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august 2012 Fauna sensitive road design guidelines keeping victorians connected 2 Fauna sensitive road design guidelines Fauna Sensitive Road Design Guidelines Revision 0 / August 2012 Document ID: 1447218 VicRoads Fauna Sensitive Road Design Guidelines © VicRoads 2012 This document is an uncontrolled copy and may be updated from time to time. The issue date on the front cover and inside cover of this document will be updated following any revisions to this guideline. Please refer to the VicRoads website or intranet for the most current version of this document. The information contained in these guidelines is for general information only and is not intended to constitute legal advice. VicRoads accepts no responsibility for any loss arising out of reliance on any information contained in this document. Acknowledgements These guidelines were prepared by VicRoads Environmental Sustainability. VicRoads would like to acknowledge the assistance of all who provided comments on these guidelines. 3 Glossary Aquatic – Animals living in waterways. Arboreal – Adapted for living and moving about in trees. Invertebrates – Animals such as insects that lack a backbone. Baffle – Flat plate that controls or directs the flow of water or energy through aquatic culverts. Landscape - Total spatial and visual entity that includes all the physical elements of landforms including manmade environments. Barrier Effect – A road which acts as a barrier or physical obstacle which results in the increased likelihood of levels of animal mortality due to animal/ vehicle collision. Landscaping – This is the modification of the existing landscape and includes visible features of an area of land. Biodiversity – A number, variety and genetic variation of plants and animals found within a specific geographic region. Connectivity – Where plants and animals are able to disperse/move through the landscape without obstruction to maintain genetic diversity. DSE – Victoria Department of Sustainability and Environment. Ecosystem – A biological system consisting of all living organisms or biotic components. Edge Effect – Term used to describe the [conjunction of] a boundary between natural habitats (e.g. forests) and disturbed or developed land. EPBC – Environment Protection and Biodiversity Conservation Act 1999 (Cth). Fauna Fence – Free standing structure and/or barrier designed to prevent wildlife from moving beyond a specific point or boundary. Macropod - Herbivorous group of hopping mammals including kangaroos and wallabies. Marsupial - Any mammal of the order Marsupialia, in which young are born in an immature state and continue development in the pouch. Mulch – Protective cover of chipped plant material placed over the soil to retain moisture, reduce erosion and suppress weeds. Riffle – A rocky shoal lying just below the surface of a waterway, often forming rest pools. Sandbar – Ridge of sand or fine gravel in a river or along a shore formed by the action of waves or currents. SEWPaC – Department of Sustainability, Environment, Water, Population and Communities. Substrate – Surface or layer of sediment on an object such as a bridge, river or within a culvert. Terrestrial – Animal or plants living on the land (not aquatic). Fragmentation – Breakup of continuous habitat into smaller populations. Vertebrate – All animals which have a backbone including amphibians, birds and mammals. Indigenous – Plants endemic to a given area or geological zone. Wetland – A land area that is saturated with water. Wetlands can be permanent or seasonal and often have a distinct ecosystem. 4 Fauna sensitive road design guidelines 5 Contents Introduction6 1. Purpose 1.1 Implementing fauna sensitive road design 6.4 Culverts to aquatic animals 21 7 Locating aquatic crossings 21 7 Culvert designs 22 Baffles22 2. Conduct biodiversity assessments 8 Culvert rehabilitation 23 Culvert maintenance 23 8 Fish ladders 23 2.3 Targeted flora and fauna survey 8 Rock ramps 23 2.4 Early/pre-installation monitoring 9 2.1 Desktop flora and fauna investigations 8 2.2 Detailed flora and fauna assessments 3. Design and installation of fauna sensitive road design treatments 10 3.1 Minimise biodiversity impacts and habitat fragmentation 10 3.2 Determining fauna sensitive road design treatments 11 3.3 Evaluate landscape objectives 12 3.4 Incorporate relevant biodiversity management requirements into contract specification 12 4. Construction 13 4.1. Contractors Environmental Management Plan (cemp) 13 4.2 Fauna protection during construction 13 5. Managing and monitoring fauna sensitive road design installations 5.1 Ongoing monitoring surveys 14 14 6.2Overpass 24 6.2.1Canopy bridge 24 Maintenance27 6.2.2Canopy connectivity 27 6.2.3Land bridges 28 Target species 28 Design specifications 29 Maintenance29 6.3.Fencing Kangaroo and Koala resistant fencing 30 Arboreal resistant fencing 30 Frog resistant fencing 30 Maintenance31 6.4 Habitat enhancement 32 6.4.1Frog ponds 32 Banks32 Shape and size 6. Fauna sensitive road design 15 6.1Underpasses 15 6.2 Bridge underpasses 15 6.3 Culverts for terrestrial animals 16 Entry landscaping 16 Culvert furniture 17 Large culverts 18 Multiple culverts 18 Fauna culverts along waterways 19 Approaches to crossings 20 30 32 Vegetation32 6.4.2Nesting boxes 33 Maintenance33 6.4.3Traffic management 34 Maintenance34 6.4.4Other considerations 35 Light mitigation 35 Fauna relocation 35 Appendix A. Types of fauna mitigation 36 References41 6 Fauna sensitive road design guidelines Introduction Road infrastructure covers vast areas of land; it traverses rivers, wetlands, valleys, deserts, coastlines, mountains and forests. In addition, roads in the landscape create new habitat edges, alter hydrological dynamics, and disrupt natural processes and habitats. Roads and their traffic can impose significant dispersal barriers to most non-flying fauna, and vehicle traffic can cause the death of large numbers animals per year (refer Figure 1). Issues associated with the impact of roads on biodiversity can include: Habitat loss - Construction of roads and railroads usually involves a net loss of wildlife habitat. The physical encroachment on the land gives rise to disturbance and barrier effects that contribute to overall fragmentation. Disturbance - Roads and traffic disturb and pollute the physical, chemical and biological environment and consequently alter habitat suitability for many plant and animal species for a much wider zone than the width of the road itself. Corridor - Roadsides can provide refuges, new habitats or serve as movement corridors for wildlife. These beneficial effects of infrastructure are a major challenge to planners and ecologists, as management and design must consider the wider landscape context. Figure 1: Roads have significant impact on wildlife movements. Mortality - Traffic can cause the death of many animals that utilise verge habitats or try to cross the road. Traffic mortality has been growing constantly over the years, but is considered a severe threat to only a few species. Collisions between vehicles and wildlife are also an important traffic safety issue. Barrier - For most non-flying terrestrial animals, road infrastructure can create movement barriers that restrict the animal’s range, make habitats inaccessible and can lead to an isolation of populations. The barrier effect is the most prominent factor in the overall fragmentation caused by road infrastructure. These guidelines aim to promote the movement of wildlife across roads whilst helping to find solutions to ongoing public concerns about fauna mortality around roadkill. The treatments outlined here are intended to connect local wildlife linkages and keep fauna away from high risk areas. Going forward, fauna sensitive road design will enable animals to move between habitats and discourage them from setting up home ranges within road reserves where they would be at risk. 7 1. Purpose Objective 2.3 of the VicRoads Sustainability and Climate Change Strategy 2010-2015 relates to Improved Biodiversity Values, which incorporates the need to address habitat fragmentation and roadkill as referenced below: Reduced habitat fragmentation and roadkill through improved implementation of fauna crossings The road network has the potential to have a significant effect on wildlife and ecosystems through habitat fragmentation, reduced dispersal and mortality by collision with vehicles. VicRoads is committed to investigating opportunities to facilitate fauna movement, where possible, through the provision of fauna crossings (underpasses or overpasses), aiming to reduce fragmentation of habitats and improve and maintain species diversity. This will involve the investigation of best practice in this area to inform the development of detailed guidelines on fauna crossings to assist in more consistent implementation. Installed crossings will be subject to a monitoring regime that will yield information on their effectiveness, enabling better decisions to be made on future mitigation measures. 1.1 Implementing fauna sensitive road design VicRoads Projects and Regions must demonstrate that all aspects of fauna sensitive road design are considered in project planning through to maintenance (refer Figure 2). INVEST is a VicRoads tool which can be used to assess the sustainable aspects of a road project. It sets the standards for best practice and innovation in sustainability road design and construction. Going forward, all new VicRoads projects will implement INVEST from the planning phase to incorporate sustainability initiatives throughout design and construction. To assist projects and regions, Section 3 of the Biodiversity category of INVEST discusses innovation by way of design and construction of fauna sensitive roads. Projects that have incorporated fauna sensitive road design will receive points for innovation. All of these considerations are detailed within different stages of these guidelines. Step 1 Conduct Biodiversity Assessments Has native fauna been identified No Yes Step 2 Design and installation of fauna sensitive road design No fauna migration required Step 3 Construction A Lace monitor in roadside tree in north eastern Victoria (Source: VicRoads) Step 4 Managing and Monitoring fauna sensitive road design installations Evaluate maintenance and monitoring plan results Modify as required Figure 2: Fauna Sensitive Road Design Process. 8 Fauna sensitive road design guidelines 2. Conduct biodiversity assessments 2.3 Targeted flora and fauna survey More information on undertaking biodiversity assessments, including guidance on the engagement of biodiversity consultants, can be found in the VicRoads Biodiversity Guidelines. Projects are encouraged to carry out broader targeted flora and fauna surveys in areas of high quality vegetation, environmentally sensitive locations and identified fauna movement hotspots. VicRoads contract shell briefs include the requirements itemised in relation to fauna sensitive road design. These briefs can be accessed in Exchange: How To > Build and Maintain Sustainable Roads. 2.1 Desktop flora and fauna investigations In some cases, there may be the need for more than one targeted survey. It is often recommended that surveys be undertaken more than once leading up to construction to obtain a better understanding of existing conditions prior to implementing any fauna mitigation. Targeted surveys should include: The consultant should begin the assessment with a desktop investigation to determine the level and findings of previous research. The minimum requirements for this search are outlined in the contract shell briefs and include accessing the Flora Information System (FIS), the Atlas of Victorian Wildlife, DSE Ecological Vegetation Classes (benchmarks), Biodiversity Interactive Maps and Environmental Protection and Biodiversity Conservation (EPBC Act) Protected Matters Search Tool. In some cases, use of previous surveys together with brief field investigations may be adequate to meet the requirements of the biodiversity assessment brief. Details on the habitat, species richness and population size, dispersal, life cycle, reason for movement, prey, food, and behaviour. The desktop investigation will identify fauna species, or suitable habitat for those species, that have previously been recorded in the study area. Detail what other monitoring requirements may be required post construction of a fauna crossing. 2.2 Detailed flora and fauna assessments Discuss any recovery plans and other relevant published species information. In most cases, a second level of investigation is required involving thorough field assessment aimed at identifying specifically what is on site. This may involve a seasonal vegetation assessment and trapping and recording of fauna present. NB. It is important to ensure that any consultants undertaking fauna trapping have all relevant permits under the Wildlife Act 1975 (Vic), prior to commencement of fieldwork. Details on the potential impacts from the project (i.e mortality, loss of connectivity, indirect and direct impacts). What a fauna crossing would be provided for, ie dispersal, annual migration, foraging etc. What is the best type of fauna crossing? How many and how far apart should fauna crossings be? Detail any discussions with key stakeholders or relevant groups who have expert local knowledge. Other recommendations such as signage, light mitigation or habitat enhancement. Again, VicRoads contract shell briefs must be utilised to engage a consultant to undertake targeted surveys. As a part of this assessment, consideration needs to be given to the opportunity to incorporate fauna mitigation methods to improve connectivity and reduce wildlife mortality. Environmentally sensitive locations, including identified fauna movement hotspots, need to be discussed and recommendations provided on the following: What potential species may utilise the corridor? What species will be impacted on a wider landscape scale? What is the distance to core and other vegetation patches? Are any additional targeted surveys of key species (or areas) required? What are some design options, such as fauna crossings, for consideration by VicRoads? Wallaby (Source: ES Link Services) 9 2.4 Early/pre-installation monitoring Monitoring is the most important part in achieving effective fauna sensitive road design and can help determine connectivity within a given area. Fauna species move across land for a number of reasons including to colonise new territory, find mates and forage for new food sources. As discussed in Section 3 of this document, VicRoads should develop goals in response to the impact a potential road will have on fauna. Pre-installation monitoring should be conducted during project planning within a 5-10 km radius of the area in question in order to give a better understanding of landscape connectivity, especially how local fauna species move through the landscape. Where possible monitoring should be carried out as early as possible at the beginning of the planning process; the earlier that monitoring is undertaken the better the understanding of fauna movements within a given landscape. Fauna underpass on the Calder Freeway (Source:VicRoads) Southern Brown Bandicoot (Source: ES Link Services) 10 Fauna sensitive road design guidelines 3. Design and installation of fauna sensitive road design treatments Many wildlife and ecosystem processes operate at landscape scales with some animals moving many hundreds of kilometres. Maintaining wildlife connectivity in highly cleared landscapes is equally as important as maintaining connectivity across large areas of intact land. As shown in Figure 3, animals have limited opportunities to move around landscapes. Where small patches and narrow corridors of native vegetation remain, these play a very important role for maintaining wildlife connectivity. Sugar Glider (Source: VicRoads) Projects should consider the wider landscape when planning roads. Goals should be set that consider known animal movement corridors (eg. drainage lines, creeklines and strips of native vegetation) that have the potential to be used by a number of species as part of a landscape scale perspective when making decisions about wildlife connectivity measures. a) Wildlife movements b) Avoidance c) Fragmentation d) Mitigation Figure 3: Representation of wildlife movements when considering road design on a) wildlife populations b) avoidance c) fragmentation and d) mitigation. 11 3.1 Minimise biodiversity impacts and habitat fragmentation There are a wide variety of techniques and measures available to mitigate the effects of a new road or the upgrade of an existing road on flora and fauna. Mitigation must be designed to meet the requirements of the specific site and to address the identified problem. For example, it is not worthwhile installing a structure designed for arboreal fauna, such as a canopy bridge or gilder pole, if the issue is with ground fauna; likewise a culvert crossing is not suitable if the road is in a cut. In balancing decisions of changes to road design, VicRoads staff needs to consider the: As outlined in the S.M.A.R.T model detailed below, goals must be specific, measurable, achievable, realistic and timely and agreed upon between biodiversity specialist and project managers. Separate goals should be developed to address the different target species or types of impacts. Table 1: The S.M.A.R.T model for assessing wildlife connectivity Objectives Key Questions Specific What species are concerned and what are we trying to achieve? Measurable What is the criterion to measure our success? Achievable Have the objectives been agreed with relevant Stakeholders? Realistic Is there sufficient funding provided? Time Frames What is the end point? Significance of the biodiversity impacted by the road. Advice of DSE (and SEWPaC where relevant) regarding whether approval of the unchanged design element is likely. The preferences of other stakeholders such as ‘friends of…’ groups and Local Councils. Cost/benefit ratio of the design adjustment. (NB. Ensure that any native vegetation or fauna offset cost estimates are included in this analysis). A project may evaluate numerous fauna sensitive road design options (refer to Section 6) throughout the design process and should consult with relevant stakeholders such as DSE and local friends of groups to obtain the best outcome. 3.2 Determining fauna sensitive road design treatments Once all assessments and analysis has been undertaken, members from the project team should meet with both the Regional Environmental Officer and the Biodiversity Policy Officer from Environmental Sustainability to help determine fauna mitigation outcomes. The meeting will need to establish: What are the expectations and what are we trying to achieve? Which fauna species have been identified in target surveys? Do the fauna structures under consideration improve connectivity in the landscape? Will mitigation methods encourage fauna movement and reduce wildlife mortality? The outcome of these discussions will influence what fauna mitigation will be appropriate for the project. Discussions will also need to identify realistic objectives and targets in order to ensure the fauna mitigation is practical, feasible and cost effective. It is important that these goals and objectives be discussed early in order to measure success of fauna sensitive road design down the track. Section 6 of this document outlines a number of different fauna mitigation measures available to projects to prevent access to the road, or to facilitate the movement of animals from one side of the road to the other. They include bridges, culverts, canopy bridges, land bridges, fencing, habitat enhancement and local fauna management. This information will help VicRoads facilitate more feasible and practical fauna sensitive road design going forward. VicRoads currently has numerous existing crossings which have had varying degrees of success. These have used a combination of culverts, amphibian underpasses, koala crossings and rope bridges. Various studies have been conducted throughout Australia to measure the success of different fauna sensitive road design. Evidence has concluded that the following treatments, used independently, have had limited success rates: Chemical replants. Reflectors. Signage – fauna crossing and reduced speed limit signs. Amphibian underpasses. It is important that projects take this into account when designing structures, and reviewing consultant reports. 12 Fauna sensitive road design guidelines 3.3 Evaluate landscape objectives Obtain design drawings Once the project team have received the consultant’s fauna and flora report and the targeted surveys, which detail proposed options, and have discussed the goals and objectives, the next step is to engage a consultant to complete design drawings for these options. In some instances this can also be done in-house. The design should take into account the following: Number, size, location, type of each mitigation measure. What additional landscaping, revegetation, fauna furniture, and fencing is required with the structure. Additional points that should be reviewed by the project team in consultation with the consultant are: Making sure the fauna structure is buildable. Location of the fauna crossing should consider soil, location and topography. What is the overall cost to build the structure? How often will fauna structures need to be maintained, including making sure the overall cost of maintenance has been calculated for transferring over to the region. Structures should have easy access for future maintenance. Any design should include the cost of landscaping and revegetation around fauna crossings. Consideration needs to be taken with regards to likely fauna impacts if the project decided not to incorporate fauna sensitive road design. In some cases more than one fauna sensitive structure may be required. Alternative options should also be included and considered. These may include fencing, deterrents or nesting boxes for example. 3.4 Incorporate relevant biodiversity management requirements into contract specification VicRoads contract shell briefs provide standard clauses that aim to ensure that environmental impacts are addressed by the contractor. The extent of these varies depending on the contract type and will usually involve minimising areas of native vegetation removal and establishing no-go zones. It is at this stage where projects add additional contract specific clauses to address any biodiversity or fauna specific aspects significant to the particular project. It is important to ensure that any fauna sensitive road design requirements stemming from the planning process, including any permit requirements or Environmental Effect Statements (EES) outcomes, which may impact on construction activities, are incorporated into contract documents where relevant. For example: Identifying preferred fauna mitigations. The types of preferred fauna crossings. The number of crossings to be installed. Contract specification clauses should be reviewed (and preferably prepared) by someone with appropriate biodiversity knowledge. Projects that are unsure should seek advice for either the Regional Environmental Officers and/or Environmental Sustainability Biodiversity Officer. Prior to handing over all the information to the Delivery team, a project should ensure clear details are provided in VicRoads Project Environmental Protection Strategy (PEPs). Additionally, any specific requirements should be detailed in the contract specifications relevant to fauna mitigation. This may include, for example, putting aside removed trees as fauna habitat, specific fauna monitoring requirements, recommended design treatments, and translocation or relocation recommendations. At this stage of the project, the planning and design of fauna sensitive road design is largely complete. There is limited ability to change the design once construction begins. There is also a limit to the amount of funding available to change or add to fauna mitigation at this stage, especially if any issues have not been identified during the planning and design phase. 13 4. Construction 4.2 Fauna protection during construction 4.1 Contractors Environmental Management Plan (CEMP) In order to ensure that protection of fauna occurs during the pre-construction and construction stages, there should be a predetermined number of site inspections carried out by the project Environmental Officer. It is important to ensure that the contractor has incorporated all biodiversity objectives, including any fauna sensitive road design requirements, into their Environmental Management Plan. In general the Contractors Environmental Management Plan (CEMP) should include the following: All fauna sensitive road designs identified during the planning stage. All relevant information regarding the fauna sensitive road design including flora/ fauna assessment reports, targeted surveys and landscape plans (including information that identifies connectivity between habitats). Required ‘no-go zones’ including available habitat for fauna during construction. Matters to be monitored and reported should include all recommended fauna mitigation identified in the PEPs and CEMPs. It should be noted that the requirements for each project will be different depending on the proposed impacts of construction activities. Any changes to site conditions or impacts which may arise from changes should be updated in approved plans. If a non-compliance with fauna safety measures occurs, a timeframe for compliance and remedial works should be specified by the Contractor and signed off by the VicRoads Contract Superintendent. All incidents that arise on site should be recorded in VicRoads Enviro Tracker system available on Exchange: How To>Build and Maintain Sustainable Roads. Requirements for planting and rehabilitation at the end of construction including providing adequate connectivity and in accordance with landscape plans. The project Environmental Officer should monitor the impacts of demolition, earth works, and installation of temporary infrastructure including site fencing, drainage works and vegetation removal works. It is important to note that CEMPs are essential for construction, maintenance and monitoring contracts and should ensure all fauna sensitive road design maintenance and monitoring requirements are adequately addressed by VicRoads. Monitoring of construction works should occur at regular intervals and in consultation with the site manager to check fauna protection is adhered to on site at all times. Red Kangaroo (Source: ES Link Services) 14 Fauna sensitive road design guidelines 5. Managing and monitoring fauna sensitive road design installations The long term maintenance and monitoring of installed fauna sensitive road design treatments is important to verify if the installation has actually been successful. The success of fauna mitigation is measured in terms of: Compliance. Maintaining landscape connectivity. Use of the structures by fauna. Ongoing success is dependent on maintaining installations. Projects and Regions should make sure that funding is available for fauna mitigation maintenance. 5.1 Ongoing monitoring surveys Post construction monitoring determines whether fauna species are actually using the structures put in place. Factors such as population dynamics and behaviour may influence the outcome of it success of the structure. This monitoring also helps VicRoads to develop a better understanding of which structures work best in varying situations. Monitoring of connectivity measures can: Improve our understanding of the effects that proposed roads and expected traffic volumes may have on wildlife. Ensure wildlife mitigation methods are evaluated on the effectiveness in maintaining connected landscapes. Assess value for money by measuring the success of the outcome. Quantify potential impacts of roads on wildlife. Failure to undertake monitoring may impact and jeopardise the success of fauna mitigation in road design. This is particularly important in the long term as monitoring also identifies previous failures. More often than not consultants will recommend the need for a number of studies after the implementation of fauna structures. This requirement can often be time-consuming and expensive for projects to implement. Before committing to ongoing monitoring it is the responsibility of the project, Regional Environmental Officer and Biodiversity Policy Officer to understand what the overall objectives are for postconstruction monitoring. In some cases, if the previous planning steps have been correctly followed, and the right structures have been implemented, then monitoring may not be required. For example, the state of the science is such that for some species we already know that culverts will facilitate the movement of individuals across roads. VicRoads along with other States road authorities now have a number of reports in place supporting a good knowledge based on the effectiveness of previous fauna structures. Monitoring has shown that at least 23 species of native animals have used this wildlife crossing under the Slaty Creek Bridge, Calder Highway at Macedon. The crossing connects two large patches of remnant vegetation (Source: VicRoads) 15 6. Fauna sensitive road design There are a number of different fauna mitigation measures available to facilitate the movement of animals from one side of the road to the other they include; bridges, culverts, canopy bridges, land bridges, fencing, habitat enhancement and local fauna management. 6.1 Underpasses An underpass is a structure that allows wildlife to cross the road beneath the road surface. It includes culverts, tunnels or pipes, bridges and viaducts. The size or “openness” of the underpass appears to be the primary factor influencing crossing rates. Wherever possible, the height and width of underpasses should be maximised. 6.2 Bridge underpasses Of the various wildlife crossing types available, the bridge underpass is acknowledged as the most effective but also the most costly. The structure maintains the grade of the road or elevates the traffic above the surrounding land, allowing animals to pass under the road. Bridges typically traverse watercourses and can be the chosen preference when building a road through flood-prone areas. A few factors to consider when choosing this option for fauna mitigation include: Different types of bridges can be used to accommodate a number of fauna species including both terrestrial and aquatic. Bridges are suitable for a vast array of fauna including fish, crustaceans, platypus, native water rats, small to medium sized marsupials, frogs, flightless birds (emu), large macropods (kangaroo) and reptiles. In general, the bridge crossing should be designed to accommodate koalas and larger macropods such as kangaroos. If accommodating larger macropods, the bridge crossing should provide a minimum clearance of three metres in height with a span of 10 metres. Smaller spans are suitable for smaller species such as echidnas, wombats, reptiles and bandicoots. Bridges can be built to encompass both water bodies and dry passage to allow for both terrestrial and aquatic fauna movement. For dry passage, a minimum of three meters will support the movements for most terrestrial animals. When designing bridges, projects should consider two lanes where possible, as the gap between lanes (Figure 4) allows the continued ingress of light to the forest floor, allowing plants to continue to grow. Projects should also consider providing shelter (e.g. logs, rocks and leaf litter). This is particularly important when designing underpasses for target species. Finally, it is important that projects implement appropriate fencing in conjunction with bridge underpasses. Correct fencing guides fauna to the right locations allowing them to cross under the roads safely and reducing roadkill (refer Section 6.3 page 30). Bridge limitations Figure 4: Two lanes, Slate Creek Underpass, Calder Freeway. Very high cost. Needs to be located within a known fauna movement corridor. Requires targeted landscaping and fencing. May require other structures or retention of large trees to encourage usage by arboreal fauna. It may be difficult to establish vegetation under some structures. 16 Fauna sensitive road design guidelines 6.3 Culverts for terrestrial animals A culvert is largely used to channel water under roads, railway lines and embankments. They come in many shapes and sizes including round, square, rectangular and arching. Culverts can be made of a variety of different materials with steel, polyvinyl chloride (PVC) and concrete being most common. In the right situation, culverts can be designed to accommodate and be modified to allow for wildlife passage. The culvert is typically a three metre x three metre precast concrete unit positioned on a cast in-situ base and located along ephemeral lines, thus serving as a drainage culvert as well as potentially a wildlife underpass. Ideally the length of a culvert should not exceed 25 m to allow light penetration and avoid a cave like appearance which can often deter animals from moving through the system. Where possible projects should maintain a practical ‘openness measure’ when designing culverts to accommodate wildlife movements. Further factors to consider when designing wildlife friendly culverts: The openness of the culvert will need to increase as the culvert length increases. Culverts are best located in areas where the road has been built on fill. Three metre x three metre box culverts are considered optimal for allowing the movement of a wide variety of fauna including (macropods, koalas and flightless birds). Incorporate appropriate fencing to help guide fauna to culverts. Culverts which have been designed to drain floodwater, should not retain water after flood events. Culverts that retain water are ineffective as the water deters terrestrial fauna from moving through the structures. If this is likely to be a problem, then projects should consider multi-celled systems (see Figure 10, page 19). Figure 5: Standard culvert with natural substrate. (Source: Transport Roads and Maritime Services, Wildlife Connectivity Guidelines. November 2010). As discussed in Section 6.4 provided water movements on creek and river flows are not impeded, correct culvert design can accommodate a number of aquatic species including native water rat and platypus. When designing culverts, projects should consider the types of species they expect to accommodate. For example, larger culverts are suitable for a number of fauna species including low flying birds, small flightless birds, bats, invertebrates, macropods, reptiles and small to medium mammals. Small-medium sized culverts are more suitable for animals that are familiar in underground or burrowing environments, these species include wombat and echidna. Entry landscaping It is very important that culverts retain as much of a natural appearance as possible. Projects should make sure that vegetation is established as close as possible to the ends of the culverts; this would also include small local logs, rock and natural leaf litter (refer page 20). Terrestrial culvert limitations high cost cannot be used where the road is in cut should not be used where the total tunnel length is greater than 25 metres might encourage the predation of some fauna requires the added costs of targeted landscaping and fencing to encourage fauna use. 17 Culvert furniture Culvert furniture installed correctly can facilitate the movement of arboreal species such as possums sugar gliders and even koalas in larger culverts. By providing a dry ledge or similar structure that allows arboreal species to move through the landscape, dual purpose culverts can provide safe passage for a variety of fauna species. Substrate design Culverts without dry ledges or poles are known to be avoided by arboreal fauna. Substrate design is important when considering ground dwelling species; culvert furniture should be designed to encourage a number of small mammals and reptiles. Underpasses are more likely to be used by fauna if the base is a natural substrate such as dirt or mulch. Likewise, culverts that hold water over extended periods or are often muddy often deter use by some species. Ideally if the area is known or likely to be wet then a multi-level culvert should be considered or culverts should be shifted slightly to drier locations. Horizontal logs placed strategically in culverts can provide dry passage for a number of species whilst providing refuge from predators. General furniture for reptiles and small marsupials include: VicRoads Projects and Regions should consider the following when adding furniture to culverts: Include horizontal and vertical poles and netting attached to pylons where appropriate to target species. Place horizontal logs for passage as high above the base of the opening as practical, allowing 1 metre clearance from the culvert ceiling. Tiles, logs, mulching and rocks. Note: you can add too much furniture to culverts. Fauna friendly culverts need a healthy balance of open ground, small rocks and logs. Too many large rocks for example can deter animals as well. Vertical logs should be secured to the invert of the base of the underpass using attachment brackets. Arboreal species will only use large culverts three metres x three metres or greater. Anything smaller will not be used by these species due to the treat from predators and because they prefer not to travel along the ground where possible. At either end of the culvert, lead-up logs should be used to allow movement of species. Ideally lead-up logs should connect to trees or other off ground structures, so arboreal species can move freely while avoiding the ground and possible attack by predators (refer to Figure 6 below). Figure 6: If correctly positioned, arboreal species such as koalas and possums should be able to move through structures and along horizontal logs without going on the ground. 18 Fauna sensitive road design guidelines Large culverts Multiple culverts For larger culverts under four or six lane roads, it is preferable to provide a break in the middle of the culvert (if a median exists), to maximise the amount of natural light entering into the culvert. Strategically placed light wells may also be used to achieve this (refer Figure 7). Installation of several underpasses at one location deceases the possibility of interference caused by other fauna movements, including predators such as the fox. In some cases there may be a requirement of projects to build culverts for targeted species (refer Appendix A). Light wells should be built higher than the surrounding ground, and should never be designed with drainage in mind. Ideally water should flow either side of the light well ensuring the culvert stays as dry as possible. Any water that does enter these culverts should drain quickly away. Small culverts will only be used by smaller animals such as echidna, bandicoot and reptiles (refer Figure 8). Multiple underpasses also increase opportunities for species interaction by providing alternative routs and decreasing travel time from one side of the road to the other. Small culverts should have entrances as natural as possible and be free of human disturbance and artificial light. Light wells are good for providing natural light in long culverts however there is the potential ‘especially if poorly designed’ that they become a focal point to collect litter, road pollution, and increase noise with in the structure. Some studies question the effectiveness of light wells so projects should seek expert advice if such structures are being considered. Fencing It is important that culverts are constructed early before erection of permanent fencing, as with all wildlife crossings fencing helps funnel fauna to the underpass (refer Figure 8). Fencing is discussed further in Section 6.3 page 30. It is possible to plant out some small vegetation in the middle of a culvert as long as plants get maximum exposure to sunlight and rainfall. Vegetation (if possible) is culvert furniture alongside rocks, logs and mulch and could provide safety for native fauna against predators. Figure 7: Cross section of a multi lane culvert. The light well in the middle of the median allows natural light to entre a long dark culvert. Also the well is built higher than the surrounding ground, so water does not drain into the culvert. Figure 8: Small culverts are used by small mammals and reptiles, while fencing is important in funnelling wildlife to underpasses. 19 Fauna culverts along waterways Wildlife is known to traverse along creeks and rivers. Water is important for terrestrial fauna especially in Australia’s dry climate. Roads built over creeks and rivers often have culverts that maintain water flow or drainage, but very rarely consider the need for wildlife to move through the landscape. In such scenarios, terrestrial fauna is forced to move up embankments and across roads, leading to increases in fauna mortality. Fauna culverts along creeks should be designed with three factors in mind: maintain water flow encourage the movement of aquatic animals maintain terrestrial fauna movement. Culverts along creeks should be created in as natural a condition as possible with rocks, logs and riparian vegetation. Ideally the raised embankment should always be designed above the main water level (refer Figure 9). Obviously these embankments will be subject to flooding from time to time however the designs should ensure that water drains away quickly allowing the ground to dry out. Embankments which permanently hold water or are extremely muddy will deter fauna from moving through culverts. Again, natural substrates including rocks, logs and bare ground are preferred over concrete bases. In this case, projects should avoid using mulch. Mulch is problematic in such environments due to the risk of flooding. Finally, this type of design can make life easier for maintenance teams needing to access the culverts in the future. Factors to consider when designing culverts for terrestrial fauna movements along creeks: Culverts should be made as wide as possible to encompass water flow, stream bank and riparian vegetation, preferably on both sides of the water course. A raised section should be considered on both sides of the creek, encouraging terrestrial fauna movements. If the culvert width is narrow, it is better to design one embankment wider than the other, rather than have two narrow embankments. If it is difficult to have two embankments, then one embankment is better for terrestrial fauna than providing nothing at all (refer Figure 9). Figure 9: The raised walkway in this example caters for both aquatic animals and terrestrial animals. Figure 10: Series of box culverts with varied floor levels maintain both creek flows, while allowing dry culvert passage for terrestrial wildlife passage. 20 Fauna sensitive road design guidelines Approaches to crossings The entrance to a culvert is very important in encouraging wildlife to use fauna mitigation structures. Ideally, projects should retain as much natural vegetation as possible and cause minimal disturbance to the corridor link they are trying to maintain. At times when it is too difficult to avoid disturbance, careful consideration should be taken in order to establish as natural a landscape as possible at the approach to crossings. The entrance to culverts will need to be enhanced by the provision of ‘furniture’ including habitat logs and refuges within the corridor, including the placement of standing dead hollow bearing trees or ‘stags’ (refer Figure 11). In some locations it may be necessary to encourage connectivity with additional indigenous plantings. Extensive planting should consist of a variety of species and mimic existing bushland type and Ecological Vegetation Class (EVC), and plantings should be shaped to encourage wildlife towards the crossing points. Strategic habitat creation will enhance the overall effectiveness of wildlife connectivity and can re-connect important parts of the landscape away from the road. Factors to consider when designing the approach to culverts: Most plants are a food source of native animals or attract food such as insects which other species feed on. Important or preferred food strategically planted in corridor links can be used to tempt animals near or into crossing structures. Habitat restoration should typically use indigenous stock. Some plantings can change dependent on targeted species or species specific requirements, e.g. for smaller animals more thick ground cover plantings with some open spacing should be considered. For reptiles, more rocks and logs should be placed in and around culvert entrances. Culverts for animals Avoid humanising wildlife friendly structures. Culverts and bridges that encourage humans and their pets to walk in, near or across can often discourage wildlife. Culvert entrances should be free of human disturbance and artificial light. Close vehicle access should be considered however for on-going maintenance requirements. Figure 11: Landscaping with rocks, logs and revegetation help funnel fauna into culverts. 21 6.4 Culverts to aquatic animals Locating aquatic crossings The location of aquatic crossings for species movement is very important . Ideally, the primary objective during the planning and investigation stage of a project is to minimise the total number of road crossings across creeks and rivers. When locating aquatic crossings, the following principles should be considered: Avoid crossing waterways near sharp bends, sections of unstable banks or naturally strong “riffle” systems. Riffles are shallow rocky shoals or sandbars lying just below the surface of the waterway. These areas act as natural important bank stabilisers and often provide essential habitat pools. Any alteration of these systems may impact habitat, change bank stability and potentially initiate severe riparian erosion. Avoid locating crossing in areas where the river is likely to continue meandering into the future. Naturally meandering rivers undergo natural reshaping and erosion, especially during times of strong flow. Meandering rivers cause maintenance headaches as changing waterways can damage structures such as culverts. Future misalignment of the channel crossing may result from natural reshaping, rendering culvert and aquatic mitigation structures pointless. Avoid works that change the frequency and spacing of existing natural habitat pools and riffle systems. Avoid the removal of essential shade trees, especially in areas which have already lost a lot of natural vegetation cover. Road construction can have a significant effect on streams and rivers. Vegetation removal causes enhanced runoff and soil erosion leading to sedimentation of natural waterways, generally modifying stream hydrology. These changes have adverse effects on natural remnant vegetation and habitat. Projects should avoid disturbance to sections of a waterway channel or its associated bank vegetation, particularly where such areas represent either a unique, endangered or highly valued section of the water way. Figure 12: Roads and bridges should be place in areas that are least likely to have environmental impacts. 22 Fauna sensitive road design guidelines Culvert designs When designing culverts for aquatic species most people naturally think about fish. However Australia’s creeks and rivers are home to a number of aquatic species including platypus, native water rats, crustacean and turtles. Where possible, culverts under creeks and rivers should be designed to accommodate the movements of aquatic species and not impede movement from one side of the road to the other. Fish passage along our waterways is critical to the survival of Australian native fish. Of the 83 species of freshwater fish in southeastern Australia, half migrate at least once as part of their life cycle. These include; Silver perch, Murray Cod and Dwarf Galaxias. Factors to consider when designing culverts for aquatic species: Culverts that are not as wide as natural stream beds restrict water flow and therefore increase water velocity. This is detrimental to fish passage as a majority of fish cannot maintain strong burst speeds for long enough to swim to the other side of the culvert if the distance is too great. In this scenario, fish tire before they reach the other side and are swept back downstream (refer Figure 13). Small culverts are dark and easily get blocked with debris, blocking aquatic species movements. Ideally, culverts should be less than six meters long especially when no resting areas are available and given that water velocity is likely to increase after the construction of new structures. Maximise natural light by making the dimensions of culverts as large as possible. Large diameter culverts provide easy access and are easier to maintain. Also, the wider the culvert the easier it is to maintain natural flows. Baffles Consider installing baffles on one or both sides of the culvert (refer Figure 14). Baffles are appropriate for new culverts designs and projects should seek expert advice to ensure correct placement. Baffles act as energy dissipators, slowing water velocity. They also change the flow pattern in the vicinity of the culvert, creating zones of fast and slow moving water zones. This allows fish to use short bursts of energy while allowing periods of rest. For multiple parallel culverts, only those fitted near stream beds should be fitted with baffles (see Figure 10 on page 19). Figure 13: Water velocity is important for fish movement upstream (Source: QLD Transport and Main Roads (June 2010) Fauna Sensitive Road Design Manual Vol 2). Figure 14: a) A baffle design in a pipe culvert b) Cross–section of baffles installed on both sides of a culvert. (Source: QLD Transport and Main Roads (June 2010) Fauna Sensitive Road Design Manual Vol 2). 23 Culvert rehabilitation Fish ladders Existing culverts can be rehabilitated to encourage aquatic fauna movement, especially fish. One of the biggest problems with some existing culverts is their inadequate design and its impact on water level across inlet and outlet. In these circumstances, water flow varies from being high and flowing fast during high flows and low water levels during dry periods. Existing culverts can be rehabilitated to improve fish passage conditions. Actions can include: Fish ladders are structures on or around artificial barriers such as culverts and weirs and can be used to facilitate natural migration. The velocity of water falling over the steps must be great enough to attract the fish to the ladder, but cannot be too strong that it washes fish back downstream or exhausts them to the point that they can’t maintain the energy needed to move through the stream system. There are several types of fish ladders including: Upstream modifications to improve flow in to culverts by raising low flow water levels within culverts. fish pools Where high flow velocity is a concern, baffles could be installed. This would change flow regimes and provide various slow and fast water zones. rock Ramps. Upstream channel modifications could remove the issues associated with deep drops or excessively steep rock ramps. Culvert maintenance Maintenance for culverts is important and should be considered during the planning stages of projects. Funds will need to be made available at the project bid stage and handed to regions once the project has moved on. Culverts designed for aquatic species movement in general require more maintenance than culverts for terrestrial species. Creeks and rivers in flood or flowing fast can move large bodies of water and are renowned for picking up and moving debris such as vegetation, wood, litter and even rock over great distances. This process blocks culverts and can act as a barrier for aquatic wildlife. Maintenance requirements for aquatic culverts include: fish elevators; and Rock ramps In Australia, rock ramps are commonly used to facilitate fish movements and are a good tool for slowing water velocity down and encouraging fish movement through culverts. Rock ramps are constructed by placing large rocks within streams to form a fish ladder type system. Gradient and designed are determined by maximum swimming speeds of various fish. Full width rock ramps are optimal but partial rock ramps are most common. Rock ramps cater for a variety of fish behaviour and movement patterns and allow mitigation even during low flow. Controlling silt buildup and undertaking inspections annually as a minimum. Ensuring vegetation and weeds don’t become established at entrances to culverts. As a minimum, maintenance should be ongoing and occur annually. Substrate The substrate should be as natural a possible and incorporate a wide range of furniture including; large rocks, deep pools and fine gravel. Where possible, consider using a three sided culvert with no base. This maintains a natural streambed instead of hard concrete base and is more attractive to some species such as water invertebrates, fish, crustaceans and platypus. Furniture must not adversely impede water flow but can be considered in culverts where water velocity is a problem. Fish ladder under construction (Source: VicRoads) 24 Fauna sensitive road design guidelines 6.2 Overpass 6.2.1 Canopy bridge Whilst surface crossings, culverts and bridges address the needs for ground dwelling fauna, a new road can introduce a significant break in tree canopy, particularly along existing vegetation linkages. Canopy bridges provide for genetic connectivity, dispersal movements and home range movements. When designed correctly, daily crossings by some individuals are common. Target animals for cable crossings include possums, phascogale and sugar gliders. There is even evidence of some arboreal reptiles such as lace monitors using canopy bridges. Typically, a canopy bridge consists of a woven polyethylene cover over a 12 mm diameter steel cable. The polyethylene provides a surface that allows animals to secure grip. The cable is supported either side of the carriageway at the end of the mid point by tension cables. The tension cables help keep the canopy bridge clear of traffic lanes and reduce whip. At the mid point a hooded protective cowl will offer animals refuge from airborne predators (refer Figure 18 page 26). Ringtail possum on Hume Highway Rope Bridge (Source: VicRoads) Factors to consider when designing canopy bridges: Canopy bridges must be linked to canopy vegetation. If targeting specific species, then canopy bridges should be placed near known habitat trees. Supports can usually be constructed using recycled materials such as old electricity poles. Suitable poles should be placed behind fauna proof fencing and at a safe distance away from the roads edge. Safety requirements must be complied with when structural supports are placed in the median (e.g. wire rope barrier). Crossing opportunities should be provided for possums every 100-120 metres when possum home ranges coincide with the road corridor. The distance between the road and canopy bridge should be maximised. Ideal minimum distance from the road is seven metres with a maximum of 12 metres. Canopy bridges are shown to be quite successful in encouraging arboreal movement across roads. Some studies may recommend building a four sided rope tunnel (refer Figure 15) however this design is probably not necessary because most animals generally don’t climb through such structures and instead traverse along the top. Figure 15: Generally there are two types of rope structures, one is a rope tunnel and the other is a rope ladder. Studies and monitoring indicate that the tunnel though still doing its job is less effective because arboreal species such as possums only cross on top. (Source: QLD Transport and Main Roads (June 2010) Fauna Sensitive Road Design Manual Vol 2). 25 Figure 16: Fauna crossing detail – not to scale. When designing canopy bridges consider the following safety requirements: Potential conflict with powerlines and other service infrastructure. Roadway safety and clear zone requirements. Design must not impede the safety of road users. Ideally, poles should be placed behind fauna fencing in vegetation with connection to trees. In the diagram above the cowl attached to the pole in the median ensures animals are unable to descend in the middle of the road between traffic lanes. 26 Fauna sensitive road design guidelines Figure 17: Typical cable end cowl and optional record Pad (not to scale). Figure 17 is an example of the type of cable end used for canopy crossings on the Calder Freeway. It should be noted that in this instance a replaceable record sheet was included for the purpose of monitoring wildlife. It is not always necessary to monitor canopy bridges for their effectiveness as studies indicate that such structures have already been proven to be successful in facilitating arboreal movements. Figure 19: Avian predator guard and PVC pipes for shelter on support poles. (Source: NSW Transport and Maritime Services (Nov 2011) Wildlife Connectivity Guidelines). Figure 18: Fauna cable details (not to scale). Possums, phascogale and sugar gliders once out in the open are very exposed to avian predators such as owls. Ideally all poles should have avian predator guards (refer Figure 19). Predator guards can be made of various materials including metal, plastic or even shade cloth. Generally predator guards should be placed 500 mm above the rope ladder or cable. For added protection, additional PVC pipes placed along cross sections also provides predator protection. Canopy bridge limitations Minor cost of building but with maintenance implications. May be difficult to match cable design to suit claws of various fauna. 27 Figure 20: Canopy connectivity is a form of non-structural mitigation (Source: QLD Transport and Main Roads (June 2010) Fauna Sensitive Road Design Manual Vol 2). Maintenance 6.2.2 Canopy connectivity Maintenance for canopy bridges is important and should be considered during the planning stages of projects. Funds will need to be made available at the project bid stage and handed to regions once the project has moved on. Canopy bridges require regular maintenance of rope tension to maintain clearance above the road and reduce sway. Ropes that sway too much are likely to not be used by arboreal animals such as possums. Other maintenance considerations include: The diagrammatic example above is a relatively inexpensive way of maintaining canopy connectivity in the landscape. Here, vegetation clearing is kept to a minimum width allowing the tree canopy to remain continuous, or where not continuous, small enough to allow species like gliders to move across the road from one side to the other. This type of mitigation is suitable for a number of species including arboreal animals, bats, birds and flying invertebrates. Inspect on an annual basis as a minimum especially after storm events (fallen trees etc). Heavy vegetation should be pruned away from wire ropes. Vegetation growing on ropes will add stresses to the structures especially when the vegetation is wet. Ropes should be checked for decay and deterioration. Landscaping Where trees are unable to be saved during road widening or maintenance, then VicRoads officers should consider re-establishing trees through landscaping. This is not ideal however as trees take an average of ten or more years to develop a canopy similar to the one destroyed. This time delay is critical for some arboreal species that are endangered. Without canopy connectivity, many of these species face extinction due to a number of factors including lack of habitat, reduced home ranges and /or genetic inbreeding due to the barrier effects from roads (Source: QLD Transport and Main Roads (June 2010) Fauna Sensitive Road Design Manual Vol 2). 28 Fauna sensitive road design guidelines 6.2.3 Land Bridges An overpass or land bridge is similar to an underpass, except the road goes beneath the bridge which has been constructed for wildlife. Land bridges are also referred to as ‘green bridges’ or ‘ecoducts’ and can facilitate the movement of a number of terrestrial and arboreal fauna. Land bridges have been used in many countries across Europe and North America and are considered a very attractive option for facilitating movement of a large variety of fauna to cross roads, from invertebrates to large fauna. In Australia, there are two known land bridge crossings used to re-establish connectivity. These include; the Yelgun to Chinderah Project on the Pacific Highway in NSW and Compton Road land-bridge in Queensland (refer Figure 21). Typically, a land bridge is more expensive to construct than underpass mitigation. However in the right circumstances there is the opportunity for land bridges to incorporate other features such as the opportunity to pass over drainage lines or gullies. Factors to consider when constructing a land bridge: Overpass structures vary in design and come in various shapes and sizes including hourglass and rectangular shapes. Hourglass shape structures should be wider at the entrance points and taper in towards the arch of the bridge. The best location for such structures is where the road is already in cut. Fencing should be used to funnel species to the land bridge and prevent animals from falling on to oncoming traffic. Evidence suggests that rather than using one or two large land bridges, a greater number of smaller land bridges are preferred. Land bridge furniture If designed correctly, land bridges are suitable for a large variety of wildlife. All land bridges should incorporate soil, vegetation and be enhanced with other habitat features such as logs, rocks and even shallow water bodies. For optimal vegetation growth and longevity of the projects objectives, soil should be made as deep as possible. The ideal depth of the soil will depend on the type of vegetation planted e.g. 0.3 metres of soil for grasses, 0.7 metres for shrubs and 1.5-2 metres soil for trees. Ideally the design should mimic surrounding bushland or EVC and should include a mixture of indigenous vegetation. Some other furniture to consider in land bridge design might include: Most plants are a food source of native animals or attract food such as insects which other species feed on. Important or preferred food strategically planted in land bridges can also be used to tempt animals near or into crossing structures. For reptiles, more rocks and logs should be placed along the stretch of the land bridge. Consider building a water body such as a wetland at either side of the structure. Being a dry climate, water is important in the Australian landscape. Placing water bodies at each end will encourage a vast array of animals as they will be drawn to the water for drinking. Wetlands can be designed as frog habitat; encouraging frogs to move over land bridge structures (refer Section 6.4). Target species Land bridges provide one of the most natural crossings for fauna, particularly disturbance sensitive species. All species, excluding aquatic use the structures including kangaroo, wallaby, koala, wombat, echidna, bandicoot, possums, reptiles, birds (especially emu and Malleefowl), bats and frogs. Figure 21: Compton Road land-bridge is a great example of land bridge design in Australia. Photo: L Harrison (Source: NSW Transport and Maritime Services (Nov 2011) Wildlife Connectivity Guidelines). 29 Land bridges for animals Land bridges that encourage humans and their pets to walk in, near or across can often discourage wildlife. Where possible avoid the development of walking or bike paths. Domestic dogs and cats deter native wildlife. Land bridges or ecoducts should be designed with the interests of wildlife in mind. Maintenance Figure 22: Wildlife Crossing on the 26 Motorway in the Hardt Forest in Germany. Javier Martinez de Castilla, Head of the Environmental Department, Ferrovial Agroman. Consideration will need to be made for ongoing maintenance and should be included in the Total Estimated Cost during the planning stage of projects. Once handed back to regions, ongoing maintenance should include: Minimum yearly and annual maintenance as required. Design specifications The success of land bridges is dependent on a number of factors including width, fauna exclusion fencing, vegetation, noise disturbance, suitability of vegetation, provision of artificial shelter and minimised human disturbance. Currently no standard design principles have been established in Australia. Within the first few years, landscaping should be checked for survival rates, and money set aside for any failures. Possible ongoing maintenance for other furniture including any canopy bridges. Land bridge limitations Very high cost. As a rule of thumb, the following principles should be considered: Design is dependent on the purpose of what is trying to be achieved. Topography, environmental surroundings, target species, climate should all be factored into the designs. For example, birds and larger terrestrial animals such as kangaroo and koala would prefer a wider bridge. 50 metres or greater width will be used by the widest variety of species and provide as natural a connection as possible for animals to exhibit natural behaviors. Narrower bridges will be used by more targeted species. The minimum width required is around 5 metres. Bridges should be located in areas of high wildlife traffic areas, and should consider all animals including birds, invertebrates, bats and reptiles. Approach embankments should be 1 in 3 gradient and vegetated. It is important to seek specialist advice when considering such structures. They are very costly to implement, and projects spending such a large amount of money would need to make sure they achieve the goals and objectives of fauna sensitive road design. For land bridges, fencing is important. Fencing both funnels wildlife to use the structures and prevents animals from falling into traffic below. For further information on fencing (refer Section 6.3, page 30). Not yet trialed in Victoria. High cost for ongoing landscaping and maintenance. 30 Fauna sensitive road design guidelines 6.3. Fencing Small animals Fencing forms an integral part of the operation of the wildlife crossings. When deigned correctly, fencing can direct fauna to the right crossing locations and prevents animals from accessing the road. Fencing should be used along both ends of fauna structures in order to prevent animal-vehicle collisions. Both fences discussed in this section have large mesh that will not prevent smaller species such as lizards, snakes and frogs from climbing through. A fence with large mesh for large animals can include fine mesh at the base to prevent small species from climbing through. The type of fencing required changes depending on species specific requirements. As a general rule the following basic types are considered acceptable. All fencing requires a clearance of at least three metres on the forest side of the fence. Mesh size for amphibians is less than 4 mm. Mesh or metal sheeting for smaller species should be made 400 mm–600 mm high. Figure 23: Calder Freeway fencing, note the metal sheeting to stop climbing species such as koala from entering the road reserve. Figure 24: Pinned down skirt, Photo: Rodney Abson (Source: The use by vertebrate fauna of the Slatey Creek a Wildlife Underpass, Calder Freeway, Black Forest, Macedon, Victoria). Kangaroo and Koala resistant fencing This type of fencing involves a 2,100 mm high standard chain mesh fence to prevent larger types of wildlife entering the road reserve. The top 300 mm of the fence is not secured and is bent over in the form of a ‘floppy top’. Climbing animals tend to find the floppy top difficult to negotiate and will either let go or back down. The fence also has a 600 mm pinned down skirt on the forest side of the fence to discourage burrowing animals (refer Figure 24). This type of fencing will not stop small animals as the mesh size is approximately 50mm square. Arboreal resistant fencing Arboreal resistant fencing is typically made of 1,800 mm high with the bottom 1,200 mm made of 20 mm square chain mesh and the top 600 mm rolled metal sheeting. The smaller mesh prevents passage of adult species such as possums, sugar gliders and phascogale, while the metal sheeting discourages climbing. Again, the fence has a 600 mm pinned down skirt to discourage burrowing animals (refer Figure 24). This type of fencing has to be placed in areas known to be frequented by arboreal animals. Avoid fencing with barbed wire. Arboreal animals such as the squirrel glider pictured right can become entangled in barbed wire fencing. Squirrel glider mortality, Photo: Rodney van der Ree (Source: NSW Transport and Maritime Services [Nov 2011] Wildlife Connectivity Guidelines) 31 Frog resistant fencing Frog resisting fencing is 400 mm high and dug into the ground at a depth of at least 100 mm. The most important factor in determining the success of frog fencing is the design of a pre-fabricated galvanised lip along the top of the fence. Materials can consist of recycled polyethylene sheeting with galvanised star pickets or plastic Square Hallow Posts (SHS posts), galvanised roof purlin and galvanised SHS posts or fine wire mesh of less than 4 mm in diameter. Overseas studies in relation to use of underpasses or tunnels by frogs have shown that frogs have difficulty in finding these structures if fences are not installed. Frog fencing should be used along both ends of all underpasses and culverts. Amphibian fencing must take into account the climbing and digging capabilities of the target species. Vegetation ideally should be cleared 1 metre either side of the fence. Figures 25 and 26 demonstrate the principles of frog fence design. Keeping fencing clear Vegetation plays an important role in the success of frog fencing. Grass and plants which are allowed to grow up and over frog fencing will be ineffective in preventing frogs going onto roads. Frogs are good climbers and so will more than likely climb up vegetation avoiding the fence. Projects need to take ongoing maintenance into consideration and factor these costs before hand over to the region. Maintenance Fencing should always be built using solid quality products that are study, robust and durable. The better the materials used in fauna sensitive fencing, the least amount of maintenance is required going forward. The following maintenance requirements will need to be considered: Maintain the three metre of vegetation clearance “excluding” grass on the forest side of the fence. Fencing will require regular inspection. Fencing will require regular inspection and maintenance. Vehicle access tracks adjacent to the fence will facilitate rapid inspection and repair. Vehicles only require 1.5 metre clear-zone on the habitat side of the fence. Fence limitations Fencing is mainly associated with underpasses and culverts, leaving large sections of road unfenced. Escape from fire may be difficult. Figure 25: Free standing frog fence (adapted from 3003181 -BFF-020-6003) (PacificLink Alliance 2006d). All types require ongoing maintenance to ensure ongoing success. Unknown life span. Figure 26: a) Frog fence attached to an existing fence (adapted from 3003181-BFF-020-6003) (PacificLink Alliance 2006d) and b) Cross-section of the fence (Source: QLD Transport and Main Roads (June 2010) Fauna Sensitive Road Design Manual Vol 2). 32 Fauna sensitive road design guidelines 6.4 Habitat enhancement 6.4.1 Frog ponds Regardless of the presence of key habitat characteristics at a particular wetland, previous research has shown that a landscape approach to habitat creation and management is required . For example, it has been shown that the likelihood of frogs occupying a particular wetland is largely dependant upon the distance to nearby occupied sites. Therefore any frog ponds designed by VicRoads must be located within close proximity to existing populations. Generally speaking, studies suggest that frogs are highly dispersive and given the right opportunity frogs have a high ability to colonise newly created habitat. The creation of frog habitat and the spatial location of frog ponds are important. The following factors should be considered when building frog ponds: Banks Wetland banks should vary in the degree and slope, from areas of gentle undulation to steep banks that drop off sharply. A variety of edge types and the provision of different microhabitats such as rocks and vegetation will also create a diversity of habitat. Shape and size There is no written rule with regards to the shape and size of frog ponds. Preferably, ponds which are long and narrow have been favored in the past, with frog ponds on Pakenham Bypass being shown to be quite successful (refer Figure 27). The longer and more rectangular shaped the wetland is, the more the frogs will have a high edge to area ratio, and smaller areas of open water. A general guide for frog ponds applies: 20 metres x 5-10 metres for the smaller ponds; no less than 40 metres x 10 metres in diameter for larger ones. This configuration maximizes the refuge area around the wetland for frogs and provides a variety of habitat sources. Limitations Generally only possible in areas with a wide right of way boundary. Cost may be high. Limited opportunities due to limited availability of land in some areas. Vegetation Vegetation should be structurally diverse, and areas around the perimeter of the wetlands should be planted with a healthy dense aquatic and semi aquatic range of indigenous wetland species. As with all fauna mitigation requirements, expert advice from amphibian experts should be sought during the planning and design phase of the project. Landscaping Figure 27: Packenham Bypass Growling Grass Frog Wetlands and frog fence (Source:VicRoads). Dense plantings of trees and shrubs should be discouraged in close proximity to wetlands, because, when established, this vegetation may shade out wetlands, thus rendering them unsuitable for most frog species. A healthy banks zone with a combination of sun and shady spots should be considered. The Growling Grass Frog is a common concern among VicRoads Projects (Source: VicRoads) 33 6.4.2 Nesting boxes Nesting boxes are specially constructed boxes that are placed in trees to provide artificial habitat for hollowdwelling arboreal mammals and birds. The size of the aperture of the nest box varies according to the species being targeted (refer Figure 28). In nature only very old trees provide hollows for arboreal animals such as Feathertail Glider, Leadbeaters Possum and Brushtailed Phascogale. For projects where the removal of important habitat trees in unavoidable, nesting boxes should be considered in order to replace this lost resource. Design recommendations to consider for nesting boxes include: Highly valuable in some landscapes where nesting location have become rare. When a hollow tree is to be removed, carry out investigations and note the species that potentially utilize the hollows. Ensure that replacement nest boxes are species specific and appropriate for what the project team is trying to achieve. Different species utilise different heights and hollows within trees and so require different styles of boxes. The height of the nest box will determine its use. As a rule most nesting boxes should be installed between three and eight metres above the ground. Consider the natural nesting habits of the species under consideration. Orientation The orientation of nest boxes needs to consider a number of surrounding environmental factors such as wind direction, rainfall and the levels of exposure to full sun. For example, nesting boxes placed in the full sun during the summer months would be far too hot to support the animals you are trying to create the habitat for. On all occasions, it is best to seek specialist advice with regards to the type of nest boxes required. Natural nesting habits are species specific and will require baseline surveys prior to the removal of tree hollows. All projects removing trees during construction will require a qualified fauna specialist or ecologist on site during clearing to ensure hollows and replacements are removed and reinstated with minimal impact and disturbance. Maintenance Considerations will need to be made for ongoing maintenance and should be included in the Total Estimated Cost during the planning stage of projects. Maintenance considerations include: nesting boxes can be damaged during fire and storm events and will need to be monitored and replaced control exotic pests including European Wasp and feral birds check annually to maintain success Nest box limitations Vulnerable to invasion by pest species like bees and exotic birds. Monitoring and maintenance required for success. Figure 28: Sugar Glider using a nesting box provided after road construction (Source: VicRoads). 34 Fauna sensitive road design guidelines 6.4.3 Traffic management Traffic management is one of the cheapest forms of fauna mitigation on roads. Numerous methods can be incorporated to change local driver behaviour including road signage, reflector lights, rumble strips and road closures. Traffic management is suitable for all animals where traffic volumes and speed contribute to high levels of roadkill. In Victoria, warning signage is the most common method used to reduce fauna mortality on roads. Limitations Reduces but does not eliminate risks of roadkill. Not likely to be practical on highest speed roads or roads with high traffic volumes. Success of permanent signage in reducing roadkill and public awareness diminishes over time, particularly with local residents familiar with the signs. The effectiveness of traffic management is dependent on a number of factors including: Adjusting driver speed by installing temporary or permanent reduce speed signs. Speeds may be signed or advisory. Warning signs are most suitable for roads with low traffic volumes. Speed reductions are best achieved when used with other devices such as rumble strips or speed humps that force drivers to slow down. Warning signs are probably most suited for use on tourist roads where protection of fauna is valued and expected. VicRoads has a set of standard drawings for animal warning signs are available on Exchange > Road Management and Design. Maintenance Signage should be kept clear of overgrown vegetation. Can become damaged and will need replacing. Kangaroo warning sign Mickleham Road (Source: VicRoads) 35 6.4.4 Other considerations Light mitigation Street lights and vehicle headlights can have both negative and positive impacts depending on the fauna species in question. Negative impacts include: lights attract some fauna including bats as they are drawn to food sources such as moths at night illuminated areas potentially attract some species onto oncoming traffic some fauna actively avoid artificial light preventing movement across the landscape reduces habitat quality in surrounding areas artificial light potentially increases stress levels of fauna by changing normal animal behavior and energy levels. Light however is thought to have some positive impact with species which are sensitive to light as it prevents some animals from heading onto the road. Target species for light mitigation include frogs, gliders and turtles. It should be stressed that there are still levels of uncertainty on the overall effectiveness of light mitigation, and further study in the area is required. Limitations Studies suggest that it has limited effect on reducing roadkill. Is not always consistent with the requirements of other road safety initiatives. Fauna relocation Fauna relocation occurs when projects physically capture and release fauna into alternative habitat sites. Fauna relocation is a requirement of all projects where construction impacts on native wildlife, or where the capture and relocation of fauna is identified within vegetation zones to be cleared. Fauna relocation: ensures potentially impacted species are protected relatively inexpensive may reduce pain and suffering for individual animals. Limitations Can be species dependant. Doesn’t necessarily address population issues. Generally inappropriate for territorial animals. For species that are sensitive to artificial light, VicRoads Officers should consider: using fewer streetlights (only where this does not impact safety) use streetlights with reduced intensity consider using barrier mounds, or densely planted vegetation to limit the intensity of street lights from penetrating far into the road reserve decrease the height of light poles consider reducing glare from streetlights by using flat glass aeroscreen instead of a reflector glass cover in streetlights use alternatives to lighting such as pavements with light-emitting diodes or fluorescents paint Increasing the reflectivity of signs and road stripping (retro-reflectivity) can increase visibility for drivers (QLD Roads) Light mitigation can only have limited effect and does not reduce roadkill. Lighting is one aspect that should be considered with other forms of mitigation. Example of one of several fauna crossings developed along the Calder Freeway (Source: VicRoads) 36 Fauna sensitive road design guidelines Appendix A. Types of fauna mitigation Animal Background Road impact Suggested mitigation Amphibians (frogs and toads) Direct impact Habitat creation including frog pond and wetland design. Road projects often interact with frogs such as the Growling Grass Frog. Growling Grass Frog Amphibians are found in a variety of habitats including rivers, wetlands, trees and drier terrestrial habitats such as grasslands. Different species are adapted to different habitats with a majority of species requiring a mixture of aquatic and terrestrial habitat. Frogs are commonly killed by road traffic. Indirect impacts Fragmentation - can lead to isolation of populations which may result in reduced population sizes and an increased risk of extinction. Roads can also create ‘barrier effects’ which restrict movements across roads. Pollution - Amphibians are at risk from absorbing chemicals from pollutants washing off roads. Chemicals can retard tadpole growth, damage their sense of smell and poison adult species. Wildlife connectivity should be maintained where possible to prevent mortality from traffic collision. Frog culverts should be designed using specialist advice. Generally speaking frogs have low levels of mobility so crossing zones should be strategically placed. All crossing zones will need to be fenced using design concepts listed in Section 6.3, page 31. Predication – More vulnerable when on the road due to increased visibility on the roadway. Arboreal animals – such as the Squirrel Glider, sugar glider and Brushed tailed Phascogale spend most of their time in the trees and rarely move along the ground. Squirrel Glider Brushed tailed Phascogale Arboreal animals are well adapted to living in the trees and included a number of endangered species. Direct impact Arboreal animals are commonly killed by road. Indirect impacts Fragmentation - road, construction often create gaps in the canopy of trees. Species such as possums may therefore need to move across the ground where they could potentially increase rates of roadkill. Habitat removal – many arboreal animals rely on the hollows created by old trees. By removing old trees through construction activities, projects are potentially removing nesting sites. Several mitigation options exist including; ▪Where possible maintain natural canopy connectivity above the road to facilitate crossing through branches. ▪If removing trees consider the installation of canopy bridges (Section 6.2, page 24). ▪For species that glide, canopy gaps should not exceed their gliding capacity. Glide distance is dependent on a number of factors including; the glide starting height (ie tree height) and the size of the animal. Nest Boxes – projects removing old growth trees with hollows should consider replacing the hollow with nesting boxes (Section 6.4.2, page 33). 37 Animal Grey Crowned Babbler Background Road impact Suggested mitigation Birds and Bats Direct impact Australia is home to a vast array of bird and bat species, many of which are unique to this country. Birds and bats are commonly Animals that fly are affected by road traffic. Several mitigation options are available including; Birds have colonised almost every habitat imaginable with different species adapted to different habitats. In Victoria some birds including emus malleefowl and lyrebirds are ground dwelling species that spend all or a majority of their life on the ground. Indirect impacts Fragmentation – loss of connectivity and disturbance of habitat mean many birds must search for new territory. The rates of mortality in some species are high due to the low flying nature of the species. Behaviour – traffic noise interferes with the acoustic nature of some species, while streetlights and headlights are thought to interfere with the vision of some species. Attraction – A number of conditions including storm water treatment wetlands, food plants on road reserves and water that puddles on the side of roads, attract birds and bats. Dwarf Galaxias ▪Where possible maintain natural connectivity. ▪Consider bridge options such as Slaty Creek Underpass or land bridges. Both options are suitable for birds and bats as it is easier to maintain vegetation connectivity. For ground dwelling birds, underpasses such as bridges and large culverts are suitable. Natural substrates that maintain continuous or near continuous cover are best (Section 6.1, page 15 and 6.2.3 page 28). Fish Direct impact Mitigation methods include; Freshwater fish in Victoria are diverse and geographically extensive however many native fish have declined both in their range and abundance during the last 100 years and habitat changes are thought to be the major cause of the decline. Roads themselves do not directly impact fish species, but road construction does. Construction activities which damage aquatic habitats, impact water quality or increase turbidity and erosion into creeks are all detrimental to freshwater fish. ▪Consider installing baffles in new and existing culverts. Fish such as the threatened dwarf Galaxias are a concern for VicRoads as many projects interact with the species. Indirect impacts Roads constructed over waterways have several impacts: ▪Bridges can shadow riparian zones and wetlands changing characteristics and impacting on vegetation. ▪Roads can change the flooding characteristics of waterways, while stormwater runoff has impacts on water quality. ▪Where culverts have been placed under roads, water velocities can change and impact on the movements of aquatic species (Section 6.4, page 21). ▪Create habitat such as rock ramps which encourage fish movement along the waterway. ▪Avoid crossing waterways near sharp bends, sections of unstable banks or naturally strong “riffle” systems (Section 6.4, pages 21 – 23). Construction phase – establish protocols for the management of fish populations at the beginning, during and after construction. Protective measures including No-Go Zones should be devised, the purpose of which is to prevent encroachment into and damage of the aquatic habitat during both temporary and permanent construction works. 38 Fauna sensitive road design guidelines Animal Golden Sun Moth Background Road impact Suggested mitigation Invertebrates Direct impact Mitigation methods include; Invertebrates are animals without a backbone, and usually have hard external shells. Invertebrates are critical in ecosystem function and play important roles in the pollination and seed dispersal of a variety of native plants. Road traffic has great impact on the mortality of slow and low flying invertebrates. ▪When designing land bridges and underpasses for larger species, consider designs that cater for species such as the Golden sun moth. Threatened invertebrates such as the Golden Sun Moth are a concern for many VicRoads as projects regally interact with the species. Koala Indirect impacts Reduced connectivity is likely to have significant impacts for species living along the ground. Dust - pollution from construction or along dirt roads may impact on the breeding cycle of some moths and butterflies by damaging mouthparts and killing young and their eggs (eg caterpillars). Also, vegetation covered in dust creates difficulties for plant eating invertebrate species. ▪Landscape using habitat plants which cater for species such as the Golden sun moth. Consider planting species such as Short Wallaby Grass Astrodanthonia carphoides, Bristly-Wallaby Grass A. setacea, Lobed Wallaby Grass A. auriculata and Clustered Wallaby Grass A. racemosa. With regards to pollen, food and habitat. In general landscape plantings should use indigenous species and should consider catering for invertebrates. Koala Direct impacts Mitigation methods include; The Koala is a small bear like, tree dwelling marsupial which averages around 9kg in weight. Koalas are commonly killed annually by road traffic. ▪Koalas have been reported using a number of fauna crossing structures. The Koala lives in social groups and is quite widespread over larger areas of Victoria. Their ‘home range’ consists of a number of eucalypt trees, some of which are ‘home range trees’ and others that are more ‘food trees’. Of the 600 known eucalyptus trees, only a small number are eaten by the Koala. Indirect impacts Primary impacts - Koala mortality from individuals in search of habitat, especially food trees. Barrier effect - Koalas spend large amounts of time in the trees however unlike other arboreal animals, Koalas often come down and walk along the ground. Roads and their traffic act as a ‘barrier effect’ to these movements. Habitat removal - VicRoads would also impact on the habitat of the Koala especially during times of road construction when tree removal is unavoidable. ▪Large culverts with dry poles strategically placed as high above the ground as practicable is best (Section 6.3, page 17). ▪Consider bridge underpass structures which maintain trees and natural vegetation (Section 6.1, page 15). ▪Land bridges designed with the correct landscaping including known Koala food trees would encourage these animals to cross the road at strategic locations (Section 6.2.3, page 28). Fencing - Correct fencing is required to channel the animals to cross roads and avoid animal/vehicle collision (Section 6.3, page 30). 39 Animal Background Road impact Suggested mitigation Macropods – kangaroos and wallabies Direct impact Kangaroos and wallabies are the largest groups of marsupials in Australia. Fauna crossings should cater for the size and movement of the species. Kangaroos such as the Eastern Grey Kangaroo live and travel in groups and typically graze in open scrub and grassland. Eastern Grey Kangaroo Wallabies are more solitary and tend to be found in areas with thicker understory vegetation and scrub. Kangaroos and wallabies are commonly killed by traffic on roads. Kangaroos can cause significant vehicle damage. Indirect impacts Attraction – moisture in drier areas and freshly mown grass are known to attracted macropods to roadsides. Barrier effect – macropod species have defined movement pathways. Roadkill rates are highest where roads and pathways cross. Small to medium sizedmammals (including echidna, bandicoots and wombats) Echidna Small to medium-sized mammals mainly travel along the ground and many species have adapted to varying habitats and ecological requirements. In Victoria most small mammals require areas of thick vegetation; however some animals including echidnas and wombats live or graze in areas where low level vegetation is sparse. Southern Brown Bandicoot Mitigation includes; ▪Large culvert designs no smaller than 3 metres X 3 metres (Section 6.3, page 16). ▪Bridge underpasses. ▪Land bridges should be as wide as practical (Section 6.2.3, page 28). Fragmentation – especially where roads separate grazing areas from waterways. Mortality is highest on the bends of roads. Fencing – is critical in the success of overpass and culvert structures. (Section 6.3, page 30). Direct impact Evidence suggests that small to medium-sized mammals are known to frequently use fauna crossing structures. Small to medium-sized mammals are impacted greatly by road and their traffic. Wombats and bandicoots account for a significant number of roadkill along Victorian roads. Wombat roadkill has been associated with bends in the road, presumably limiting driver visibility. Indirect impacts Fragmentation - loss of connectivity and disturbance of habitat. High rates of mortality are known to occur in areas where vegetation is found along the edge of roadsides. Barrier effect - Roads can also create ‘barrier effects’ which restrict movements across roads. Existing culverts used for other purposes (eg drainage) in some cases have become known fauna crossings. Both wombats and echidnas have been identified using such structures. Mitigation structures include; ▪Land bridge structures are very successful in encouraging crossing zones (Section 6.2.3, pages 28). ▪Culverts and tunnels should be designed with as natural a substrate as possible by using rocks, logs and branches. ▪Natural and continuous vegetation should be maintained. Fencing – is critical in the success of overpass and culvert structures (Section 6.3, page 30). 40 Fauna sensitive road design guidelines Animal Platypus Background Road impact Suggested mitigation Semi aquatic fauna Direct impacts Such as the Platypus and Native Water Rat are air breathing animals that live in fresh water. Construction activities can disturb river banks, burrows and nesting sites. Construction activities which damage aquatic habitats, impact water quality or increase turbidity and erosion into creeks are all detrimental semi-aquatic fauna The platypus has a home range up to 4 – 5 km so it is important projects do not impede animal movements during construction and after construction. In Victoria, the platypus can be found in all areas except for the north-west. While the native water rat is more wide spread. Both species have webbed feet and commonly shelter in burrows on the banks. Platypus usually cross roads via culverts and pipes however at times they have been known to leave the waterways and cross roads on foot, sometimes getting run over in the process. Incorrect culvert design – culverts that have strong water velocity, and flow strong down stream can get blocked by debris because of inadequate maintenance, impede platypus and native water rat movements. Native Water Rat Striped legless lizard Indirect impacts Reptiles (snakes and lizards). Direct impacts Are found all over Australia in a wide variety of habitats including semi-rural and suburban locations. Reptiles are commonly killed by road traffic because they often use roads to warm their bodies. All reptiles require the warmth of the sun to maintain body heat and as a result, a majority of reptiles are active during the day. In Victoria, many reptiles hibernate over winter. Indirect impacts Connectivity – can be an issue as some species avoid the roads and adjacent disturbed habitats. Others become trapped on the road by infrastructure including gutters, noise walls and other fencing. Mitigation measures include; ▪The most effective aquatic crossings are where culverts and bridge underpasses are as wide as possible. ▪Avoid culverts with a concrete base. Instead use a natural stream bed considering three sided culverts. Culvert and underpass designs for semi-aquatic animals should follow guidance under (Section 6.4, page 21-23). Reptiles can have low levels of mobility so fauna sensitive road design should: ▪Provide a natural continuous cover of vegetation, rocks and branches leading up to culvert structures. ▪Include furniture (Section 6.3, page 17). ▪Include mitigation measures for semi aquatic fauna. Measures most likely to be suitable for reptiles include land bridge structures and bridge underpasses. Fencing – fine mesh is needed at the bottom 400 – 600 mm of any fauna fencing when catering for reptiles. 41 References Abson, R. (2004). ‘The use by Vertebrates of the Slaty Creek Wildlife Underpass, Calder Freeway’, School of Geography and Environmental Studies, University of Tasmania. Abson, R., Lawrence, R. E. (2003). ‘Slaty Creek wildlife underpass study, Final Report.’ Centre for sustainable regional communities, Latrobe University, Bendigo: Kyneton. Australian Government Department of the Environment and Heritage (December 2008) Review of mitigation measures used to deal with the issues of habitat fragmentation. (Major Linear Infrastructure). Bond, A. and Jones, D. (2006) Fauna use of Underpasses and Land Bridges at Compton Road: Results for Six Months Passive Monitoring. Report for the Brisbane City Council. Suburban Wildlife Research Group, Griffith University, Brisbane. Environmental Institute of New Zealand (9th – 8th May) Symposium Handbook – Breaking the Barriers: Engineering Solutions to Ecological Problems (Environment Institute of Australia and New Zealand). Fairfull and Witheridge (2003). ‘Why do Fish Need to Cross the Road? Fish passage Requirements for waterway Crossings’. Available at dpi.nsw.gov.au Robertson et al (2002). Hamer et al 2002) Robertson, 2002. Discussion Paper – Design requirements for structures to ameliorate the potential effects on frog movements of construction and operation of the proposed Craigieburn Bypass. Wildlife Profiles Pty Ltd Report for VicRoads. Seiler, A. (2001). Ecological Effects of Roads – A review. Department of Conservation Biology, Swedish University of Agricultural Sciences. Transport and Main Roads (2010) Fauna Sensitive Road Design Manual, Vol 2. Preferred Practices. Queensland Government. Available at tmr.qld.gov.au Transport Roads and Maritime Services (2011). Wildlife Connectivity Guidelines – improving wildlife connectivity on RTS Projects. New South Wales Government. Transport Roads and Maritime Services (2011). Wildlife Connectivity Guidelines – Managing wildlife connectivity on road projects. New South Wales Government. Queensland Department of Main Roads (Qld Main Roads) (2000) Fauna Sensitive Road Design Vol 1 – Past and Existing Practices. (Queensland Department of Main Roads, Technology and Environmental Devision, Brisbane). keeping victorians connected 08.12 Authorised and published by VicRoads, 60 Denmark Street, Kew, Victoria, 3101. For further information please phone 13 11 71 or visit vicroads.vic.gov.au