Note: Many species are affected by more than one threat.
Source: Australia's Environment: Issues and facts (Cat. No. 4140.0 p 25).
(http://www.abs.gov.au/Websitedbs/c311215.nsf/20564c23f3183fdaca25672100813ef1/bc7dc08a640751f8ca2569e70003c7f6!OpenDocument) The largest present and future threat is from low numbers. While the present and future threat from agriculture is less than half the past threat, the threat from industrial and urban development remains the same. The threat is exacerbated because most of the threatened species in developing areas and areas proposed for development fall into the "low numbers" category. Residential development prevents the reinstatement of habitat and of necessity involves "roadworks" and other listed activities so that the real figure for industrial and urban development could be much higher. Since there is no reason why development needs to occur in areas where species are at risk (there are invariably suitable alternatives), prohibition of development in these areas could substantially reduce the risk or at least stop it from becoming worse and therefore possibly make a similar contribution to that made by agriculture. It may also allow reinstatement of habitat.
The following map shows the extent of biodiversity reference material for local government areas around Melbourne.
Source: “A Reference Guide to the Ecology and Natural Resources of the Melbourne Region” Mark J. McDonnell et al 1999 ARCUE.
It is not surprising that development tends to occur where there is the least information about biodiversity. The map shows that the most information is available in areas where there are few threatened communities while the least is available in areas with the most threatened communities, which is where development tends to occur.
The following information is taken from Victorian Flora and Fauna Guarantee act Action Statements and elsewhere and highlights the proposition that concentrations of threatened species frequently occur near development or areas proposed for development.
No 41 Regent Honeyeater Xanthomyza phrygia.
The significant distribution to the Northeast of Melbourne coincides with areas of Valley Grassy Forest a principal species of which is Yellow Box one of the favourites of the Regent Honeyeater. The draft Port Philip and Westernport Naive Vegetation Plan shows that development has diminished Valley Grassy Forest (BVT) from a pre-1750 coverage of 28, 891 hectare to an extent of just 274 hectare (August 2000). More recent sightings to the north and west of Melbourne probably occur in River Red Gum Plains Grassy woodland. The River Red Gum is also on its list of more favoured species. Proposed development in these areas poses a significant threat to its survival as one of our most endangered Honeyeaters.
No 43 Orange-bellied Parrot Neophema chrysogaster.
The occurrence of the Orange-bellied Parrot to the west of Melbourne and in developing coastal areas means that development poses a significant threat to its survival.
51 Little Tern Sterna albifrons sinensis.
The distribution of the Little Tern to the west of Melbourne and in developing coastal areas means that development poses a significant threat to its survival.
54 Leafy Greenhood Pterostylis cucullata.
Because Leafy Greenhood mainly occurs in developed and developing areas further development in these areas poses an unacceptable threat.
No 66 Plains Wanderer, Pedionomus toquatus.
The action statement distribution map shows significant Plains wanderer territory to the north of Melbourne. Because this area is being (or has been) developed new development will further destroy crucial habitat.
68 Large-fruit Groundsel Senecio macrocarpus
The distribution of this listed species to the north and west of Melbourne means it is in the areas proposed for development as well as those already developed. Development poses a significant threat to its survival.
Appendix D. Extracts from “Threats to our water environments” 2005 (http://www.epa.sa.gov.au/water_threats.html) Pollution by urban stormwater
Urban stormwater is run-off from buildings, streets and footpaths, and includes the major flows during and following rain as well as 'dry-weather flows'. Dry weather flows come from garden watering, wash-downs and illegal discharges.
Stormwater can contain litter, dust, soil, oil and grease from roads, garden waste, chemicals, and excess nutrients from animal faeces and fertilisers. This pollution can kill fish, cause unsafe swimming conditions, entangle aquatic animals in rubbish, and create toxins in them.
Nutrients can accumulate in waters naturally and increase aquatic plant growth. However, some human activities can accelerate this process, creating excessive nutrient loads (eutrophication) in lakes, rivers, harbours and estuaries. Nutrients from human activities include, sewage effluent, urban stormwater……
An increase in nutrients (nitrogen and phosphorus) results in an increase in the growth of algae. In this environment algae often multiply quickly to dominate an ecosystem and cause a bloom. Algal blooms can have many different and adverse effects on an ecosystem. Blooms can smother aquatic plants and compete with plants and other organisms for light and space. When they die they reduce the amount of oxygen in the water, killing fish.
Some blue green algae (cyanobacteria) release toxins when they die. This has been a major problem in the River Murray, where it has killed fish and poisoned stock water. Blue green algae is also a health hazard for humans who come into contact with the water, causing skin irritation, swollen lips, eye soreness, earache, and asthma.
Nutrient enrichment of Gulf St Vincent has resulted in an increase in algae that attach themselves to other aquatic plants for support (epiphytic algae). Epiphytic algae has resulted in the loss of over 6000 hectares of seagrass between Port Gawler and Aldinga. Loss of seagrass has led to more sediment in our coastal waters, an increase in coastal erosion, and a dramatic loss of biodiversity in sub-tidal reefs.
In the Port River, nutrient enrichment from urban stormwater and industries causes the water to turn red/brown. The discolouration of the water, known as a 'red tide', is due to blooms of algae. Some of these blooms can produce toxins which can cause severe gastro-intestinal and neurological illnesses such as paralytic shellfish poisoning (PSP).
Algal blooms can force water restrictions and the closure of waterways to fishing, swimming and boating. It can cause fish kills and severe economic costs to agriculture, tourism and water authorities. It has been estimated that algal blooms cost Australia $150m a year (Land and Water Resources Development Commission, 1999).
Sedimentation occurs when mineral and organic particles of different sizes are transported from their place of origin by water, wind, gravity, or ice. This process occurs naturally; however, human activities can accelerate it, causing unnaturally high levels of sediment in our rivers, lakes and streams.Human activities that increase sedimentation include:·
land clearance, which can lead to gully erosion ·
poorly managed building sites, which allow soils and other pollutants to enter the stormwater system ·
unsealed roads near waterways ·
uncontrolled stock access to streams and rivers, which increases erosion of river banks ·
construction of dams and reservoirs.
Sediments carry nutrients, and nutrient enrichment reduce water quality and promote algal blooms. Increased sedimentation leads to increased turbidity in our waterways, in-filling of creek pools, and weed growth. High levels of sedimentation can also smother plants, suffocate fish, and make habitats unsuitable for native wildlife.
Oils, heavy metals and other chemicals
Pollutants such as oils, heavy metals and chemicals can cause substantial environmental damage. They often contaminate the stormwater system that flows untreated into natural waterways. Sources of pollution include:·
leaking cars · fuel stations and mechanical repair shops ·
auto dismantlers and crash repairers ·
auto services ·
paint · batteries ·
timber treating works ·
leather tanning works ·
carpet cleaning ·
airconditioning coolants ·
pesticides and fertilisers
Oil and grease are toxic to animals and plants and form a film over the water surface, making it difficult for organisms to breath. Heavy metals such as cadmium, chromium, copper, zinc and lead are also toxic. These substances can accumulate in aquatic animals such as mussels and have a dangerous impact through the food chain.
Alteration of natural flows
Water is pumped from rivers and underground water supplies for use by rural towns, farms, industries and cities. Many rivers also feed dams and reservoirs for public water supplies and hydro-power, and are used as transport routes for boats.While these activities provide economic and social benefits, there are many adverse environmental impacts associated with altering the natural flow of rivers (river regulation). These include the decline and loss of native species of plants and animals, encouragement of habitats favourable to pest species (carp, gambusia and redfin), declining water quality, and loss of amenity.
River regulation in the Murray-Darling Basin is so severe that giant river redgums which rely on frequent flooding are dying and the Murray cod is threatened.
Native vegetation clearance has wide-ranging impacts on water quality, local habitats and biodiversity. Clearing the landscape of trees and shrubs also changes the direction and rate of rain run-off, and increases erosion. This means more sediment, nutrients, salt, pesticides and other toxicants are transported into rivers and streams.
Towns and cities cause an increased volume of stormwater due to their large area of impervious surfaces (roads, roofs, footpaths, carparks) compared to well-vegetated catchments.
Loss of habitats
Habitats are the places where organisms live. Loss of habitat can range from the removal of whole wetland ecosystems, to the removal of a small stand of reeds in a swamp or creek. The major effect of the loss of habitats is invariably the loss of biological diversity.
This can limit the ability of the local environment to tolerate the effects of climatic variation and the adverse impacts brought about by human activities. It can also affect the ability of the environment to recover from the effects of a major event such as a drought, or the significant discharge of a pollutant.
Pests or invasive species are usually introduced by humans. They threaten the survival of native plants and animals; they can also damage valuable agricultural and personal resources.
Terrestrial and aquatic pests impact on the health of our waterways as well as native animals and plants. For example, mosquito fish (gambusia holbrooki) were introduced from the USA to control mosquito numbers. However, they now outnumber native fish in many parts of south eastern Australia as they out-compete the indigenous species for food. Exotic trees such as willows (Salix sp) are another problem. Willows create a dense shade, resulting in bare banks that are susceptible to erosion. The trees provide a poor wildlife habitat for land animals, while the number and diversity of aquatic invertebrates and native fish is greatly reduced under their canopy.
Threats to groundwater
Processes and activities threatening groundwater include ………… urban and commercial development……………….
Overuse of groundwater supplies can dehydrate many ecosystems and habitats by lowering the groundwater level to beneath the rooting depth of many plants, reducing the water seeping into rivers, and destroying habitats in cave and aquifer ecosystems.
Diversion or impoundment (i.e. dams) of surface waters can elevate groundwater levels and cause similar problems. Some groundwater-dependent species may be advantaged over others, while some may die from waterlogging. The elevated groundwater levels hold accumulated salts, causing salinity that can lead to plant death, and the loss of native fauna that depend on those plants.
Excavation during construction activities and the lowering of groundwater levels can activate acid sulphate soils and severely impact aquatic ecosystems. Acid sulphate soils are wetland soils and unconsolidated sediments that contain iron sulphides. When covered permanently with groundwater, the iron sulphides are stable and the soils are weakly alkaline. However, when groundwater levels are lowered, the iron sulphides are exposed to oxygen, the sulphides oxidise and, in the presence of water, form sulphuric acid (Powell and Ahern 1997). This process has a disastrous effect on aquatic ecosystems by poisoning them with heavy metals, acidified water, and iron.
New urban or commercial developments can lower and raise groundwater levels through increased domestic watering, and recreational and industrial uses. In turn, native vegetation and wetlands are threatened, and salinity increases. Urban development can also affect the quality of groundwater through effluent from septic tanks, leakage from underground fuel tanks, and the use of chemicals and fertilisers.
………………………… and residential development often pump large quantities of water from under the ground and aquifers. This action can lower the level and flow rate of underground water, and reduce aquifer pressure.
Appendix E Urban impact buffer distances.
1. Urban impact notes. (RMIT 2006)
How wide should buffers be?
1-2 km (Pal, Ghosh et al. 1998).
Domestic and feral cats
Limited information in the Melbourne context. Studies in Canberra suggest that domestic cats will hunt up to 900 m into bushland adjacent to urban areas (Barrett 1998).
Seasonally up to 3.5 km (Robinson and Marks 2001).
Limited data – possibly not more than 50 m on flat country – considerably further downslope. Would vary considerably depending on soils and climate. (Leishman, Hughes, et al 2004)
Strong temporal as well as spatial element as weed populations spread. Few detailed studies available as there are many weed taxa with a wide range of dispersal mechanisms. Weeds may readily invade natural ecosystems from neighbouring pasture and croplands. A majority of bird-dispersed seeds are avoided within 250 metres of feed source in wet forest (XXXX XXXX Unpublished data).
Limited comprehensive information in urbanising environments, particularly in Australia. Most information available on invertebrate and vertebrate fauna. Very little on plants. A Netherlands study found that the density of bird nests was statistically lower up to 300 m away from lights in a lighted area compared with unlighted areas (De Molenaar, Jonkers et al. 2000; Longcore and Rich 2004).
Limited information. Overseas studies have indicated that multi-laned highways (>30 000 vehicles/day) can impact on grassland birds for a distance of approximately 1200 m from the road and the impact of multi-laned highways on forest birds occurs for several hundred meters (Forman, Reineking et al. 2002). Impacts on grassland birds can be detected up to 700 m from a road carrying 15 000 to 30 000 vehicles per day and for 400 m from roads carrying 8 000 to 15 000 vehicles/day (Forman, Reineking et al. 2002). Traffic noise is the most likely cause of these impacts. The amount of distance where there is an impact is likely to vary with the continuity of the sound, that is, whether it is chronic, singular or intermittent. Singular or intermittent noises may have a greater impact than chronic noises. The extrapolation of overseas results on road noise to Australia may be confounded by different road management practices. Australia has been recognised for its ecological approach to road management by, for example, leaving natural vegetation strips of 10 – 200 m in many agricultural landscapes in contrast to other countries such as the United States of America (Forman and Alexander 1998).
2. Bushland modification and styles of urban development: their effects on birds in south-east Queensland
Sven R. Sewell and Carla P. Catterall
PDF available from: http://www.publish.csiro.au/?act=view_file&file_id=WR96078.pdf
Variation in bird assemblages associated with forest clearing and urbanisation in the greater Brisbane area was assessed by counting birds in sites within six habitat categories: large remnants, small remnants, no- understorey remnants, canopy suburbs (original trees present), planted suburbs, and bare suburbs. Total bird abundance and species richness were generally highest in canopy suburbs. Individual species showed many significant abundance differences among the habitat types, and were classified into three major response categories: bushland species (3 in summer, 13 in winter), tolerant species (13 in summer, 13 in winter), and suburban species (12 in summer, 11 in winter).
The commonly proposed notion that urbanisation results in lowered bird species richness and increases in introduced species is broadly consistent with the observed differences between bare suburbs and large remnants. However, it does not adequately describe the situation in the planted and canopy suburbs, where there was high species richness and extremely high abundance of some native species (including noisy miners, lorikeets, friarbirds, and butcherbirds) but low abundance of a majority of the species common in the original habitats (including fantails, wrens, whistlers, and other small insectivores). Retained forest remnants are essential for the latter group. Urban plantings of prolifically flowering native species do not reverse the effects of deforestation, but promote a distinctive group of common native suburban bird species. Origins of the urban bird assemblage are discussed.
Wildlife Research 25(1) 41 - 63
Full text doi:10.1071/WR96078
3. Frontiers in Ecology and the Environment: Vol. 2, No. 4, pp. 191–198, Ecological light pollution ,Travis Longcore,a and Catherine Richa
The Urban Wildlands Group, PO Box 24020, Los Angeles, CA 90024-0020 (firstname.lastname@example.org)
Ecologists have long studied the critical role of natural light in regulating species interactions, but, with limited exceptions, have not investigated the consequences of artificial night lighting. In the past century, the extent and intensity of artificial night lighting has increased such that it has substantial effects on the biology and ecology of species in the wild. We distinguish “astronomical light pollution”, which obscures the view of the night sky, from “ecological light pollution”, which alters natural light regimes in terrestrial and aquatic ecosystems. Some of the catastrophic consequences of light for certain taxonomic groups are well known, such as the deaths of migratory birds around tall lighted structures, and those of hatchling sea turtles disoriented by lights on their natal beaches. The more subtle influences of artificial night lighting on the behavior and community ecology of species are less well recognized, and constitute a new focus for research in ecology and a pressing conservation challenge.
4. Journal of Animal Ecology Volume 73 Page 434 - May 2004 doi:10.1111/j.0021-8790.2004.00814.x Volume 73 Issue 3
The impact of environmental noise on song amplitude in a territorial bird, HENRIK BRUMM, Institute of Biology, Behavioural Biology, Free University, Berlin. Journal of Animal Ecology (2004) 73, 434–440 Blackwell Publishing Ltd.
1. The impact of environmental background noise on the performance of territorial songs was examined in free-ranging nightingales (Luscinia megarhynchos Brehm). An analysis of sound pressure levels revealed that males at noisier locations sang with higher sound levels than birds in territories less affected by background sounds.
2. This is the first evidence of a noise-dependent vocal amplitude regulation in the natural environment of an animal.
3. The results yielded demonstrate that the birds tried to mitigate the impairments on their communication caused by masking noise. This behaviour may help to maintain a given transmission distance of songs, which are used in territory defence and mate attraction. At the same time, birds forced to sing with higher amplitudes have to bear the increased costs of singing.
4. This suggests that in songbirds the level of environmental noise in a territory will contribute to its quality and thus considerably affect the behavioural ecology of singing males.
5. Annual Review of Ecology and Systematics Vol. 29: 207-231 (Volume publication date November 1998) (doi:10.1146/annurev.ecolsys.29.1.207)
ROADS AND THEIR MAJOR ECOLOGICAL EFFECTS Richard T. T. Forman and Lauren E. Alexander
Harvard University Graduate School of Design, Cambridge, Massachusetts 02138
A huge road network with vehicles ramifies across the land, representing a surprising frontier of ecology. Species-rich roadsides are conduits for few species. Roadkills are a premier mortality source, yet except for local spots, rates rarely limit population size. Road avoidance, especially due to traffic noise, has a greater ecological impact. The still-more-important barrier effect subdivides populations, with demographic and probably genetic consequences. Road networks crossing landscapes cause local hydrologic and erosion effects, whereas stream networks and distant valleys receive major peak-flow and sediment impacts. Chemical effects mainly occur near roads. Road networks interrupt horizontal ecological flows, alter landscape spatial pattern, and therefore inhibit important interior species. Thus, road density and network structure are informative landscape ecology assays. Australia has huge road-reserve networks of native vegetation, whereas the Dutch have tunnels and overpasses perforating road barriers to enhance ecological flows. Based on road-effect zones, an estimated 15–20% of the United States is ecologically impacted by roads.
6. Urban effects on native avifauna: a review, Jameson F. Chace, John J. Walsh (2004), www.elsevier.com/locate/landurbplan