EDP Foz Tua Otter (Lutra lutra) - Complementary Studies [2010]

Study Extent

The data were collected in the river Tua sub-basin and in a section of river Douro sub-basin near the tua's mouth (about 15 km to the south), in the municipalities of Carrazeda de Ansiães, Alijó, Vila Flor, Murça, Mirandela, Macedo de Cavaleiros, Valpaços, Vila Pouca de Aguiar, S. João da Pesqueira and Tabuaço.

Sampling

Sampling was designed to cover the course of river Tua and its main tributaries, from the spring to the mouth, and a portion of river Douro and the mouths of its tributaries located in the vicinity of river Tuah. The same grid of 10x10 km squares sampled in the last otter national census (Trindade et al., 1998) was used to sample the Tua's sub-basin. In each square, two sampling plots were randomly established in the selected water line(s). In each sampling point, a transect of 200-600 m was performed along the margins, looking for signs of presence (mostly scats) in suitable places (prominent stones and vegetation in the margins of the water line). Each plot was visited once in February 2010, in dry or light rain periods, to minimize the chance of leaching of the feacal material. The scats were identified "in loco" by expert researchers.

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, 1 family, 1 genus and 1 species.

1. Chordata
   rank: phylum
2. Mammalia
   rank: class
3. Carnivora
   rank: order
4. Mustelidae
   rank: family

The data were collected in the river Tua sub-basin and in a section of river Douro sub-basin near the tua's mouth (about 15 km to the south), in the municipalities of Carrazeda de Ansiães, Alijó, Vila Flor, Murça, Mirandela, Macedo de Cavaleiros, Valpaços, Vila Pouca de Aguiar, S. João da Pesqueira and Tabuaço.