The effect of femel- and small scale clear-cutting on ground dwelling spider communities in a Norway spruce forest in Southern Germany

Abstract

The early effects of femel-cutting (removing 20% of the trees) and small scale clear-cutting on ground-living spiders in a Norway spruce (Picea abies (L.) Karst.) forest in Southern Germany were investigated. The study was carried out as BACIP (before and after, control-impact, many paired samplings) study: Spiders were sampled during the pre-treatment year, the year of cutting, and the year after cutting. In total 7101 individuals were sampled, of which 4530 individuals were identified, 4468 were adult and 2633 individuals were juvenile. We identified 107 species, but a single species, Coelotes terrestris, dominated the control (spruce stand) comprising up to 49% of the total identified individuals. Clear-cutting changed the species composition in the traps, while the first step in femel-cutting preserved it. The number of individuals of the families Linyphiidae, Amaurobiidae, Agelenidae and Clubionidae decreased drastically within the 2 years after the clear-cutting, while the Lycosidae became numerically dominant in the clear-cut stands. The number of individuals with the following characterisation decreased significantly after clear-cutting: Small (<3.0 mm) and large spiders (>10.5 mm), web builders, 'forest habitat species', species favouring hygrophilic to medium moisture conditions, and preferences to live below ground or in and on the moss layer. On the other hand, middle-sized spiders, free hunters, 'open habitat species', spiders favouring dry conditions or that are euryoecious, preferring patterns covered by grasses or uncovered patches, increased in number. Clear-cut habitats with dense spruce regeneration showed a delayed and less pronounced response. With femel-cutting, species composition of ground-living spider communities may be preserved during the first step of regeneration of mature forest stands.

Effects of alternative harvesting methods on boreal forest spider assemblages

“…In contrast with retention felling and gap felling, our thinning treatment produced similar spider fauna as the unlogged control, as shown earlier for spiders (Huhta 1965;Huber et al 2007), ground beetles (Koivula 2002b) and some soil-dwelling arthropods (Siira-Pietikäinen et al 2003). Huhta (1965) also found that new spider species may colonize thinned sites, whereas we did not detect colonizers in the thinned stands.…”

“…Also, species that are indifferent towards light intensity, but have an affinity for (medium-) moist habitats suffer from clear-cutting (Huhta 1971). Especially abundant in clearcuts are hunting spiders, such as Lycosidae sp., whereas Linyphiidae and other webbuilding spiders tend to dominate older forests (e.g., Huhta 1971;Larrivée et al 2005;Huber et al 2007). Although forest spiders may occur in clearcuts for a few years after logging (Huhta 1965(Huhta , 1971McIver et al 1992), they eventually decline in favour of more open-habitat species.…”