Psaralexi, M., Lyberopoulos, G., Theodoropoulou, E., Tsaknakis, Y., Tragos, A., Lazaros, Y., Voumvoulaki, N., Rosell, C., Torrellas, M., Psaroudas, S. y Mertzanis, Y. Mapping and monitoring large mammal underpasses on motorway A29. 2020 IENE International Conference. Abstract book. Évora: Infrastructure & Ecology Network Europe. 2021, Vol. 4.3.2, Num. 4, pags. 101-102. ISSN 978-972-778-182-9
In Greece, the brown bear (Ursus arctos) is a priority species listed in Annex II and IV of the EU Habitats Directive (92/43/EEC) and thus, it is implied that Member States should avoid the deterioration and disturbance of bear habitats. However, motorway A29 cuts through brown bear habitat in northwestern Greece and acts as a barrier which restricts gene flow, isolates populations and ultimately, reduces overall landscape connectivity. Within 5 years of operation, more than 20 bear-vehicle collisions occured on A29, until a bear-proof fence was installed in 2014 to prevent animals from reaching the roadway. This resulted in the drastic reduction in bear-vehicle collisions with only one incident ever since. Nonetheless, this bear-proof fence also increased the barrier effect and thus, the need for evaluation of the motorway’s permeability is undeniable. In the framework of the LIFE SAFECROSSING project (LIFE17NAT/IT/464), we performed field inspections along the motorway and identified potential passages for brown bears and other large mammals. We recorded all crossing structures, inspected and registered their condition and relevant features (i.e. size, surrounding landscape, evidence of use by smaller or larger mammals). We also identified barriers to animal movement, and places where there is access to the road surface due to problematic fence-ends or human tampering with the fence. Following, we selected 45 structures to be monitored (spring/summer 2019-spring 2020) via solar-panel/battery powered cellular (4G) cameras. The monitoring system is supported by a back-end infrastructure capable of passages visualization on map, along with associated info, automated camera snapshots/videos storage, snapshots depiction per passage, statistics per passage, etc. via a user-friendly graphical environment. The monitoring system was installed on underpasses along the 55km segment and underpass selection criteria were primarily evidence of use by large mammals and even distribution throughout the motorway, and secondarily, theft/vandalism risk and network reception We found that along this motorway there are ca. 140 underpasses of variant size and the calculated Openness Index ranges from values close to 0 (culverts with a 2x2m entrance and length >100m) to 175, which is the maximum value calculated at a viaduct (height: 35m, width: 125m, length: 25m). The first pilot camera was installed in March and the rest 44 in July (2019). Five cameras have been installed at underpasses with no reception and are manually checked periodically. Today, only after a couple of months, we have already collected thousands of pictures and accompanying videos, which attest the use of underpasses by both humans and large mammals. Recorded wildlife species which use the underpasses to cross the motorway, include brown bears, wolves (Canis lupus), wild boars (Sus scrofa), foxes (Vulpes vulpes), mustelids (e.g. Meles meles) and small mammal species. Recorded use by humans usually involves vehicles used in the primary sector, shepherds with livestock herds and occasional passersby. According to our findings, improvement actions will be proposed to increase attractiveness of the underpasses for animal use. Hopefully, in this manner we will guarantee a safe and permeable motorway, as well as robust mammal communities.
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