Pressures affecting riverine ecosystems

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Queensland

Pressures on Queensland's waterways vary between regions and are generally linked to catchment land uses.

Overall, sediment, nutrients and chemicals are the major catchment pressures that broadly impact Queensland rivers but these also vary in their relative importance between regions.

Healthy Waterways South East Queensland report card

The Healthy Waterways Report Card helps us understand the pressures affecting ecosystem health in freshwater, estuarine and marine areas.

Much of the natural riparian or riverbank vegetation was cleared to make way for agriculture and urban development as South East Queensland became more populated. This loss of vegetation is identified as a major pressure affecting the health of freshwater creek and river systems. Riparian vegetation provides shade for rivers helping to regulate temperature to support habitat for freshwater creatures and filters nutrients and sediments that pollute waterways.

Historically, freshwater creek and river systems are also impacted by nutrients such as from sewage treatment effluent. A major program of sewage treatment plant upgrades has significantly reduced this pressure over the past 15 years. The 2015 report card has identified sediments from agricultural and urban activities as the main pollutant sources.

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Great Barrier Reef report card

The Great Barrier Reef Report Card helps us understand the pressures affecting the Great Barrier Reef from the adjacent catchments. The decline in marine water quality associated with run-off from the adjacent catchments is a major cause of the current poor state of many of the key marine ecosystems.

The main source of excess nutrients, fine sediments and pesticides in the Great Barrier Reef catchments is from agriculture.

The report card assesses changes in catchment indicators including riparian vegetation and ground cover as they are important to help reduce pollutant flow to waterways and prevent erosion. Wetland and riparian areas have a water quality protection function and a value in their own right.

The loss of wetlands and riparian vegetation is mostly caused by clearing, often for agricultural use. Wetland modification through bunding can increase the extent of wetlands.

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Fitzroy Basin report card

Water quality in the Fitzroy River is heavily influenced by activities in its catchment.

The Fitzroy Basin is the largest catchment on the east coast of Australia (142,000km2). It is home to around 120,000 people, mostly in the urban centre of Rockhampton. Current land use across the basin is:

  • 81% grazing
  • 6% cropping
  • 6% conservation
  • 5% forestry
  • 1% urban
  • 0.5% mining
  • 0.5% irrigation.

Twenty-eight dams and weirs regulate water flows.

High sediment volumes and turbidity result from its highly variable flow regime, ephemeral streams in its upper reaches, large tidal volumes in the estuary and periods of extensive riverine flooding.

Water quality varies because of natural variations in geography, geology, climate and soils as well as human activities and land use. Proposed increases in agricultural development, more mining operations and increasing coal seam gas extraction have potential to further impact water quality.

Rainfall is a major influence on the annual fluctuation of report card scores. Higher than average rainfall and significant flooding in 2010-2011 and 2011-2012 was followed by lower than average rainfall in 2013-2014 associated with the beginning of the current El Niño. Many western catchments went without significant flows in this dryer period, which contributed to decreases in scores for the Comet, Theresa and Upper Isaac catchments. However, results for the Lower Dawson, Nogoa, Connors and Mackenzie catchments improved.

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Gladstone Harbour report card

Freshwater ecosystems not analysed in report card publication.

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Mackay-Whitsunday report card

The Mackay–Whitsunday Healthy Rivers to Reef Partnership Pilot Report Card helps identify the regional pressures affecting waterway health in freshwater, estuarine and marine environments.

Current pressures in the Mackay–Whitsunday region range from those occurring on an international level such as climate change to reef-wide and localised pressures, among them coastal and agricultural development, tourism and litter.

Activities in the catchment strongly influence waterway health scores. As a major agricultural area with a significant area of the catchment under cane production, one of the major pressures is catchment run-off of pollutants, particularly nutrients and pesticides.

Loss of wetlands and riparian vegetation is also a key pressure on the region’s basins and estuaries.

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Condamine Catchment report card

Technical reports for water, land and nature provide contextual information on pressures from which score card grades are drawn for the Condamine catchment.

Significant pressures for water come from:

  • irrigated agriculture
  • grazing
  • coal mining
  • coal seam gas production
  • energy generation.

Intensive agriculture is the most significant pressure identified in the Condamine catchment. The catchment has high quality agricultural soils and is one of the most cleared catchments in Queensland, which has led to reduced tree canopy cover, groundcover, reduced habitat and fragmentation of vegetation.

Ground cover plays a pivotal role in retaining biodiversity in cleared areas and in protecting land quality in intensive agricultural areas. However, ground cover is only one of many factors influencing the quality of biodiversity habitats and land quality. Other factor include weather patterns, regional ecosystem locations, soil types, farming tillage patterns, erosion hot spots, soil conservation structures, elevation and urban development patterns.

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QCatchment Bulloo

Conceptual models are used to determine catchment specific condition indicators based on the relevant pressures in the catchment.

The main threats for the Bulloo catchment were:

  • introduced aquatic fauna
  • deposited sediment
  • introduced riparian fauna.

The overall rating for the Bulloo catchment 2012 was ‘slightly disturbed’.

Introduced aquatic fauna such as European carp, goldfish, eastern mosquitofish and red claw crayfish pose the highest potential risk to riverine ecosystems in the Bulloo catchment, but currently represent a ‘low threat’.

Deposited sediment (sediment settling to the bottom and filling waterholes) was identified as a high potential risk to riverine ecosystems in the Bulloo catchment, but only a ‘slight current threat’.

Activities such as vegetation clearing and introduced animals in riparian zones (vegetation on the banks of the river) can increase the chances of sediment entering waterholes.

Introduced riparian fauna, such as feral pigs and unfenced cattle, were identified as a ‘moderate risk’ and ‘moderate current threat’ to riverine ecosystems of the Bulloo catchment, which can cause physical damage to banks and water quality issues.

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QCatchment Paroo

Conceptual models are used to determine catchment specific condition indicators based on the relevant pressures in the catchment.

The main threats for the Paroo catchment were:

  • introduced aquatic fauna
  • deposited sediment
  • introduced riparian fauna.

The overall rating for the Paroo catchment 2012 was ‘moderately disturbed’.

Introduced aquatic fauna such as European carp, goldfish, eastern mosquitofish and red claw crayfish pose the highest potential risk to riverine ecosystems in the Paroo catchment and currently represent a ‘moderate threat’.

Deposited sediment (sediment settling to the bottom and filling waterholes) was identified as a ‘high potential risk’ to riverine ecosystems in the Paroo catchment but only represents a ‘slight current threat’.

Activities such as vegetation clearing and introduced animals in riparian zones (vegetation on the banks of the river) can increase the chances of sediment entering waterholes.

Introduced riparian fauna, such as feral pigs and unfenced cattle, were identified as a ‘moderate risk’ and ‘moderate current threat’ to riverine ecosystems of the Paroo catchment, which can cause physical damage to banks and water quality issues.

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QCatchment Warrego

Conceptual models are used to determine catchment specific condition indicators based on the relevant pressures in the catchment.

Main threats to the Warrego catchment were:

  • introduced aquatic fauna
  • deposited sediment
  • introduced riparian fauna.

The overall rating for the Warrego catchment 2012 was ‘moderately disturbed’.

Introduced aquatic fauna such as European carp, goldfish, eastern mosquitofish and red claw crayfish pose the highest potential risk to riverine ecosystems in the Warrego catchment, but only a ‘slight current threat’.

Deposited sediment (sediment settling to the bottom and filling waterholes) was identified as a ‘high potential risk’ and ‘moderate current threat’ to riverine ecosystems in the Warrego catchment, with activities such as vegetation clearing and introduced animals in riparian zones (vegetation on the banks of the river) increasing the chances of sediment entering waterholes.

Introduced riparian fauna, such as feral pigs and unfenced cattle, were identified as a ‘moderate risk’ and ‘moderate current threat’ to riverine ecosystems of the Warrego catchment, which can cause physical damage to banks and water quality issues.

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QCatchment Nebine

Conceptual models are used to determine catchment specific condition indicators based on the relevant pressures in the catchment.

Main threats for the Nebine catchment were:

  • introduced aquatic fauna
  • deposited sediment
  • introduced riparian fauna.

Introduced fauna such as European carp, goldfish, eastern mosquitofish and red claw crayfish pose the highest potential risk of the risks considered and a ‘moderate current threat’ to riverine ecosystems in the Nebine catchment.

Deposited sediment (sediment settling to the bottom and filling waterholes) was identified as a ‘high potential risk’ to riverine ecosystems in the Nebine catchment, but a ‘low current threat’.

Activities such as vegetation clearing and introduced animals in riparian zones (vegetation on the banks of the river) can increase the chances of sediment entering waterholes.

Introduced riparian fauna, such as feral pigs and unfenced cattle, were identified as a ‘moderate risk’ but only a represent a ‘slight current threat’ to riverine ecosystems of the Nebine catchment.

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QCatchment Wet Tropics

A qualitative risk assessment of threats to riverine ecosystems in the Wet Tropics identified six priority threats for further investigation:

  • introduced riparian fauna
  • introduced riparian flora
  • a reduction of low flow discharge
  • riparian (the vegetation on the banks of the river) habitat disturbance
  • lateral connectivity disturbance
  • introduced instream flora.

No overall score was provided for the Wet Tropics, however most sites in 2009 were in ‘slightly disturbed‘ or ‘good‘ condition.

Feral pigs are the main introduced riparian fauna, as well as some unfenced cattle, which are considered a ‘moderate potential risk’ (pressure) but only a ‘slight current threat’ as disturbance is patchy.

Introduced riparian flora (weeds) and riparian habitat disturbance represent a ‘slight pressure’ and ‘moderate current threat’.

While the Wet Tropics is relatively undisturbed with about 45% of conserved areas, weeds have the ability to disperse widely from their initial release area.

Overall there is limited disturbance to riparian habitat; localised areas of disturbance to riparian zone cover have been recorded from agricultural activity.

Reduction of low flows from water resource development represents a slight current pressure and threat. Disturbance of lateral connectivity (the ability of a river to connect to its floodplain) by levee banks or other barriers to flow represents a slight pressure and unknown threat.

There was insufficient information to rank the current level of pressure or threat for introduced instream flora (instream weeds).

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QCatchment Lake Eyre

An ecological risk assessment of threats to waterways in the province identified three threats for further investigation:

  • introduced riparian fauna
  • introduced aquatic fauna
  • introduced riparian weeds.

No overall condition score was provided for the Lake Eyre and Bulloo Province.

Introduced riparian fauna (feral pigs and cattle) was assessed as a ‘moderate risk’, as pigs and cattle have access to the riparian zone (vegetation on the banks of the river). Slightly higher risks (in the high end of the ‘moderate’ range) were observed in the Georgina and Diamantina catchments. Overall, cattle impact was more severe than pig impact at surveyed sites across the Province.

The province as a whole was ranked at ‘moderate risk’ from introduced aquatic fauna, based on the Georgina and Cooper being at ‘moderate risk’. However the Bulloo and Diamantina were at ‘no risk’.

Risk to ecosystem condition from introduced riparian weeds was assessed to be ‘slight’ in the Bulloo catchment, ‘moderate’ in the Diamantina and Cooper Creek catchments and ‘high’ in the Georgina catchment. Risk overall from riparian weeds was ‘moderate’.

The highest numbers of targeted weed species were recorded in the Cooper and Georgina catchments.

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Indicator: Pressures identified in report card area

Pressures identified in various water quality report card areas across Queensland.

Download data from Queensland Government data