Wetlands,
Biodiversity and Salt
Wetlands as landscape units
August 2006
Overview
Findings
Non-riverine wetlands provide many important
ecosystem services, including sediment and
nutrient cycling and retention at the catchment
level. These ecosystems are particularly
important habitat for local and regional
biodiversity and, yet, the management of
wetlands outside of riverine floodplains (nonriverine wetlands) is difficult. There is limited
understanding of non-riverine wetlands and of
the processes that threaten them, such as
secondary salinisation.
• Spatial analyses indicated that the
distribution of the study wetlands was not
random.
Aims
We describe the patterns of variation in nonriverine wetland salinity and water chemistry
across a regional landscape that is threatened
by secondary salinisation (Map 1) to allow us
to better understand these water bodies and
the threat that increasing salinity poses.
Specifically, we
• We found considerable positive spatial
auto-correlation in water chemistry among
wetlands, which indicates a lack of
independence.
• We detected massive variation in water
chemistry among wetlands compared to
minimal within-wetland variation.
• Conductivity accounted for most of the
among-wetland variation, confirming its
prominence in non-riverine wetland water
chemistry.
• Wetland salinities were classified by their
chemical evaporative pathway.
• Around 25% of the study wetlands were
secondary salinised.
• describe patterns of variation in the salinity
and water chemistry of wetlands at a
landscape scale
• compare the variation in salinity and water
chemistry within and among wetlands
• look for evidence indicating changes to
natural salinity regimes.
Map 1: Study area and study sites
Collins Swamp. Photo: Michael Smith
A Victorian
Government
initiative
• Management of wetlands should be
approached at multiple scales - thus
introducing a broader context that includes
other wetlands in the area and should be
closely linked to the management of
groundwater systems.
Toolongrook State Forest.
Photo: Michael Smith
Outcomes
• The spatial organisation of wetlands can
have considerable bearing on their biotic
and abiotic composition.
• Understanding variability in water chemistry
at the landscape scale is important because
biotic diversity may rely on abiotic diversity.
• Groups of wetlands in an area can have
shared input from the surrounding biotic
and abiotic environments (eg, shared
geological and biological environments).
• Wetlands are likely to be connected to
groundwater aquifers that show
complicated spatial arrangements and are
likely to be strongly influenced by
precipitation and surface water flows - the
effects of which can act over larger spatial
scales.
• Integration of the management of surface
and groundwater systems is still in its
infancy in Australia. It should become an
important focus of research into the study
and management of wetlands and their
associated water quality and biological
diversity.
• Because there is usually little readily
available information on the long-term
salinity of most wetlands, an approach with
multiple lines of evidence is recommended
for making inferences about the causes of
salinisation.
• An approach with multiple lines of evidence
requires independent lines of data
collection and should incorporate oral
histories as well as other sources of data,
such as paleolimnological information.
• Successful integration of multiple lines of
evidence will rely on collaboration between
the social and physical sciences, an area
that is currently receiving considerable
support.
Photo: Michael Smith
Published by the Victorian Government Department of Sustainability and Environment
Melbourne, August 2006
© The State of Victoria Department of Sustainability and Environment 2006
This publication is copyright. No part may be reproduced by any process except in accordance with the provisions of the Copyright Act 1968.
Authorised by the Victorian Government, 8 Nicholson Street, East Melbourne.
ISBN 1 74152 531 4
For more information contact the DSE Customer Service Centre 136 186 or Dr Michael Smith on (03) 9450 8612 or michael.smith@dse.vic.gov.au, Arthur Rylah Institute, Department
of Sustainability and Environment, PO Box 137, Heidelberg 3084.
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your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication.
www.dse.vic.gov.au/ari/
the Wetlands, Biodiversity and Salt project can be found by following ‘Research Themes’ to ‘Salinity and Climate change’