Flow regimes and ecological assets.A technical report from the Ecological Responses to Altered Flow Regimes Flagship Research Cluster (SubProject 2)

[摘要] Climate, natural flow regimes, river habitats and catchment attributes differ substantially across the 1,000,000 km2 plus area covered by the Murray-Darling Basin (MDB), yet a comprehensive and spatially explicit characterisation of river and wetland habitats across the basin is lacking. Differences in riverscape setting influence the character of aquatic ecosystems, their water regime requirements, and the way in which they are likely to their responds to altered watering regimes and climate change. Describing the ecohydrological characteristics and diversity of aquatic ecosystems is fundamentally important in efficiently managing the Murray-Darling Basin’s natural resources. This project, a part of the Ecological Responses to Altered Flow Regimes Flagship Research Cluster, generated a range of spatial information layers that help describe and simplify the underlying spatial variability in environments and species distributions. Outputs of this work include:• Identification and classification of ecological assets and values within the Basin: Much consultation has already been undertaken to gain a shared understanding of the range of important environmental assets and values that exist within the MDB. However, in spite of efforts to compile a broad range of environmental and ecological datasets, there are strong taxonomic biases and other shortcomings in datasets describing the characteristics of aquatic systems across the region. As a first step in trying to better characterise that variability, this project generated a spatial information database (MDB Aquatic Ecosystems Database) containing spatially consistent and Basin-wide mapping products and environmental attribute information capable of supporting a range of analyses. This Geodatabase was used to classify aquatic ecosystems (rivers, lakes, wetlands and floodplains) across the basin.• The identification of ecologically relevant flow regime types across the MDB and how these map against geomorphic and biogeographic components: Flow regimes are a primary determinant of the structure and function of aquatic ecosystems (Arthington et al., 2006, Poff et al., 2009). Understanding natural patterns of hydrology in time and space and the associated ecological consequences of altering these patterns of flow variability is fundamental to the assessment and management of environmental water allocations for river and wetland ecosystems (BunnArthington, 2002; Richter et al., 2006). Here we focussed on the spatial extrapolation of statistics describing the hydrologic characteristics of rivers calculated from the network of gauging stations and modelling nodes distributed across the basin. This dataset facilitates the linking of existing biological survey data to hydrologic summary data that previously was only available for specific gauging sites.• Development of predictive models of species distributions: This component drew on existing datasets for freshwater fish occurrences, and linked these to spatial data describing climate, catchment physiography and hydrology to develop predictive models of fish distributions. This work extends information on species distributions in poorly sampled river basins, providing an improved basis from which to develop systematic decisions about how to prioritise future investment in river protection and restoration.• Assessment of flow-related threats and restoration opportunities: In this section, we quantify the spatial distribution of threats flow regimes throughout the basin. Different parts of the Basin are each subjected to distinctive combinations of water use, such as interception by farm dams, direct extraction, and storage in large on-channel reservoirs. We also mapped the spatial distribution of areas and aquatic ecological assets (described in Section 2) that could potentially receive the benefits of managed flow releases from dams. This knowledge could help identify key gaps in the current environmental watering strategy and prio

[发布日期] 2014-10-16 [发布机构] CSIRO

[学科分类] 地球科学(综合)