EDP Foz-Tua: Cabrera vole (Microtus cabrerae) - Ecological Monitoring Program, Exploration Phase [2017-2020]

Study Extent

The data were collected within a 3-km buffer around the Tua lower valley (Northeast Portugal), up to 50 km from the mouth, in the municipalities of Carrazeda de Ansiães, Vila Flor, Murça and Mirandela.

Sampling

Sampling was designed to cover all sites with potential habitats for the Cabrera vole (fallows, bushes, river habitats with herbaceous vegetation) located in a buffer of 3 km around the lower Tua valley affected by the Foz Tua dam. All areas surveyed during the previous phases of the project (EIA and Baseline Studies) that were not flooded (50) were included. These areas, were prospected for indirect signs of the Cabrera vole presence (number of tracks, faeces or latrines, and heaps of grass clippings) in November of 2017 and in spring/summer (April-May) and autumn (November-December) of 2018-2020. In each known or potential area surveyed, a detailed description of all the relevant biotopes was performed. This description included (a) the type of biotope, (b) the height of vegetation, (c) the characteristics of the landscape surrounding the demarked areas, namely in relation to the land-use and disturbance. Any changes in these parameters observed between sampling periods were recorded. This description, linked with the type of evidences found, was used to classify each area in one of five possible cases: (a) confirmed colony (active and occupied colony of M. cabrerae), (b) confirmed but unoccupied colony (absence of recent evidence in a colony previously identified by molecular tools), (c) potential colony (with evidences of possible, but not (genetically) confirmed, presence of the target species, like tracks and heaps of grass clippings), (d) potential habitat (patches with suitable habitat but without recorded evidences), and (e) no habitat (habitat patches currently without suitable conditions to the occurrence of the species – eg., agriculture or plowed terrain, flat areas without herbaceous cover, riverbeds, with no confirmed occurrences of the species). All faecal samples found in each visit to a colony were collected for subsequent genetic analysis (mitochondrial gene cytocrome-b) in a dedicated laboratory in CIBIO-InBIO (non-invasive samplings), using specific protocols to extract, sequence and analyze the resulting DNA information. This dataset only provides information about the faeces collected (and subjected to molecular analysis) along the study period, thus excluding the “subjective” evidences (tracks, heaps…). Thus, in all, only 34 of the 50 surveyed sites were really useful to assess the occurrence of the species.

Quality Control

All identifications were performed by qualified technicians

Method steps

1. To be completed

The taxonomic coverage of this dataset spans 1 phylum, 2 classes, 3 orders, 5 families 6 genera and 7 species.

1. Chordata
   rank: phylum
2. Mammalia
   rank: class
3. Rodentia
   rank: order
4. Soricomorpha
   rank: order
5. Passeriformes
   rank: order
6. Muridae
   rank: family
7. Cricetidae
   rank: family
8. Soricidae
   rank: family
9. Sylviidae
   rank: family
10. Turdidae
    rank: family

The data were collected within a 2-km buffer around the valley of the River Tua (Northeast Portugal), up to 50 km from the mouth, in the municipalities of Carrazeda de Ansiães, Murça, Vila Flor and Mirandela.