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Environment

The environment of the Ningy Ningy land has gone through the same problems of other lands taken by Europeans, in that European land management practices were imposed on an environment vastly different. From introduced species (flora and fauna) to the clear felling of forests for farming and housing, the environment has changed dramatically.

Some of the topics covered below are Pine River & Bramble Bay, Moreton Bay, De-silting, Impacts of modifying catchment flow.

Pine River and Bramble Bay environment

Bramble Bay is the most degraded embayment of Moreton Bay . This is primarily a result of the high levels of nutrients and sediments that are transported into Bramble Bay from the Brisbane and Pine Rivers . Approximately 63% of the total sediment load and 51% of the nitrogen load into Moreton Bay is predicted to enter via the Brisbane River alone. Significant proportions of nutrients are also transported into Bramble Bay from Hays Inlet and Cabbage Tree Creek. Also contributing to Bramble Bay ’s poor condition is poor flushing, the area possessing the longest residence time of Moreton Bay (59 to 62 days). Bramble Bay is within a General Use Zone of Moreton Bay Marine Park and contains areas within the Moreton Bay Ramsar site” (Angela Grice, Paul Maxwell and Ivan Holland, p.11-12 chapter 15 in State of South-east Queensland Waterways Report 2001).

Water quality

Nutrients

“Nutrient concentrations in Bramble Bay , including inorganic and total nitrogen and phosphorus, are the highest in Moreton Bay . As in the other embayments within Moreton Bay , levels of inorganic nitrogen remain low during dry periods. However, during wet periods both ammonium and nitrate levels increase considerably For example, in February 2001 ammonium and nitrate concentrations were recorded at 10µM and 40µM N, respectively. These levels are extremely high for coastal embayments, and have considerable ecological implications. The high nutrient concentrations in Bramble Bay are largely attributable to inputs from the Brisbane and Pine Rivers, though isolated nutrient plumes containing ammonium and nitrate also extend from Cabbage Tree Creek” (Angela Grice, Paul Maxwell and Ivan Holland, p.11-12 chapter 15 in State of South-east Queensland Waterways Report 2001).

Sewage plumes

“The most prominent sewage plumes of Moreton Bay occur in Bramble Bay . The extent of these plumes varies with season. In summer, two distinct sewage plumes emanate from the Brisbane and Pine Rivers , extending up to 20km away from the point sources. In winter, the sewage plume is considerably reduced, probably due to reduced flows from the river estuaries into the Bay” (Angela Grice, Paul Maxwell and Ivan Holland, p.11-12 chapter 15 in State of South-east Queensland Waterways Report 2001).

Water clarity

Bramble Bay also contains the highest levels of suspended particles, based on high turbidity and low secchi disc values. This is caused by the deposition of new sediments from the catchment in combination with continual resuspension of existing muddy sediments. Studies on sediment patterns in Bramble Bay have shown that wind and tidal current provide sufficient energy to resuspend fine muddy sediments from the shallow sea floor on a daily basis” (Angela Grice, Paul Maxwell and Ivan Holland, p.11-12 chapter 15 in State of South-east Queensland Waterways Report 2001).

Seagrass loss

“ Historically, dugongs and turtles grazed on seagrass beds within Bramble Bay , but high turbidity and nutrients eliminated these beds at least 30 years ago. Current water quality conditions of Bramble Bay are unsuitable for the re-establishment of seagrass meadows” (Angela Grice, Paul Maxwell and Ivan Holland, p.11-12 chapter 15 in State of South-east Queensland Waterways Report 2001).

Moreton Bay & the environment

“Description of the waterways

Moreton Bay is a semi-enclosed embayment 80km in length, ranging in width from 35km in the north to 5km in the south. Many of the major rivers and creeks in south-east Queensland flow into the Bay; these include the Caboolture, Pine, Brisbane, Bremer and Logan Rivers. The combined catchment area of rivers and creeks discharging into Moreton Bay is approximately 22 000km2, while the area of the Bay itself is (1523km2). Moreton Bay was declared a Marine Park in 1993 and has been listed as a wetland of international significance under the Ramsar Convention” (p. 98 Abal, E.G., Moore, K. B., Gibbes, B. R. and Dennison, W. C., (eds) 2002. State of South-east Queensland Waterways Report 2001. Moreton Bay Waterways and Catchments Partnership).

“Flora and fauna

Moreton Bay is home to a very diverse range of flora and fauna, largely due to the biogeographical overlap of tropical and subtropical taxa. Ecosystems occurring within this region include rocky and coral reefs, seagrass meadows, saltmarshes, mangroves and ocean beaches” (p. 99 Abal, E.G., Moore, K. B., Gibbes, B. R. and Dennison, W. C., (eds) 2002. State of South-east Queensland Waterways Report 2001. Moreton Bay Waterways and Catchments Partnership).

“Fringing vegetation

Extensive mangrove forests line intertidal and estuarine waterways and cover approximately 140km2 (0.6%) of Moreton Bay’s area. “Eight species of mangroves are found in Moreton Bay [and the surrounding waterways]: Acrostichum speciosum [mangrove fern], Aegiceras corniculatum [river mangrove], Avicennia marina [grey (or white) mangrove], Bruguiera gymnorrhiza [large leaf orange mangrove], Ceriops australis [yellow mangrove], Excocecaria agallocha [milky (blind-your-eye) mangrove], Lumnitzera racemosa [black mangrove] and Rhizophora stylosa [red mangrove]. They provide important habitat for the juveniles of many fish, crab and prawn species and are important as roost sites and feeding grounds for local and migrating birds. Mangroves cover large areas on the islands and on the mainland coasts of Moreton Bay [as well as the river systems]. Mangroves play an essential role in stabilising coastal foreshore areas [and river banks,] and in binding up fine silt sediment. Erosion is reduced, along with turbidity, and deeper estuarine channels are maintained. Coastal wetland areas including saltmarshes, samphire, grassland, swamp oak, sedgeland, paperbark and heath communities cover approximately 190km2 in Moreton Bay and are found fringing its islands and coastal areas” (p.99 Abal, E.G., Moore, K. B., Gibbes, B. R. and Dennison, W. C., (eds) 2002. State of South-east Queensland Waterways Report 2001. Moreton Bay Waterways and Catchments Partnership). “Between 2500 and 3500 tonnes of seafood are harvested annually from the Bay by 400 commercial fishing boats. An estimated 2000 tonnes of fish are caught by 300 000 recreational fishers in the Bay each year. A 1988 study valued the Bay’s mangroves at $8,380 a hectare based on the catch of marketable fish alone. (Wetlands – More than just wet land: Moreton Bay – The State of Queensland . Environmental Protection Agency 2000 BP916 February 2000 p.1)”

” Seagrass

Seagrass meadows are found in shallow, subtidal and intertidal areas of Moreton Bay and cover almost 250km2 (1.1%) of the Bay’s area. Despite this relatively small coverage, seagrasses form one of the critical habitats for biodiversity in the region. They provide a major food source for dugongs and turtles, and nursery grounds for commercially important species including prawns. Additionally, seagrasses assimilate and recycle nutrients within the ecosystem, trap sediments and stabilise the seabed. Seven seagrass species are found in the bay: Zostera capricorni, Halophila ovalis, Halophila spinulosa, Halophila decipens, Halodule uninervis, Syringodium isoetifolium and Cymodocea serrulata” (p. 99 Abal, E.G., Moore, K. B., Gibbes, B. R. and Dennison, W. C., (eds) 2002. State of South-east Queensland Waterways Report 2001. Moreton Bay Waterways and Catchments Partnership).

“Coral

Coral communities are broadly distributed throughout Moreton Bay. They occur on the mainland coast at Wellington Point and Cleveland, on the islands of Waterloo Bay; Peel, Goat, Coochiemudlo, and Macleay Islands; and at Myora off North Stradbroke Island. Corals require a hard substrate on which to attach and most are found in Moreton Bay at depths of less than 3m. Approximately 40 species of corals have been identified from reefs and are often patchy and interspersed amongst seagrass and sandy substrates” (p. 100 Abal, E.G., Moore, K. B., Gibbes, B. R. and Dennison, W. C., (eds) 2002. State of South-east Queensland Waterways Report 2001. Moreton Bay Waterways and Catchments Partnership).

“Other fauna

Approximately 600 dugongs inhabit Moreton Bay. Dugongs are listed as vulnerable to extinction by the World Conservation Union due to the large-scale hunting that occurred around the end of the 19th century. Dugongs graze on the shallow seagrass beds in Moreton Bay, highlighting the importance of seagrass conservation. Moreton Bay is also an important feeding ground for approximately 10 000 marine turtles. Six species have been identified: loggerhead turtle, green turtle, hawksbill turtle, leatherback turtle, olive ridley turtle and flatback turtle. Only the green, loggerhead and hawksbill turtles have resident populations in the Bay. More than 273 species of birds from 65 families have been recorded in Moreton Bay; these include 33 species of migratory and 11 species of resident shorebird. The Moreton Bay-Great Sandy Straits Region is the second most important migratory shorebird refuge in terms of population numbers in Queensland . For roosting and feeding sites it is particularly important for seven species of migratory shorebirds: Pacific golden plover (Pluvalis fulva), grey-tailed tattler (Heterosceles brevipes), lesser sand plover (Charadrius mongolus), eastern curlew (Numenius madagascariensis), bartailed godwit (Limosa lapponica), curlew sandpiper (Calidris ferruginea) and the pied oystercatcher (Haematopus longirostris). The protection of roosting and feeding sites in Moreton Bay under the Ramsar Convention is vitally important for the protection of shorebird populations” (p. 100 Abal, E.G., Moore, K. B., Gibbes, B. R. and Dennison, W. C., (eds) 2002. State of South-east Queensland Waterways Report 2001. Moreton Bay Waterways and Catchments Partnership).

“More than 50 000 migratory waders, particularly eastern curlews and grey-tailed tattlers, depend on the Bay for survival during their non-breeding season. At least 34 species of migratory waders including eastern curlews, red-necked stints, ruddy turnstones, bar-tailed godwits and sandpipers visit Moreton Bay each September to April. Thirty of the 43 shorebird species which visit Moreton Bay ’s intertidal flats are migratory species listed under the Japan Australia Migratory Bird Agreement (JAMBA) or the China Australia Migratory Bird Agreement (CAMBA). Most migrate from Arctic or sub-Arctic regions at the end of the breeding season moving to the southern hemisphere and stopping to rest before the next stage of their long journey. Not only do waders feed here but they store energy for their return trip north to breed again” (Wetlands – More than just wet land: Moreton Bay – The State of Queensland. Environmental Protection Agency 2000 BP916 February 2000 p.1).

“Distribution of invertebrate and fish communities

Approximately 3225 species of invertebrates and 713 fish species have been recorded in Moreton Bay … The Bay serves as a refuge for several species of both temperate and tropical animals, and in some cases is the boundary of their ranges. This is particularly evident for fish species, where 141 species are at the southern limit of their range and 24 at their northern limit” (p. 100 Abal, E.G., Moore, K. B., Gibbes, B. R. and Dennison, W. C., (eds) 2002. State of South-east Queensland Waterways Report 2001. Moreton Bay Waterways and Catchments Partnership).

Summary of Developmental Impact

Since European alteration of the environment many species have been displaced; from a massive increase in human population, and therefore a strain on the ecosystem, to the destruction of habitat for construction practices, the environment has suffered greatly in the past, and if practices do not alter to a sustainable format, will continue to suffer into the future (tokenistic attempts at protecting habitat are not sustainable and therefore a serious process must be put in place to not only stop the destruction but to reverse it where possible).

De-silting

Without a long term catchment management plan relating to de-silting works mangrove forests and other fauna will continue to be impacted upon. With an overall plan for catchment management regarding silting and weed control the waterways can be looked after and the local provenance species can be encouraged to retake an area to both promote biodiversity and bank stabilisation.

Impacts of modifying catchment flow

The “natural flow paradigm is based on emerging evidence that the full range of natural intra and inter-annual variation in the hydrological regime is critical in sustaining the full native biodiversity and integrity of aquatic ecosystems (Richter et al. 1997). Such hydrological variability is characterised by the magnitude, timing, frequency, duration and rates of change in river flow. There is considerable evidence that hydrological variation, as well as volume of flow, plays a major part in structuring biotic diversity within river ecosystems through controls on key habitat conditions within the river channel, and links with the floodplain and the river influenced groundwater (hyporheic zone) (Richter et al. 1996, Stanford et al. 1996, Arthington 1998). Fluvial processes maintain a dynamic mosaic of channel and floodplain habitats that sustain the diverse range of biota in healthy rivers” (Australian and New Zealand Environment and Conservation Council and the Agriculture and Resource Management Council of Australia and New Zealand ‘NATIONAL WATER QUALITY MANAGEMENT STRATEGY’ An Introduction to the Australian and New Zealand Guidelines for Fresh and Marine Water Quality 2000, p. 8.2-73).

Reference material:

Abal, E.G., Moore , K.B., Gibbes, B.R. and Dennison, W.C., (eds) 2002. State of South-east Queensland Waterways Report 2001 Moreton Bay Waterways and Catchments Partnership.

Gutteridge, Haskins & Davey Pty Ltd, 1996 Task M2 State of the Brisbane River and Moreton Bay and Waterways Brisbane River Management Group, Brisbane River and Moreton Bay Wastewater Management Study, Working Draft Version 1.4

For more general info on waterways and the environment see the Turrbal environment web page and to see some photos of Ningy Ningy view the link below.