach to modelling this variation in population studies. Forecast changes in climate have the potential to alter the seed bank dynamics of species with physical dormancy regulated by this mechanism, with implications for their capacity to delay germination and exploit windows for recruitment. © 2014 The Author.

Chessman B.C.,New South Wales Office of Environment and Heritage
Journal of Applied Ecology | Year: 2013

Summary: Assessment of the performance of protected areas in conserving freshwater biodiversity has been limited, has mostly involved small-scale studies and has produced mixed findings. I analysed monitoring data from Australia's Murray-Darling Basin (>106 km2 and mostly arid or semi-arid) to compare fish assemblages between rivers inside and outside of protected areas. The average richness and abundance of native species were significantly lower at sites within protected areas, but these sites were weighted towards steeper terrain and colder climates. When analysis was confined to a subset of geographically and environmentally matched sites, the richness and abundance of native species did not differ significantly between protected and unprotected areas, and only two native species were significantly more abundant within protected areas, whereas another two were significantly more abundant outside. Synthesis and applications. Protected status probably has little effect on native fish in the Murray-Darling Basin because it does not, by itself, exclude threats such as alien fish and alteration of water regimes. My findings therefore support the view that reserves need to be designed and managed specifically for freshwater species if they are to be most effective in their conservation. In the Murray-Darling Basin, and in similar regions around the world, actions such as greater control of alien species and allocation of adequate environmental flows will likely be critical to enabling protected areas to realize their potential for aquatic conservation. Protected status probably has little effect on native fish in the Murray-Darling Basin because it does not, by itself, exclude threats such as alien fish and alteration of water regimes. My findings therefore support the view that reserves need to be designed and managed specifically for freshwater species if they are to be most effective in their conservation. In the Murray-Darling Basin, and in similar regions around the world, actions such as greater control of alien species and allocation of adequate environmental flows will likely be critical to enabling protected areas to realize their potential for aquatic conservation. © 2013 British Ecological Society.

Chessman B.C.,New South Wales Office of Environment and Heritage
Biological Conservation | Year: 2013

Trait analysis has potential to identify species that are vulnerable to climate change, but its predictive strength has not been adequately examined. Conditions during the recent 'Millennium Drought' in Australia's Murray-Darling Basin resembled the projected future climate of the region and provided an opportunity to test the ability of traits to predict population responses to a warmer and drier environment. I used data from a large-scale monitoring program to assess how 14 dietary, life-history and physiological-tolerance traits related to changes in occurrence and abundance of 39 of the basin's freshwater fish species. Species that fared worse under prolonged drought were significantly more likely to have an invertivorous rather than omnivorous diet, a low age at sexual maturity, a small maximum body size, a low spawning temperature, a long spawning season, low fecundity, demersal rather than planktonic eggs, and a low upper thermal limit. Rankings of drought vulnerability of fish species derived from correlations between population changes and traits showed good agreement with a previous assessment of inter-specific variation in resistance to drought, and were corroborated by independent observations of drought responses for some species. Trait analysis should have wide application to identifying species at risk from climate change, provided that sufficient traits are assessed and that adequate consideration is given to variation in trait-vulnerability relationships among different groups of organisms, geographic regions and types of ecosystems. © 2013 Elsevier Ltd.

Walsh V.,New South Wales Office of Environment and Heritage.
Environmental and Planning Law Journal | Year: 2014

Policy-makers in New SouthWales have recognised the need for a transparent and consistent response to the assessment of offsets proposals in addressing the biodiversity impacts of major projects. This follows a high-profile rejection of a biodiversity offset proposal by the Land and Environment Court (LEC) for a coalmine extension in the Hunter Valley. A policy and methodology for calculating offset requirements has since been prepared by the New South Wales Government and will be used by consent authorities in approving new major project development. This article examines how this policy is likely to impact upon the LEC’s important role in the oversight of offset proposals in both its merits review and judicial review jurisdiction. Whether implemented administratively or through legislation, this article concludes that oversight is likely to continue despite moves by the New South Wales Government to limit recourse to the LEC. © 2015, (publisher). All rights reserved.

Berney P.,New South Wales Office of Environment and Heritage | Hosking T.,New South Wales Office of Environment and Heritage
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2016

In dryland environments, freshwater ecosystems often suffer extensive degradation through habitat modification and water regime changes. The Macquarie Marshes are located in the Murray–Darling Basin in south-eastern Australia. They are an example of an ecosystem that has experienced significant degradation in recent decades owing to upstream water diversions. Recent reforms of water management in the Murray–Darling Basin have attempted to balance environmental needs against consumptive uses of water. This paper examines the role a protected area has played in conserving the Macquarie Marshes freshwater ecosystem and discusses how Murray–Darling Basin water reform, together with social expectations of public land managers, have had impacts on the management of the Macquarie Marshes Nature Reserve. Protected areas may limit adverse impacts on habitat associated with local-scale agricultural production but struggle without formal water management arrangements to protect water-dependent ecosystems from threats operating at a catchment scale. Protected area managers balance demands from stakeholders to address local issues, such as fire management and geomorphic changes, against contributing to the achievement of environmental goals in a water planning system that operates at the catchment scale. European settlement and water resource development has marginalized local Aboriginal people from any role in land and water management activities. The water reforms have given them more opportunities for involvement in decision-making processes, but opportunities for increased access to water for cultural and spiritual purposes remain limited. Protected areas offer a means of providing greater access for Aboriginal people to their ancestral lands. The strategies and processes developed to maintain and enhance the Macquarie Marshes exemplify the evolution in understanding of freshwater ecosystem protection in Australia, and are relevant globally to water resource management in complex social-ecological systems. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Yang X.,New South Wales Office of Environment and Heritage
Soil Research | Year: 2014

Soil loss due to water erosion, in particular hillslope erosion, can be estimated using predictive models such as the Revised Universal Soil Loss Equation (RUSLE). One of the important and dynamic elements in the RUSLE model is the cover and management factor (C-factor), which represents effects of vegetation canopy and ground cover in reducing soil loss. This study explores the potential for using fractional vegetation cover, rather than traditional green vegetation indices (e.g. NDVI), to estimate C-factor and consequently hillslope erosion hazard across New South Wales (NSW), Australia. Values of the C-factor were estimated from the emerging time-series fractional cover products derived from Moderate Resolution Imaging Spectroradiometer (MODIS). Time-series C-factor and hillslope erosion maps were produced for NSW on monthly and annual bases for a 13-year period from 2000 to 2012 using automated scripts in a geographic information system. The estimated C-factor time-series values were compared with previous study and field measurements in NSW revealing good consistency in both spatial and temporal contexts. Using these time-series maps, the relationship was analysed between ground cover and hillslope erosion and their temporal variation across NSW. Outcomes from this time-series study are being used to assess hillslope erosion hazard, sediment and water quality (particularly after severe bushfires) across NSW at local, catchment and regional scales. © CSIRO 2014.

Yang X.,New South Wales Office of Environment and Heritage | Yu B.,Griffith University
Soil Research | Year: 2015

Considerable seasonal and inter-annual changes exist in rainfall amount and intensity in New South Wales (NSW), Australia. These changes are expected to have significant effect on rainfall erosivity and soil erosion by water, but the magnitude of the impact is not well quantified because of the non-linear and dynamic nature of the relationship between rainfall amount and rainfall erosivity. The primary aim of this study was to model spatial and temporal variations in rainfall erosivity and impacts on hillslope erosion across NSW. We developed a daily rainfall erosivity model for NSW to calculate monthly and annual rainfall erosivity values by using gridded daily rainfall data for a continuous 53-year period including a baseline period (1961-90) and a recent period (2000-12). Model parameters were improved based on their geographic locations and elevations to be truly geo-referenced and representative of the regional relationships. Monthly and annual hillslope erosion risk for the same periods was estimated with the Revised Universal Soil Loss Equation. We produced finer scale (100-m) maps of rainfall erosivity and hillslope erosion through spatial interpolation techniques, and implemented the calculation of rainfall erosivity and hillslope erosion in a geographic information system by using automated scripts so that it is fast, repeatable and portable. The modelled rainfall erosivity values were compared with pluviograph calculations and previous studies, and the Nash-Sutcliffe coefficient of efficiency is >0.90. Outcomes from this study provide not only baseline information but also continuous estimates of rainfall erosivity and hillslope erosions allowing better monitoring and mitigation of hillslope erosion risk in NSW. © CSIRO 2015.

Wilson N.C.,Shatterwood | Saintilan N.,New South Wales Office of Environment and Heritage
Aquatic Botany | Year: 2012

A study on the growth of . Rhizophora stylosa Griff. was undertaken in three estuaries spanning the southernmost 265. km of its range at its latitudinal limit in eastern Australia. A shoot tracking methodology was devised to follow vegetative phenological patterns and branching and to derive indices of relative growth between trees. Despite an apparent expansionary phase in distribution and a recent increased trend in mean temperature, comparisons of growth in the three estuaries do not suggest a latitudinal cline. The phenologies of leaf gain and leaf loss are generally comparable between . R. stylosa in New South Wales and elsewhere, as is the rate of growth assessed by leaf initiation. However, leaf longevity and the number of leaves held on the shoot appears to be overall greater in NSW than in lower latitudes, perhaps as an adaptive response to lower levels of assimilation. This study suggests that . R. stylosa is not close to physiological limits at the end of its range, supporting a contention that its current known southern limit is not at an absolute thermal boundary. © 2012 Elsevier B.V.

Chessman B.C.,New South Wales Office of Environment and Heritage
Wildlife Research | Year: 2011

Context While much attention has been paid to the effects of global temperature increases on the geographical ranges and phenologies of plants and animals, less is known about the impacts of climatically driven alteration of water regimes. Aims To assess how three species of freshwater turtle in Australia's MurrayDarling Basin have responded to long-term decline in river flow and floodplain inundation due to climatic drying and water diversions. Methods Turtle populations were sampled in a section of the Murray River and its floodplain in 197682 following a wet period and in 200911 at the end of the most severe drought on record. Catch per unit effort, proportional abundance in different habitat types and population structure were assessed in both periods. Key results Catch per unit effort in baited hoop nets declined by 91% for the eastern snake-necked turtle (Chelodina longicollis) and 69% for the Murray turtle (Emydura macquarii), but did not change significantly for the broad-shelled turtle (Chelodina expansa). In addition, total catches from a range of sampling methods revealed a significantly reduced proportion of juvenile C. longicollis and E. macquarii in 200911, suggesting a fall in recruitment. Key conclusions The decline of C. longicollis was likely due mainly to drought-induced loss of critical floodplain habitat in the form of temporary water bodies, and that of E. macquarii to combined effects of drought and predation on recruitment. C. expansa seems to have fared better than the other two species because it is less vulnerable to nest predation than E. macquarii and better able than C. longicollis to find adequate nutrition in the permanent waters that remain during extended drought. Implications Declining water availability may be a widespread threat to freshwater turtles given predicted global impacts of climate change and water withdrawals on river flows. Understanding how each species uses particular habitats and how climatic and non-climatic threats interact would facilitate identification of vulnerable populations and planning of conservation actions. © CSIRO 2011.

Chessman B.C.,New South Wales Office of Environment and Heritage
Journal of Biogeography | Year: 2012

Aim To test the ability of biological traits to predict climate-related changes in geographical ranges of running-water invertebrates. Location The Australian state of New South Wales and the Australian Capital Territory. Methods I analysed data from 8928 biomonitoring samples collected during a 16-year period of generally rising air temperatures and declining precipitation. I used quantile regression to test for expansions and contractions on the climatically cooler, warmer, drier and wetter edges of the ranges of 120 invertebrate taxa, and correlated these shifts with the traits of thermophily (degree of preference for high versus low temperature) and rheophily (preference for flowing versus still water). Results The most commonly inferred range shifts were cool-edge expansion plus warm-edge contraction (71 taxa) and wet-edge expansion plus dry-edge contraction (71), but contractions from both cool and warm extremes (36) and from both dry and wet extremes (28) were also frequent. High-temperature preference was associated with cool-edge expansion and low-temperature preference with wet-edge expansion and contraction from all other extremes. A preference for flow was associated with wet-edge expansion and dry-edge contraction. Main conclusions Trait analysis has potential for predicting which species will expand their ranges and which will contract, but needs to be coupled with assessment of how the landscape provides each species with opportunities to track or avoid climate change. Improved quantification of climatically relevant traits and integration of trait analysis with species distribution modelling are likely to be beneficial. © 2011 Blackwell Publishing Ltd.

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