EDP Baixo Sabor: Herpetofauna (Amphibians) - Compensatory Measures Program (MC2 and MC10): Exploration Phase (2015-2020).

For MC10.1 (road signaling) five intervention road segments and five control segments were covered once a month in March, May and October on three consecutive nights, starting early in the nightfall, when species are more active and move between patches and habitats. Sampling was always carried out in climatically favorable conditions to amphibian activity, namely by choosing nights with precipitation or relative high humidity. All individuals, dead or alive seen in the selected segments of road (both in intervened and control roads) were identified to the lowest taxonomic level as possible.

The evaluation of the use of hydraulic passages by amphibians (MC10.2) was carried out in 22 hydraulic passages (PH): eleven intervened and eleven controls. Each PH, its immediate surroundings (50 m to each side of the PH), and both sides of the respective road section, were intensively prospected for 30 minutes for the presence of amphibians. All spotted individuals were recorded, discriminating between those that used the passage (i.e., observed inside, entering or leaving) and those that used the road above, but not considering the ones that were not associated to either structure. Sampling was always carried out in periods climatically favorable to amphibians, namely nights with precipitation or high relative humidity. The PH were checked once a month, in March, May and October, on three consecutive nights.

The habitat restoration measure (MC10.4) included a component aimed to improve the habitat conditions for the amphibian populations by the restoration of riparian galleries. A total of 20 sampling points (10 intervened and 10 controls) was established to assess the effectiveness of this measure. In each point, an area of 100m x 2m along the water banks was systematically surveyed for a period of 30 minutes by two observers before the dip netting procedures. All individuals seen (adults or larvae) were recorded. Samplings were carried out in late spring (May/June) and autumn (September/October).

The implementation of dedicated built ponds for amphibian conservation (MC10.5) also had the purpose to provide supplementary food resources to the Black Stork (Ciconia nigra) (MC2.4). A total of 28 ponds were used, of which 14 were newly built “impact” ponds and eight were controls (six common to the two MC). Sampling consisted of a systematic survey of amphibians around the perimeter of the pond to count specimens present on the margins, as well as for laying identification, complemented by dip netting (one netting per every 2m of pond perimeter) for larvae and adults (anura and urudels) sampling. Each pond was visited once late winter (March) and through spring (May-July).