Influence of forest decline on the abundance and diversity of Raphidioptera and Mecoptera species dwelling in oak canopies

Abstract

http://www.eje.cz tent and frequency of declines are expected to increase worldwide (Allen et al., 2010; IPCC, 2013). As decline progresses, forest ecosystems undergo dramatic changes in terms of composition, structure and functioning. In particular, there are conspicuous changes in the structure of the canopy that are uncommon in those of healthy trees, such as dead branches and cavities, which increase the structural complexity of the canopy at scale levels of stand, tree and branch (Ishii et al., 2004). However, it may also negatively affect the amount and quality of other critical resources, such as foliage, fruit and seed (Houston, 1981). Such profound structural modifi cations can modulate microclimates, habitat opportunities, and trophic resources for canopy-dwelling communities. For instance, oak decline can promote saproxylic and generalist leaf-feeding beetles, but have a negative effect on specialist leaf-feeders (Sallé et al., 2020). Decline-induced environmental changes can also shape habitat conditions at understory and ground levels. Raphidioptera and Mecoptera are two ancient taxonomic orders of insects frequently encountered in moist temperate forests (Byers & Thornhill, 1983; Aspöck, 2002). Raphidi

Vertical Stratification of Beetles in Deciduous Forest Communities in the Centre of European Russia

“…In addition, there are species that use microhabitats under the canopy to find partners or prey. Therefore, vertical migrations of individual species occur permanently or temporarily from one tier of the forest to another, depending on the season, the stage of the life cycle and even the time of day [114,127,128]. This means that we still have little information about the functioning of arthropod communities living in various tiers of deciduous forests of the temperate zone.…”

Climate Change Alters Temperate Forest Canopies and Indirectly Reshapes Arthropod Communities

“…In addition to canopy specialists, other species occasionally or temporarily use canopy microhabitats, as a hunting ground or to find mates for instance, and vertical migrations take place from a stratum to another, depending on the season, the stage of the life cycle, or even the time of the day (Ulyshen, 2011). As an example, several recent studies reported that even common species of scorpionflies (Mecoptera) and earwigs (Dermaptera) were quite abundant in the canopy layer while they were previously rather associated with lower forest strata (Vincent et al, 2020;Martínez-Pérez et al, 2021). Similarly, canopy top can be used by aquatic insects during the imago stage, suggesting cross-ecosystem connectivity involving the canopy layer (Le Naour et al, 2019).…”

“…Many studies have focused on saproxylic beetle communities, as key components of forest ecosystems (e.g., Bouget et al, 2011;Vodka and Cizek, 2013;Plewa et al, 2017;Seibold et al, 2018b). Other taxonomic groups and/or functional guilds have received comparatively little attention (but see Tanabe, 2002;Leksono et al, 2005;Larrivée and Buddle, 2009;Sobek et al, 2009;Maguire et al, 2014;Vincent et al, 2020;Urban-Mead et al, 2021). The canopy of temperate forests may then shelter an underestimated pool of patrimonial species (Plewa et al, 2017;Tillier et al, 2020), and can be considered as a biotic frontier deserving special attention (Bouget et al, 2011).…”

“…The accumulation of biological legacies, like perched deadwood or cavities, generally promotes saproxylic organisms following major disturbances (Beudert et al, 2015;Cours et al, 2021;Kozák et al, 2021). This stands true for canopy-dwelling arthropods as the abundance and species richness of saproxylic species is generally enhanced in the canopy of declining stands (Figure 1; Stone et al, 2010;Vincent et al, 2020). These changes in sap-feeding, phyllophagous, saprophagous, and xylophagous species have in turn cascading effects on higher trophic levels and affect the community structure within the canopy (Trotter et al, 2008;Stone et al, 2010;Vincent et al, 2020).…”

“…For this, a better exploration of stressinduced horizontal gradient of inner to outer microhabitats in degraded tree crown, and fine characterization of arthropod community distribution within the canopy gradients, and in the above-tree stratum, would be necessary. Several studies have investigated the impacts of forest diebacks or declines on the diversity of specific taxonomic groups or functional, habitat, or trophic guilds (e.g., Martel and Mauffette, 1997;Trotter et al, 2008;Stone et al, 2010;Beudert et al, 2015;Vincent et al, 2020;Cours et al, 2021;Sire et al, 2021). Nonetheless, because of the mixed impacts highlighted by several studies, a multi-taxa and multi-guild approach would be necessary to have a holistic view of the conservation and functional outcomes of ongoing climate changes on forest arthropod communities (Seibold et al, 2018a;Swart et al, 2020).…”