Charles Darwin University

CDU eSpace
Institutional Repository

 
CDU Staff and Student only
 

Investigation of nutrient thresholds to guide restoration and management of two impounded rivers in south-western Australia

Novak, Peter and Chambers, Jane (2014). Investigation of nutrient thresholds to guide restoration and management of two impounded rivers in south-western Australia. Ecological Engineering,68:116-123.

Document type: Journal Article
Citation counts: Scopus Citation Count Cited 0 times in Scopus Article
Altmetric Score Altmetric Score is 7
Google Scholar Search Google Scholar

IRMA ID 84376995xPUB67
Title Investigation of nutrient thresholds to guide restoration and management of two impounded rivers in south-western Australia
Author Novak, Peter
Chambers, Jane
Journal Name Ecological Engineering
Publication Date 2014
Volume Number 68
ISSN 0925-8574   (check CDU catalogue  open catalogue search in new window)
Scopus ID 2-s2.0-84899894510
Start Page 116
End Page 123
Total Pages 8
Place of Publication Netherlands
Publisher Elsevier BV
HERDC Category C1 - Journal Article (DIISR)
Abstract Hysteresis between macrophyte and phytoplankton dominant ecological regimes has been observed in shallow lakes between 50 and 150 μg/L total phosphorus (TP). This paper explores the capacity of these thresholds, initially proposed for European systems, to guide management and the successful restoration of macrophytes in two eutrophic rivers, the Canning River and the Lower Vasse River in Western Australia. Investigation of long-term nutrient data (1996–2007), revealed alternating macrophyte and phytoplankton dominance in the Canning River at TP concentrations in the spring and summer months of 152 μg/L (±20 μg/L SE) prior to remediation. Management interventions, including the application of Phoslock™, were successful in reducing TP to approximately 100 μg/L and resulted in persistent macrophyte dominance. Despite reductions from approximately 400 to 150 μg/L TP in the Lower Vasse River, phytoplankton blooms persisted. Transplantation of four native, perennial macrophyte species simultaneously in the Canning River and Lower Vasse River resulted in only Vallisneria australis surviving within a nutrient regime of 130–300 μg/L TP, concurrent with very high epiphyte loads. This research supports guidelines to managers of 150 μg/L TP (high risk macrophyte loss), 100 μg/L TP for maintenance of existing macrophyte beds, and less than 100 μg/L TP for restoration of transplanted species other than V. australis. The efficacy of these thresholds is dependent on P limitation and we suggest optimum molar total nitrogen to total phosphorus ratio greater than 20:1 and maximum total nitrogen concentration of 2000 μg/L for macrophyte dominance.
Keywords Eutrophication
Phosphorus
Phytoplankton
Regime shifts
Submerged macrophytes
Thresholds
DOI http://dx.doi.org/10.1016/j.ecoleng.2014.03.091   (check subscription with CDU E-Gateway service for CDU Staff and Students  check subscription with CDU E-Gateway in new window)
 
Versions
Version Filter Type
Access Statistics: 14 Abstract Views  -  Detailed Statistics
Created: Wed, 19 Aug 2015, 12:07:08 CST