DOI: 10.5061/dryad.ngf1vhhvd
title: Connectivity and succession of open structures as a key to sustaining light-demanding biodiversity in deciduous forests

description: 1. European forests are facing a rapid decline of light-demanding biota.
 This has prompted active interventions to re-establish and maintain
 partial habitat openness in protected areas. Managers of protected areas,
 however, need substantially more scientific evidence to support their
 decisions on where, when, and how to intervene. 2. We investigated the
 importance of spatial continuity of open forest habitats in different
 years of succession, using six pairs of experimental clearings established
 in the formerly open, oak-dominated forests of the Podyji National Park
 (Czech Republic). In each pair, one clearing was connected to the forest
 edge, while the other was isolated in closed forest. We sampled
 butterflies (74 spp.), moths (435 spp.), saproxylic beetles (465 spp.),
 and vascular plants (567 spp.) on the 12 clearings during the first five
 years of succession. We then compared species richness, abundance, and
 composition of the four taxa between the two clearing types and along the
 succession. 3. All studied insect groups were substantially more
 species-rich and more abundant in connected than in isolated clearings.
 Species composition of plants, moths, and butterflies differed between the
 clearing types. 4. The number of species of all studied taxa generally
 increased from the first to the second or third year after cutting;
 species composition of all taxa differed among years. This suggests rapid
 changes in habitat quality and thus limited time for colonisation by
 light-demanding organisms. 5. Synthesis and applications: Our results
 offer an evidence that spatial connectivity and rapid temporal dynamics
 are important habitat features for light-demanding insects. Attempts to
 create or restore habitats for light-demanding forest biota should take
 into account that: (i) Insects benefit from direct connection of new open
 patches to open habitats or flight corridors such as forest edges. (ii)
 Considering plants, the optimal solution is to connect newly created open
 forest habitats to existing habitats with established biota of high
 conservation value. (iii) Interventions should be carried out within short
 time intervals, i.e. within years rather than decades. (iv) A fine mosaic
 of interconnected, open woodland patches in various successional stages is
 more beneficial than a single large patch with a single successional
 stage.
description: Data were collected during seasons 2011 - 2015. Day-flying
 butterflies were sampled using timed transects in each clearing (7 min per
 clearing) under suitable weather conditions (sunny, warm conditions); each
 pair of clearings was sampled within the same day. Transects were carried
 out monthly from May to August. Moths were captured in the clearings using
 ultraviolet light traps (1 trap per clearing) with 8 W fluorescent lamps
 (Philips TL 8 W/05). Traps were simultaneously exposed for one night per
 month from May to September. Saproxylic beetles were collected using
 flight-interception traps installed on trees at 1.5 m above ground (two
 traps in each clearing, samples then merged). The traps were active from
 the end of April to the beginning of August. Samples were collected
 fortnightly; insects were sorted and saproxylic beetles identified to
 species. For vascular plants, presence/absence of species was recorded in
 each clearing twice per season (at the start of June and start of August).
 Sampling was always performed by the same three botanists. For more
 details, see Kozel et al. 2021.
description: We uploaded ReadMe file for further explanation of the data. Same
 explanations are also presented in the data file.