DEA Wetlands Insight Tool (Ramsar Wetlands)

Vector product

Version:: 4.0.0
Type:: Derivative, Vector
Coverage:: 1987 to 2021
Data updates:: As needed, Ongoing

Overview

About

Our precious wetlands are dynamic and diverse environments. The Digital Earth Australia (DEA) Wetlands Insight Tool (Ramsar) gives visibility of changes to the amount of water, green vegetation, dry vegetation, and bare soil that have taken place in Australia’s Ramsar wetlands since 1987.

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Data sources

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Code examples

Key specifications

For more specifications, see the Specifications tab.

Technical name	Wetlands Insight Tool Ramsar Wetlands Polygons
Catalogue ID	146165
Parent product	DEA Water Observations (Collection 2), DEA Fractional Cover (Collection 2), and Landsat 5, 7 and 8 NBART and Observational Attributes (Collection 2)
Collection	Geoscience Australia Landsat Collection 2
Tags	geoscience_australia_landsat_collection_2_deprecated, wetlands, environmental_management
Licence	Creative Commons Attribution 4.0 International Licence

Cite this product

Data citation

Geoscience Australia, 2021. Wetlands Insight Tool Ramsar Wetlands Polygons. Geoscience Australia, Canberra. https://pid.geoscience.gov.au/dataset/ga/146165

Paper citation

Dunn, B., Ai, E., Alger, M.J., Fanson, B., Fickas, K.C., Krause, C.E., Lymburner, L., Nanson, R., Papas, P., Ronan, M., Thomas, R.F., 2023. Wetlands Insight Tool: Characterising the Surface Water and Vegetation Cover Dynamics of Individual Wetlands Using Multidecadal Landsat Satellite Data. Wetlands 43, 37. https://doi.org/10.1007/s13157-023-01682-7

Publications

Dunn, B., Ai, E., Alger, M.J., Fanson, B., Fickas, K.C., Krause, C.E., Lymburner, L., Nanson, R., Papas, P., Ronan, M., Thomas, R.F., 2023. Wetlands Insight Tool: Characterising the Surface Water and Vegetation Cover Dynamics of Individual Wetlands Using Multidecadal Landsat Satellite Data. Wetlands 43, 37. https://doi.org/10.1007/s13157-023-01682-7

Description

Background

Wetlands provide a wide range of ecosystem services including improving water quality, carbon sequestration, as well as providing habitat for fish, amphibians, reptiles and birds. Managing wetlands in Australia is challenging due to competing pressures for water availability and highly variable climatic settings. The Wetlands Insight Tool (Ramsar Wetlands) has been developed to provide catchment managers, environmental water holders, and wetlands scientists a consistent historical baseline of wetlands dynamics from 1987 onwards. The Wetlands Insight Tool (Ramsar Wetlands) is available online through the DEA Maps website.

The Ramsar Wetlands of Australia Dataset is available under a Creative Commons Attribution 3.0 Australia Licence . We created individual wetland polygons from the multipart Ramsar polygons in the dataset. The 6 Australian Ramsar Sites in external territories are excluded as they are outside of Australia’s satellite data footprint.

What this product offers

The Wetlands Insight Tool (Ramsar Wetlands) summarises how the amount of water, green vegetation, dry vegetation and bare soil varies over time within each wetland boundary. It provides the user with the ability to compare how the wetland is behaving now with how it has behaved in the past. This allows users to identify how changes in water availability have affected the wetland. It achieves this by presenting a combined view of Water Observations from Space (DEA Water Observations), Tasseled Cap Wetness (DEA Wetness Percentiles) and Fractional Cover (DEA Fractional Cover) measurements from the Landsat series of satellites, summarised as a stacked line plot to show how that wetland has changed over time.

Wetlands Insight Tool plot for Narran Lakes Nature Reserve, New South Wales, showing variations in open water, wet, green vegetation, dry vegetation and bare soil from 1987 to 2021

Applications

The product is designed to support Ramsar wetland managers, catchment managers and environmental waterholders in understanding whether or not wetlands are changing over time. In instances where the wetlands are changing, the tool allows users to identify whether the changes are gradual, rapid, once-off or cyclical in nature. For example the response of wetlands to the following drivers can be assessed:

Changes in river flow volumes
Changes in flood frequency
Long term shifts in rainfall
Wet-season/Dry-season shifts in water availability
Invasive weeds
Environmental watering events

Care should be used when interpreting Wetlands Insight Tool (Ramsar Wetlands) results as increases/decreases in particular cover types can be associated with different processes. For example an increase in green cover could indicate canopy recovery of desirable wetland species or an increase in the amount of invasive weeds.

Technical information

Every pixel within a wetland polygon is evaluated using this decision tree at every time step, and the results are tabulated to create the input data to the stacked line plot for that wetland. The image shows a flow chart where a pixel is checked to see if it is cloudy or nodata, classified by WOfS as water, the Tasseled Cap Wetness value is greater than negative 350. if yes the pixel is classified as cloudy or notdata, then open water, then wet, and if no then the Fractional Cover of Vegetation percentage is retrieved for the pixel and the percentage of green vegetation, dry vegetation and bare soil is returned.

WIT flow chart

The code base used to generate the Ramsar Wetlands Insight Tool results is available at GeoscienceAustralia/wit_tooling

References

Scarth, P., Röder, A., Schmidt, M., 2010. Tracking grazing pressure and climate interaction - the role of Landsat fractional cover in time series analysis. In: Proceedings of the 15th Australasian Remote Sensing and Photogrammetry Conference (ARSPC), 13-17 September, Alice Springs, Australia. Alice Springs, NT.

Guerschman, J.P., Scarth, P.F., McVicar, T.R., Renzullo, L.J., Malthus, T.J., Stewart, J.B., Rickards, J.E., & Trevithick, R. (2015). Assessing the effects of site heterogeneity and soil properties when unmixing photosynthetic vegetation, non-photosynthetic vegetation and bare soil fractions from Landsat and MODIS data. Remote Sensing of Environment, 161, 12-26, https://doi.org/10.1016/j.rse.2015.01.021

Muir, J., Schmidt, M., Tindall, D., Trevithick, R., Scarth, P., Stewart, J., 2011. Guidelines for Field measurement of fractional ground cover: a technical handbook supporting the Australian collaborative land use and management program. Tech. rep., Queensland Department of Environment and Resource Management for the Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra.

Mueller, N., Lewis, A. Roberts, D., Ring, S., Melrose, R., Sixsmith, J., Lymburner, L., McIntyre, A., Tan, P., Curnow, S. and Ip, A.(2016) ‘Water observations from space: Mapping surface water from 25 years of Landsat imagery across Australia’, Remote Sensing of Environment, 174, 341-352, https://doi.org/10.1016/j.rse.2015.11.003

Crist, E.P. (1985) ‘A TM Tasseled Cap equivalent transformation for reflectance factor data’, Remote Sensing of Environment, 17(3), 301-306, https://doi.org/10.1016/0034-4257(85)90102-6

Quality

Accuracy

The accuracy of the stacked line plots is dependent on the accuracy of the underlying algorithms: Water Observations from Space (Mueller et al. 2016) and the Joint Remote Sensing Research Program’s Fractional Cover algorithm (Scarth et al. 2010).

The Tasseled Cap Wetness threshold used in the Wetlands Insight Tool has been compared with independent inundation data for one major wetland complex, however the Tasseled Cap Wetness index may under or overestimate the actual extent of inundation for individual wetlands. The use of a consistent threshold means that the ‘precision’ is high, insofar as you’re measuring the same aspect of the wetland at each point in time, however the accuracy with which Tasseled Cap Wetness measures free water underneath/within wetland vegetation is not quantified.

The interpretability of the results for each polygon is dependent on the accuracy of the linework that has been used to create that polygon. The line work used in the Wetlands Insight Tool (Ramsar Wetlands) comes from the 19/03/2020 revision of the Ramsar Wetlands of Australia Dataset (available under a Creative Commons Attribution 3.0 Australia Licence) and has been processed by exploding large polygons into smaller polygons in QGIS. This means that sites where multiple boundaries exist have a separate plot for separate subsites, allowing users to understand the dynamics of the subsites separately. Users are able to manually combine Wetlands Insight Tool outputs accessed through DEA Maps as csvs to gain an understanding of combined sites. The 6 Australian Ramsar Sites in external territories are excluded as they are outside of Australia’s satellite data footprint.

The 30 metre resolution of Landsat imposes an intrinsic limitation on the Wetlands Insight Tool. Wetland areas that are small, or long and narrow in nature are likely to be inaccurate (due to inclusion of neighbouring non-wetland pixels) or difficult to interpret (stack line plots for areas with a small number of pixels have sharp steps in them).

The period of time between when Landsat 5 ceased operations (November 2011) and Landsat 8 data became routinely available (May 2013) is likely to be inaccurate. There will be some wetlands, close to the centre of Landsat paths where Landsat 7 continued to capture suitable (gap free) data, however it is safer, as a general rule, to consider this period as ‘low data quality’. Other periods where less than four observations occur in a calendar year are also considered ‘low data quality’. Regions of low data quality are hashed with a pale rectangular overlay in the Wetlands Insight Tool plots.

Wetlands Insight Tool plot for Narran Lakes Nature Reserve, New South Wales, showing variations in open water, wet, green vegetation, dry vegetation and bare soil from 1987 to 2021

Quality assurance

Quality assurance was undertaken to ensure that a Wetlands Insight Tool stacked line plot was generated for every exploded polygon in the Ramsar Wetlands polygon set, where satellite data was available through Digital Earth Australia. Sites outside continental Australia may not be available in the dataset.

Specifications

Product information

This metadata provides general information about the product.

Short name	DEA Wetlands Insight Tool (Ramsar Wetlands)	The name that is commonly used to refer to the product.
Technical name	Wetlands Insight Tool Ramsar Wetlands Polygons	The full technical name that refers to the product and its specific provider, sensors, and collection.
Version	4.0.0	The version number of the product.
Lineage type	Derivative	Derivative products are derived from other products.
Spatial type	Vector	Vector data consists of spatial polygons, lines, and points.
Temporal coverage	1987 to 2021	The time span for which data is available.
Update frequency	As needed	The expected frequency of data updates. Also called ‘Temporal resolution’.
Update activity	Ongoing	The activity status of data updates.
Catalogue ID	146165	The Data and Publications catalogue (eCat) ID.
Licence	Creative Commons Attribution 4.0 International Licence	See the Credits tab.

Product categorisation

This metadata describes how the product relates to other DEA products.

Parent product	DEA Water Observations (Collection 2), DEA Fractional Cover (Collection 2), and Landsat 5, 7 and 8 NBART and Observational Attributes (Collection 2)
Collection	Geoscience Australia Landsat Collection 2
Tags	geoscience_australia_landsat_collection_2_deprecated, wetlands, environmental_management

Access

Access the data

DEA Maps	See it on a map	Learn how to use DEA Maps.
Data sources	Access the data on AWS	Learn how to access the data via AWS.
Code examples	View code examples	Learn how to use the DEA Sandbox.

Credits

Acknowledgments

The Fractional cover (v2) algorithm is provided courtesy of the Joint Remote Sensing Research Program. The development of the algorithm was supported by field data collection by Australian State and Territory agencies, TERN and the National Ground Cover Monitoring Program, coordinated by ABARES.

The Ramsar Wetlands of Australia Dataset used as the vector file over which the WIT plots and data per wetland were generated is available from the Australian Government Department of Agriculture, Water and the Environment under a Creative Commons Attribution 3.0 Australia Licence.

License and copyright

Released under Creative Commons Attribution 4.0 International Licence.