Promotion of insect biodiversity in Swiss forests - a synthesis (FIBS)

Background

At present, insect decline is quite topical in the media, triggered by a study from Germany published in 2017 (Hallmann et al., 2017). This and other studies showed that the decline in insect diversity and biomass is not only observed in agricultural and other open habitats, but also in forests (e.g. Seibold et al., 2019). The recently published Swiss Red List of jewel beetles, longhorn beetles, rose chafers and stag beetles - most of them wood dwellers - showed that almost half of these species are endangered in Switzerland (Monnerat et al., 2016). The few forest dwellers among the butterflies have also sharply declined due to both intensified and abandoned forest management (Wermeille et al., 2014). Although insect biodiversity trends in forests are considered to be less negative than in other habitats (Scheidegger et al., 2010), the current Red Lists show that there is still a need to take action in conserving and promoting forest insects.

Current examples from Central Europe have shown that measures aimed at promoting diversity in forests do not always have the desired effect, such as near-to-nature forest management (Gossner et al., 2013) or selective timber exploitation in uneven-aged forest stands (Schall et al., 2018). An evidence-based analysis of potential measures to promote insect biodiversity in Swiss forests is desirable.

Goal

The Swiss federal research institute WSL has been conducting studies on various aspects of forest insect diversity for three decades. Besides studies on 'pest insects' and their antagonists, the focus has been on projects on the development of arthropod diversity after windthrow and fire. In addition, extensive work has been done on insect communities in forest reserves and on red wood ants. These results and findings will be compiled in a report and complemented with results from international research. On this basis, recommendations for action shall be derived.

Cited literature

Gossner M., Lachat T., Brunet J., Isacsson G., Bouget C., Brustel H., Brandl R., Weisser W.W., Müller J., 2013. Current near-to-nature forest management effects on functional trait composition of saproxylic beetles in beech forests. Conserv. Biol. 27: 605-614.

Hallmann C.A., Sorg M., Jongejans E., Siepel H., Hofland N., Schwan H., Stenmans W., Müller A., Sumser H., Hörren T., Goulson D., de Kroon H., 2017. More than 75 percent decline over 27 years in total flying insect biomass in protected areas. PLoS ONE 12 (10): e0185809.

Monnerat C., Barbalat S., Lachat T., Gonseth Y., 2016. Rote Liste der Prachtkäfer, Bockkäfer, Rosenkäfer und Schröter. Gefährdete Arten der Schweiz. Bundesamt für Umwelt, Bern; Info Fauna – CSCF, Neuenburg; Eidg. Forschungsanstalt WSL, Birmensdorf, Bern S.

Schall P., Gossner M.M., Heinrichs S., Fischer M., Boch S., Prati D., Jung K., Baumgartner V., Blaser S., Böhm S., Buscot F., Daniel R., Goldmann K., Kaiser K., Kahl T., Lange M., Müller J., Overmann J., Renner S.C., Schulze E.-D., Sikorski J., Tschapka M., Türke M., Weisser W.W., Wemheuer B., Wubet T., Ammer C., 2018. The impact of even-aged and uneven-aged forest management on regional biodiversity of multiple taxa in European beech forests. J. Appl. Ecol. 55: 267-278.

Scheidegger C., Bergamini A., Bürgi M., Holderegger R., Lachat T., Schnyder N., Senn-Irlet B., Wermelinger B., Bollmann K., 2010. Waldwirtschaft. In: Lachat T., Pauli D., Gonseth Y., Klaus G., Scheidegger C., Vittoz P., Walter T. (Eds), Wandel der Biodiversität in der Schweiz seit 1900. Ist die Talsohle erreicht? Bristol Stiftung, Zürich; Haupt, Bern. 124-160.

Seibold S., Gossner M.M., Simons N.K., Blüthgen N., Müller J., Ambarlı D., Ammer C., Bauhus J., Fischer M., Habel J.C., Linsenmair K.E., Nauss T., Penone C., Prati D., Schall P., Schulze E.D., Vogt J., Wöllauer S., Weisser W.W., 2019. Arthropod decline in grasslands and forests is associated with landscape-level drivers. Nature 574: 671-674.

Wermeille E., Chittaro Y., Gonset Y., 2014. Rote Liste Tagfalter und Widderchen. Gefährdete Arten der Schweiz, Stand 2012. . 97 S.