Predicted risks of groundwater decline in seasonal wetland plant communities depend on basin morphology
In regions of the world where the climate is expected to become drier, meeting environmental water needs for wetlands and other dependent ecosystems will become increasingly challenging. Ecological models can play an important role, by quantifying system responses to reduced water availability and predicting likely ecological impacts. Anticipating these changes can inform both conservation and monitoring effort. We used water-plant functional group models to predict the effects of a declining water table for two wetland types reliant on the surface expression of groundwater but of contrasting basin morphology. Our interest was in quantifying the relative sensitivity of these wetland types to different amounts of groundwater decline. For the shallower, grass-sedge wetland, terrestrial plant probabilities increased markedly for declines between 0.25 and 0.5 m, but amphibious and submerged functional groups changed predictably, or not at all. However, mean inundated area reduced by over 70% for a 0.5 m groundwater decline, suggesting loss of area posed the greatest risk in this wetland type. In the deeper, steep-sided interdunal wetland, inundated area changed little, but models suggest clear transitions in plant functional group composition. Sedge-group probabilities increased sharply for declines between 0.25 and 0.5 m, while declines between 0.5 and 1.0 m predicted the loss of submerged species. As might be anticipated, the risks associated with groundwater level decline depend on basin morphology. However, by quantifying probable ways in which this will manifest in different wetland types, model predictions improve our ability to recognise and manage change.
KeywordsGroundwater-dependent ecosystem Plant functional group Predictive model Wetland bathymetry Wetland monitoring Wetland typology
This work was funded by the Goyder Institute for Water Research under project E.2.5. The authors gratefully acknowledge the assistance of the Wetlands Working Group of the South East NRM Board in scenario development, particularly M. Herpich, T. Bond, S. Clark and D. Herpich. ForestrySA are also acknowledged for their support of the work.
Funding for this project was provided by the Goyder Water Research Institute, project E.2.5.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Auble GT, Scott ML, Friedman JM (2005) Use of individualistic streamflow-vegetation relations along the Fremont River, Utah, USA to assess impacts of flow alteration on wetland and riparian areas. Wetlands 25:143–154 doi:10.1672/0277-5212(2005)025[0143:uoisra]2.0.co;2Google Scholar
- Brinson M (1993) A hydrogeomorphic classification for wetlands technical report WRP-DE4. US Army Engineers Waterways Experiment Station, VicksburgGoogle Scholar
- Brock MA, Casanova MT (1997) Plant life at the edges of wetlands: ecological responses to wetting and drying patterns. In: Klomp N, Lunt I (eds) Frontiers in ecology: building the LINKS. Elsevier, Oxford, pp 181–190Google Scholar
- Brown K, Love AJ, Harrington G (2001) Vertical groundwater recharge to the tertiary confined sand aquifer, South East, South Australia. Dept. Water Resources South Australia. Report Book DWR 2001/002 (unpublished)Google Scholar
- Butcher R, Farrington L, Harding C, O’Connor P (2011) An integrated trial of the Australian National Aquatic Ecosystem Classification Scheme in South–Eastern South Australia. Report prepared for the Department of Sustainability, Environment, Water, Population and CommunitiesGoogle Scholar
- Chambers J et al (2013) Adapting to climate change: a risk assessment and decision making framework for managing groundwater dependent ecosystems with declining groundwater levels-guidelines for use. National Climate Change Adaptation Research Facility, Gold Coast, AustraliaGoogle Scholar
- Charles SP, Fu G (2014) Statistically downscaled projections for South Australia—Task 3 CSIRO final report. Goyder Institute for Water Research, Technical Report Series No. 15/1, Adelaide, South AustraliaGoogle Scholar
- Cook PG, Simmons CT, Brunner P (2008) Regional groundwater dependent ecosystems—our undiscovered assets at risk. Report to the Centre for Natural Resource Management. CSIRO Land and Water, Flinders UniversityGoogle Scholar
- Cooling M, Taylor B, Faast R, Hammer M (2010) Water quantity impacts on wetlands. In: Brookes J (ed) South east water science review. Department for Water, 2010, South East Water Science Review, Lower Limestone Coast Water Allocation Plan Taskforce, AdelaideGoogle Scholar
- Cowardin LM, Carter V, Golet FC, LaRoe ET (1979) Classification of wetlands and deepwater habitats of the United States. U.S. Department of the Interior. Fish and Wildlife Service, Washington, USGoogle Scholar
- DFW (2010) South east water science review. Lower limestone coast water allocation plan taskforce Department for Water, AdelaideGoogle Scholar
- Environment Australia (2001) A directory of important wetlands in Australia, 3rd edn. environment Australia, Canberra, AustraliaGoogle Scholar
- Goodman A (2010) Water quality impacts on wetlands. In: Brookes J (ed) South east water science review. Department for Water, 2010, South East Water Science Review, Lower Limestone Coast Water Allocation Plan Taskforce, AdelaideGoogle Scholar
- Goodman AM (2012) Impacts of an altered water and salinity regime on the condition of wetlands in the Upper South East of South Australia. University of AdelaideGoogle Scholar
- Harding C (2012) Extension of the water dependent ecosystem risk assessment framework to the South East NRM region. Department for Water, Technical report 2012/10, Adelaide, South AustraliaGoogle Scholar
- Harding C, Deane D, Green G, Kretschmer P (2015) Impacts of climate change on water resources in south australia, phase 4, volume 2—predicting the impacts of climate change to groundwater dependent ecosystems: an application of a risk assessment framework to a case study site in the South East NRM region—Middlepoint swamp. DEWNR Technical Report 2015/01, Government of South Australia, through Department of Environment, Water and Natural Resources, AdelaideGoogle Scholar
- Loomes R, Froend R, Sommer B (2013) Response of wetland vegetation to groundwater decline on the Swan Coastal Plain, Western Australia: implications for management. In: Monteiro JP, Medeiros A, Ribeiro L, Stigter TY, Chambel A, Melo MTCd (eds) Groundwater and ecosystems. CRC Press, Boca RatonGoogle Scholar
- Mustafa S, Slater S, Barnett S (2012) Preliminary investigation of seawater intrusion into a freshwater coastal aquifer—Lower South East, DEWNR technical report 2012/01. Department of Environment, Water and Natural Resources, AdelaideGoogle Scholar
- SENRMB (2013) Water allocation plan for the lower limestone coast prescribed wells area. prepared by the south east natural resources management board, Department of Environment, Water and Natural Resources. Adelaide, South AustraliaGoogle Scholar
- SKM (2009) Classification of groundwater–surface water interactions for water dependent ecosystems in the South East, South Australia. report for the Department of Water, Land and Biodiversity Conservation. Sinclair Knight Merz, Hobart, AustraliaGoogle Scholar
- Taylor A, Lamontagne S, Turnadge C, Smith S, Davies P (2015) Groundwater—surface water interactions at bool lagoon, lake robe and deadmans swamp (Limestone Coast, SA): data review. Technical Report Series No. 15/13. Goyder Institute for Water Research, Adelaide, AustraliaGoogle Scholar
- TSSC (2012) Advice to the Minister for sustainability, environment, water, population and communities on an amendment to the list of threatened ecological communities under the EPBC Act 1999. Threatened Species Scientific Committee. http://www.environment.gov.au/biodiversity/threatened/communities/pubs/97-listing-advice.pdf. Accessed 23 August 2017
- Wood G, Way D (2011) Development of the technical basis for a regional flow management strategy for the South East of South Australia. DFW Report 2011/21, Government of South Australia, through Department for Water, AdelaideGoogle Scholar