Overview
Embankments along traffic corridors provide important replacement habitats in the intensive use of landscapes anywhere. They also have a very important networking potential. The importance of this networking corridor is particularly large in the densely populated mitelland, especially for endangered species of reptiles such as the sand lizard and the smooth snake. By noise abatement transport infrastructures and increasingly road embankments are shaded and cut by noise barriers. There are great concerns that the construction of noise barriers in some locations endangers the native reptiles, since the buildings represent insurmountable obstacles and shade the habitat of the heat-needy animals. For this reason, certain precautions are taken, such as the installation of culverts reptiles in noise barriers or the installation of additional small structures in the construction of noise barriers in sensitive areas. However, hardly has been studied, how serious the impact of noise barriers have actually been and whether these accompanying protective measures unfold as planned. This research is intended to provide answers to these key questions. Using collared reptiles we want to find out how the animals use the habitat, exactly what changes if noise barriers are built, and if the artificial small structures and crossing aids are to be used by the animals. The results of the study are to be included in noise abatement and green space norms of the VSS. In this way it is ensured that the essential requirements of protection reptiles are easily accessible and widely used. Eventually bad planning can be avoided and reptiles are successfully protected.
The impact of the construction of noise barriers on reptile populations is to be studied and the success of implemented mitigation measures is examined. The study should answer the following questions:
1) How are road/rail verges used by reptiles? Is the spatial use pattern modified by new noise barriers?
2) Are new small habitat structures used by reptiles? Are they successful in mitigation of impacts?
3) Are reptile passages through noise barriers used?
The results of the study should give the basis for recommendations for effective mitigation measures, which can be integrated in the VSS Standards (noise and green areas). It should also confirm methodology for the study of reptile populations and spatial use.
This research project is part of the norm strategy of the VSS and BAFU, permitting an integration of environmental aspects in standardization of infrastructure.
M 1: experimental design, methodology development
In a first step, suitable locations and types are to be selected and evaluated for the study. For a thorough assessment of the impact of noise barriers on reptiles stocks before-after studies are ideal. This requires locations with reptiles occurrence, where the construction of noise barriers is foreseeable. Alternatively, or in addition to locations can be examined along existing noise barriers and compared with those without buildings. For this comparison, it is important to control other factors such as type of embankment (Dam vs. incision) or exposure (position of the slope).
As a model type - representative of various other species that climb poorly, and therefore noise barriers cannot overcome - is the sand lizard, which is at Thoroughfare embankments still relatively common. If possible / useful, additional species may be included.
The above criteria require a careful analysis of existing inventories of reptiles occurrence (Karch) and noise protection projects, as a prerequisite for meaningful field studies. The study will consider embankment sites of railway lines and roads. Here, the cross-linking will be investigated. For this reason, it is envisaged that a substantial proportion of investigative bodies located along railway lines, because of intense traffic roads are hardly examinable.
M 2: First field season; Test the methodology
Finally, a recent survey of reptiles stocks, possibly verify their suitability for the main study using artificial hiding places and tracking. In this phase already generating initial measurements carried out on the use of space, the measurement methodology (see below) will be tested and improved.
M 3: Second field season; Intensive measurement campaign, data analysis
There are different ways to study the habitat use of sand lizards. The traditional method of catching, Mark Release Recapture of animals is very labor intensive. If we do not succeed, just a few statements about the use of space can be gained. The modern methods of radio telemetry or the harmonic radar promise much more information about the profit space utilization. The radio telemetry or location using harmonic radar is the more appropriate method. A combination of both methods could be useful.
The animals are periodically telemetered throughout the period of activity during the summer months. Particular attention should be paid to the prospect of winter quarters, since also special winter
Funding
Results
In the Swiss Plateau many of the structurally diverse habitats originally populated by reptiles have been destroyed, as a result of the increased cultivation of our landscape. This has led to a large decline in reptile populations. However, reptiles have been able to colonize anthropogenic altered habitats, so called, "secondary habitats". Nowadays, half of all reptilian populations inhabiting the Swiss plateau live on transport verges. Transports of goods and people cause high traffic loads on Swiss roads and railway systems. In order to protect residents from increasing noise pollution, more and more noise barriers (LSWs) along transport verges are built, putting increased pressure on reptiles living in these secondary habitats.
In this study was examined the impact of the construction of noise barriers (LSWs) on populations of the sand lizard (Lacerta agilis), focusing on the two overarching factors that determine the long-term persistance of populations: connectivity and population size. Today certain management measures are being applied to counteract potential negative consequences of noise barriers on reptile populations. It was tested, in which ways these measures are able to compensate for negative effects of LSWs. Fieldwork was carried out on verges of roads and railway.
Translocation-experiments with sand lizards showed that even a multi-lane, high-traffic railway line is no obstacle for sand lizards crossing. An LSW, however, cannot be overcome by reptiles such as sand lizards and snakes. Therefore the LSW constitutes an obstacle to dispersal, preventing the transversal exchange of individuals between the two sides of railroad lines. On high traffic roads, however, LSWs could even have a protective function as the prevention of crossings may reduce road mortality.
On some railroad tracks gabions have been integrated into LSWs in order to make LSWs permeable for reptiles and other small species. A Gabion is a mesh wire basket filled with rocks. The cavities between the stones should offer reptiles the possibility to traverse the stone basket. Yet, the permeability of such stone baskets has not been investigated. By conducting translocation-experiments we showed, that sand lizards actually find a way through gabions and thus are able to cross an LSW.
The ease with which a reptile managed to cross the gabion depended on its configuration and the type of installation. Transversal crossing-frequency of such LSW-gabions might be identified by the use of population gen