A Survey of Roadside Conservation Values in the Shire of Esperance
and Roadside Management Guidelines
December 2002
Roadside Conservation Committee
CONTENTS
Introduction 3
Values of Roadsides 4
Roadside Conservation in Esperance 4
Legislation 6
Assessment Process 8
- Methods 8
- Quantifying Conservation Values 8
- Mapping Conservation Values 9
Survey Data Results 11
Management Techniques 18
Code of Practice 19
Tree Roads 19
Flora Roads and Roads Important for Conservation 20
Special Environment Areas 20
Roadside Management Planning and Strategies 22
Roadside Action Plans 25
References 26
FIGURES
Figure 1. Climate statistics Figure 2. Road reserve widths in the Shire of Esperance Figure 3. Width of vegetated roadside Figure 4. Conservation status of roadsides in the Shire of Esperance Figure 5. Native vegetation on roadsides Figure 6. Extent of native vegetation Figure 7. Number of native species Figure 8. Weed infestation Figure 9. Value as a biological corridor Figure 10. Predominant adjoining land use Figure 11. Weed occurance along roadsides in the Shire of Esperance Figure 12. SEA site marker Figure 13. Marking sites in the field
TABLES Table 1. Colour codes used to depict the conservation status of roadsides Table 2. Summary of roadside conditions in the Shire of Esperance
APPENDICES Appendix 1. Definitions of remnant vegetation types Appendix 2. Standard survey sheet Appendix 3. Raw data used to calculate conservation values Appendix 4. Plant species in the Shire of Esperance
INTRODUCTION
The Shire of Esperance covers an area of 42, 450 square km and supports a population of approximately 13,500 people. The area experiences a mediterranean climate with an average annual rainfall of 619 mm. Seasonal temperatures are characterised by warm summers, with maxima averaging from the mid to high twenties, and mild winters, with maxima in the mid teens. Mean daily maximum and minimum temperatures and rainfall statistics are shown below.
30.0 120.0
25.0 100.0
20.0 80.0
15.0 60.0 Rainfall Temperature 10.0 40.0
5.0 20.0
0.0 0.0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month Mean daily maximum temperature - deg C Mean daily minimum temperature - deg C Mean monthly rainfall - mm Figure 1 – Mean daily maximum and minimum temperature (oC) and rainfall (mm) in the Shire of Esperance
Esperance is located 725 km south east of Perth in Western Australia’s south-coast land division. The major agricultural pursuits and industries in the area are grain and cereal growing, sheep, cattle, pigs, fishing and fish processing, saltworks and viticulture. Tourism is also an important industry, with the area’s spectacular natural resources, such as magnificent coastal areas and wildflowers, being a major attraction. Pink lake, wind farms, the museum and recreational areas are salient features of the area.
The WA herbarium records more than 800 species of plants from the Shire of Esperance. Of these, 132 are Acacia species. 150 are Eucalypt species, 25 are Boronia species, and 18 are Dryandra species.
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 1
VALUES OF ROADSIDES
Since the settlement of Western Australia by Europeans, large areas of native vegetation in the south west of the state have been cleared for agriculture, roads, settlements, and other development. The fragmentation of the more or less continuous expanse of native vegetation communities by clearing has resulted in the isolation of plant and animal populations, restricted by man-made biogeographical islands of small remnants. They are prone to food shortages, disease and reduced genetic diversity. However, the presence of native vegetation along roadsides can often assist in alleviating this isolation effect by providing connectivity between bush remnants, thereby facilitating the movement of biota across the landscape.
Remnant vegetation includes more than just trees. Trees, shrubs and ground covers (creepers, grasses and herbs) combine to provide valuable food and shelter for different types of wildlife. Existing native vegetation will require less maintenance if left undisturbed.
Trees are good – bush is better Local indigenous trees, shrubs and grasses on the roadside are valuable because they: - are often the only remaining example of original vegetation within extensively cleared areas; - are easier to maintain and generally less fire prone than introduced vegetation; - provide habitat for many native species of plants, mammals, reptiles, amphibians and invertebrates; - provide wildlife corridors linking other areas of native vegetation; - often contain rare and endangered plants and animals. Currently, roadside plants represent more than 80 per cent of the known populations of 40 of the declared rare species, and three of these are known only to exist in roadside populations; - provide the basis for our important wildflower tourism industry. The aesthetic appeal of well-maintained roadsides should not be overlooked, and they have the potential to improve local tourism and provide a sense of place; - often contain sites of historic or cultural significance; - provide windbreaks and stock shelter areas for adjoining farmland by helping to stabilise temperature and reduce evaporation. - assist with erosion and salinity control, and not only in the land adjoining the road reserve per se; - are generally far less of a fire threat than annual weeds; A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 2 - provide a benchmark for the study of soil change throughout the advancement of agriculture; - are a vital source of local seed for revegetation projects in the absence of other alternatives; - provide a valuable source of seed for regeneration projects. This is especially pertinent to shrub species, as clearing and grazing beneath farm trees often removes this layer; Approval of the local shire and a CALM permit are required prior to collection.
In a time of rapid change, where the demands placed on the natural world are many, it is vital that there is a coordinated management of lands across all tenures and boundaries to ensure the sustainability and integrity of the natural biota and ecosystem processes, agricultural lands and service infrastructure.
Roadsides are the vital link ……………………. and a priceless community asset.
ROADSIDE CONSERVATION IN ESPERANCE
Wide Road Reserves
Historically, road reserves were measured in chains (approximately 20 metres) and were usually only one chain wide, particularly in agricultlural areas. Natural vegetation that occurs within narrow roadsides can be highly susceptible to disturbance, weed invasion and increased edge effects. Wider, more continuous stretches of vegetation act more effectively as wildlife corridors and provide more shelter and food than narrower ones.
In rural areas of Western Australia, wide road reserves were formed as part of a government policy to create reserves for the preservation of wildflowers and flora conservation. This government policy was put in place in 1952 and remains in force today.
The road network in the Shire of Esperance comprises a number of wide road reserves, and often the width of vegetation is greater than 20m on either side of the road (See figures 2 and 3). These unique areas provide habitat, enable connectivity throughout the landscape, and improve the overall biodiversity of the Shire. For these reasons alone, they deserve careful management.
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 3 Some of the notable roads requiring special management and protection in the Shire of Esperance include: Merivale road Norwood road Griffith road Dempster road Ridgeland road Mills road Wittenoom road Coolinup road Bishop road Grass Patch road Muntz road Cascade road Meyer road Henke road Field road Scaddan road Kettle road River road Parmango road Howick road Springdale road
Note - This is by no means a complete list of the wide road reserves in the Shire of Esperance. Please consult the Roadside Conservation Values map to identify a complete list of high conservation roadsides.
With increasingly larger capacity vehicles and greater volumes of traffic along these roads, the subsequent widening of the running surface along particular roads further diminishes the amount of native vegetation along roadsides.
Commercial Harvesting of Native Seed and Wildflowers
The Shire of Esperance currently allows the harvesting of native plant material within road reserves for commercial purposes. Under the Wildlife Conservation Act the Department of Conservation and Land Management may issue a licence following Shire approval.
Harvesting native plant material from roadsides further depletes the already scarce resource, takes away from the integrity of the roadside, reduces the number of seed bearing flowers, reduces the ability of the area to regenerate after disturbances such as fire, and threatens all roadside communities with the potential introduction and spread of two major threats – Phytophthora dieback and weeds.
Phytophthora Dieback The Phytophthora species dieback is made up of several types of introduced fungi. About one third of native plants in Western Australia’s south-west are susceptible, including species of Banksia, Hakea, Eucalyptus, Melaleuca, Verticordia, Acacia and Grevillea. The Phytophthora fungus infects the roots and inhibits the uptake of water and nutrients, eventually causing death. It is more widespread and severe in the higher rainfall zone and waterlogged sites. Esperance is a known Phytophthora dieback risk area.
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 4 Phytophthora spreads by the movement of spores in water, or by the spread of infected soil. The spores can be introduced to uninfected areas by human activities, particularly through the soil carried on vehicle tyres or footwear. Human activities, such as harvesting seed or wildflowers, have the potential to spread Phytophthora fungi. Currently, there is no practical method of eradicating Phytophthora once it is established in an area.
Weeds
Weeds are plants that are growing outside their natural range and competing with native plants for nutrients, space, water and light. Weeds often invade roadsides and interfere with the growth and survival of native plants. The effect of weed infestations on native plant populations is severe, and causes flow on effects for native fauna. Once native plants begin to diminish, due to heavy competition, native fauna suffers due to reduced availability of habitat and food.
Once weeds become established in an area, they become a long-term management issue, costing many dollars to control or eradicate.
Various weeds were recorded and mapped, as part of the roadside survey, and their locations within road reserves can be observed in the weed overlays provided with the Roadside Conservation Values map. They include Veldt grass, African Lovegrass, Wild Radish, Bridal Creeper, Boxthorn and Victorian Tea Tree, see Figure 11.
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 5 LEGISLATION
Uncertainty often exists in the minds of many with regard to the ‘ownership’, control and management of the roadside. When a public road is created, a corridor of land is dedicated for a road, i.e. a road reserve. The road formation and its associated infrastructure are accommodated for within the road reserve. The remaining area on each side of the road is called the road verge or roadside. It is in the control and management responsibilities of this area (and the plants and animals residing within it) that the uncertainty exists.
With the proclamation of the Wildlife Conservation Act 1950 the responsibility for flora conservation, including the control of harvesting of protected flora (this includes seed), was given to the Minister of the Crown responsible for Fisheries and Wildlife and the Department of Fisheries and Wildlife. With the formation of the Department of Conservation and Land Management in 1984 and the accompanying Conservation and Land Management Act 1984, the conservation and management of all native wildlife passed to the Minister responsible for that Department and the Department itself. As a consequence the Department of Conservation and Land Management has the authority to exert controls.
In addition to the general provisions relating to protected flora under the Wildlife Conservation Act, special protection is afforded to flora that is declared as rare or threatened under section 23F of the Wildlife Conservation Act.
The legislation pertaining to the management of road reserves is complex and includes those listed below.
State legislation i Aboriginal Heritage Act 1972 i Agriculture and Related Resources Protection Act 1976 i Bush Fires Act 1954 i Conservation and Land Management Act 1984 i Environmental Protection Act 1986 i Heritage of WA Act 1990 i Land Act 1933 i Local Government Act 1995 i Main Roads Act 1930 i Mining Act 1978 i Soil and Land Conservation Act 1945
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 6 i State Energy Commission Supply Act 1979 i Water Authority Act 1987 i Wildlife Conservation Act 1950-1979
Commonwealth Legislation i Environment Protection and Biodiversity Conservation Act 1999
Other legislation also applies to the activities on roadsides which may affect the clearing of vegetation or other disturbance to the roadside.
It is recommended that a cautionary approach be taken when working within roadsides or special environment areas, and that the relevant authority be contacted if there is any doubt about the management or protection of heritage or conservation values present in the roadsides.
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 7 ASSESSMENT PROCESS
Methods The methods to assess and calculate the conservation value of the roadside reserves are described in Hussey (1991). The process involves scoring a set of pre-selected attributes, which, when combined, represent a roadside's conservation status. A list of these attributes is presented on a standard survey sheet, see Appendix 2. This provides both a convenient and uniform method of scoring. Ideally, the survey is undertaken by a group of local volunteers, who, aided by their knowledge of the area, are able to provide an accurate and cost effective method of data collection. Community participation also ensures a sense of ownership of the end product, which increases the likelihood of its acceptance and use by the local community and road managers (Lamont and Blyth, 1995).
Fieldwork was carried out throughout 1999 and 2001. The enthusiastic efforts of the volunteer surveyors, of project coordinator Coral Turley and the support provided by the Shire of Esperance ensured that this project was successfully completed. It is now hoped that the data collected will be used by all sectors of the community who have an interest in the roadside environment.
Quantifying Conservation Values
The following attributes were used to produce a quantitative measure of conservation value: - native vegetation on roadside; - extent of native vegetation along roadside; - number of native species; - weed infestation; - value as a biological corridor; and - predominant adjoining land use.
Each of these attributes was given a score ranging from 0 to 2 points. Their combined scores provided a conservation score ranging from 0 to 12. The conservation values, in the form of conservation status categories, are represented by the following colour codes
Conservation Value Conservation Status Colour Code 9 – 12 High Dark Green 7 – 8 Medium High Light Green 5 – 6 Medium Low Dark Yellow 0 – 4 Low Light Yellow
Table 1: Colour codes used to depict the conservation status of roadsides.
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 8
The following attributes were also noted but did not contribute to the conservation value score: • width of road reserve; • width of vegetated roadside; • presence of utilities/disturbances; • dominant native species; • dominant weeds; • fauna observed; • general comments.
It is felt that the recording of these attributes will provide a community database that would provide information useful in many spheres local government and community interest.
Mapping Conservation Values
A computer generated map (using a Geographic Information System, or GIS), depicting the conservation status of the roadside vegetation and the width of the road reserves within the Shire of Esperance was produced at a scale of 1:250 000, and 1:100 000 for dense areas. The data used to produce both the map and the following figures and tables are presented in Appendix 3.
Data obtained from the Department of Conservation and Land Management and the Department of Agriculture was used in the base map, and depicts the location of remnant vegetation on both the Crown estate and privately owned land.
The roadside conservation values map initially provides an inventory of the status quo of the condition of the roadside vegetation. This is important as quality of roadside vegetation has far reaching implications for sustaining biodiversity, tourism and Landcare values. Moreover the data and map can be incorporated as a management and planning tool for managing the roadsides per se, as it enables the condition of roadside vegetation to be easily assessed. This information can then be used to identify environmentally sensitive areas, high conservation roadsides or strategically important areas, and thus ensure their conservation. Conversely, it enables degraded areas to be identified as areas important for strategic rehabilitation or in need of specific management techniques and weed control programs.
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 9 The map can also be used as a reference to overlay transparencies of other information relevant to roadside conservation. This enables the roadside vegetation to be assessed in the context of its importance to the shire’s overall conservation network. Other overlays, such as the degree of weed infestation, or the location of environmentally sensitive areas or future planned developments, could also be produced as an aid to roadside management.
As well as providing a road reserve planning and management tool, the survey data can also be used for: • regional or district fire management plans; • tourist routes - roads depicted as high conservation value would provide visitors to the district with an insight to the flora of the district; • Landcare / Bushcare projects - would be able to incorporate the information from this survey into 'whole of' landscape projects.
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 10
SURVEY DATA RESULTS
A summary of the general roadside conditions in the Shire of Esperance is presented in Table 2. The survey data has been combined to provide the total kilometres, and percentages, of roadside occupied by each of the conservation status categories and the attributes used to calculate the conservation values (see Table 2). As roadsides occur on both sides of the road, roadside distances (km) are equal to twice the actual distance of road travelled.
Summary Information: Shire of Esperance
Length of roads surveyed: 3717 km
Conservation Status Native Vegetation on Roadside Weed Infestation Total (km) (%) Total (km) (%) Total (km) (%) Low (0-4) 665.7 9.0 0 vegetation layers 115.0 1.6 Heavy 530.5 7.1 Medium-low (5-6) 657.1 8.8 1 vegetation layer 639.1 8.6 Medium 1842.9 24.8 Medium-high (7-8) 1758.8 23.7 2-3 vegetaion layers 6672.3 89.8 Light 4874.2 65.6 High (9-12) 4337.7 58.4 No data 7.7 0.1 No data 186.3 2.5 No data 14.6 0.2 Total (km) 7434.0 100.0 Total (km) 7434.0 100.0 Total (km) 7434.0 100.0
Conservation Values Extent of Native Vegetation Value as a Biological Corridor Total (km) (%) Total (km) (%) Total (km) (%) 0 20.3 0.3 <20%, Low 770.9 10.4 Low 2611.7 35.1 1 36.6 0.5 20-80%, Medium 2407.7 32.4 Medium 2575.6 34.7 2 55.7 0.8 >80%, Good 4130.2 55.6 High 2240.3 30.1 3 173.0 2.3 No data 125.2 1.6 No data 6.4 0.1 4 380.2 5.1 5 238.6 3.2 Total (km) 7434.0 100.0 Total (km) 7434.0 100.0 6 418.5 5.6 7798.310.7Number of Native Species Adjoining Landuse 8 960.6 12.9 Total (km) (%) Total (km) (%) 9 1124.6 15.1 0-5 species 854.3 11.5 Cleared 3727.0 50.1 10 1407.3 18.9 6-19 species 2572.7 34.6 Scattered 2600.1 35.0 11 1179.5 15.9 Over 20 species 3835.5 51.6 Uncleared 937.6 12.6 12 626.3 8.4 No data 171.5 2.3 Other 0.0 0.0 No data 14.6 0.2 Urban/Industrial 47.4 0.6 Total (km) 7434.0 100.0 Railway 89.9 1.2 Total (km) 7434.0 100.0 Drain 0.0 0.0 Plantation 14.7 0.2 No data 17.3 0.2
Total (km) 7434.0 100.0
Table 2: Summary of the roadside conditions in the Shire of Esperance.
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 11 Whilst data for road reserve width was only collected for 61% of the total roads surveyed in the Shire of Esperance, the results showed that only 9% of roads were between 80m and 100m in width. 17% of road reserves were 60m in width, 14% were 40m in width, 7% were 30m in width and 14% were 20m in width. (Figure 2).
Road reserve widths in the Shire of Esperance
4% 5%
17% 39%
14%
7% 14%
100m 80m 60m 40m 30m 20m no data
Figure 2 – Road reserve widths in the Shire of Esperance
The ‘width of vegetated roadside’ value provides an insight into the width vegetation occuring along roadsides in the Shire of Esperance. Roadside sections with more than 20m of native vegetation covered 42% of the Shire. 41% of roadsides supported vegetation between 5-20m in width, and only 16% of the roadsides contained native vegetation between 1- 5m in width (Figure 3).
Width of vegetated roadside
1% 16%
42%
41%
1-5metres 5-20metres over 20metres no data
Figure 3 – Width of vegetated roadside
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 12 Roadside sections of high conservation value covered 4337.7 km of roadside, 58.4% of the length of roadside surveyed. Medium-high conservation areas accounted for 1758.8 km of roadside, 23.7% of the total surveyed. Medium-low conservation roadside covered 657.1 km, 8.8% of the total surveyed. Areas of low conservation value occupied 65.7km, 9% of the roadside surveyed (Table 2, Figure 4).
Roadside conservation values in the Shire of Esperance
0.2% 9.0%
8.8%
58.4% 23.7%
Low (0-4) Medium-low (5-6) Medium-high (7-8) High (9-12) No data
Figure 4 – Roadside conservation values in the Shire of Esperance
The ‘ native vegetation on roadside’ value is determined from the number of native vegetation layers from either the tree, shrub or ground layers. Sections with at least two layers of native vegetation covered 89.8% of the roadside. 8.6% had only one layer and 1.6% had no layers of native vegetation (Table 2, Figure 5).
Native vegetation on roadsides
1.5% 8.6%
89.8%
0 vegetation layers 1 vegetation layer 2-3 vegetation layers
Figure 5 – Native vegetation on roadsides
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 13 Roadside vegetation with extensive cover, i.e. greater than 80%, occurred along 55.6% of the length of road surveyed. Survey sections with 20 to 80% cover accounted for 32.4% of the roadsides. The remaining 10.4% had less than 20% native vegetation, and therefore, a low ‘extent of native vegetation’ value (Table 2, Figure 6).
Extent of native vegetation on roadsides
1.7% 10.4%
32.4%
55.6%
<20%, Low 20-80%, Medium >80%, Good No data
Figure 6 – Extent of native vegetation
The ‘number of native species’ score provided a measure of the diversity of the roadside vegetation. Survey sections with more than 20 plant species spanned 3835.5 km (51.6%) of the roadside. Roadside sections with 6 to 19 plant species accounted for 2572.7 km (34.6%) of the roadside. The remaining 854.3 kms (11.5%) had less than 5 plant species. (Table 2, Figure 7).
Number of native plant species on roadsides
2.3% 11.5%
51.6% 34.6%
0 - 5. 6 -19. Over 20. No data
Figure 7 – Number of native species A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 14 65.6% (4874.2 km) of the roadsides surveyed were only lightly infested by weeds. Medium level weed infestation occurred on 24.8% (1842.9 km) of the roadsides. 7.1% (530.5 km) were heavily infested with weeds. (Table 2, Figure 8). See Figure 11 for the abundance of specific weed species along roadsides in the Shire of Esperance.
Weed infestation on roadsides
2.5% 7.1%
24.8%
65.6%
Heavy infestation Medium infestation Light infestation No data
Figure 8 – Weed infestation. Light weed infestation = weeds less than 20% of total plants. Medium weed infestation = weeds 20 to 80% of the total plants. Heavy infestation = weeds more than 80% of the total plants
Roadsides determined to have high value as biological corridors (as determined by the roadside surveyors) were present along 30.1% (2240.3 km) of the roadside, medium value made up 34.7% (2575.6 km), and roadsides with low value as a biological corridor occurred along 35.1% (2611.7 km) of the roadsides surveyed.
Value as a biological corridor
30.1% 35.1%
34.6% Low Medium High
Figure 9 – Value as a biological corridor
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 15 A scattered distribution of native vegetation was present on 35.0% (2600.1 km) of the land adjoining roadsides, whilst 12.6% of roadsides surveyed were adjoined by land that had not been cleared. 50.1% of the roadsides surveyed were bordered by land that had been totally cleared of vegetation. Railway reserves adjoined 1.2% (89.9 km), and plantations, urban and industrial landuses made up the remaining 0.8% (62.1 km). (Table 2, Figure 10).
Predominant adjoining landuse along roadsides in the Shire of Esperance
1.2% 0.2% 0.6%
0.2% 12.6%
50.1%
35.0%
Cleared Scattered Uncleared Urban/Industrial Railway Plantation No data
Figure 10– Predominant adjoining landuse
African Lovegrass was present along 4990 kms of the roadsides surveyed (67%), whilst Veldt grass was recorded along 1605 kms of roadsides (22%). Victorian Tea Tree was the next most commonly recorded weed, occurring along 751 kms (10%). Wild Radish was present along 508 kms (7%), Bridal Creeper 420 kms (6%), and Boxthorn along 91 kms (1%) of roadsides. Other weeds comprised 2821 kms (38%) of the roadsides surveyed (See Figure 11).
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 16
Weed occurance along roadsides in the Shire of Esperance (km)
4990 5000
4500
4000
3500
3000 2821 roadsides (km) 2500
2000 1605 1500
1000 751 Occurance within 420 508 500 91 0 Victorian Tea Boxthorn Bridal Wild Radish African Veldt grass Other Tree Creeper Lovegrass
Figure 11 – Occurance of specific weeds along roadsides in the Shire of Esperance
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 17
MANAGEMENT TECHNIQUES
The following section provides management recommendations that will assist in retaining and enhancing roadside conservation value. These guidelines are taken from the Roadside Conservation Committee’s Roadside Manual and or the Roadside Handbook. The Executive Officer of the Roadside Conservation Committee is also available to assist on all roadside conservation matters, and can be contacted on (08) 9334 0423. The primary aim of road management is the creation and maintenance of a safe, efficient road system. However, the following management procedures should be adopted.
High Conservation Value Roadsides
Management Goal Maintain and enhance the native plant communities.
Management Guidelines Minimal disturbance to existing vegetation. Disturbance leads to weed invasion, which downgrades the conservation value, and increases the fire threat.
Minimal disturbance can be achieved by: - adopting a road design that occupies the minimum space; - diverting the line of a table drain to avoid disturbing valuable flora; - pruning branches, rather than removing the whole tree or shrub; - not dumping spoil on areas of native flora; - observing dieback control measures as required; - apply the Fire Threat Assessment (Roadside Manual) before burning roadside vegetation; - use methods other than fuel reduction burns to reduce fire threat; if roadside burning must be undertaken, incorporate it into a district fire management program; - encourage adjacent landholders to set back fences to allow roadside vegetation to proliferate; - encourage adjacent landholders to plant windbreaks or farm tree lots adjacent to roadside vegetation to create a denser windbreak or shelterbelt; - encourage revegetation projects by adjacent landholders.
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 18
Medium Conservation Value Roadsides
Management Goal Maintain native vegetation wherever possible, and encourage its regeneration.
Management Guidelines Minimise disturbance to existing vegetation.
Low Conservation Value Roadsides
Management Goal Retain remnant trees and shrubs and encourage their regeneration. Encourage revegetation projects using indigenous plants.
Management Guidelines Minimise soil disturbance to reduce weed invasion. Encourage revegetation projects by adjacent landholders.
Code of Practice A Code of Practice has been developed through collaboration with Main Roads Western Australia, the Western Australian Local Government Association and the Roadside Conservation Committee. This document will provide defined parameters for all roadside management works and also provide the local community with an overview of management practices that will ensure the sustainability of native roadside vegetation. Please contact the Roadside Conservation Committee Executive Officer for further information.
Tree Roads Tree roads are defined as those roadsides with a sufficient density of mature trees to create an attractive tunnel effect. Besides the aesthetic benefits, these areas also provide valuable habitat for birds and other arboreal fauna. Since mature trees are slow growing and hard to replace, care should be taken to conserve these avenues wherever possible. The following points should be considered when working on tree roads: - prune offending branches rather than remove the whole tree; - cut branches off close to limb or tree trunk; - divert line of table drain to avoid disturbing tree roots; - import fill to build up formation, rather than using side-borrow from roadside; - when using herbicide for weed control on the roadside do not use a soil residual type, such as Siomazine or Atrazine. Eucalypts are especially sensitive to these; - encourage the adjoining landholders to plant shelter belts on their property that will complement the roadside vegetation.
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 19
Flora Roads and Roads Important for Conservation
Flora Roads are significant sections of road having a special conservation value due to the vegetation growing on the road reserve. Signs are available to mark these roads as Flora Roads. This has a twofold effect of drawing the attention of tourists to the high conservation value roadside and it also alerts all that work in the roadside environment that the marked section of roadside requires due care to protect the values present.
In order to plan roadworks so that important areas of roadside vegetation are not disturbed, road managers should know of these areas. It is suggested that the Shire establish a Register of Roads Important for Conservation. The following guidelines should be considered prior to establishing this registrar.
- the roadside must contain a significant population of native vegetation (introduced trees and grasses are not important for conservation), - the native vegetation must be in as near to its natural condition as possible, - in undisturbed vegetation, several layers of plants occur, ie. trees, shrubs and groundcovers (herbs or native grasses). If one or more of the expected layers are missing, the conservation value is reduced, - the roadside may be the only remaining example of original vegetation within a cleared area. It thus assists in vegetation mapping and distribution studies, provides a benchmark for study of soil change during agricultural development, may provide a source of local seed for revegetation projects and acts as wildlife habitat , protecting fauna, - rare or endangered plants and animals may occur on the roadside, - it may provide nest sites and refuges for native animals. Dense vegetation provides habitat for avifauna and invertebrates.
Special Environment Areas
A Special Environmental Area is a section of roadside, which has such significance that it requires special protection. Reasons for establishing Special Environmental Areas can include: - protection of rare or threatened species of native plants; - protection of sites that have other high conservation, scientific or aesthetic values; - Protection of Aboriginal or European cultural sites.
Special Environmental Areas can be delineated by the use of site markers. See Figures 9 and 10 for design and placement of SEA markers. Workers who come across a
A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 20 ‘Special Environmental Area’ marker in the field should not disturb the area between the markers unless specifically instructed. If in doubt, the Supervisor, Shire Engineer or CEO should be contacted.
Western Power and West Net rail also have systems for marking sites near power or rail lines. Examples of these are seen in the figure below.
V.P. IDENTIFYING 2 PLATE WELDED ON
WHOLE PAINTED YELLOW
STEEL PICKET
Figure 12- Special Environmental Area site marker.
Special Environmental Area Register
To ensure that knowledge of rare flora and other sites does not get lost due, perhaps, to staff changes, a Local Authority should establish a Special Environmental Area Register. This should outline any special treatment, which the site should receive, and be consulted prior to any work being initiated in the area.
The Special Environmental Area Register should be consulted by the appropriate person prior to starting work on any particular road, to ensure that inadvertent damage does not occur. All Special Environment Area sites should be marked on the Shire map, which records Roadside Conservation Value
Local Government is encouraged to permanently mark Special Environmental Areas to prevent inadvertent damage to the rare flora or other values being protected. Markers of a uniform shape and colour will make recognition easier for other authorities using road reserves. A survey of the roadside conservation values in the Shire of Esperance and roadside management guidelines - - 21
Figure 13 - Marking Special Environment Area (SEA) sites in the field. In this case, a declared rare flora (DRF) site has been marked.
When notified of a population needing marking, the Local Authority should contact the appropriate Department of Conservation and Land Management Regional or District office for assistance to ensure the exact site location and correct positioning of marker posts.
Roadside Management Planning and Strategies
Planning The RCC is able to provide good models of Roadside Management Plans and encourages all shires to adopt this practice of planning for roadside conservation. The following actions greatly enhance likelihood of a plan that changes behaviour and results in on-ground actions: