Module 4: Planning Tools

This module is dealing with the tools on how to minimise habitat fragmentation due to various factors, such as transportation or land use changes. Different planning tools aimed at minimising and reducing habitat fragmentation are described.

The planning tools can be split into four main categories:

Legal, institutional and financial measures
Technical and ecological measures
Managerial and organizational measures
Monitoring measures

In the rest of the material, we will take a closer look at these categories and provide necessary context and useful examples for improved understanding of these tools.

Legal, institutional and financial measures

Under the first category belong the planning tools and measures related to the legal system, institutional arrangements and financial matters. Below are some examples from practice.

Roadless and low traffic areas by law

Compensatory measures may be required in the case of (IUELL ET AL, 2003):

I. a) International legislation: the EU Birds Directive (1979) and the EU Habitats Directive (1992).

b) National legislation on compensation.

Underlying principles when compensation is required by international or national legislation:

Species and habitats protected under (inter)national regulations require stringent constraints within the planning process and it is usually difficult to justify the social necessity for developments in protected areas, or areas with protected species.
Financial compensation or compensation in terms of other values than the impacted ones (trading-off) should not be permitted.
Ecological compensation must address physical and functional aspects of the impact.
According to the Birds and Habitats Directives compensatory measures should be implemented before the start of the infrastructure development.

II. Formal compensation policy: non-legislative regulation, e.g. laid down in national policy plans.

Where compensation is linked to formal national policy usually less stringent measures are required:

Economic or social necessity may, in exceptional cases, justify project development, under the condition that ecological damage is compensated for.
Compensation in terms of 'comparable' ecological values as well as financial compensation are both permitted, though less preferable.
Compensatory measures do not necessarily have to be implemented before the project starts.

III. Compensation based on voluntary agreements, implying that it has neither a legislative nor a policy basis.

Non-legislative policy requires less stringent conditions on the implementation of the compensation principle. In the assessment process, socio-economic and nature conservation interests are weighed against each other.

Codification of the rules by legal documents (e.g. land use plans, the concept of ecological compensation, legal obligations, special taxes, allowances...)

Ensuring sufficient ability to pass the transportation network is from the point of view of achieving migrating capacity only one step. In the country of central European type with dense settlement structure there exist a number of other barriers in form of built-up areas, intensive agricultural areas etc. Areas of species dispersion are therefore in form of small islands and populations are mutually separated by landscape which as a whole is not fitting for permanent existence. Possibilities to connect these populations are still diminishing and gradually are turning into small corridors. Slovak and Czech legal system ensures protection of these corridors in form of supra-regional, regional and local network of territorial system of ecological stability (HLAVÁČ & ANDĚL, 2001).

When managing the ability to pass across the highways it is important to include wider territorial relations of the surrounding landscape such as territorial studies, plans, projects and territorial systems of ecological stability. These documents are connected to spatial planning guarantees protection of the elements of the territorial systems of ecological stability even in the future. It is crucial to include the knowledge of dispersion of species, their migration requirements, wider territorial migration context and concrete terrain configuration in the place of construction (HLAVÁČ & ANDĚL, 2001).

Significant problem with spatial planning is the issue of future use of plots in the surrounding of constructed passings. In practice it can occur that in the future the constructions which are limiting or directly disturbing the functionality of constructed passings are permitted. Such constructions are causing on the one hand non-passability of the line barrier and, on the other hand, also are causing losing the purpose of previously invested money for building a passing (HLAVÁČ & ANDĚL, 2001).

The connection between ensuring the ability to pass the highways and the territorial systems of ecological stability and spatial planning can be summarized in the following principles:

The ability to pass the line barriers needs to be dealt with in wider territorial context taking into account the status of the landscape, extension and migration of species
One of the essential background documents when dealing with ability to pass are the elaborated territorial systems of ecological stability on all levels
Ability to pass of the highways for freely living species cannot be limited to crossing of elements of territorial systems of ecological stability
When designing the passings it is important to also deal with the issue of surrounding plots which are conditioning the functionality of the passing. Ensuring protection of these plots can take place with a number of measures (agreement/contract with owner, announcing it as an element of territorial system of ecological stability, regulation of huntsmanship, building ban etc.). Ensuring protection of these plots cannot be just requested from the investor, but the initiative should be taken by relevant nature protection body.

Technical and ecological measures

The largest category includes a variety of technical measures and tools implemented in the countryside and urban areas to mitigate the negative effects of land use change and transportation. The list of these measures is extensive, so we provide just a short overview. For more detailed list and concrete specifications, you can find information in the list of recommended readings.

Fauna Passages and other Technical Solution

Fauna passages and other structures adapted to increase the crossing of transport infrastructure by animals should never be considered in isolation. They should be part of a general 'permeability concept' to maintain connectivity within and between populations of animals. This concept emphasizes connectivity between habitats at least at a regional scale and considers not only the transport infrastructure but also the distribution of habitats and other potential barriers such as built-up areas. Fauna passages can then be regarded as small but important elements used to connect habitats by enhancing the movements of animals across transport infrastructure (IUELL ET AL, 2003).

At a more specific level, a permeability concept can be produced for a particular road or railway project. All connecting elements, such as tunnels, viaducts or elevated roads, stream and river crossings, culverts, and passages designed specially for animals should be integrated into the permeability concept. Again, the primary objective must be to maintain the permeability of the transport infrastructure for wildlife to ensure the connectivity of the habitats at a larger scale (IUELL ET AL, 2003).

Mitigation measures, in particular fauna passages, are necessary if transport infrastructure bisects important patches of habitat, creates a barrier to migration routes and if avoidance by altering the route is impossible. Fauna passages are necessary for animals where (IUELL ET AL, 2003):

A road or railway line results in significant damage or loss of special habitats, communities or species.
A road or railway line affects species particularly sensitive to barriers and traffic mortality.
The general permeability of the landscape, i.e. the connectivity between habitats in the wider countryside, is significantly impaired by the infrastructure development.
Fauna passages are considered to be a suitable solution for mitigating the barrier effect in the specific context.
Other less costly measures are unlikely to be effective.
The road or railway line is fenced along its length.

Tunnels

A tunnel may be the best design solution to protect high-value landscapes. Though construction costs may be high the benefits to the natural environment will be incalculable (see Chapter 6). The scale of these benefits is dependent upon the method of tunnel construction. Bored tunnels allow sites of high nature conservation value to remain undisturbed and are least damaging environmentally. Cut-and-cover tunnels may be more appropriate for sites of lower conservation interest, but where the maintenance of connectivity between habitats is desirable. Methods of habitat restoration can be employed to provide safe crossing for a range of wildlife (IUELL ET AL, 2003).

Siting of the tunnel portals, their landscape treatment, the alignment of the approach road and the design and siting of any ventilation shafts and control buildings are the major environmental design issues for any tunnels. They may intrude into habitats and cause disturbance and pollution locally for sensitive species (IUELL ET AL, 2003).

A cut-and-cover treatment may be a desirable alternative to the open cutting as it permits the landscape to be restored over the line of the infrastructure. The landscape elements appropriate to the particular location should be carefully designed to be carried over the engineering structure, which must be capable if necessary of supporting large forest tree species. The reuse of the original soils should be considered if they can be stripped and stored in such a way as to minimise compaction and loss of structure (IUELL ET AL, 2003).

The soil profile should be constructed to match the adjoining profile in order to reproduce the hydrological characteristics as well as the physical structure and chemical properties of the original substrates. Where the cut-and-cover tunnel is to be used by a range of fauna, the natural vegetation type for the species' habitat should be planted over the tunnel and on the approaches (IUELL ET AL, 2003).

Use of vegetation

At the design stage it is important to understand the type of vegetation and species composition that is appropriate to the setting of the new transport infrastructure. Integration with the landscape, nature conservation benefit and passenger interest are key considerations. Where possible, species included in planting designs should be locally indigenous (especially in rural areas) and occur naturally on the soil type adjacent to the route. They should not require irrigation for successful establishment. Where suitable, natural regeneration should also be considered as an alternative method for vegetating new landscapes. Allowing vegetation to regenerate naturally will produce a habitat most suited to the local surroundings. Some Mediterranean regions have special legislation to regulate the use of vegetation on verges. The high number of forest fires that begin beside roads has obliged highway authorities for example Catalonia in northeastern Spain, to forbid the use of pyrophytic plants such as rock roses on road verges. In the same region there is a requirement to prevent continuity of canopies between trees and shrubs on the verges and the forest trees on adjacent land (IUELL ET AL, 2003).

Cuttings and embankments

Embankments are suited more to wide, shallow valleys as they (IUELL ET AL, 2003):

Can maintain some degree of connectivity through the use of appropriately sited and dimensioned culverts and underpasses. In other situations, lower alignment may allow the construction of an overpass.
Can be integrated with the adjacent landform by good use of earthworks and planting; and
Offer more scope for screen planting.

Where lateral views of the infrastructure are intrusive, a cutting is one of the best means of hiding it. However, cuttings may themselves become intrusive, fragmenting habitats, creating a notch in the skyline or taking the edge of one side of a hill leaving an ugly scar. A curved alignment over high ground and the careful siting of bridges can help reduce the impacts of a cutting on the skyline. Bridges can be adapted to provide a green connection for fauna and flora (IUELL ET AL, 2003).

Cuttings are usually constructed to a uniform gradient of 1:2 and contrast with natural gradients which are more varied and irregular. Good design can provide better integration with natural landforms and provide opportunities for a variety of habitats to be created (IUELL ET AL, 2003).

Different rock types give rise to different natural slopes and cuttings should reflect these where possible.
Minor cutting faces especially in upland areas can produce rock exposures with potential nature conservation value.
It is desirable to reveal the natural bedding plane of the rock to provide a stable slope that will not require for reasons of safety the use of catch fences, wire mesh or other unnatural engineering elements.
In areas of woodland and rough pasture, an irregular cutting surface finish will provide better integration with the adjacent areas. They can provide niche habitats for certain plants and invertebrates.
There are benefits in rounding off the tops of cuttings to a gentle profile to create a smooth transition to the natural landform.

Crossing valleys

Infrastructure can be carried across valleys on embankments or viaducts. Viaducts have environmental advantages subject to the choice of the appropriate crossing point.

Viaducts are suited to narrow, steep-sided valleys as they (IUELL ET AL, 2003):

Minimise landtake and fragmentation within a valley by allowing watercourses and any existing nature conservation interest to continue under the structure;
Maintain connectivity for species movement; and
Retain views up and down the valley.

Fencing

The main reason for fencing along the highway is to limit the contact between automobiles and species crossing the highway. It is obvious that the ideal solution would be sufficient number of passages of all categories together with full fencing of all segments between these objects. Practical experience, though, demonstrate difficult implementation of these theoretical findings. Firstly, it is important to stress that fencing in order to fulfil its function must be kept in functional state which turns out to be a difficult requirement. Whenever the integrity of fencing is destroyed, species can get into the fenced area and act confused, attempts to flee, hits the fencing and eventually up on the road hit by passing vehicles. The same issue is with wrongly finished fencing where species are also frequently entering the fenced area (HLAVÁČ & ANDĚL, 2001).

Proper positioning of fencing is of crucial importance, too. From the point of view of limiting the entrance of species into highway space the fencing should be constructed between maintained grass stripe along the road and the beginning of line of trees or bushes. Positioning the fence to the edge of the hillside with surrounding vegetation (often several tens of meters from the edge of the highway) is inappropriate. In these places the fencing is very often damaged by boar species, agriculture machines or humans. Locating fencing in the proximity of the highway behind the maintained stripe of grass allows the panicking species, e.g. during agricultural activities, to stop at the vegetation stripe in front of fencing, evaluate the situation, calm down and leave the highway space. In case the fencing is located inside the vegetation stripe, the panicking species from the fields are often looking for shelter created by surrounding highway vegetation and attempts to get into the fenced area. In case of boar species such an attempt is oftentimes successful (HLAVÁČ & ANDĚL, 2001).

Noise and glass walls

Noise barriers are constructed close to human settlements to reduce noise emissions, although in certain situations they are erected to protect, for example, colonies of breeding birds from disturbance. However, even if not constructed for wildlife they have to be mentioned because they can increase habitat fragmentation even more than fences. In densely built-up areas noise barriers do not usually provide any problems in this respect. In more natural surroundings they are complete barriers for all terrestrial animals (IUELL ET AL, 2003).

Noise barriers built of concrete, wood or other material are complete barriers for animals. In natural environments they must therefore be combined with fauna passages. This has to be considered also in cases of low noise screens along railway lines, which may hinder the movement of small vertebrates like snakes, which without barriers would not have been greatly affected by the railway line. In combination with passages noise screens can function as guiding structures. Noise screens are usually built on a solid concrete base. They thus completely isolate the road verges from the surrounding habitats. For small animals, especially invertebrates, they are therefore a more complete barrier than fences. No experience exists as to the effects on the animal populations or regarding possible solutions to reduce the barrier effects, such as small openings at the base of the structures (IUELL ET AL, 2003).

Transparent screens are erected in areas where planners wish the drivers or passengers to be able to see the surrounding landscape. They entail a high risk of mostly fatal collisions for birds, which don't recognise the wall as an obstacle, in particular where natural vegetation can be seen through the glass or where the glass reflects bushes or trees. It has been shown that with appropriate markings the number of collisions can be reduced substantially (IUELL ET AL, 2003).

Managerial and organizational measures

The barrier effect of roads for small animals is partly an effect of the width of the tarmacked surface. The number of vehicles and their speed, however, also affect the number of animals killed. Different types of measures can be beneficial for wildlife (IUELL ET AL, 2003):

Reducing the width of the infrastructure

Agricultural and forestry roads which are not tarmacked are more easily crossed by small animals, e.g. invertebrates.
On agricultural roads an alternative to a fully tarmacked road is the provision of two concrete tractor-strips. The area between the strips is kept vegetated, thus providing cover for invertebrates.

Reducing the amount of traffic

Temporary closure of roads is a suitable measure in cases where animals only cross a road during a limited period. It is recommended, for example, to protect amphibians on their migration to spawning grounds (closure during humid nights in spring) or to allow wild reindeer to move to their wintering grounds undisturbed (closure of a road during critical periods in winter).
Any other common measure to reduce the amount of traffic (one-way streets, restricted access, etc.) can also be used as a measure to reduce collisions with wildlife.

Reducing the speed of the vehicles

Reducing the width of the road can reduce the speed of the vehicles and thus reduce the risk of collisions with mammals. This measure is suitable for rural roads with relatively light traffic.
Temporarily or permanently lowered speed limits at high-risk spots can contribute to reducing the risk of collisions with mammals.
Where collisions happen mainly during the night, speed limits at night might be sufficient.
Speed ramps are recommended on roads with light traffic.

Monitoring measures

After the construction of roads, railways and waterways the application of monitoring is of crucial importance as it is this mechanism that allows planners to check the effectiveness of measures which have been applied in order to reduce the infrastructure's impact on habitat fragmentation. A well-designed monitoring scheme will help to achieve several goals (IUELL ET AL, 2003):

To detect failures in the installation, construction or maintenance of measures.
To establish if the mitigation measures fulfil their purpose.
To evaluate if the measures provide long term mitigation for the species and habitats.

In short, monitoring will contribute to establishing whether or not suitable and sufficient mitigation measures have been provided for during the planning and construction phases of a transport infrastructure, guaranteeing minimum impact on the fragmentation of animal populations and habitats (IUELL ET AL, 2003).

The dissemination of the results of the monitoring scheme is also very important for gaining knowledge on the development of more effective and less expensive measures. Therefore, important objectives of monitoring include helping the infrastructure planners to (IUELL ET AL, 2003):

Avoid repeating mistakes.
Provide new information for improving the design of mitigation measures.
Identify the measures with an optimum relationship between cost and benefit.
Save money for future projects.

Monitoring schemes should be an integral part of the routine technical management that leads to the adaptation and improvement of the design of measures which avoid or reduce the effects of transport infrastructure on habitat fragmentation (IUELL ET AL, 2003).

All mitigation measures have to be routinely inspected and maintained to ensure their long-term functionality. Maintenance considerations, including cost, have to be considered at the earliest possible stage, i.e. when a measure is designed. Planning should define the type and frequency of maintenance procedures and the organisation of and responsibility for maintenance. In most cases maintenance will be carried out by road maintenance teams, but giving a mandate to nature conservation organisations and farmers, etc., has proven to be a good alternative for certain types of measures. Specific maintenance aspects are dealt with in the sections on the different measures (IUELL ET AL, 2003).

The maintenance and monitoring of measures are closely linked. Monitoring procedures are mainly designed to check whether a measure fulfils its purpose, but at the same time they can identify maintenance deficits and needs. Monitoring requires clear definition of the objectives of the measures, and programmes should be planned in parallel with the design of the measures themselves (IUELL ET AL, 2003).