Journal of Insect Conservation · 2025
In June 2021 a fire tore through 559 hectares of pine forest at Finsjöbrännan. From the charred wood, 2,258 beetle specimens — 559 species, 36 of them red-listed — were drawn out by five different sampling methods. This is a field guide to what the fire left behind, and to how the way you look changes what you find.
The place
The burn at Finsjöbrännan (57°10′1.4″N, 16°14′18.1″E) was a high-intensity crown and surface fire on 2021-06-18. Before it, the stand was Scots pine (Pinus sylvestris) dominated, with Norway spruce, aspen, pedunculate oak and silver birch. Most beetles here arrived after the fire, tracking sun-exposed dead wood and fresh fungal substrates. The reserve was protected in 2024.
Because of logistics, traps ran in different years post-fire — flight-intercept and Malaise in 2022–2023, trunk and pheromone in 2024. Method is therefore confounded with successional stage; the paper is careful, and so is this site, to read differences as method and timing.
How they were caught
Each method intercepts a different slice of the community — flyers, trunk-dwellers, the pheromone-susceptible, the cryptic. Photographs of the actual traps are from the paper (M. Franzén).
FITTransparent acrylic panels (30×40 cm) in a cross-frame over a tray of 70% propylene glycol, intercepting beetles in flight. Set at ~250 m intervals across the burn.
Highest species richness (331) and abundance
TTA 30 cm polyethylene collar sealed around fire-killed trunks at ~1.3 m, funnelling beetles moving along the bole. Three traps each on pine, birch, aspen and oak.
Highest share of red-listed species (13.4%)
MTTent-style flight-interception traps guiding flying insects into a collecting head. Chiefly for Diptera/Hymenoptera but effective for many small, fast-flying beetles.
Second in richness (232); many small fliers
PTOne multi-funnel trap baited with a blend of longhorn and click-beetle pheromones plus a species-specific lure for Elater ferrugineus. Draws beetles from wide areas.
Most red-listed species per event (2.75)
Five coleopterists searching 3–4 h per visit: under bark, in charred stumps and log hollows, beating vegetation, and hand-collecting. Adds cryptic, non-attracted species.
+44 species caught by no passive trap
What the numbers say
Every value below is transcribed from the published tables and figures — nothing is re-estimated here.
Observed species (bar) with the Chao asymptotic estimate. Flight-intercept traps lead; trunk traps sample a small but complete slice.
Trunk traps catch few species but the highest share of red-listed ones (13.4%).
327 of 515 trap species (63.5%) were caught by one method only; just 19 (3.7%) by all four.
Efficiency, not totals: the pheromone trap returns 2.75 conservation-priority species per event.
All pairwise similarities are low (0.26–0.37): any two methods share only about a quarter to a third of their species.
| FIT | MT | PT | TT | |
|---|---|---|---|---|
| FIT | — | 0.37 | 0.36 | 0.26 |
| MT | 0.37 | — | 0.31 | 0.28 |
| PT | 0.36 | 0.31 | — | 0.29 |
| TT | 0.26 | 0.28 | 0.29 | — |
Flight-intercept + trunk traps reach ~89% of estimated richness at ~40% of the effort.
Sample-based curves standardised to 95% coverage (paper Fig. 3).
Venn diagrams for all 515 trap species and for the 36 red-listed taxa (paper Fig. 4).
No single method captures a post-fire beetle fauna. Because 61% of red-listed species turned up in just one method, an inventory that drops a method risks dropping threatened species with it. The paper recommends a multi-method core — flight-intercept plus trunk traps, with a pheromone trap for priority targets — deployed with temporal consistency.
Conservation priority
The paper singles out four beetles; below them, every red-listed taxon in the material. Each links to its own page with a live distribution map and photographs.
New to SwedenA jewel beetle recorded new to Sweden, collected in a Malaise trap.
VUA fire-associated jewel beetle strongly tied to pines; exclusive to flight-intercept traps.
REThe oak pinhole borer — the single Regionally Extinct taxon in the material.
VUA bostrichid beetle of hard oak wood.
RE
VU
VU
VU
VU
VU
VU
VU
VU
VU
VU
VU
VU
NT
NT
NT
NT
NT
NT
NT
NT
NT
NT
NT
NT
NT
NT
NT
NT
NT
NT
NT
NTThe whole fauna
Search and filter all 509 taxa. Each card opens a page with GBIF occurrence maps, live iNaturalist photographs, taxonomy and links to GBIF, Catalogue of Life, iNaturalist and Artfakta.
About
This site is an interactive companion to Franzén, M., Forsman, A. & Persson, O. (2025), “Evaluation of sampling methods for characterisation of post-fire beetle assemblages”, Journal of Insect Conservation 29:92 (doi:10.1007/s10841-025-00728-x, CC BY 4.0). All reported figures — Tables 1–3, the Sørensen indices, the Venn overlaps and the method-combination coverage — are transcribed verbatim from the paper.
The reported statistics come from the paper and are authoritative. The specimen layer — the 1,911 rows behind the species pages, maps and records tables — is an Artportalen export dominated by flight-intercept + Malaise + manual work in 2022–2023. It does not fully contain the 2024 trunk/pheromone catch, so it resolves 509 taxa rather than the paper's 559. Named highlight species missing from the export (e.g. Elater ferrugineus, Dircaea australis) are added from the paper and marked “paper record”.
Enrichment. 506 of 509 taxa were matched to the GBIF backbone; 480 carry a CC-licensed lead photograph (via GBIF) and 460 a direct Catalogue of Life link. Distribution maps are GBIF occurrence-density tiles; species galleries are fetched live from iNaturalist. Coordinates were converted from SWEREF99 TM to WGS84.
Red-list status follows the Swedish Red List 2020 (Eide et al. 2020); IUCN European Red List of Saproxylic Beetles (Nieto & Alexander 2010). Analyses in the paper used R 4.4.3, iNEXT 3.0.1, vegan (metaMDS), VennDiagram.