several unusual invertebrate species can be found in the killarney valley. some of these species, including the northern emerald dragonfly ("somatochlora arctica") and several caddisfly and stonefly species are usually found much further north in europe. they are thought to be relict species that were left behind in killarney after the last retreat of ice. the northern or moorland emerald dragonfly, the rarest irish dragonfly, is confined to the park. it breeds in shallow pools in bogs.