Peräjärvi is surrounded by agricultural landscape, which might have affected its water quality (relatively high EC, 96 uS).

So far, it is the only lake with a large population of S. vulgatum. In 2016, 76 of the 94 collected excuviae belonged to S. vulgatum.

Dragonfly observations Peräjärvi
 SpeciesFinnish nameAdultExuviae
1A. grandis-+
2C. aenae-+
3S. vulgatum-+
4L. quadrimaculata-+