Objectives

To identify the stretches of the transport infrastructure where most animals are run over or where traffic security must be improved.

Description

Checking how many casualties of different species occur on the road or railway per unit length once the transport infrastructure is operational.

Procedure

Follow the road under study in a slow-moving vehicle (15 km/h) or walk along the railway line. This should be done very early in the morning before scavengers such as magpies can remove the remains of animals that have been killed. For each animal that has been run over the species should be identified and the variables listed below recorded. The periodicity of sampling varies depending on the target species but in general monitoring of various taxonomic groups should be repeated at least every 10 to 15 days during main periods of animal movement, which include periods of dispersal of young individuals, migration periods and the hunting season.

Variables to be recorded

Date and the time the survey starts and ends. For each casualty it is necessary to identify the species or taxonomic group, kilometric point of the road or railway where it was found, its exact location on the carriageway/railway, state of decay and any other observation (sex, age, etc.). Registering other variables such as road section, landscape characteristics or presence/absence and state of fences can help to analyse the factors which contribute to increases in road casualties.

Standards

It is very difficult to achieve the goal of zero casualties. For this reason the recommended standard variable is the maximum number of animals of each species (or taxonomic group) per kilometre that is permissible for a certain population size. If casualties are above this number then corrective measures should be applied.

Observations and possible variations

Monitoring can also focus on identifying black spots where target species are run over. This method can be applied for example to determine black spots for amphibian, lynx, wolf, otter or badger casualties and to identify the places where their migratory routes cross transport infrastructure. Extensive monitoring of a large length of transport infrastructure is often necessary and it is recommended to involve volunteers and/or people responsible for maintenance to provide data about the location of dead animals or crossing points. A co-ordination centre should compile the information and check all the blacks spots to determine the corrective measures that can be applied in each case.

Examining dead animals on a stretch of road with heavy traffic is a dangerous activity. For these reasons the security of workers who carry out these activities must be taken into account.

Objectives

To identify the ratio of animals that live in the vicinity of the infrastructure and successfully cross it. This can also be used both to determine the proportion of animals which cross using fauna passages, culverts or other structures and the proportion crossing directly over the road or railway.

Description

Counting the number of animal tracks registered near the infrastructure and determining the number of animals that cross it and the number of animals that refuse to cross.

Procedure

This method is particularly recommended in regions where there is often snow cover. In the winter when snow covers the ground, the length of the infrastructure should be walked at a distance of approximately 20 m from the road or railway and the length of the transect line should be measured. The tracks of different species, the number of animals walking alongside the infrastructure, the number of animals that refuse to cross it and return to their original habitats and the number of animals that succeed in crossing the infrastructure should be determined. Both sides of the road should be inspected. The distance of the transect line from the road should be adapted to the home range of the target species.

The operation should be repeated at least every 10 to 15 days during periods of maximum animal movement when there is snow cover present. Main periods of animal movement include periods of dispersal of young individuals, migration periods and the hunting season.

Variables to be recorded

The date and time the survey starts and ends. For each track it is necessary to identify the species and the behaviour of the animal in relation to the infrastructure.

Standards

The ratio of individuals successfully crossing or failing to cross the infrastructure to the total population of each species.

Observations and possible variations

Determining the age class of the individuals by means of the length of the footprint can provide information about differences in the behaviour of resident adults and young animals in the dispersal phase. In countries where it is not possible to record tracks in the snow this method can be adapted by constructing strips of a suitable surface such as sand. This is more intensive as it is necessary to remove the existing vegetation and build a strip at least 50-100 cm wide alongside the infrastructure (depending on the target species).

Objectives

To evaluate the use of culverts, fauna passages and other structures as crossing points by different species of vertebrates.

Description

This method consists of detecting the crossing of animals by recording the footprints they leave in suitable natural surfaces (sand or loose clay), or strips of artificial surfaces, such as marble dust, which are located on the structure to be studied.

Procedure

The middle section of the fauna passage should be covered across its entire width with a thin layer of sand or marble dust (ideally dust with a particle diameter of 800 µm). The strip should be wide enough to stop animals jumping over it easily. For culverts a strip of 1 m is wide enough but on larger overpasses a width of at least 2 m it is recommended. As an alternative method, two strips can be installed, one near each entrance, which allows the comparison of footprints registered at each entrance to see if animals successfully use the passage. The strip of sand or marble dust should be checked every day and the tracks recorded. After recording the tracks, the sand should be smoothed with a brush and more sand added if necessary. Monitoring should be repeated for 10 to 15 days during the main periods of animal movement, which include dispersal periods of young individuals, migration periods and the hunting season.

Variables to be recorded

Date and the time the survey starts and ends, weather, structure identification number, location, species identified, direction of tracks. Registering details of the infrastructure (dimensions, materials, surface, vegetation at the entrances, existence of pits, steeped canals, etc.) helps to determine the reasons for failure and the requirements of different species.

Standards

The evaluation often focuses on determining if footprints of target species are present or absent inside the fauna passage, indicating if the structure is used or not used by each target species.

The frequency of use (the number of days with a positive result as a proportion of the number of survey days) can also be used as a standard measurement.

Observations and possible variations

Marble dust absorbs water very easily which limits the application of the method to dry conditions. When the surface of the structure is damp, the floor of the structure should be covered with a film of plastic before sprinkling with marble dust. The measurement of footprint length can provide additional information on the number of different individuals using the fauna passages. When marble dust is used all the material must be removed after the monitoring period because of the problems it can pose to the movements of small animals, such as snails, which need to avoid desiccation.

Objectives

To evaluate different species' use of walkways (catwalks) located in fauna passages, modified culverts or other passages.

Description

The detection of animals by recording the footprints they leave on a sheet of paper after passing over an ink bed.

Procedure

In the middle section of the passage (no longer than 100 cm) a mix of liquid paraffin with carbon powder is spread on a sheet of plasticised paper with a small folded vertical edge. On either side of the ink container sheets of paper are fixed. The recommended length of the ink container is 50 cm and the length of each paper sheet is 100 cm. The ink container and papers must cover the whole width of the passageway. Footprints are imprinted on the paper sheets after the animals have passed over the ink container. The paper should be replaced periodically (for example every week) and the tracks can be analysed back in the office.

Variables to be recorded

The date and the time the survey starts and ends, weather, structure identification number, location, species identified, direction of the tracks. Recording details of the infrastructure (dimensions, materials, surface, vegetation at the entrances, existence of pits, stepped channels, etc.) helps to determine the reasons for failure and the requirements of different species.

Standards

The presence of footprints of target species inside the fauna passage allows the use by each target species to be determined. The frequency of use (the number of days with a positive result as a proportion of the number of survey days) can also be used as a standard measurement.

Observations and possible variations

This method facilitates the measurement of footprint length and allows information on the use by different individuals of the same species to be obtained.

Objectives

To detect the use of culverts, fauna passages and other measures by different species of vertebrates and to identify the behaviour of the animals using the structures.

Description

This method consists of filming with infra-red light at night time using photographic systems activated by a light or pressure sensor to provide images of the species which cross the structure. The equipment is set up at the entrance of the structure. Some devices are provided with long life batteries and may be left for long periods. This has the advantage of reducing the effects of human presence on crossing rates where sensitive species are concerned.

Procedure

The video camera and infra-red light should be installed where it will not block the entrance. Alternatively a photoelectric cell can be installed so that the beam crosses the width of the structure and a camera can be placed at the middle or entrance of the structure. The camera is activated when the animal breaks the beam. The beam should be at the correct height so that any animal which crosses the structure will break it. Cameras should be hidden by plants or other elements found in the surrounding area (stones, piles of logs) or with elements which help to mask the scent of humans, which mammals would probably be aware of even if cameras are hidden. Equipment may also need to be protected by boxes against bad weather. Systems should be operational at least for 10 to 15 days during the main periods of animal movement, which include dispersal periods of young individuals, migration periods and the hunting season.

Variables to be recorded

Date and time the cameras were set up and dismantled, weather, structure identification number, location, species identified, its time of using the structure. This information is obtained when the video has been watched or the photographs developed.

Standards

The main standard measurement should be whether or not the animal has used the measure. The frequency of use (the number of days with a positive result as a proportion of the number of survey days) can also be used as a standard measurement.

Observations and possible variations

One of the main advantages of using video cameras is that the behaviour of animals can be analysed. The theft of equipment is a major problem when fauna passages are also used by humans.

Infra-red detectors

Standard infra-red detectors, also called trail traffic counters, can be used to determine the number of animals using the passage. The movement of an animal activates the counter and records the total number of animals that have used the structure during a set period. The detectors are fixed to the walls of fauna passages or culverts and some of them can be modified to record the movement of small animals and to register the date and time of movements. The disadvantage of this method is that the species is not recorded so that the information provided is of limited value.

Hair registering

Pieces of wood are smeared with gum and fixed to each side or to the roof of the culvert. The hair of the animals using the structure sticks to the gum and can be analysed by specialists to determine which species are using the passage. This method is limited to small culverts and only provides information about mammals. Nevertheless it can for example be useful when the target species is a badger or otter

Examining the recordings of security or traffic control video cameras

Some overpasses, tunnels or waterways have CCTV cameras to monitor traffic and security. Recordings often contain images of animals that cross the causeway or are in the vicinity of the transport infrastructure. This information can be used to detect inappropriate use of fauna passages, the failure of fences or other information related to animal behaviour with respect to transport infrastructure.

Tracking movements with the aid of fluorescent ink

Fluorescent ink can be placed in a small container at the entrance or in the vicinity of a fauna passage. Animals that pass through the container leave fluorescent footprints that are visible at night with a special lamp. This method is especially useful for following the movements of small mammals and has the advantages of low cost and simplicity. Nevertheless this method has not been used very much and it has never been used with big mammals so the scope of its application is not well known.

Capture-recapture data

This method has been used with animals with high population densities which are easy to capture such as small mammals. Traps (Shermann traps or similar) are located on embankments and cuttings on either side of the transport infrastructure. The captured animals are marked and released and successive re-capture of these animals allows analysis of whether their movements are restricted to one side of the road or railway or if their home range includes both sides of the infrastructure. Long trapping periods are needed to obtain enough information and this method does not allow the identification of the location of crossing point.

Telemetry
Marking animals with transmitters can provide much more information than capturerecapture data about the behaviour of the animals in relation to the transport infrastructure. Transmitters can be fixed to collars, adhered to hair, inserted under the skin or fixed to the peritoneum of the animals. The receiver provides information about the movement of the animals, their home range and the location of infrastructure crossing points. This method is only recommended when endangered species are involved because it requires a large investment of time and money both to capture the animals and to monitor their movements.