The Brana Rubia and its Alcaian lake are located in Coristanco's lands, in the green and uninhabited heart of Bergantinos. The area is an ideal place for hunting and fishing, especially in the river Anllons and in the Verdes area. 
   
The fertile valleys of  Coristanco produce the best potato in the world and its mountains contain rich minerals soils, mainly kaolin and wolfram. Despite the fact that the titanium exploitation in Brana Rubia has ruined this natural area, the ecosystem still conserves an interesting attractiveness.

Coristanco is one of the few places in Galicia where the Wolf howl can still be heared at night. The lake and its surroundings are habitat for some reptiles like the Lacerta lepida, Lacerta scheiberi, Podarcis bocagei, Vipera seoanei, and amphibious like the Hyla arborea and Rana perezi, most of them only found in Galicia. 
   
Regarding the bird community, it is possible to observe predators like the Buteo buteo, Accipiter gentilis and Accipiter nisus. Concerning the aquatic birds, we only find the Anas platyrrhynchos, Saxicola rubetra and Lanius collurio. In the Campelo mountain some concentrations of Tetra tetrax can be observed mainly at the end of summer.   
   
The Brana Rubia has got as well a very important botanic interest, finding here the Sphagnum, Turberaria globulariefolia, Myrica gale, Eriophorum augustifolium, and the Drosera rotundifolia and Drosera intermediate, rare and small insectivorous plants.