DOI: 10.5061/dryad.c2fqz61gv
title: A decadal study reveals that restoration guided by an umbrella species does not reach target levels

description: Maintaining structural and functional elements of ecosystems are essential
 in order to preserve biodiversity and ecosystem function. As a means of
 guiding conservation work, the umbrella species concept was developed. In
 Sweden, one putative umbrella species, the white-backed woodpecker, has
 guided conservation and restoration of deciduous forests for two decades.
 Here, we evaluate the decadal effects of restoration aimed at the
 white-backed woodpecker on biodiversity of saproxylic beetles. We compare
 stands that were restored twelve to twenty-one years ago to non-restored
 stands and historical white-backed woodpecker habitats acting as
 restoration target stands. Restored stands contained higher deciduous
 deadwood volumes than non-restored stands but lower volumes than
 restoration target stands. The deadwood in restored stands was
 concentrated in later decay stages whereas target stand deadwood was more
 evenly distributed across decay stages. Restored stands had similar
 species richness and abundance of most groups of saproxylic beetles
 compared with non-restored stands while not reaching the levels of
 restoration target stands. Species assemblages differed among all stand
 types with restored stands supporting late decay stage and generalist
 species while target stands supported more deciduous associated and
 threatened species. 5. Synthesis and applications: We conclude that after
 one to two decades, restoration improve stand structure and benefit beetle
 diversity but that target levels are not yet reached. Thus, only partial
 restoration is achieved. Our results stress that for restoration to be
 successful both continuous and repeated restoration efforts are needed and
 that it is important to identify target levels of important habitat
 characteristics when assessing restoration outcome.
description: Three IBL2, flight-intercept traps were strung between trees at
 breast height in a North, Southeast, Southwest pattern based on the centre
 of each stand, approximately 30-70 m from the stand centre. IBL2 traps are
 large (base 1 m, height 1m, intercept area 0.3 m3); semi-transparent
 flight-intercept traps shaped like downward facing triangles (Bell et al.,
 2015). All flying invertebrates were contained in bottles, filled to
 one-third with 70% propylene glycol and some detergent, at the bottom of
 the traps. The traps were equipped with water-diverging modules that
 prevent rainwater from entering and flooding the bottles. The traps were
 set out in the first week of June 2021 and collected in mid-October 2021.
 An expert taxonomist identified all saproxylic beetles to species level.
 We then categorised beetles based on their affiliation to deadwood, decay
 stage, tree species, their conservation status and if they were recorded
 as prey species for the white-backed woodpecker. This resulted in the
 following categories: a) Saproxylics, b) Saproxylic species of
 conservation concern, meaning that they have had the conservation status
 of NT or higher during the last three Swedish red lists (Gärdenfors, 2010;
 Swedish Species Information Centre, 2015;2020), c) WBW prey species,
 species pointed out as especially attractive as food for the white-backed
 woodpecker according to Aulén, (1988), g) Coniferous preferring, h)
 Deciduous preferring, i) Generalist, with no tree species preference, j)
 Early, species occurring at early stages of deadwood decay, k) Middle,
 middle decay species, l) Late, late decay species and m) decay stage
 generalists, with no known preferences of decay stage. The same species
 can occur in several groups. Classifications of ecological preferences
 were based on available literature (Koch, 1992; Hagge et al., 2019;
 Seibold et al., 2015) and personal communication with taxonomic experts;
 nomenclature following the Swedish Dyntaxa system (Dyntaxa,
 n.d.). Tree species and diameter at breast height (DBH,
 1.3m) were recorded for all living trees higher than 1.3 m and &gt; 5
 cm in DBH within a 10 m circular sample plot at the centre of each stand.
 Coarse woody debris (DBH &gt;10 cm, length/height &gt;1.3 m) was
 measured within one 25 m circular sample plot, at the centre of each
 stand. We divided all deadwood by type (logs and snags), tree species and
 decay stage following Gibb et al., (2005) for logs and Jung et al., (1999)
 for snags. Top- and bottom diameter and length was measured for logs. For
 snags, we measured diameter in breast height and assessed height. Deadwood
 volumes for logs and snags up to 6 m height (as these snags were usually
 broken) were calculated as cylinders. For taller snags (&gt;6 m) we
 used Brandel, (1990)’s southern Sweden volume functions for pine and
 spruce with birch being used for all deciduous tree species.
description: # A decadal study reveals that restoration guided by an umbrella species
 does not reach target levels
 Species richness and
 abundance per trap as well as forest structure variables for each plot.
 Methods described in methods section Column explanations: | Plotid |
 Unique ID for the Plot | | :-------- |
 :----------------------------------------------------------------------- |
 | Trap | Trap number within the plot | | Plot | Plot number within the
 treatment type | | Treatment | Treatment type. C = Non-restored. R =
 Restored sites. W = Target stands. | | trapid | Unique ID for the Trap | |
 ab | Number of individuals per trap | | spr | Number of species per trap |
 | trt | Treatment type again | | declog | Deadwood volume deciduous logs |
 | decsnag | Deadwood volume deciduous snags | | conlog | Deadwood volume
 coniferous logs | | consnag | Deadwood volume coniferous snags | | log |
 Deadwood volume logs | | snag | Deadwood volume snags | | dw | Deadwood
 volume | | decdw | Deciduous deadwood volume | | condw | Coniferous
 deadwood volume | | rlab | Red-listed abundance | | rlspr | Red-listed
 species richness | | wbab | White-backed woodpecker prey species
 individuals | | wbspr | White-backed woodpecker prey species richness | |
 sxab | Saproxylic abundance | | sxspr | Saproxylic richness | | predab |
 Predator abundance | | predspr | Predator richness | | fungab | Fungivore
 abundance | | fungspr | Fungivore richness | | woodab | Wood borer
 abundance | | woodspr | Wood borer richness | | conab | Coniferous
 specialist abundance | | conspr | Coniferous specialist richness | | decab
 | Deciduous specialist abundance | | decspr | Deciduous specialist
 richness | | bothab | Tree sp generalist abundance | | bothspr | Tree sp
 generalist richness | | earlyab | Early succession abundance | | earlyspr
 | Early succession richness | | midab | Middle succession abundance | |
 midspr | Middle succession richness | | lateab | Late succession abundance
 | | latespr | Late succession richness | | generab | Succession generalist
 abundance | | generspr | Succession generalist richness |