Changes in species composition and diversity of a montane beetle community over the last millennium in the High Tatras, Slovakia: implications for forest conservation and management

Montane biomes are niche environments high in biodiversity with a variety of habitats. Often isolated, these non-continuous remnant ecosystems inhabit narrow ecological zones putting them under threat from changing climatic conditions and anthropogenic pressure. Twelve sediment cores were retrieved from a peat bog in Tatra National Park, Slovakia, and correlated to each other by wiggle-matching geochemical signals derived from micro-XRF scanning, to make a reconstruction of past conditions. A fossil beetle (Coleoptera) record, covering the last 1000 years at 50- to 100-year resolution, gives a new insight into changing flora and fauna in this region. Our findings reveal a diverse beetle community with varied ecological groups inhabiting a range of forest, meadow and synanthropic habitats. Changes in the beetle community were related to changes in the landscape, driven by anthropogenic activities. The first clear evidence for human activity in the area occurs c. 1250 CE and coincides with the arrival of beetle species living on the dung of domesticated animals (e.g. Aphodius spp.). From 1500 CE, human (re)settlement, and activities such as pasturing and charcoal burning, appear to have had a pronounced effect on the beetle community. Local beetle diversity declined steadily towards the present day, likely due to an infilling of the forest hollow leading to a decrease in moisture level. We conclude that beetle communities are directly affected by anthropogenic intensity and land-use change. When aiming to preserve or restore natural forest conditions, recording their past changes in diversity can help guide conservation and restoration. In doing so, it is important to look back beyond the time of significant human impact, and for this, information contained in paleoecological records is irreplaceable.