EDP Foz-Tua: Diurnal Butterflies (Lepidoptera) - Ecological Monitoring Program (2014-2017)

Study Extent

The data were collected within a 5-km buffer around the lower Tua River valley and in Ferradosa stream, in the Douro sub-basin (Northeast Portugal), up to 45 km from the mouth in the municipalities of Carrazeda de Ansiães, Vila Flor, Alijó, Murça and Mirandela.

Sampling

Sampling was designed to cover the main habitat types for diurnal butterflies in and around the lower River Tua valley affected by the Foz Tua dam and in the Ferradosa stream (Douro basin). Each sampling point was visited twice per year in spring (April-June) and summer (July-August). Each sampling transect, of about 500 m in lenght, was walked on foot at a constant speed and avoiding stops at hotspots (ie., places with a large influx of Lepidopterans) in order to avoid sampling biases. Adults were monitored during their flight period, between 9:30 and 16:30, on days with appropriate weather conditions (temperature above 13ºC, light wind, little cloudiness, no rain or fog), with a hand-held net. All individuals observed or captured in 5 m buffer in front or to the sides of the observer (never to the backwards) were recorded, to avoid duplication of counts. Identification was performed by visual observation, using appropriated field guides. Although this method is optimized to monitor flying adults, whenever caterpillars or pupae were observed they were also recorded and photographed for later identification.

Quality Control

All 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, 5 families, 44 genera and 61 species and 1 subspecies.

1. Insecta
   rank: class
2. Lepidoptera
   rank: order
3. Hesperiidae
   rank: family
4. Lycaenidae
   rank: family
5. Nymphalidae
   rank: family
6. Papilionidae
   rank: family
7. Pieridae
   rank: family

The data were collected within a 5-km buffer around the valley of the River Tua (Northeast Portugal), in Trás-os-Montes e Alto Douro region, up to 50 km from the mouth, and in a small stream in the Douro sub-basin (Ferradosa stream), in the municipalities of Carrazeda de Ansiães, Alijó, Murça, Vila Flor and Mirandela.