Bat Overpasses Help Bats to Cross Roads Safely by Increasing Their Flight Height

Abstract

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Identification of the Key Determinants of Bats’ Altitude Increase over the S3 Expressway in Poland with Mesh Screens Applied

“…Their graphic interpretation is given in Figure 7. The patterns of the presented characteristic movement trajectories agree in general with the results of other surveys conducted at transverse obstacles, e.g., steel structures [21,32] or spherical structures [36,37]. As regards Case V shown in Figure 7, the authors of the report [60] proposed a hypothesis that such behaviour can be linked mainly to the presence of the mesh screen installed on the timber barrier, as the openwork screens absorb heat during the day to give it off during the night, thus attracting insects that are an easy prey for small bats of the Myotis and Pipistrellus species.…”

“…Additionally, this condition of extending the supplementary vegetation guiding bats up to the screen was given special attention by the authors of the article when identifying the determinants of the effectiveness of the mesh screens under analysis. In line with the conclusions of the publications [10,19,[36][37][38], the height of the new trees or hedges and the continuity of the type of guiding features are also important, as different bat species have their commuting routes at specific altitudes. Based on the bat species determined in Additionally, this condition of extending the supplementary vegetation guiding bats up to the screen was given special attention by the authors of the article when identifying the determinants of the effectiveness of the mesh screens under analysis.…”

“…Taking into account the recommendations of the design guidelines [10][11][12][13][14][15][16][17][18][19][20] and the conclusions from the completed research studies [21,22,29,30,36,37,54,56] on the measures to ensure the continuity of linear landscape features along bat commuting and migration routes and on providing natural features to funnel the bats through the areas with severed flight lines, the authors of this article formulated a hypothesis on the importance of the above-mentioned factors, which are probably related to bat mortality.…”

“…For instance, it was assumed that the likely bat commuting routes existing until the start of construction, at places where they crossed the S3 expressway, would be analysed. In accordance with the recommendations given in the guidelines [11,17,18] and the conclusions set out in the publications [10,[19][20][21][22][36][37][38]43,44] on completion of the road construction work, when analysing the determinants, particular attention would be paid in particular to retaining the continuity of linear landscape features used by bats for navigation. In accordance with the recommendations of the guidelines [11,[17][18][19][20], new trees or hedges should be planted along the bat commuting route to provide a natural funnel channelling bat movements and extended directly to the edge of the expressway, and where appropriate, of the screen.…”

“…In many countries, various structures built over roads were tried, whose direct purpose was to extend the severed bat commuting routes. These include support structures constructed in England [21], timber structures built in the Netherlands [11], spherical structures installed in France [36,37] or natural features using plantings, called "hop-overs", installed in the Netherlands [11], gantry structures installed in Poland [38], corrugated plate tunnels installed in Germany [39], mesh tunnels hung on trees in England [40] and many other structures [11][12][13]. Their main purpose is to extend or supplement severed linear landscape features that guide bats to the old migration routes.…”