Pseudoscorpions ( Arachnida : Pseudoscorpiones ) in Strict Forest Reserves in Hesse ( Germany )

doi: 10.5431/aramit5006 Abstract. In 1990 the Federal State of Hesse (Germany) started a long-term faunistic research programme in selected Strict Forest Reserves. Here we report the results of the inventory of pseudoscorpions from seven reserves: Goldbachsund Ziebachsrück, Hasenblick, Hohestein, Kinzigaue, Niddahänge east of Rudingshain, Schönbuche and Stirnberg. A total of 4567 specimens (315-1314 per site) belonging to 13 species (4-9 per site) were recorded using a broad spectrum of methods. The bulk of material comes from pitfall traps (83 %), followed by various types of stem eclectors (16 %). The structure and quality of the species assemblage in the oak-dominated flood plain forest of the Kinzigaue differs strongly from those of the remaining reserves, which are all dominated by beech. In the Kinzigaue a species-rich community (9 species) with balanced dominance structure (Shannon-Index 1.67) has been recorded. At this site, rare or moderately common species reach abundance proportions of more than 50 %. Most importantly, two species with strong affinities to pristine forests, Dendrochernes cyrneus and Chernes cimicoides, were exclusively recorded from this reserve. In contrast, the beech-dominated reserves were strongly dominated by a single species, Neobisium carcinoides (59-91 % of the specimens, Shannon-Index < 1), and the abundance proportion of the very common species exceeded 90 % in each of these areas. Temperature and altitude determine the composition of the species communities significantly. Of the recorded species, two will be categorized in the forthcoming Red Lists of pseudoscorpions of Germany and Hesse. Dendrochernes cyrneus (cat. 3 “vulnerable”) reached an abundance proportion of 20 % in the reserve Kinzigaue. Dinocheirus panzeri (cat. G “indeterminate risk”) has been recorded in single specimens from the reserves Hasenblick, Stirnberg and Niddahänge. The preferred habitat for most of the species is the forest. Species with strong affinities to forests make up more than 95 % of the specimens in all reserves except for Kinzigaue, where this proportion was 89 %. Species richness and abundances were not different between the Strict Forest Reserves (management was stopped at the end of the 1980’s) and the reference areas with continued forestry. However, the proportions of rare and moderately common species were higher in the Strict Reserves as compared to the reference areas.

Here we present the results from 7 reserves (5 of them have an adjacent managed site = reference area).With a total of 4567 specimens this is the second most comprehensive faunistic and ecological study on pseudoscorpions in Germany, outnumbered only by Drogla &c Lippold (2004, ca.Reserves in Hesse/Germany (acronyms in rectangles); the remai- ning sites of the 31 Strict Forest Reserves in Hesse are marked as black dots (after Dorow et al. 2010a).Shaded areas: forest Abb.1: Lage der bearbeiteten hessischen Naturwaldreservate (Kürzel in Quadraten); die übrigen der 31 in Hessen ausgewie- senen Naturwaldreservate sind mit schwarzen Punkten darge- KI -Kinzigaue NI -Niddahänge E Rudingshain (with managed reference area) SB -Schönbuche (with managed reference area) ST -Stirnberg Field work.In the seven reserves the fauna has been recorded with a broad set of trap types and trapping methods over two entire years (inch winter)   in a standardized way (Dorow et al. 1992, 2010a).
Pitfall traps (generally as groups of three = triplets), window traps (different types, see Tab. 2), colour pans (free, not at the bark) and trunk eclectors at the dominating tree species as well on living trees as on standing and lying trunks (with total contact to the ground and partly without) were used.The applied trunk eclectors were open at the bottom, thus the fauna running up the trunks is captured (for details see Behre 1989, Blick 2011).All trunk eclectors were installed on common beech ( Fagus sylvatica ), except for the Kinzigaue, where one eclector was on a living ash tree (Fraxinus excelsior) and the others on oak ( Quercus robur).Furthermore tent eclectors on stumps and tent eclectors covering dead wood (thick branches) were used (details see Tab. 2 and Dorow et al. 1992).
Statistics.The similarity of the species assembla- ges of the seven forest sites has been examined using the non-metric multidimensional scaling method (NMDS), based on Bray-Curtis dissimilarities.This Tab. 1 : Short characterization of the seven investigated Strict Forest Reserves in Hesse .For abbreviations of sites see text above Tab.al. (2001,  2004a,   2004b)   unpubl.
Tab. 2: Overview of the trapping methods and trap numbers (in brackets: numbers in reserve/reference site) .For abbreviations of sites see text above.
Trapping methods.The large majority of the pseudoscorpions was caught by pitfall traps (3787 speci- mens, 82.9 %), followed by the different types of trunk eclectors (734 specimens, 16.0 %) and the window traps on the bark (27 specimens, 0.6 %).With other methods only single specimens were trapped, with a maximum of 5 specimens per method (Tab.4).
A few species were trapped exclusively by a single method: Neobisium simoni with pitfall traps, Al- lochernes wideri in trunk eclectors on dead standing trees and Lamprochernes nodosus with window traps.
The remaining species were trapped with up to 10 different methods.These methods, however, show quite different efficiencies for the recording of individual species: Neobisium carcinoides and N simile were trapped principally with pitfall traps, N sylvati- cum and Pselaphochernes dubius mostly in eclectors on living trees, Chernes cimicoides , Dendrochernes cyrneus and Lamprochernes chyzeri mainly in eclectors on dead standing trees, Pselaphochernes scorpioides pre- dominantly in eclectors on lying trunks (only partly with contact to the ground) and Dinocheirus panzeri mainly with window traps near the bark.Furthermore, specific life cycle stages may prefer different vegetation strata.In Neobisium sylvaticum , 53 % of the specimens in pitfall traps were adults, while in trunk eclectors 79 % belonged to nymph stages.This illustrates the importance of using a broad set of methods to register the species assemblages as rep-Tab.3: Total numbers of specimens in the seven reserves in Hesse including information on association with forests and rarity cat- egory (RC) according to Muster & Blick (in press): vc = very common, c = common, me = moderately common, r = rare.See Material and methods for abbreviations of forest association and site names Tab.Comparison of the reserves with their managed reference areas.The quality of this research program is increased through the inclusion of 22 ad- jacent managed sites/reference areas, where forestry is continued.Five of the seven reserves included in this study have such reference areas (not present in Kinzigaue and Stirnberg).
Neither the species numbers nor the numbers of pseudoscorpion individuals were significantly different between the reserves and the reference areas (Mann-Whitney U-Tests, p > 0.05).In Hohestein and Niddahänge the species number was higher in the unmanaged areas (reserves), whereas in Hasenblick and Schönbuche it was higher in the managed reference areas, while no differences were observed in Goldbachs-und Ziebachsrück (Fig. 2).A higher number of individuals were trapped in the reserves of Hasenblick and Hohestein compared to their reference areas, and lower numbers in Goldbachs-und Ziebachsrück, Schön- buche and Niddahänge (Fig. 3).Note that the re- cording scheme was not completely identical in the reserves and the corresponding reference areas (see Tab. 2).The number of pitfall trap sites reflects the number of different structures in the reserves and the reference areas.Tab.5: Abundance (standardized to individuals/pitfall trap) of pseudoscorpion species from pitfall traps in strict forest reserves as compared to managed reference sites (Kl and ST omitted due to lack of reference sites).For abbreviations of sites see text above Tab.5: Vergleich der standardisierten Abundanz von Pseudoskorpionen (Individuen/Bodenfalle) aus Bodenfallen in Totalreservaten (SFR) und deren Vergleichsflächen (REF) in 5 hessischen Naturwaldreservaten (in Kl und ST wurden keine Vergleichsflächen beprobt).Flächenkürzel wie oben im The species were classified into seven criteria-classes (from extremely rare to very abundant) based on records on the 1:25000 grid squares of Germany (mean value about 129 km 2 per grid) (Staudt 2014).Extre- mely rare and very rare species have not been found in the reserves.The very common species reach about 50%, with the exception of Kinzigaue, where the per- centage was rather lower (Fig. 4).This is even more obvious regarding the abundance proportion (Fig. 5): whereas the percentage of the individuals of the very common species was higher than 90 % in all other reserves, it was about 1/3 in the Kinzigaue.Here, the relative abundance of the moderately common and rare species reaches more than 50 %.The analysis of the pseudoscorpion assemblages with respect to their relationship to forest habitats results in the (unsurprising) insight, that all recor- ded species are typical forest dwellers (categories W and M including their subcategories) (Tab.3).More than 98 % of the specimens belong to species which are strongly associated with forest habitats (Tab. 6: F and fl).Again there is one exception, the Kinzigaue, where 10.8 % of the specimens belong to Pselapho- chernes scorpioides , a species that can be found regularly in forests, but has its focus outside of forests.
Relationships of the species communities.The relationships of the species communities of the se- ven reserves (inch their reference areas) and the in- fluence of abiotic variables was examined by means of non-metrical multidimensional scaling (NMDS).
The NMDS-ordination (stress < 0.1) shows the area Hasenblick in the centre of the diagram (Fig. 6), in nearly equal distance to the other beech forests.
Along axis 1 of the NMDS the oak dominated reser- ve Kinzigaue has a separated position.Axis 2 divides the beech forests on acidic soils (GZ, HB, SB) from those on basic and calcareous soils (HO, NI, ST), which are, at the same time, the three with the high- est elevation.Of the tested abiotic factors, altitude and the average temperature correlate significantly with the position of the reserves in the ordination (Tab.7, Fig. 6).In contrast, an influence of precipitation or geographical position is not detectable.The species Allochernes widen , Cherries cimicoides , Dendrochernes cyrneus and Lamprochernes chyzeri are asso- ciated with the lower sites with higher temperature, Tab.6: Association of the species assemblages with forests in the seven reserves (see text and Tab. 3) Tab.6: Waldbindung der Artengemeinschaften in den einzelnen Naturwaldreservaten (vgl.Text und Tab. while Neobisium simoni shows a relationship with si- tes of higher elevation.As expected, the ubiquitous Neobisium carcinoides is positioned in the centre of the ordination (Fig. 6).

Discussion
This study of seven Strict Forest Reserves in Hesse (including five reference areas) resulted in records of 13 species of pseudoscorpions.This is equivalent to 26 % of the 50 species known from Germany (Muster <5c Blick in press) and 50 % of the 26 species known from Hesse (Muster & Blick in prep.).These ratios are higher than the average in other groups of animals (23 % resp.32 %, Dorow et  Due to the low overall number of species we refrained from using rarefaction methods to assess the completeness of the inventory.But the intensity of the sampling and the broad spectrum of applied methods imply a rather comprehensive survey.There exist only few regional faunistic studies on Central European pseudoscorpions of similar magnitude.
Compared to other sites, the nine species in the Kin- zigaue is a fairly high number, and even four to six species in the other reserves are not unusually low.
Some examples are given to illustrate this: Strebel (1961) collected four species in the "Siebengebirge" (North Rhine -Westphalia), Helversen & Martens   (1971) listed nine species from the gorge of the "Wutach" (Baden-Württemberg), Drogla (1977)  & Kräsny (2007) in the valley of the lower Vltava (Czech Rep.).On the other hand, Drogla (1988)   found in a forest near "Deutsch Paulsdorf" (Upper Lusatia, Saxony) only a single species (Neobisium car- cinoides) and 587 specimens from a floodplain for- est at the river Rhine which is poorly structured compared to other tree species.In line with our results, Ressl & Beier (1958)   reported records of corticolous pseudoscorpions from 36 species of trees and shrubs, but none from common beech [Fagus sylvatica).
The comparison of the reserve areas with refer- ence areas (where forestry is continued) showed no distinct quantitative differences in the assemblages of pseudoscorpions.This fits with the results of other analysed groups of animals (e.g.simply too short to achieve a final balance.The development of natural dynamics in forest ecosystems is a long-lasting process, which needs much more time to be reflected in the species composition of predator guilds. An evaluation of the conservation value of the seven Hessian reserves results in the extraordinary status of the Kinzigaue.Here, not only the biodiver- sity reaches its maximum, but the qualitative criteria also underline the distinctiveness of the area.The proportion of Red Listed species was 24.3 % (in the other areas < 1 %!), and the abundance proportions of rare and moderately common species reached > 50 % (in the other areas < 10 %).Remarkable are the exclusive records of two species in the Kinzigaue, which are attached to "primary" forests, Cherries cimicoides and Dendrochernes cyrneus.On the contrary, the beech forest reserves are collectively inhabited by a very similar, species-poor and unspectacular assemblage of species.Besides climatic parameters and influences of the structures of the forests, other factors, like forest continuity (i.e., long-term persistence of forest habitats at a given site), may play a role (Wulf 1994).For example, the pseudoscorpion species Dendrochernes cyrneus may be restricted to ancient woodland (Muster 1998, Drogla 6c Lippold 2004, but see Anthrenochernes stellae (see Drogla 2003), which is definitely to be expected in Hesse.
The investigation of the pseudoscorpions of the Strict Forest Reserves increased the knowledge on pseudoscorpiones in Hesse considerably.The hitherto most thorough studies from Hesse comprised 554 individuals (Helversen 1966) and 428 individuals (Jost 1982).The inventory of the forest reserves, with a total of 4567 specimens, is an important basis for a Red Data List for Hesse (Muster 6c Blick in prep.).
As compared to other groups of animals (including spiders and harvestmen), the knowledge about pre-ferred habitats, microhabitats and ecological prefer- ences of the German pseudoscorpions is still limited.
Therefore, the results of this study have also national relevance.
, Kinzigaue, Niddahänge and Stirnberg one of these two species has been recorded.The reserve Kinzigaue has the highest proportionate abundance(24.3%) of Red Data List species (< 1 % in all other reserves).Figs.4 and 5show the proportions of species and individuals of rarity categories, as included in the latest Red Data List(Muster & Blick in press).
In the Red Data List of the German pseudoscorpions (Muster & Blick in press) two species from the Strict Forest Reserves in Hesse are listed.Dendrochernes cyrneus is classified as vulnerable (German category "3"), while the degree of endangerment of Dinocheirus panzeri could not be classified in detail (German category "G").In each of the reserves Hasenblick 3) (Zaenker 2001, Reiss et al. 2009rences in the representation of the more species-rich families among the pseudoscorpions.Whilst 33 % of the German and 80 % of the Hessian Neobisiidae and 53 % of the German and 73 % of the Hessian Chernetidae have been found, the species-rich family Chthoniidae (14 species in Germany, 5 species in Hesse) was lacking completely in the collections from the Strict Forest Reserves in Hesse.With regard to the high intensity of trapping and the broad spectrum of survey methods this lack of Chthoniidae remains unexplainable.In fact, it is known that some species of Chthoniidae show ag- with this method in the course of biospel- eological surveys in Hesse(Zaenker 2001, Reiss et al. 2009).In the forest of Ettlingen (Baden-Württemberg) C. tetrachelatus made up 24 % of the specimens caught with pitfalls(Braun &c Beck 1986)and in the Luxembourgian forest "Schnellert" even four species of Chthonius have been found(Groh 2007). collected re-corded five species in a mixed deciduous forest in the low mountain range of the nature reserve "Tiefental NMDS ordination of the pseudoscorpions of seven Hessian Strict Forest Reserves (reference areas included) (black dots), based on the Bray Curtis dissimilarity matrix.The abiotic factors temperature and altitude correlate significantly with the ordinated data.Positions of the species in grey Abb.6: NMDS-Ordination der hessischen Naturwaldreservate (schwarze Punkte) basierend auf der Bray-Curtis-Unähnlichkeitsma- trix der Pseudoskorpion-Artabundanzen.Die Umweltvariablen Temperatur und Höhe korrelieren signifikant mit den ordinierten (Rhineland-Palatinate)(Marx  et al. 2008) as well as 3777 specimens in the forest species numbers; respectively 20 and 23 species.The comparably low numbers of species and individuals in trunk eclectors of the beech-dominated Hessian reserves are surely not a result of methodology.Corticolous taxa may de facto avoid the bark of beeches, to higher presence and dominance of less abundant species in the reserves was detectable, as compared to the reference areas.That the respectable efforts for process conservation in the Strict Forest reserves in Hesse have not yet resulted in a more clear distinctiveness, may have several reasons.The most important is the time.A period of 15 years is Dorow et al.2010b,Blick et al. 2014).However, in the pseudoscorpions (in contrast to, e.g.spiders, see Blick 2012) a clear tendency Esser 2011).Future investigations in Hessian forest reserves should include forest types other than beech forest (Dorow et al. 2010a, Blick et al. 2014).Sifting of mould in cavities of old trees may eventually result in records of the FFH pseudoscorpion species