Pressures affecting Queensland’s aquatic ecosystems

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Key finding

The pressures affecting Queensland's aquatic ecosystems vary depending on local conditions and level of development. Broadly, sediments, nutrients and pesticides are the main catchment pressures on our aquatic ecosystems. Climate change is also a pressure on aquatic ecosystems, particularly the Great Barrier Reef.

Queensland

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

Overall, the main catchment pressures broadly impacting Queensland rivers are:

  • sediment
  • nutrients
  • chemicals.

Relative importance of these pressures varies between regions.

Climate change also impacts aquatic ecosystems, particularly the Great Barrier Reef.

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 in South East Queensland (SEQ).

Loss of natural riverbank vegetation, cleared for agriculture and urban development, is the prime pressure affecting the health of freshwater creek and river systems in the region.

  • Riparian vegetation provides shade for rivers, helping regulate temperature to support habitat for freshwater creatures.
  • Riparian vegetation filters nutrients and sediments that pollute waterways.

Historic and current land management practices have caused substantial erosion in SEQ catchments.

  • Erosion leads to sediment or mud entering waterways. This can smother seagrass and reduce water clarity, affecting estuarine and marine habitats.

Sediment from diffuse rural and urban sources is the current primary threat affecting estuarine and marine health. The amount and source of sediment entering waterways annually is dependent on the level of rainfall.

Nutrients from sources such as agricultural runoff and effluent from treated sewage also impact waterways. A major program of sewage treatment plant upgrades has significantly reduced the adverse role of effluent in waterways’ health over the past 15 years.

More information:

Great Barrier Reef report card

The Great Barrier Reef extends 2,300km from the tip of Cape York to the Burnett–Mary regions. Its catchment area is more than 400,000km2—an area larger than Japan.

Reef health over such a vast area varies; strongly influenced by activities in the adjacent catchment. For example, water quality in the northern third of the Reef (north of Cooktown) and in outer reef waters in the southern two-thirds is generally good to very good overall as they are less impacted by catchment runoff. However, water quality in the inner reef area in the southern two-thirds is generally ‘poor’ due to the impact of sediments and nutrients. Pesticides pose a risk to freshwater and some inshore and coastal habitats.

Long-term, climate change impacts are expected to become an increasing pressure on the Great Barrier Reef. Sea temperature increases and ocean acidification already affect corals and movement patterns for marine wildlife.

The Great Barrier Reef Report Card helps us to understand the pressures affecting the Reef’s health and measures progress towards Reef Water Quality Protection Plan targets for improving land management practices and reducing loads of pollutants entering the reef.

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Fitzroy Basin report card

The Fitzroy Basin — the largest catchment on the east coast of Australia — is characterised by a highly variable flow regime, ephemeral streams in its upper reaches, large tidal volumes in the estuary and periods of extensive riverine flooding. High sediment volumes and turbidity result from these characteristics.

Waterways are heavily modified, with 28 dams and weirs across the basin regulating flows.

Land use is varied from grazing and cropping to urban development and mining. Future land use changes with potential impacts on water quality include proposals for increasing agricultural development, more mining operations and increasing coal seam gas extraction.

Rainfall is a major influence on the annual fluctuation of report card scores. Significant flooding in 2010-2011 and 2011-2013 influenced river conditions, followed by lower than average rainfall from 2013-2014. Many western catchments went without significant flows. Catchments to consequently receive lower scores were:

  • Comet
  • Theresa
  • Upper Isaac.

Catchments that recorded water quality improvements were:

  • Lower Dawson
  • Nogoa
  • Connors
  • Mackenzie.

Drier conditions in 2013-2014 saw improvements also for estuaries, rated in ‘good condition’.

More information:

Gladstone Harbour report card

Gladstone Harbour and associated waterways are used for a wide range of activities—from agricultural, and urban and industrial development to shipping, fishing and dredging. These exert pressure on the harbour ecosystems and species.

The population of Gladstone (local government area) is expected to double by 2030. This will add further pressure on harbour-related infrastructure and ecosystems.

More information:

Mackay-Whitsunday report card

The Mackay–Whitsunday Healthy Rivers to Reef Partnership 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 regional pressures, among them coastal, port and agricultural development, tourism and litter.

Activities in the catchment strongly influence waterway health scores. Mackay–Whitsunday region is a major agricultural area with a significant area of the catchment under cane production: catchment run-off of pollutants, particularly nutrients and pesticides, presents a major pressure.

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

More information:

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 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.

More information:

QCatchment Bulloo

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

The main threats for Bulloo catchment are:

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

The overall rating for Bulloo in 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, as they can cause physical damage to banks and water quality issues.

More information:

QCatchment Paroo

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

The main threats for Paroo catchment the threats identified as most relevant are:

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

The overall rating for the Paroo in 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, as they can cause physical damage to banks and water quality issues.

More information:

QCatchment Warrego

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

Key threats to the Warrego catchment are:

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

The overall rating for the Warrego in 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.

Activities such as vegetation clearing and introduced animals in riparian zones (vegetation on the banks of the river) 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 Warrego catchment as they can cause physical damage to banks and water quality issues.

More information:

QCatchment Nebine

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

Key threats identified for 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.

More information:

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. They were considered a ‘moderate potential risk’ (pressure) but only a ‘slight current threat’ due to patchy disturbance.

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 was assessed as a ‘moderate risk’: feral 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’: the Bulloo and Diamantina rivers were at no risk.

Overall risk from introduced riparian weeds was ‘moderate’ varying across the catchment:

  • ‘slight’ in the Bulloo catchment
  • ‘moderate’ in the Diamantina and Cooper Creek catchments
  • ‘high’ in the Georgina catchment.

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

More information:

Indicator: Pressures identified in report card area

Pressures identified in various water quality report cards across Queensland.

Download data from Queensland Government data