Biotic and abiotic thresholds to recovery of degraded spring wetland communities

Biotic and abiotic thresholds to recovery of degraded spring wetland communities Conference Paper

16th Australian Rangeland Society Biennial Conference

  • Author(s): Caddy, H.A.R., Gross, C.L., Whalley, R.D.B. , Price, J.N.
  • Published: 2010
  • Publisher: Australian Rangeland Society

Abstract: Human impacts have dramatically altered the structure and composition of many communities often resulting in new or novel states that are difficult (and potentially impossible) to reverse. New ecosystem states may be irreversible once biotic and abiotic thresholds have been crossed. Artesian spring wetlands are rare vegetation communities restricted to areas of natural discharge from the Great Artesian Basin, south eastern Australia. Human impacts on disturbance regimes and hydrology have dramatically altered the structure and ecosystem function of these wetland communities. We explore the recovery potential of these communities by examining biotic and abiotic constraints to restoration. Abiotic thresholds to restoring ecosystem function are loss of ground water discharge, excavation and soil salinisation. Biotic thresholds include introduced stock grazing and propagule supply. The soil seedbank of the springs was examined to determine propagule availability, species endemism, and proportion of introduced vascular plant species. We found the biotic structure of these communities constrained by limited propagule availability in the soil seedbank, with species richness relatively low in all spring wetlands and no evidence of an endemic flora. We examined the response of the plant communities to the total removal of grazing, and found recovery dependent on site characteristics, water and pre-existing vegetative species. We have suggested a state-andtransition approach that considers these abiotic and biotic constraints to enable land managers to assess transitions and thresholds between the main spring states. Rehabilitation of these degraded vegetation communities may require active management, including return of discharge water, to overcome some hard-to-reverse thresholds.

Cite this document

Suggested Citation
Caddy, H.A.R., Gross, C.L., Whalley, R.D.B. , Price, J.N., 2010, Biotic and abiotic thresholds to recovery of degraded spring wetland communities, Conference Paper, viewed 15 August 2022, https://www.nintione.com.au/?p=3622.

Endnote Mendeley Zotero Export Google Scholar

Share this page

Search again