Contribution of semi-open areas to the long-term conservation of insects: a perspective on ground beetles (Coleoptera: Carabidae and Cicindelidae)

Insects play a crucial role in ecosystems and human existence, but their decline is largely due to land-use change. To preserve insect diversity, nature conservation should aim to maintain high-quality nature-based heterogeneous habitats and integrate them within ecological corridors. European landscapes restored to their prehistoric state should contain a significant proportion of semi-open areas. Semi-open areas, consisting of forest-like patches dominated by trees or shrubs, can contribute to insect conservation by providing high-quality habitats and increasing functional connectivity. However, evidence supporting habitat or corridor function is scarce, particularly in the temperate region. The thesis explores the ground beetle assemblages in semi-open areas, as well as their associations with open and forest habitats. Ground beetle species can be divided into several groups based on their associations, with most entering semi-open areas. Habitat preference and specialisation play a significant role in determining ground beetles' responses to environmental conditions found in semi-open areas. Open and forest habitat species display opposite microhabitat preferences, with species with increased habitat specialisation being more sensitive to microhabitat structures. The study concludes that semi-open areas could fulfil several functions for ground beetles in the temperate region, but the focus should be on enhancing connectivity rather than habitat creation for ground beetle conservation. The reintroduction of grazing should consider the strength of the association between ground beetles and semi-open areas when evaluating nature conservation strategies. The thesis further focused on ground beetle dispersal in real-world conditions, which revealed significant differences between flightless forest ground beetles and flight-active generalist species. These findings highlight the limitations of our knowledge in this aspect of ground beetle biology, making it challenging to predict future distributional changes due to climate change or landscape changes.