EDP Baixo Sabor: Bat Feeding Habitats [acoustic sampling] - Ecological Monitoring (PME) and Compensatory Measures (PMC) Programs: Reservoir Filling and Operation Phase (2015-2020)

Study Extent

The study was carried out in the Sabor Lower River Valley (Northeast Portugal). The data were collected at sampling sites located in several habitats, both in the area to be flooded by the reservoirs and within a 5-km buffer around the flooded area by the reservoirs at the full storage level of the Sabor dams, encompassing a river extension of 90 km upstream of the mouth. Sampling was carried out in the municipalities of Torre de Moncorvo, Alfândega da Fé, Mogadouro, Macedo de Cavaleiros, Vimioso and Bragança

Sampling

Sampling was designed to cover the dominant habitats of the study area, normally used by foraging bats. A total of 70 sampling points (10 impact and 30 controls, for the PME and 30 survey points for the PMC) was surveyed. The impact points were selected among those surveyed in the previous phases, and the subset of the points already established under the monitoring program of the compensatory measures MC1, MC2 and MC3 were also used as control points for bat activity. Each sampling site was visited once per month during the main bat activity period (June-August). In each month, one third of the control points (10 points) were covered, along with the impact points. Sampling was carried under favourable weather conditions, including temperature above 10º and absence of strong winds and rainfall. Acoustic sampling started at sunset and ended 2-3 hours later. Each site was sampled for 15 minutes. In all sites, the air temperature, relative humidity and wind velocity (m/second) were recorded, independently of the confirmed presence of bats. The detection of specimens in flight was made with a bat detector (Pettersson Elektronik, D240X model), with a frequency range of 10-120 kHz. The detector was connected to an automatic digital recorder (model Sony ICD-PX312) which saved the recordings in a “Wave” format, at a frequency of 44 kHz and at an expanded mode of 10x, making them audible to the human ears while, at the same time, preserving the original acoustic characteristics. The analysis of the acoustic records was performed using the sound analysis program BatSound Pro (Pettersson Elektronik AB). This program generates graphs (oscillogram, sonogram and power spectra) using the various sound variables that allow the identification of species or complexes of species detected. The exact identification of the bat species by sound analysis is not always possible, due to problems in detectability and/or identifiability. Whenever it was not possible to perform the identification to the species level, all the compatible species within these phonic groups (or “species complexes”) were considered as with possible occurrence.

Quality Control

All individual identifications were performed by qualified technicians

Method steps

1. To be completed

The taxonomic coverage of this dataset spans 1 phylum, 1 class, 1 order, 4 families, 4 genera and 12 species identified.

1. Chordata
   rank: phylum
2. Mammalia
   rank: class
3. Chiroptera
   rank: order
4. Rhinolophidae
   rank: family
5. Vespertilionidae
   rank: family
6. Miniopteridae
   rank: family
7. Molossidae
   rank: family

Data were collected in an area of 62,500 ha around the lower Sabor river valley affected by the Sabor Dams (impact area), and in an additional area of 30,000 ha not directly affected by the dams (control area), in the municipalities of Torre de Moncorvo, Alfândega da Fé, Mogadouro, Macedo de Cavaleiros, Vimioso and Bragança.