State of the Environment Report 2007
Removal of native vegetation, both historic and current, is a major threatening process affecting biodiversity in WA. It includes the traditional concept of clearing, but also involves other substantial damage to native vegetation (e.g. burning, overgrazing and draining or flooding of land) which results in the removal of at least some native vegetation, and can result in degradation or loss of whole ecosystems. The loss of habitat area through clearing is currently the primary cause of declines in species and populations worldwide (Millennium Ecosystem Assessment, 2005).
Historic clearing commenced with the arrival of Europeans and settlement in WA. A strong development culture and aggressive agricultural expansion resulted in broadscale clearing of vast areas of the South West between 1945 and 1982 (Commonwealth of Australia, 2000). During the 1960s, 'a million acres a year' was released for agriculture, much of it in areas prone to land salinisation. Clearing rates slowed significantly in the 1970s, but widespread recognition of the growing salinity problem did not occur until the 1980s, when clearing controls were enforced. Broadscale clearing for intensive agriculture has now largely ceased, but it has left a legacy of environmental problems. Widespread clearing has also occurred along coastal zones of the South West, in particular the Perth metropolitan area, to accommodate a growing population and developing industries. Although clearing for cropping and grazing is generally not allowed in the rangelands, clearing for agriculture has occurred in the Ord River Irrigation Scheme and Fitzroy River catchments. Native vegetation in some pastoral areas is also under pressure from overgrazing (including pastoral livestock, introduced and native animals) and frequent extensive fires. More recently, most clearing occurs in small pockets of the South West for urban development and in other regional locations for mining. Clearing of native vegetation across the State is now regulated under the Environmental Protection Act 1986 unless exemptions apply.
Removal of large areas of native vegetation fragments the landscape, leaving behind small and unconnected remnants. Many flora, fauna and communities are threatened, often resulting in diminished biodiversity and extinctions in some areas. Clearing in the South West has resulted in other environmental issues including salinisation of land and inland waters, enhanced spread of weed species and exacerbated soil erosion, and has also contributed to reduced carbon stores of greenhouse gases. It is also believed that broadscale clearing in the South West may be responsible for reduced rainfall in cleared areas (due to a change in the land's surface and a reduced ability to form moisture-carrying clouds) (Lyons, 2002).
Many Western Australian terrestrial subregions have a high percentage of their native vegetation remaining (i.e. 41 of the 54 terrestrial subregions have 96% or more remaining), with most in the rangelands (Figure B0.1). The most extensively cleared subregions in WA are both the Avon Wheatbelt (AW2 and AW1), the Dandaragan Plateau (SWA1), the Western Mallee (MAL2), the Lesueur Sandplain (GS2), the Swan Coastal Plain (SWA2), Geraldton Hills (GS1) and the Recherche (ESP2) subregions (Table B2.1). These areas have diminished biodiversity and have a higher proportion of threatened flora and ecological communities (Table B2.1). Vegetation types that inhabit valley floors and lower slopes in the landscape are more than 90% cleared in the agricultural Wheatbelt zone, and comprise about one-third of all vegetation types in the Avon Wheatbelt and Western Mallee subregions (McKenzie et al., 2003). After broadscale clearing for agriculture, the whole agricultural Wheatbelt zone (including upper catchment areas) retains only 7% of its native vegetated area (Beecham, 2004). The Perth subregion (SWA2) (bound by Jurien Bay, Dunsborough and the Darling Scarp) contains 42% of the known threatened ecological communities, and this is certainly due to the clearing and fragmentation of native vegetation, but may also be influenced by a disproportionately high number of research studies in the area.
Some local government areas in the Wheatbelt retain very small amounts of native vegetation (Table B2.2). This is a good gauge of the present and future loss of biodiversity (and other environmental problems), but it does not represent the current areas of concern for ongoing loss of native vegetation (namely areas subject to urban development and mining). Further, 33 (40%) of the 83 non-metropolitan local governments in the South West have less than 15% vegetation remaining (Shepherd et al., 2001).
The change in native vegetation cover for the Perth metropolitan region has been assessed for the period 1998 to 2004 (Figure B2.1). Large areas in outer Perth suburbs have been cleared. Between 1998 and 2004 a total of 5974 ha were cleared in the Perth metropolitan region - an average rate of 853 ha per year (Western Australian Local Government Association Perth Biodiversity Project, unpublished data, 2007). Two-thirds of the total area cleared has occurred since 2001, with an average rate of nearly 1000 ha per year between 2001 and 2004. Over 2% of the total native vegetation that was present in 1998 was cleared by the end of 2004. This is over one football oval per day being cleared in the Perth metropolitan region. The total area of native vegetation within the Perth metropolitan region includes large areas of State Forest, national parks and other vegetated areas in the Darling Scarp, and it is clear that the vegetation of the Swan Coastal Plain suffered the most clearing. The rate of clearing in Perth is likely to have continued (or possibly accelerated) with the economic boom and increased demand for housing in the past 3 years.
It should be noted that there are limitations of 2001 and 2004 data, including
![Figure B2.1: Clearing in the Perth metropolitan region, 1998–2004. [Data source: Department of Agriculture and Food [ver. 2007]. Data analysis: Department of Agriculture and Food and EPA; Presentation: EPA. Note: Carnac, Penguin, Garden and Rottnest Islands, Kings Park and the Wilbinga extension to the Perth Metropolitan Region Scheme are not included in these data.]](/site/files/images/Figure-B2.1_Large.jpg)
Most recent clearing between 2001 and 2004 was concentrated in the outer Perth suburbs. The cities of Wanneroo and Rockingham have the highest areas of native vegetation cleared (over 1100 and 800 ha respectively) as a result of housing and infrastructure development (Table B2.3). Similarly, the cities of Joondalup and Bayswater have undergone the largest percentage decreases (17% and 12% respectively) in the area of native vegetation remaining over this timeframe (Table B2.3).
![Table B2.3: Top 10 local governments by area of land cleared (total number of hectares and percentage of remaining vegetation), 2001-04. [Data source: Western Australian Local Government Association Perth Biodiversity Project unpublished data [ver. 2007], based on data provided by the Department of Agriculture and Food [ver. 2006]. (a) City of South Perth results are likely to have been due to differences in mapping of vegetation in the two time periods.]](/site/files/images/Table-B2.3_Large.jpg)
Two local governments (towns of Bassendean and Cambridge) slightly increased the amounts of vegetation found in their areas, probably as a result of replanting and/or landscaping works. Some local governments have very small areas of native vegetation remaining (e.g. South Perth), and so changes in vegetation were probably due to methodology rather than loss of native vegetation. Local governments with less than 20 ha of native vegetation remaining and excluded from this analysis were Claremont, East Fremantle, Fremantle, Mosman Park, Peppermint Grove, Perth, Subiaco, Victoria Park and Vincent. The amount of legal or long term protection given to remnants of native vegetation varies according to local government area and land tenure. The condition on native vegetation was not addressed in these data sets (Western Australian Local Government Association Perth Biodiversity Project, unpublished data, 2007).
Broad vegetation change in the South West can be assessed through the Land Monitor program, but it is not possible to accurately distinguish native vegetation from other vegetation (such as orchards and plantations), or vegetation removal as a result of bushfires. Loss or degradation of vegetation cover appears to be continuing across the South West, which may be attributed to the effects of a drying climate (and therefore less vegetation cover or tree foliage) (Figure B2.2). Loss in the eastern agricultural Wheatbelt areas (east of Katanning) may be attributed to fires, with much of this vegetation likely to regrow over time. Agricultural Wheatbelt areas may be losing vegetation cover (or perhaps tree foliage) due to the effects of land salinisation. In coastal South West areas, loss of vegetation cover is likely to have been caused by direct clearing for urban development, expanding agriculture, harvesting of plantations, or the effects of Phytophthora dieback. Further investigation is required to explain the loss of vegetation cover in these areas.
![Figure B2.2: Vegetation loss or decline in the South West by local government area, 1996-2004. [Data source: Department of Land Information – Land Monitor [ver. 2004]; Analysis: EPA; Presentation: EPA.]](/site/files/images/Figure-B2.2_Large.jpg)
Monitoring results from the Western Australian Rangeland Monitoring System were analysed at the bioregional scale to determine change in vegetation condition, i.e. shrub density or perennial grass frequency (Figure B2.3). Change was determined by comparing data for the most recent sampling period (1999-2004) with that of the period 1993-2002. A majority of sites in bioregions showed stable or improving vegetation cover over the past decade (Figure B2.3). Only a few bioregions in the Murchison and Pilbara showed a majority of sites with declining vegetation density or frequency. While these areas recently experienced a prolonged drought, there are also indications that inappropriate grazing management has contributed to the decrease (Department of Agriculture, unpublished). Overgrazing, a form of indirect clearing, can be caused by a variety of animals including domestic stock (cattle, sheep and goats), native animals (kangaroos) and introduced animals (camels, donkeys, horses, pigs, feral cattle, feral goats, rabbits).
![Figure B2.3: Change in native shrub density and perennial grass frequency at Western Australian rangeland monitoring sites, by bioregion. [Data source: Department of Agriculture – WARMS [ver. 2005]; Analysis: EPA; Presentation: EPA.]](/site/files/images/Figure-B2.3_Large.jpg)
Patterns of richness of native perennial species, revealed by similar analysis of monitoring system data, are quite different (Figure B2.4). The Kimberley bioregions have declining richness (loss of biodiversity), but most other areas show stable or increasing richness. It is believed that perennial tussock grasses in the Kimberley, although still common and widespread, have been replaced in many areas by annual grasses as a result of heavy grazing and changed fire regimes (Start, n.d.). As a result of grazing activity, threatened ecological communities have been declared in the rangelands, including themeda grasslands (at Hamersley Station in the Pilbara) and many Kimberley mound springs.
![Figure B2.4: Per cent of monitoring sites showing stable or improving species richness of native perennials at Western Australia rangeland monitoring sites, displayed at terrestrial subregion scale. [Data source: Department of Agriculture – WARMS [ver. 2005]; Analysis: EPA; Presentation: EPA.]](/site/files/images/Figure-B2.4_Large.jpg)
Historically, widespread clearing occurred for development of intensive agriculture in the South West, namely sheep and wheat farming. Since the 1980s agricultural expansion has slowed and clearing controls have been enforced. Recent expansion of the wine and plantation industries has renewed clearing activity in small pockets of the South West.
Population increases result in increased housing demand, and consumption patterns show that West Australians have a preference for larger houses and fewer people per household compared to other parts of the world (see 'Settlement patterns'). This results in large land areas being needed to accommodate urban centres and consequent clearing of native vegetation and farmland for housing. Urban expansion has increased dramatically around Perth and other major coastal regional centres in the South West. The urban area of Perth has doubled since the 1970s and this has resulted in clearing of large areas of native vegetation, fragmentation of remaining areas and leads to the loss of species and ecosystems. Vegetation communities of the Swan Coastal Plain are highly represented on the list of threatened ecological communities, although this is in part due to the more extensive research in this area and it's under representation in the conservation reserve system. Continued loss of native vegetation in the Perth metropolitan region is forecast as many areas have been zoned urban in the planning system but have not yet been developed (see 'Settlement patterns').
Outside the South West, mining activity is the primary reason for vegetation clearing. The current resources boom has accelerated clearing of native vegetation in the rangelands but the proportion of land impacted is relatively small. In many cases mining companies are required to undertake land rehabilitation and revegetation upon completion of extraction activities. This sector's growth is projected to continue into the foreseeable future.
Comprehensive statistics on the rate of clearing of native vegetation are difficult to obtain and there are major challenges in accurately representing the data. Since July 2004, clearing regulations under the Environmental Protection Act 1986 have enabled comprehensive records to be kept of all applications approved and refused to clear native vegetation. Prior to the clearing provisions, a system of 'notice of intent' to clear applied under the Soil and Land Conservation Act 1945. These figures do not give accurate clearing statistics, but rather an indication of the trend in clearing proposals (Figure B2.5).
Prior to the change in native vegetation clearing regulations in 2004, both the number of notices and the approved area to clear for agricultural purposes were generally in decline. It is interesting to note the area approved to clear without objection in the late 1980s was more than 30 000 hectares per year (and as high as 62 000 ha in 1988-89), and this had declined to around 1000 ha by the early 2000s (Figure B2.5). The Soil and Land Regulations 1992 were introduced and then a memorandum of understanding was made in 1997 between state agencies, both of which resulted in significant decreases in area clearing notified for agriculture (Figure B2.5). However, there was a sharp increase in the number of notices of intent to clear in 2003-04, when introduction of the Environmental Protection (Clearing of Native Vegetation) Regulations 2004 was imminent.
Notices of intent to clear for mining purposes ranged from 2880 to 30 442 ha annually between 1998-99 and 2003-04, but these statistics are not reliable. Additionally, many areas previously cleared for mining have been rehabilitated and revegetated.
![Figure B2.5: Number of notices of intent to clear for agriculture purposes, and area involved, 1986-2004. [Data source: Department of Agriculture [ver. 2005]. Presentation: EPA.]](/site/files/images/Figure-B2.5_Large.jpg)
Statistics on clearing applications improved significantly after introduction of regulations in 2004 (which operated under the Environmental Protection Act 1986) (Figure B2.6). During 2005 and 2006, applications were made to clear approximately 15 000 ha of vegetation each year. Of this, a total of 7058 ha were approved for clearing under this legislation in 2005, and 8030 ha in 2006. This equates to about 10 football ovals per day approved to clear in 2005 and 11 per day in 2006. These figures cannot be directly compared to data from the notice of intent process. The year 2004 is excluded because it does not include a full year of data. Mining and other extractive industries still represent the primary reason for clearing approvals under the Environmental Protection (Clearing of Native Vegetation) Regulations 2004. The new clearing provisions are far more comprehensive in the assessment processes for granting or refusing applications than the previous notices of intent to clear process. However, the statistics do not consider clearing approvals granted through the Environmental Protection Authority's environmental impact assessment process, especially for large mining proposals or projects with significant environmental impacts. Therefore it is not possible to provide the total rate (or area) of native vegetation approved for clearing in WA. Unauthorised (illegal) clearing continues to occur, although the scale of this problem remains unknown.
![Figure B2.6: Number of applications and area approved for clearing under the 2004 clearing regulations, by activity type, 2005–06. [Data source: Department of Environment and Conservation [ver. 2007]. Analysis: EPA. Note: Data for calendar year 2004 is not included because it was for Aug to Dec of that year only (Environmental Protection (Clearing of Native Vegetation) Regulations 2004 came into effect in June 2004). Percentages on graphs show the proportion of total applications were approved. These data are for areas formally approved for clearing only, they do not include applications that were declined, refused or withdrawn.]](/site/files/images/Figure-B2.6_Large.jpg)
Legislation and policy: Legislation and policy direction has proven an effective means of influencing the clearing rate. The Environmental Protection (Clearing of Native Vegetation) Regulations 2004 were gazetted on 30 June 2004 and clearing provisions of the Environmental Protection Act 1986 commenced on 8 July 2004.
All clearing of native vegetation now requires a permit (unless an exemption applies) and the principles in Schedule 6 of the Environmental Protection Act 1986 allow proposals to be assessed so that land, water quality and biodiversity values are taken into account. Clearing is administered by the Department of Environment and Conservation with a delegation of clearing for mining and petroleum under the Mining Act 1978 and various Petroleum Acts to the Department of Industry and Resources.
Natural Heritage Trust/National Action Plan for Salinity and Water Quality (NHT/NAP): These are two Commonwealth Government programs that aim to ensure environmental (on-ground) improvements occur via a targeted strategic approach at the regional level. This covers a wide range of actions aimed at progressively limiting clearing and preventing further loss of species and ecosystems, and limiting degradation of land and water.
Revegetation groups: There are many government programs and non-government organisations which focus on revegetation, rehabilitation of areas that have already been cleared, and preventing further degradation of remaining bushland by landscape-level threats such as salinity and soil erosion. Programs include the Greening Challenge (Department of Agriculture), Landcare and Greening Australia (non-government organisations).
Off-reserve conservation: There are many programs focused on preventing further clearing of bushland, and in some cases these assist with management of land that is not in the formal conservation reserve (see 'Conservation'). Examples include Bushland Benefits, Bush Forever, Roadside Conservation Committee initiatives, Nature Conservation Covenant Program, Land for Wildlife, Urban Nature, biodiversity incentives administered by the Department of Environment and Conservation, Gondwana Link, and the Threatened Species Network and Woodland Watch (WWF).
Planning: Many planning and policy instruments are designed to minimise clearing in the metropolitan area of Perth, and provide protection for remnant bushland. Examples include Bush Forever, Coastal Planning and Network City. Bush Forever has recently expanded from areas around Perth to include surveys and protection of remnant bushland on the northern and southern parts of the plain.
Biodiversity Conservation Strategy: The Department of Environment and Conservation has released A 100-year Biodiversity Conservation Strategy for Western Australia: Blueprint to the Bicentenary in 2029 for public comment. A final biodiversity conservation strategy is in preparation (Department of Environment and Conservation 2006a).
Local government: The Perth Biodiversity Project is a partnership project between 30 local governments, the Western Australian Local Government Association, the Swan Catchment Council, Department of Environment and Conservation, the Department for Planning and Infrastructure and Greening Australia WA. Local Governments participating in the Project are encouraged to become more involved in bushcare and biodiversity conservation (Western Australian Local Government Association, n.d.). The Local Government Biodiversity Planning Guidelines were released in 2004 to describe a consistent, staged process that can be used by local government to prepare local biodiversity strategies (Del Marco et al., 2004). The process encourages biodiversity targets and criteria to be set, enabling local governments to identify biodiversity values and integrate biodiversity conservation into their planning and decision making processes.
Removal of native vegetation has obvious environmental implications, but it also has significant social and economic implications. In some parts of WA (especially the Wheatbelt and parts of the Swan Coastal Plain) native vegetation has been cleared beyond safe ecological limits. Continued clearing will result in loss of biodiversity and extinctions, with fragmented habitats becoming more susceptible to climate change, disease, and weed and introduced animal invasion. Salinisation of land and inland waters, altered water regimes, soil erosion, eutrophication and increased greenhouse gas emissions are all direct consequences of clearing native vegetation. Benefits of retaining native vegetation include cultural benefits (i.e. 'sense of place' and recreational value) and ecosystem services (e.g. pollination, maintenance of local climates, healthy land and waterways, sequestration of greenhouse gases) that underpin the economy and society. Consequently everyone has a role in preventing further clearing and protecting existing native vegetation remnants, not just landholders.
5.8. Prohibit clearing in local government areas with less than 15% native vegetation remaining and prohibit further clearing of vegetation types that are found to be at less than 10% of their pre-European extent.
5.9 Develop and implement a policy of 'no net loss' of native vegetation due to land use that comprehensively considers biodiversity values in clearing applications.
5.10 Establish a central database to make information on all clearing activities (including environmental impact assessment) publicly available.
5.11 Carefully monitor for illegal clearing and breaches of conditions set under the Environmental Protection Act 1986 and take appropriate action should they occur.
