Zur Dimension von Amphibiendurchlässen und zur Anlage von Ersatzlebensräumen - Empfehlungen für eine verbesserte Praxis

Despite a long tradition in the construction of amphibian tunnels, there is insufficient quantita- tive information available for such structures longer than approximately 20 to 25 meters. Even the sustainable usability of short culverts is doubtful, so far as those with small opening widths are concerned. Additionally, due to inadequate maintenance, the effectiveness of amphibian tunnels, measured against the avoidance requirement, is in some cases severely limited in the medium term. Based on a literature review, consultations, and empirical values, this article provides information and recommendations for dimensions of amphibian tunnels/underpasses in the context of target values for minimum crossing rates for amphibian individuals. The priority for sufficient avoidance and mitigation is always the creation or optimization of functional compensation habitats on both sides of the road in conjunction with barriers and individual, large-volume underpasses (every 500 meters to the main migration direction). For cases in which this is not or not completely possible, recommendations are given for culvert dimensions (height and width) depending on their length. A reform of prior “standards” and practice is necessary.