Corresponding author: Roberto Magnolini (
Academic editor: Ivan H. Tuf
Soil centipedes (
Soil centipedes (
In comparison with other major groups of soil predators, many facets of the diversity of geophilomorph communities and their ecology are almost unknown (
This paper presents the results of a survey of some geophilomorph communities in the forests of Val Camonica (Fig.
The aims of the study were: (i) to contribute to filling the knowledge gap for the geophilomorph fauna of the Southern Prealps, by focusing on the Val Camonica forest soils and (ii) to estimate the species richness of selected communities with statistical models in order to adjust for incomplete detection.
A total of five sites were studied in Val Camonica (Fig.
Each site was defined as a circular area of radius 8 m, within a continuous forest patch of at least 0.25 ha, with uniform vegetation structure and at least 10 m away from forest edges, other ecotonal zones and roads.
The five sites were visited between November 2021 and July 2022, for a total of 2-7 sampling sessions for each site (Suppl. material
All specimens of geophilomorphs were collected in test tubes and fixed with 70% ethanol.
Specimens were identified to species level using a Leica DMLB microscope with magnification up to 400×, after mounting the specimens on temporary microscopic slides (
Species identification was conducted by means of Chilokey (
Differences in species composition between sites were evaluated with the Jaccard similarity index, which is based on presence-absence data. A Correspondence Analysis was also performed in order to assess the pattern of diversity between sites. Since sites received different sampling efforts, the analysis was performed on presence-absence data, not on abundance data. The analysis was performed with the FactoMineR package in R (
The number of species in each site was estimated using two non-parametric estimators: the Chao-1 estimator, which is based on the proportion between the number of species collected once and the number of those collected twice (
Chao-1 and ACE were calculated using PAST 4.08 (
In order to compare species richness amongst sites, rarefaction and extrapolation were integrated from the numbers of detected species, with 95% confidence intervals based on “unconditional” variance, as proposed by
A total of 38 hours of sampling sessions allowed us to collect 242 specimens. Between 31 and 85 specimens were collected per site. All specimens were identified to species level, for a total of 18 species detected (Table
Considering the species detected in the five communities, the pairwise values of the Jaccard similarity index were between 0.11 (between sites D and E) and 0.38 (between sites B and C), with a mean value of 0.26 (Table
The Correspondence Analysis performed on presence-absence data produced three main coordinates, accounting for 38%, 30% and 19% of the total variance, respectively (Fig.
Between 4 and 12 species were detected in each of the five sites (Fig.
The rarefaction analysis with 95% confidence intervals, based on “unconditional” variance (Fig.
This study provides the first insights on species richness and composition variation of the geophilomorph communities living in the forests of Val Camonica. Therefore, it contributes to fill a gap in the knowledge of the geophilomorph fauna of the central sector of the Southern Prealps, which has been poorly investigated up to date (see above in Introduction). Only two species had been already previously recorded in Val Camonica, namely
On the other hand, three species, previously recorded in Val Camonica, were not found in the five studied sites, namely
Other species reported from contiguous areas were not found in Val Camonica (Table
There are few studies that compare local communities of geophilomorphs in terms of species richness (e.g.
Results of this work could be affected by some methodological limits. The estimates of species richness and their comparisons between sites could be biased by different probability of detection between species and between different sites for the same species. Despite this, the hand-searching method adopted by us permitted us to maximise the sampling rate of geophilomorphs and to also capture strictly endogeic species, unlike other commonly employed methods (e.g. pitfall traps), as also shown by
Real data as well as non-parametric estimators indicate that more than 12 species of geophilomorphs – not considering high level of uncertainty because of large confidence intervals – can regularly live in syntopy in the study area (Fig.
Considering the Southern Prealps and Dinarides, a few other studies estimated centipede species richness using statistical tools to account for incomplete detection (
We thank Luca Gregnanin, Enrico Carta and Emiliano Peretti for their help in research planning, fieldwork and specimen identification. We are also greatful to Ivan Tuf, Małgorzata Leśniewska, George Popovici and Ivan Kos for insightful suggestions to revise the manuscript.
No conflict of interest to declare
Disclaimer: This article is (co-)authored by any of the Editors-in-Chief, Managing Editors or their deputies in this journal.
Sampling sites in the Val Camonica (yellow dots). Background from Stamen Design.
Sampling sites (see Table
Contribution biplots of the Correspondence Analysis performed on the presence-absence of species in five sites in Val Camonica. Red arrows correspond to species, blue dots correspond to sites.
Observed and estimated species richness of
Comparison of the estimated species richness of
Geographic features of the sampling sites in Val Camonica. Lithological data are from
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A |
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760 | N | Schistose |
1162 | 9.9 | |
B |
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695 | SW | Carbonate | 1178 | 10.3 | |
C |
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1070 | WNW | Carbonate and mixed |
1346 | 7.8 | |
D |
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525 | WNW | Siliciclastic |
964 | 11.0 | |
E |
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1190 | NNW | Glacial drift | 1343 | 7.5 |
Species of
* Putative undescribed species.
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- | - | 3 | - | 4 | 7 | |
- | - | - | - | 1 | 1 | |
- | - | 1 | - | - | 1 | |
- | 2 | 3 | 1 | - | 6 | |
23 | 54 | - | 29 | 4 | 110 | |
- | 2 | - | - | - | 2 | |
- | 6 | - | - | - | 6 | |
- | 1 | - | - | - | 1 | |
- | 2 | - | - | - | 2 | |
- | 3 | 2 | - | - | 5 | |
3 | 7 | 12 | - | 13 | 35 | |
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- | - | 1 | 1 | - | 2 | |
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- | 2 | 10 | - | 8 | 20 | |
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13 | 2 | 11 | 1 | - | 27 | |
7 | 2 | 2 | - | - | 11 | |
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46 | 85 | 48 | 32 | 31 | 242 |
Jaccard similarity index amongst five sites in Val Camonica.
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- | 0.33 | 0.27 | 0.33 | 0.25 |
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0.33 | - | 0.38 | 0.23 | 0.20 |
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0.27 | 0.38 | - | 0.27 | 0.23 |
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0.33 | 0.23 | 0.27 | - | 0.11 |
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0.25 | 0.20 | 0.23 | 0.11 | - |
Observed and estimated values of species richness of
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4 | 12 | 10 | 4 | 6 |
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4.00 | 12.07 | 10.33 | 6.91 | 6.97 |
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4.00 | 29.79 | 17.83 | 6.91 | 8.90 |
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4.00 | 12.50 | 12.05 | 6.91 | 7.68 |
Species of
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Number of species present in geophilomorph communities of the Southern Prealps, from studies based on high sampling efforts and statistical analyses accounting for incomplete detection.
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Current paper | Brescia and Garda Prealps | A = Acquebone: near Ca' de Gos | 4 | 46 |
Bergamasque Alps and Prealps | B = Stramazzano: Torrente Supine | 12 | 85 | |
Bergamasque Alps and Prealps | C = Borno: under Fienili Mensi | 10 | 48 | |
Brescia and Garda Prealps | D = Sacca: Valle del Resio | 4 | 32 | |
Southern Rhaetian Alps | E = Passo Crocedomini: over Degna | 6 | 31 | |
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Dinaric Alps | Near Iska, south of Ljubljana | 16 | - |
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Dinaric Alps | Kumrova Vas | 4 | - |
Dinaric Alps | Mala Gora | 10 | - | |
Dinaric Alps | Zeljne | 8 | - | |
Dinaric Alps | Somova Gora | 12 | - | |
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Dolomites | A = Costagranda: Ponte dei Ross | 11 | 126 |
Dolomites | B = Val del Mis: California | 12 | 75 | |
Dolomites | C = Maragno | 10 | 50 | |
Dolomites | D = Monte Tamberella | 10 | 37 | |
Dolomites | E = Pian d'Avena | 9 | 63 | |
Dolomites | F = Lago della Stua | 11 | 58 | |
Dolomites | G = Val Pegolera | 9 | 66 | |
Dolomites | H = Caiada: Casera d'Igoli | 7 | 26 | |
Dolomites | I = Maragno | 8 | 25 | |
Dolomites | J = Le Boscaie | 6 | 26 |
Sampling sessions for
dates and time spent in each sampling session.
File: oo_841004.xlsx