Corresponding author: Jan Klimaszewski (
Academic editor: L. Penev
Increased interest in biomass harvesting for bioenergetic applications has raised questions regarding the potential ecological consequences on forest biodiversity. Here we evaluate the initial changes in the abundance, species richness and community composition of rove (
Increased interest in the use of forest biomass for bioenergy production has been met with concerns related to potential negative impacts of increased biomass harvesting on biodiversity (
Litter dwelling beetles have been recognized as useful indicators of forest change and ecosystem functioning (
Here we present initial responses of rove and ground beetles to removal of logging residues following clearcut harvesting. As with any study examining a relatively high number of species, we expected to observe a variety of species-specific responses. However as an initial starting hypothesis, we speculated that removal of forest overstory combined with removal of residual forest biomass in the form of logging debris would result in lower abundances of individual species compared with sites where only overstory was removed. We further expected that these would translate to overall assemblage-level differences between harvested sites where additional biomass had been removed and sites that had experienced only clearcut harvesting.
We sampled beetles using pitfall traps within the Montmorency Teaching and Research Forest (47°13' and 47°22'N, and 71°05' and 71°11'W)approximately 70 km north of Quebec City, Quebec (
Schematic representation of treatments with pitfall trap locations, Forêt Montmorency, Quebec.
Photographs of experimental plots taken one year following harvest (2012)
Woody debris volumes were estimated from two 20-m-long perpendicular transects intercepting the centre of each plot using the line intersect method (
We used commercially produced pitfall traps 12 cm in diameter (Bio-Control Inc., Quebec City) with rain covers spaced 10-15 m apart (see details of trap design in
Debris volumes for both small and coarse woody material were compared separately among treatments using linear models where the stem-only harvesting (SOH) treatment was chosen as a reference. Abundances were converted to catch rates to account for differences in trapping effort between sites, which varied due to infrequent disturbances to particular traps by vertebrates over the course of the sampling season and the total number of traps placed within each experimental parcel. Abundances at individual traps were pooled to calculate catch rates for each experimental plot. Thus in harvest plots, catch rates reflect the combined trapping effort of three traps over the course of the season (231 trap days/plot). The number of traps per control plot varied between 3 and 6, corresponding to 203 and to 462 total trap days. We compared overall catch rates among silvicultural treatments using simple linear regression where total catch rate was square root transformed to meet assumptions of normality. We also compared catch rates of the 19 most abundant species (those that comprised more than 2% of the total catch rate) among treatments using non-parametric Kruskal-Wallis rank sum tests.
We analyzed differences in beetle species composition using multivariate regression tree (MRT) analysis (
Volumes of both fine and coarse debris were higher in clearcuts following harvest as compared with uncut stands (fine debris ANOVA
Boxplots showing volume of fine and coarse woody debris in stem-only harvested plots (SOH), whole-tree harvested plots (WTH), and in uncut forest (Control). Bold line depicts median value, box denotes 25–75% quantile range, whiskers correspond to 1.5 times the interquartile range.
We collected 70 species of rove and ground beetles representing 1665 individuals between June 9 and August 25, 2011 (Appendix
Boxplots depicting overall catch rates (beetles/day) where forest was
Boxplots depicting catch rates (beetles/day) for eight abundant species collected from experimental plots where forest was
Abundance of beetle species in dead wood reduced plots (WTH), and in deadwood intact plots (SOH), and in uncut forest (Control). Rove and ground beetle species mixed and listed alphabetically.
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0 | 0 | 1 |
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0 | 0 | 1 |
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0 | 0 | 3 |
1 | 1 | 0 | |
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0 | 1 | 0 |
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1 | 0 | 0 |
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2 | 2 | 15 |
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0 | 0 | 1 |
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0 | 1 | 1 |
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0 | 0 | 3 |
1 | 0 | 1 | |
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4 | 7 | 52 |
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40 | 31 | 334 |
1 | 0 | 1 | |
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1 | 0 | 66 |
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10 | 17 | 3 |
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2 | 0 | 0 |
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7 | 5 | 6 |
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1 | 1 | 1 |
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0 | 1 | 1 |
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19 | 4 | 12 |
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0 | 0 | 1 |
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29 | 16 | 2 |
0 | 1 | 0 | |
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0 | 1 | 0 |
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4 | 0 | 0 |
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3 | 0 | 0 |
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33 | 25 | 12 |
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5 | 3 | 1 |
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1 | 2 | 0 |
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1 | 0 | 0 |
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9 | 0 | 11 |
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0 | 1 | 0 |
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27 | 12 | 1 |
0 | 0 | 1 | |
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0 | 0 | 3 |
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0 | 1 | 0 |
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5 | 3 | 13 |
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0 | 2 | 0 |
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0 | 1 | 0 |
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1 | 1 | 1 |
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0 | 1 | 18 |
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0 | 0 | 3 |
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1 | 0 | 0 |
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8 | 5 | 2 |
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7 | 2 | 0 |
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0 | 0 | 2 |
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1 | 2 | 7 |
2 | 1 | 3 | |
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109 | 32 | 40 |
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91 | 47 | 52 |
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1 | 0 | 1 |
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24 | 19 | 30 |
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6 | 5 | 17 |
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14 | 1 | 5 |
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4 | 0 | 1 |
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9 | 2 | 10 |
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0 | 1 | 0 |
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3 | 2 | 0 |
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0 | 1 | 1 |
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2 | 0 | 0 |
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6 | 4 | 120 |
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0 | 1 | 1 |
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0 | 0 | 11 |
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9 | 5 | 1 |
1 | 1 | 0 | |
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5 | 5 | 1 |
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0 | 1 | 1 |
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0 | 0 | 1 |
Kruskal-Wallis comparison of abundant rove and ground beetle species that responded to harvest.
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6.13 | 2 | 0.047 |
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6.18 | 2 | 0.046 |
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8.29 | 2 | 0.016 |
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6.78 | 2 | 0.034 |
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6.51 | 2 | 0.039 |
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7.00 | 2 | 0.030 |
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6.30 | 2 | 0.043 |
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8.68 | 2 | 0.013 |
The sum-of-squares multivariate regression tree divided 11 sites into three nodes which explained 64.5% of the total variance (
Multivariate regression tree based on sum-of-squares depicting differences in beetle assemblages among experimental plots where forest was
Species variance associated with splits in the multivariate regression tree model.
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15.44 | 0.04 | 15.48 | 16.65 |
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9.63 | 0.12 | 9.74 | 12.45 |
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6.55 | 0.03 | 6.58 | 6.80 |
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0.68 | 2.38 | 3.06 | 5.82 |
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1.01 | 0.33 | 1.33 | 5.23 |
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2.49 | 0.00 | 2.49 | 3.87 |
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0.46 | 1.05 | 1.52 | 3.41 |
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2.02 | 0.25 | 2.27 | 2.62 |
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0.02 | 0.06 | 0.07 | 2.51 |
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0.51 | 0.12 | 0.63 | 2.37 |
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1.27 | 0.07 | 1.34 | 2.25 |
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0.04 | 1.02 | 1.06 | 2.17 |
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0.03 | 0.92 | 0.94 | 2.11 |
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0.47 | 0.70 | 1.17 | 1.92 |
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0.86 | 0.03 | 0.89 | 1.80 |
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0.45 | 0.00 | 0.45 | 1.77 |
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0.08 | 0.06 | 0.14 | 1.53 |
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0.29 | 0.03 | 0.32 | 1.41 |
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0.33 | 0.01 | 0.34 | 1.27 |
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0.13 | 0.01 | 0.14 | 1.27 |
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0.11 | 0.13 | 0.24 | 1.24 |
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1.02 | 0.00 | 1.02 | 1.08 |
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0.39 | 0.26 | 0.66 | 1.07 |
Species with < 1% of species totals combined | 2.19 | 2.35 | 4.54 | 17.40 |
Totals | 46.47 | 9.96 | 56.43 | 100.00 |
We were able to detect differences in beetle assemblages among harvested and unharvested plots (Control), and between stem-only (SOH) (i.e. logging residues left on site) and whole-tree (WTH) (i.e. logging residues removed) harvesting treatments. By far the most common species response that we observed was a reduction in abundance in response to removal of the overstory by harvesting, suggesting that at least initially, removal of forest overstory is more important than depletions in the overall volumes of downed deadwood. Of the species with clear responses to harvesting in general, three
While we were able to distinguish assemblages in stem-only harvested (SOH) stands from those in whole-tree harvested (WTH) stands, this split was defined primarily on increased catches of
Numerous hypotheses can be advanced to explain these responses, including changes in microclimate (for all species) or loss of potential feeding sites such as decaying mushrooms infested with dipteran larvae (for
Based on 1 year of sampling, we were able to characterize differences in beetle assemblages between clearcut sites (SOH, WTH) and mature stands (Control), as well as differences between clearcut sites where harvest residues had been removed (WTH) or left on site (SOH). The overall assemblage response was largely a recapitulation of the responses of several abundant species. While community-level analysis represents the response of abundantly captured species, we believe that we are likely unable to detect the full extent of the effects of residue removal based on a 1-year experiment. While the MRT allowed us to distinguish different assemblages that were attributable to experimental plots, we were unable to definitively explain assemblage differences on the basis of volumes of either coarse (CWD) or fine woody debris (FWD). This does not necessarily preclude conclusions as to the effect of the silvicultural treatments and the biomass removals, but it does to an extent preclude finer scale mechanistic explanations of changes in particular species. The long-term monitoring studies should allow us to better understand the influence of various levels of postharvest debris removal on biodiversity, nutrient production and circling and eventually tree growth.
We are grateful to the following individuals and organizations for contributing to our research: authorities of the Laurentian Forestry Centre (LFC), summer students partici- pating in field collecting and laboratory sample processing, and technical assistance: A. Gilbert, L. Helie, and R. Batista. Ricky Batista provided all the colour beetle images presented in this publication. We thank Pamela Cheers (LFC) for editing the text. Jon Sweeney of the Atlantic Forestry Centre provided some unpublished data on rove beetle species from his study in red spruce forests. Université Laval provided assistance in field preparation and access to research plots.
Colour images of the most abundant rove and ground beetles, and detailed list of specimens examined.
List of rove beetle species (
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0 | 1 | 0 | 7 | 2 | 2 | 0 | 0 | 0 | 12 | 0.9 | |
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0 | 1 | 0 | 7 | 2 | 0 | 0 | 0 | 0 | 10 | 0.8 | |
1. |
0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0.1 | 20 |
2. |
0 | 1 | 0 | 7 | 1 | 0 | 0 | 0 | 0 | 9 | 0.7 | 15 |
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0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0.1 | |
3. |
0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0.1 | 20 |
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0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0.1 | |
4. |
0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0.1 | 20 |
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0 | 0 | 0 | 1 | 1 | 1 | 1 | 0 | 3 | 7 | 0.5 | |
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0 | 0 | 0 | 1 | 1 | 1 | 1 | 0 | 3 | 7 | 0.5 | |
5. |
0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0.1 | 20 |
6. |
0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 3 | 6 | 0.5 | 16 |
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6 | 5 | 17 | 13 | 4 | 42 | 2 | 8 | 87 | 184 | 14.4 | |
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5 | 2 | 16 | 9 | 3 | 39 | 2 | 6 | 78 | 160 | 12.5 | |
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9. |
0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 2 | 0.2 | 19 |
10. |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 11 | 11 | 0.9 | 14 |
11. |
0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 2 | 0.2 | 19 |
12. |
5 | 1 | 0 | 3 | 2 | 1 | 1 | 2 | 0 | 15 | 1.2 | 13 |
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1 | 3 | 1 | 4 | 1 | 3 | 0 | 2 | 9 | 24 | 1.9 | |
13. |
0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0.1 | 20 |
14. |
0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 2 | 0.2 | 19 |
15. |
1 | 1 | 1 | 4 | 1 | 3 | 0 | 1 | 9 | 21 | 1.6 | 10 |
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16 | 6 | 2 | 17 | 18 | 8 | 5 | 4 | 3 | 79 | 6.2 | |
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17. |
3 | 1 | 0 | 1 | 2 | 0 | 1 | 0 | 1 | 9 | 0.7 | 15 |
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34 | 13 | 23 | 14 | 6 | 56 | 53 | 46 | 437 | 682 | 53.4 | |
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0 | 0 | 0 | 0 | 0 | 0 | 2 | 2 | 0 | 4 | 0.3 | |
18. |
0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 0.1 | 20 |
19. |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0.1 | 20 |
20. |
0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 2 | 0.2 | 19 |
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7 | 2 | 2 | 2 | 3 | 3 | 1 | 2 | 19 | 41 | 3.2 | |
21. |
0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 3 | 0.2 | 18 |
22. |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 18 | 19 | 1.5 | 12 |
23. |
0 | 0 | 1 | 0 | 0 | 2 | 0 | 0 | 0 | 3 | 0.2 | 18 |
24. |
1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0.1 | 20 |
25. |
6 | 2 | 1 | 1 | 2 | 1 | 1 | 1 | 0 | 15 | 1.2 | 13 |
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1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0.1 | |
26. |
1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0.1 | 20 |
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0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 0 | 2 | 0.2 | |
27. |
0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 0 | 2 | 0.2 | 19 |
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26 | 11 | 21 | 12 | 3 | 51 | 50 | 42 | 417 | 633 | 49.5 | |
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30. |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0.1 | 20 |
31. |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 2 | 0.2 | 19 |
32. |
0 | 0 | 0 | 0 | 0 | 2 | 1 | 0 | 64 | 67 | 5.2 | 5 |
33. |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 3 | 0.2 | 18 |
34. |
0 | 0 | 11 | 0 | 1 | 3 | 2 | 1 | 1 | 19 | 1.5 | 12 |
35. |
1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 2 | 0.2 | 19 |
36. |
1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 2 | 0.2 | 19 |
37. |
0 | 0 | 0 | 7 | 0 | 5 | 2 | 0 | 6 | 20 | 1.6 | 11 |
38. |
22 | 10 | 1 | 2 | 0 | 0 | 3 | 2 | 0 | 40 | 3.1 | 8 |
39. |
0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0.1 | 20 |
40. |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 3 | 0.2 | 18 |
41. |
2 | 0 | 0 | 0 | 0 | 0 | 1 | 2 | 0 | 5 | 0.4 | 17 |
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0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0.1 | |
42. |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0.1 | 20 |
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1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 2 | 0.2 | |
43. |
1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 2 | 0.2 | 19 |
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10 | 6 | 11 | 40 | 16 | 11 | 59 | 10 | 18 | 181 | 14.2 | |
44. |
10 | 6 | 11 | 40 | 16 | 11 | 59 | 10 | 18 | 181 | 14.2 | 2 |
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1 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 0.2 | |
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1 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 0.2 | |
45. |
1 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 0.2 | 18 |
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34 | 28 | 5 | 21 | 10 | 12 | 12 | 1 | 5 | 128 | 10 | |
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2 | 10 | 2 | 8 | 7 | 1 | 0 | 0 | 0 | 30 | 2.3 | |
46. |
2 | 10 | 2 | 8 | 7 | 1 | 0 | 0 | 0 | 30 | 2.3 | 9 |
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32 | 18 | 3 | 13 | 3 | 11 | 12 | 1 | 5 | 98 | 7.7 | |
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11 | 3 | 1 | 8 | 1 | 10 | 8 | 0 | 5 | 47 | 3.7 | |
47. |
4 | 1 | 0 | 4 | 0 | 2 | 6 | 0 | 3 | 20 | 1.6 | 11 |
48. |
2 | 0 | 0 | 1 | 0 | 1 | 1 | 0 | 0 | 5 | 0.4 | 17 |
49. |
5 | 1 | 1 | 3 | 1 | 7 | 1 | 0 | 2 | 21 | 1.6 | 10 |
50. |
0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0.1 | 20 |
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21 | 15 | 2 | 5 | 2 | 1 | 4 | 1 | 0 | 51 | 4 | |
51. |
1 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 3 | 0.2 | 18 |
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53. |
0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0.1 | 20 |
List of ground beetle species (
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0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 2 | 0.5 | |
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0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 2 | 0.5 | |
1. |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 2 | 0.5 | 10 |
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4 | 5 | 2 | 8 | 6 | 6 | 2 | 0 | 0 | 33 | 8.5 | |
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2 | 2 | 0 | 3 | 4 | 2 | 0 | 0 | 0 | 13 | 3.4 | |
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3. |
0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 2 | 0.5 | 10 |
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2 | 3 | 2 | 5 | 2 | 4 | 2 | 0 | 0 | 20 | 5.2 | |
4. |
1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 2 | 0.5 | 10 |
5. |
1 | 3 | 2 | 5 | 2 | 4 | 1 | 0 | 0 | 18 | 4.7 | 5 |
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75 | 38 | 69 | 48 | 27 | 44 | 26 | 14 | 11 | 352 | 91 | |
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72 | 34 | 57 | 30 | 25 | 36 | 20 | 12 | 7 | 293 | 75.7 | |
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7. |
0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 2 | 0.5 | 10 |
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0 | 0 | 0 | 5 | 0 | 0 | 2 | 1 | 0 | 8 | 2.1 | 8 |
10. |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0.3 | 11 |
11. |
0 | 0 | 0 | 3 | 0 | 0 | 1 | 0 | 0 | 4 | 1 | 8 |
12. |
0 | 0 | 0 | 2 | 0 | 0 | 1 | 0 | 0 | 3 | 0.8 | 9 |
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3 | 4 | 12 | 13 | 2 | 8 | 4 | 1 | 4 | 51 | 13.2 | |
13. |
0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0.3 | 11 |
14. |
0 | 0 | 2 | 0 | 0 | 1 | 0 | 0 | 0 | 3 | 0.8 | 9 |
15. |
0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 2 | 0.5 | 10 |
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17. |
1 | 2 | 5 | 0 | 0 | 2 | 0 | 0 | 0 | 10 | 2.6 | 7 |