We analyzed a total of 55 fresh spraints following a four steps methodology: (1) Extraction of ADN from otter spraints (figure 1), (2) replication of the DNA by PCR using a set of 11 microsatellites, (3) sex identification using a sex typing approach, and (4) analysis of ADN fragments by electrophoretic mobility of PCR products.
We identified a total of 12 otter individuals in the study area; 7 females and 5 males (see figure 2). Five of these individuals (3 males and 2 females) were found in the lagoon system and their close surroundings, and are quite likely to correspond with the otter family photographed by the camera-traps (see previous blog posts). The location of the spraints of these 5 individuals confirms that otters are using the ditch as a path to get to the river, highlighting the importance of these artificial channels to increase connectivity of restored gravels.
We also found a male (identified by a red triangle in figure 2), both in the lagoon system (including the ditch and the irrigation channel), and in the Duero River 15km east from the quarry. This finding is particularly useful for Áridos Sanz gravel quarry. On the one hand, it confirms the connectivity of the gravel with its far surroundings, and on the other hand, it reflects the good state of the otter population in the region and how the gravel lagoon system is a key habitat for this population, which is something to be proud of.