A hoverfly survey in the inner alpine municipality of Bergün-Filisur (Switzerland) by means of variable route sampling (Diptera, Syrphidae)

By

Bisschop, Jan
Fisler, Lisa
Pétremand, Gaël
Mengual, Ximo

Type

Article

Date of Publication

2025-10-27

Original Publication

Metabarcoding and metagenomics

Volume

9

Pages

79--90

Subjects

Biodiversity , faunistic surveyance , flower flies , Graubünden , Swiss Alps

Contributed by

Pensoft Publishers

Language

English

Published by

Bulgaria Pensoft Publishers 2017-

Identifiers

DOI: https://doi.org/10.3897/alpento.9.170334

 

Abstract

<br> A field survey of hoverflies (Diptera, Syrphidae) was conducted in the municipality of Bergün-Filisur, Canton of Graubünden, in the inner Swiss Alps during 2023 and 2024. This study aimed at: (i) recording a high species richness using a comparatively low sampling effort by experienced syrphidologists along haphazardly selected routes; and (ii) setting a baseline reference for long-term future surveyance. The repeatability of the survey method was tested by comparing the survey results of 2023 with 2024 using rarefaction analyses, and found to be adequate. A total of 173 hoverfly species were recorded in the Bergün sampling area in 2023 and 2024, which is, respectively, 84% and 51% of the known species richness of the municipality of Bergün-Filisur (206 species) and the Canton of Graubünden (341 species). We recorded 3 species new to the Canton of Graubünden (<br> Platycheirus transfugus<br> ;<br> Sphaerophoria estebani<br> ;<br> Psilota exilistyla<br> ), and 14 species that are on the European Red List of Hoverflies, by being endangered (11 species) or vulnerable (3 species). We propose a practical framework for future hoverfly surveyance in Bergün-Filisur, central Alps. The annual survey effort is minimal and can be achieved within the 15–30 June timeframe, requiring either six days of sampling by a single surveyor or three days by two surveyors.<br>