Impacts of deep open drains on water quality and biodiversity of receiving waterways in the Wheatbelt of Western Australia

Stewart, Barbara A.; Strehlow, K.; Davis, Jennifer

doi:10.1007/s10750-008-9603-x

Cited by 12 publications

(9 citation statements)

References 17 publications

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“…Many studies have found freshwater invertebrate species richness to decrease with an increase in salinity (Cale et al 2004, Waterkeyn et al 2008, Stewart et al 2009). Pinder et al (2005) identified 4.1 g TDS/L as the threshold above which species richness declined in isolated wetlands in the Australian wheatbelt.…”

Section: àmentioning

confidence: 99%

A global perspective on wetland salinization: ecological consequences of a growing threat to freshwater wetlands

et al. 2015

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Abstract. Salinization, a widespread threat to the structure and ecological functioning of inland and coastal wetlands, is currently occurring at an unprecedented rate and geographic scale. The causes of salinization are diverse and include alterations to freshwater flows, land-clearance, irrigation, disposal of wastewater effluent, sea level rise, storm surges, and applications of de-icing salts. Climate change and anthropogenic modifications to the hydrologic cycle are expected to further increase the extent and severity of wetland salinization. Salinization alters the fundamental physicochemical nature of the soil-water environment, increasing ionic concentrations and altering chemical equilibria and mineral solubility. Increased concentrations of solutes, especially sulfate, alter the biogeochemical cycling of major elements including carbon, nitrogen, phosphorus, sulfur, iron, and silica. The effects of salinization on wetland biogeochemistry typically include decreased inorganic nitrogen removal (with implications for water quality and climate regulation), decreased carbon storage (with implications for climate regulation and wetland accretion), and increased generation of toxic sulfides (with implications for nutrient cycling and the health/functioning of wetland biota). Indeed, increased salt and sulfide concentrations induce physiological stress in wetland biota and ultimately can result in large shifts in wetland communities and their associated ecosystem functions. The productivity and composition of freshwater species assemblages will be highly altered, and there is a high potential for the disruption of existing interspecific interactions. Although there is a wealth of information on how salinization impacts individual ecosystem components, relatively few studies have addressed the complex and often non-linear feedbacks that determine ecosystem-scale responses or considered how wetland salinization will affect landscape-level processes. Although the salinization of wetlands may be unavoidable in many cases, these systems may also prove to be a fertile testing ground for broader ecological theories including (but not limited to): investigations into alternative stable states and tipping points, trophic cascades, disturbance-recovery processes, and the role of historical events and landscape context in driving community response to disturbance.

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Section: àmentioning

confidence: 99%

A global perspective on wetland salinization: ecological consequences of a growing threat to freshwater wetlands

et al. 2015

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“…Stewart et al. (2008) found that no recovery had occurred up to 20 km downstream of a deep drainage complex discharging saline, acidic ground water into a natural watercourse.…”

Section: Which Models Best Conceptualise Ecological Change In Shallowmentioning

confidence: 99%

“…Ground waters in the eastern wheatbelt are generally strongly acidic (pH <3.5) and typically very saline (6000–8000 mS m −1 ). As a consequence, deep drains in this region, which often discharge to streams or wetlands, contain high levels of iron, aluminium, cobalt, copper, zinc and lead, and during periods of low flow, exhibit extreme acidity (pH < 3) and salinity (10 000–20 000 mS m −1 ) (Stewart, Strehlow & Davis, 2008).…”

Section: What Stressors Occur In Southwestern Australia?mentioning

confidence: 99%

Multiple stressors and regime shifts in shallow aquatic ecosystems in antipodean landscapes

Davis

Sim²,

Chambers

2010

Freshwater Biology

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SUMMARY1. Changes in land management (land use and land cover) and water management (including extraction of ground water and diversion of surface waters for irrigation) driven by increases in agricultural production and urban expansion (and fundamentally by population growth) have created multiple stressors on global freshwater ecosystems that we can no longer ignore. 2. The development and testing of conceptual ecological models that examine the impact of stressors on aquatic ecosystems, and recognise that responses may be nonlinear, is now essential for identifying critical processes and predicting changes, particularly the possibility of catastrophic regime shifts or 'ecological surprises'. 3. Models depicting gradual ecological change and three types of regime shift (simple thresholds, hysteresis and irreversible changes) were examined in the context of shallow inland aquatic ecosystems (wetlands, shallow lakes and temporary river pools) in southwestern Australia subject to multiple anthropogenic impacts (hydrological change, eutrophication, salinisation and acidification). 4. Changes in hydrological processes, particularly the balance between groundwaterdominated versus surface water-dominated inputs and a change from seasonal to permanent water regimes appeared to be the major drivers influencing ecological regime change and the impacts of eutrophication and acidification (in urban systems) and salinisation and acidification (in agricultural systems). 5. In the absence of hydrological change, urban wetlands undergoing eutrophication and agricultural wetlands experiencing salinisation appeared to fit threshold models. Models encompassing alternative regimes and hysteresis appeared to be applicable where a change from a seasonal to permanent hydrological regime had occurred. 6. Irreversible ecological change has potentially occurred in agricultural landscapes because the external economic driver, agricultural productivity, persists independently of the impact on aquatic ecosystems. 7. Thematic implications: multiple stressors can create multiple thresholds that may act in a hierarchical fashion in shallow, lentic systems. The resulting regime shifts may follow different models and trajectories of recovery. Challenges for ecosystem managers and researchers include determining how close a system may be to critical thresholds and which processes are essential to maintaining or restoring the system. This requires an understanding of both external drivers and internal ecosystem dynamics, and the interactions between them, at appropriate spatial and temporal scales.

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“…The intent is to drain low-lying land, using a network of deep drains and bunding (an artificial embankment that prevents water entering a wetland, diverting it to a drain). However, these drains often intercept acid sulphate soils, leading to acidification of nearby wetlands, as has occurred elsewhere in the Wheatbelt (Stewart et al 2009).…”

Section: Management Of Wetlandsmentioning

confidence: 99%

Prioritising wetlands subject to secondary salinisation for ongoing management using aquatic invertebrate assemblages: a case study from the Wheatbelt Region of Western Australia

Delaney

Shiel

Storey

2015

Wetlands Ecol Manage

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Secondary salinisation is recognised worldwide as a threat to aquatic biodiversity. Wetlands in the Wheatbelt Region of Western Australia are particularly affected as a result of clearing of deeprooted native vegetation for agriculture. Between 1996 and 2001, the Western Australian government nominated six natural diversity recovery catchments (NDRCs), being catchments with high value and diverse wetlands in need of protection. One, the BuntineMarchagee NDRC, supports approximately 1000 wetlands in varying states of salinisation. The challenge is to prioritise these wetlands for ongoing management. In this paper we propose an approach to prioritise representative wetlands using aquatic invertebrates. On the basis of hydrology, salinity and remnant vegetation, 20 wetlands covering a range of salinities were selected for sampling of water quality and aquatic invertebrates. Of the 202 taxa recorded, most endemic taxa occurred in fresh/brackish wetlands, while hypersaline wetlands supported predominantly cosmopolitan species. Taxa richness was greater in fresh/brackish than saline and hypersaline wetlands, with conductivity explaining 83 % of between-wetland variation in taxa richness. Classification using invertebrate assemblages separated fresh/brackish, saline and hypersaline wetlands, with greatest between-year variability within saline and hypersaline sites. Wetlands were ranked using taxa diversity, presence of conservation-significant taxa and temporal similarity. Mean rank across indices provided the final overall order of priority. Hypersaline wetlands were ordered separately to the fresher water wetlands (fresh/brackish and saline) so that priority for future management was detailed for both types of wetlands. The analysis indicated that although fresh/brackish sites support the highest biodiversity, naturally saline sites also supported wetland assemblages worthy of ongoing protection.

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Impacts of deep open drains on water quality and biodiversity of receiving waterways in the Wheatbelt of Western Australia

Cited by 12 publications

References 17 publications

A global perspective on wetland salinization: ecological consequences of a growing threat to freshwater wetlands

A global perspective on wetland salinization: ecological consequences of a growing threat to freshwater wetlands

Multiple stressors and regime shifts in shallow aquatic ecosystems in antipodean landscapes

Prioritising wetlands subject to secondary salinisation for ongoing management using aquatic invertebrate assemblages: a case study from the Wheatbelt Region of Western Australia

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