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Journal of Insect ConservationAn international journal devoted tothe conservation of insects and relatedinvertebrates ISSN 1366-638XVolume 18Number 5 J Insect Conserv (2014) 18:757-769DOI 10.1007/s10841-014-9677-x
Diversity of grass-dwelling spiders(Arachnida: Araneae) in calcareous fens ofthe Coastal Lowland, Latvia
Maija Štokmane & Voldemārs Spuņģis
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ORIGINAL PAPER
Diversity of grass-dwelling spiders (Arachnida: Araneae) incalcareous fens of the Coastal Lowland, Latvia
Maija Štokmane · Voldemārs Spuņģis
Received: 27 August 2013 / Accepted: 26 July 2014 / Published online: 9 August 2014
© Springer International Publishing Switzerland 2014
Abstract Calcareous fens have a high conservation pri-
ority in the European Union. They are very unique, very
sensitive and very rare habitats in Latvia as well as in many
other European countries. Because of their rarity, many
organisms living in calcareous fens are nowadays consid-
ered threatened. The same is applied to spiders. Spiders
have been suggested as good biodiversity indicators
because they have numerous direct and indirect relation-
ships with other organisms. Only few investigations have
been carried out on fen inhabiting spiders. The knowledge
of grass-dwelling spiders is especially lacking. Thus the
aim of this study was to evaluate grass-dwelling spider
diversity in several calcareous fens of Latvia, compare
these fens and to find out the habitat features that might
affect grass-layer inhabiting spiders. The research was
carried out in eight calcareous fens located in the Coastal
Lowland of Latvia. A total of 760 spiders from nine fam-
ilies and 20 species were collected with a sweep net. Two
of the most abundant spider species were Dolomedes fim-briatus (Clerck, 1757) and Tibellus maritimus (Menge,
1875). Diversity indices suggested that the grass-dwelling
spider community consists of few abundant species and
numerous rare species. Correlation analysis as well as DCA
showed that plant species diversity did not significantly
affect spider species richness and diversity, although at the
same time there were a lot of significant associations
between spiders and individual plant species. It was shown
that various spider species responded very differently to the
presence of particular plant species, and thus habitat
structural heterogeneity emerges to be an important factor
influencing the grass-dwelling spider diversity and com-
munity structure. Correlation analysis also revealed that
spider abundance was negatively affected by the vegetation
height and wind speed.
Keywords Araneae · Grass-dwelling spiders ·
Species diversity · Calcareous fens
Introduction
Fen ecosystems were previously common in temperate
Europe (Van Diggelen et al. 2006). Nowadays, however,
they are very rare because during the past few centuries
almost all fens have been selectively drained and changed
into low-productive meadows and pastures (Sefferova et al.
2008). Furthermore, large-scale impacts such as eutrophi-
cation, acidification, habitat fragmentation and climate
change have resulted in the degradation of many fens
(Saunders et al. 1991; Chapman et al. 2003). As a result,
many organisms living in these habitats are nowadays
considered threatened (Koponen 2003).
Calcareous fens are considered a subtype of rich fen
habitats. This group of fens is very unique ecosystems
because they support a number of plant and animal species
that are specially adapted to conditions of high pH and high
calcium concentration—so-called “calcicoles” or calcium-
loving species (Rydin and Jeglum 2006). Fen habitats are
ecologically valuable also for a number of other reasons,
for example, they provide multiple ecosystem services such
as water retention, drought prevention and nutrient removal
as well as they are important carbon sinks and stores
(Gorham 1991; Zedler and Kercher 2005). Fens also have
important scientific value because their peat deposits might
M. Štokmane (&) · V. SpuņģisDepartment of Zoology and Animal Ecology, Faculty of Biology,University of Latvia, Kronvalda Boulevard 4, Riga LV-1586,Latviae-mail: [email protected]
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DOI 10.1007/s10841-014-9677-x
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contain paleoecological information on past vegetation and
climate (Barber 1993). Fens have recreational importance
as well. Because of their rarity, calcareous fens have a high
conservation priority in the European Union—they belong
to natural habitat types of community interest listed in
Annex I of the EU Habitats Directive (EC 1992). Calcar-
eous fens are also very rare in Latvia—they occupy only
about 0.015 % of the whole territory. The largest calcare-
ous fens are situated in the western part of Latvia,
especially in the Coastal Lowland (Aunins et al. 2010).
The ecology of the spider fauna of calcareous fens is
poorly known because, not only in Latvia, but also in many
other countries studies on fen inhabiting spiders are almost
completely lacking. Therefore, taking into account that
calcareous fens are becoming increasingly rare in Europe,
it is important to obtain as much data on fen species as
possible. Besides, such studies are necessary for the
assessment of the conservation value of these unique
habitats. Spiders are among the most abundant insectivo-
rous predators of terrestrial ecosystems (Nyffeler and Benz
1987; Wise 1995) and one of the most diverse arthropod
orders, with over 44,000 species (Platnick 2013). Spiders
are playing an important role in the balance of nature
because they occupy a strategic functional position in ter-
restrial food webs—they act as regulating agents in
terrestrial arthropod communities and are important food
source for higher organisms (Whitcomb 1974; Young and
Edwards 1990; Nyffeler et al. 1994; Wise 1995; Oxbrough
et al. 2005). Spiders have a great potential as biodiversity
indicators because they have high abundances and
numerous direct and indirect relationships with other taxa;
besides they also have the advantage of being efficiently
sampled and relatively easily identified compared to other
invertebrate groups (Churchill 1997; Marc et al. 1999;
Gravesen 2000; Oxbrough et al. 2005; Hore and Uniyal
2008).
The main aim of this study was to evaluate grass-
dwelling spider species richness and diversity in the cal-
careous fens located at the Coastal Lowland of Latvia and
to compare the differences between grass-layer inhabiting
spider communities within several different fens. In addi-
tion, we aimed to find out the habitat features (mainly
associated with vegetation) that might potentially affect
this group of spiders.
Materials and methods
Study sites
The research was carried out in eight calcareous fens of the
Coastal Lowland of Western Latvia (Fig. 1): (1) Apsuciems
fen; (2) fen of the lake Engure; (3) Platene fen; (4) fen of
the lake Kanieris; (5) fen in the marshy depression (called
viga) of Slıtere; (6) fen in the meadow complex of Vıtini;
(7) Kirba fen; and (8) Jeci fen. All these fens are located in
Fig. 1 Map showing the location of the sampled calcareous fens. All of the studied fens are located in the Coastal Lowland at the Western part of
Latvia
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protected areas which are also included in the Natura 2000network of European specially protected nature territories.
Besides, two of the wetlands—lake Engure and lake
Kanieris—are Ramsar sites which means that these are
wetlands of international importance, designated under the
Ramsar Convention (Ramsar Convention 1971).
Sampling
The samples were collected on 16th and 17th July 2011. To
collect spiders, the sweep netting was chosen which is a
semi-quantitative sampling method and appropriate tech-
nique for grass-dwelling arthropod collection. Spiders were
collected along transects (25 m in length each) which were
placed in the way to proportionally represent the diversity
of microhabitats of the particular fen. So the number of
transects was different in each of the fen—more transects
were placed in those fens in which there were more veg-
etation types. One sample consisted of 50 sweeps—25
strokes were performed along one side of transect and the
rest 25—along the other side. The number of transects
within each fen and their coordinates are given in Table 1.
The vegetation was described using 1 m2 quadrats which
were located on each transect at 5 m intervals (thus there
were five quadrats on each transect). In these quadrats the
percentage cover of each plant species with an accuracy of
5 % was measured. The values of vegetation cover were
averaged for each transect. Almost all plants were identi-
fied to species level (in very few cases to genus level).
Plants were classified into groups according to their life-
form: trees, shrubs, evergreen dwarf shrubs, herbs (forbs
and graminoids) and bryophytes. Prior to data analysis all
vegetation cover values were converted to numerical
rankings according to Braun-Blanquet scale: () \ 1 %
cover; (1) 1–5 %; (2) 6–25 %; (3) 26–50 %; (4) 51–75 %;
(5) 76–100 % (Mueller-Dombois and Ellenberg 1974). The
mean vegetation height (cm) in each of the fens was
measured as well. Additionally, before taking each sweep
Table 1 The number of
transects within each fen and
their coordinates
No. Fen The abbreviation
of a transect
Coordinates of a transect
Latitude Longitude
1 Apsuciems Ap1 57°03´11.73´´N 23°19´00.25´´E
Ap2 57°23´13.31´´N 23°18´58.74´´E
Ap3 57°03´14.34´´N 23°18´53.26´´E
Ap4 57°03´11.23´´N 23°18´57.95´´E
Ap5 57°03´10.87´´N 23°19´02.58´´E
2 Engure En1 57°10´05.24´´N 23°10´23.57´´E
En2 57°10´05.53´´N 23°10´22.97´´E
En3 57°17´13.64´´N 23°08´58.54´´E
En4 57°17´12.01´´N 23°08´57.20´´E
3 Platene Pl1 57°22´41.10´´N 21°43´30.64´´E
Pl2 57°23´29.16´´N 21°43´28.75´´E
Pl3 57°22´43.74´´N 21°43´37.31´´E
Pl4 57°22´43.23´´N 21°43´23.32´´E
4 Kanieris Ka1 56°58´52.46´´N 23°27´37.31´´E
Ka2 56°58´52.75´´N 23°27´39.02´´E
Ka3 56°58´53.27´´N 23°27´37.89´´E
Ka4 56°58´53.86´´N 23°27´40.66´´E
5 Slıtere Sl1 57°42´45.96´´N 22°26´38.05´´E
Sl2 57°42´44.93´´N 22°26´38.46´´E
Sl3 57°41´57.63´´N 22°24´47.28´´E
Sl4 57°41´59.47´´N 22°24´49.74´´E
6 Vıtini Vi1 56°29´26.28´´N 21°05´08.51´´E
Vi2 56°29´25.47´´N 21°05´08.75´´E
7 Kirba Ki1 56°12´28.24´´N 21°08´25.47´´E
Ki2 56°12´29.30´´N 21°08´25.28´´E
Ki3 56°13´06.59´´N 21°08´17.33´´E
8 Jeci Je1 56°16´31.28´´N 21°09´28.18´´E
Je2 56°16´29.70´´N 21°09´27.01´´E
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net sample, the air temperature was measured (°C) and the
cloudiness (%) and the wind speed (according to the
Beaufort scale) were estimated.
Since spider species identifications are based primarily
on genitalia, only adult specimens were identified to spe-
cies level while most immature spiders were identified to
family only. Adult spiders were identified using various
taxonomic keys: Locket and Millidge (1953); Roberts
(1996); and Nentwig et al. (2012). The nomenclature of
spiders follows Platnick (2013). All spiders collected were
stored in 70 % ethanol and the material is deposited in the
Department of Zoology and Animal Ecology, Faculty of
Biology, University of Latvia.
Data analysis
For quantifying plant and spider species diversity, a num-
ber of alpha diversity indices were calculated: species
richness (S), Shannon-Wiener diversity index (H), Simpson
diversity index (D) and species evenness (E). Shannon and
Simpson indices (so-called biodiversity indices) were
selected as descriptors of species diversity because of their
widespread use, well-known properties, and the comple-
mentary information that they provide (Magurran 2004).
The difference between these two indices is that Shannon
index is sensitive to the presence of rare species but
Simpson index is more sensitive to the presence of the
dominant species. The Shannon index is probably the most
widely used and is defined as:
H ¼XS
i¼1
Pi � lnPi
where Pi represents the proportion of the ith species but S
—species richness.
Mathematical formula for the calculation of the Simpson
index is:
D ¼ 1�XS
i¼1
Pi � Pi
The species evenness (E) was also calculated. It is a
measure of how similar the abundances of different species
are. The range of the index is from 0 to 1 (E = 1, if the
species are very evenly distributed). Species evenness is
incorporated into the Shannon index and it is calculated
using the following formula:
E ¼ H
log2S
where H is the Shannon index but S—species richness.
As a measure of spider species dominance the Berger–
Parker index (d) was used. An increase in the value of the
index accompanies a decrease in species diversity and
increase in dominance of a single species. The Berger–
Parker index is not greatly influenced by the observed
species number and is one of the best to use (Southwood
and Henderson 2000). This index is very easy to calculate:
d ¼ Nmax
N
where Nmax is the number of individuals of the most
abundant species, and N is the total number of individuals
in the sample. The Berger–Parker index was calculated
only for the spider communities (not for plants).
Calculations of spider species diversity and dominance
were based on adult individuals only. Diversity indices
were calculated using the program package PC-ORD for
Windows—version 5 (McCune and Mefford 2006).
In order to find out the relationships between spiders and
different abiotic and biotic factors, correlation analysis was
performed. Because the data were not normally distributed
(tested by the Kolmogorov–Smirnov test), Spearman’s
rank correlation analysis was used. But since this correla-
tion method requires at least seven pairs of observations
(Fowler et al. 1998), only the most abundant spider species
were included in the analysis. The relationships were
analyzed between individual spider species or spider
diversity indices and different vegetation and non-vegeta-
tion variables. The statistical significance of the correlation
analysis was checked by comparing the calculated value of
Spearman’s rank correlation coefficient rS with the
obtained p value. Correlation analysis was conducted with
R software (R Development Core Team 2011).
To better observe the patterns of spider community
structure among the eight fens, a detrended correspondence
analysis (DCA) was performed. This analysis arranges the
data so that sites close together in the plots are similar in
species composition, while those that are positioned far
apart are completely different. We used the following
parameter protocol for the DCA ordinations: downweight
rare species; rescale axes; number of segments = 26. DCA
was conducted using quantitative (abundance) data. Prior
to ordination the spider species data were square-root
transformed to reduce the effects of the most abundant
species. Juveniles were excluded from the analyses. Ordi-
nations were performed using the PC-ORD software
(McCune and Mefford 2006).
Results
Spider richness and faunistic characteristics
A total of 760 spider specimens belonging to nine families,
16 genera and 20 species were collected in the eight cal-
careous fens. The total number of adult spiders was low,
760 J Insect Conserv (2014) 18:757–769
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and there were a lot of juvenile spiders which were
excluded from the most analyses. In general, the most
abundant spider families were Araneidae (126 specimens),
Pisauridae (91 specimens), Philodromidae (80 specimens),
and Salticidae (68 specimens). All other families were
represented by less than 40 individuals each (Fig. 2).
Wherever possible spiders were identified to species
level; only in three cases the morphospecies criterion was
used. The most abundant spider species collected was
Dolomedes fimbriatus (Clerck, 1757), accounting for
32.2 % of all adult spiders detected. The next most abun-
dant spiders were Tibellus maritimus (Menge, 1875)
(31.0 %), Evarcha arcuata (Clerck, 1757) (10.1 %),
Marpissa radiata (Grube, 1859) (5.0 %), Pardosa sphag-nicola (Dahl, 1908) (5.0 %) and Xysticus ulmi (Hahn, 1831)(3.9 %). There were no species that was collected at all
eight fens but ten of the species were collected at only one
fen: Erigone dentipalpis (Wider, 1834) was collected only
in Apsuciems; Dolomedes plantarius (Clerck, 1757), Eri-gone sp. and Araneus sp. only in Kanieris; Gnathonariumdentatum (Wider, 1834) only in Platene; Phylloneta im-pressa (L. Koch, 1881) and Cheiracanthium erraticum(Walckenaer, 1802) only in Vıtini; Larinioides cornutus(Clerck, 1757) only in Slıtere; Enoplognatha ovata (Clerck,1757) only in Kirba; and Kaestneria pullata (O.P.-Cam-
bridge, 1863) only in Jeci. Moreover, two of the species
were collected only in two fens: Araneus diadematus(Clerck, 1757) was collected only in Apsuciems and Kirba
but Microlinyphia pusilla (Sundevall, 1830) – only in
Kanieris and Slıtere. The remaining species found were
Argiope bruennichi (Scopoli, 1772) and Cheiracanthiumsp.
Spider guild composition
The foraging guild composition of spiders was also ana-
lysed. Guilds are groups of species utilizing the same
resource in similar ways. We separated our detected spider
families into three guilds (modified from Uetz 1977;
Canard 1990; Roberts 1996): (1) web spinners (collected
families: Araneidae, Linyphiidae and Theridiidae); (2) sit-
and-wait ambushers (collected families: Lycosidae, Pisau-
ridae and Thomisidae); and (3) active hunters (collected
families: Clubionidae, Miturgidae, Philodromidae and
Salticidae).
The number of individuals collected was very similar in
each spider guild: 140 web spinners, 138 sit-and-wait
ambushers and 156 active hunters. But if we put together
both of the wandering spider guilds (i.e. the sit-and-wait
ambushers and active hunters), it can be seen that in most
fens wanderers are more abundant group than web spin-
ners. Only in two of the fens—Kanieris and Vıtini—most
individuals were web builders (Fig. 3), though, it should be
taken into account that very few spider specimens were
collected at Vıtini so the guild ratio in this fen may not be
adequate.
Spider diversity
Several diversity indices were used in the present study to
measure the plant and spider species diversity of each fen.
The numerical values of diversity indices are given in
Table 2. Taking into account, that the value of the Shannon
index usually falls between 1.5 and 3.5 but the value of
Simpson index ranges from 0 to 1 (Magurran 2004), it can
be concluded that there are very low values of the Shannon
index but relatively high values of the Simpson index for
spiders in the studied fens. Anyway, each of these indices
shows that Apsuciems and Kanieris are the most diverse
fens in terms of spiders while the least diverse spider
communities were found in Platene. In contrast, according
to the Berger–Parker index, the least diverse fens were Jeci
(d = 0.585), Engure (d = 0.571) and Slıtere (d = 0.500)
because the high value of the Berger–Parker index shows
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Rel
ativ
e ab
unda
nce
(%)
Engur
e
Kaier
is
Platen
eV
tii
Sl tere irb
aJe
i
Ap u
ciem
s
Clubionidae
Thomisidae
Theridiidae
Salticidae
Pisauridae
Philodromidae
Miturgidae
Lycosidae
Linyphiidae
Araneidae
Fig. 2 Family composition of
grass-dwelling spider
communities from the eight
studied calcareous fens
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that to the large extent there are only a single spider species
that dominates within each of the three fens. The domi-
nance was most even (and hence the diversity was higher)
in Apsuciems (d = 0.262) and Vıtini (d = 0.286) where
there were no species with very high dominance. Fens that
had neither high nor low diversity according to Berger–
Parker index were Platene (d = 0.375), Kanieris
(d = 0.391) and Kirba (d = 0.412).
Factors affecting spiders
The result of correlation analysis revealed that associations
between many of the spider species with studied factors
were insignificant. For example, none of the three plant
diversity indices (Shannon index, Simpson index and spe-
cies evenness) had an influence on the spider species
richness and diversity. However, at the same time there
were quite a lot of associations between spiders and indi-
vidual plant species (Table 3). It seems that the most
sensitive spider species was E. arcuata (Clerck, 1757)—it
had the highest number of associations with vegetation, and
it tended to concentrate on particular shrub and herb spe-
cies at the same time avoiding other ones. In general, the
presence of a willow Salix sp. and the common reed
Phragmites australis was associated with lower total spider
abundance. Vegetation height also negatively affected
spider species richness and diversity as well as the total
number of spider individuals (in both cases – calculated
with and without juveniles). It has been shown that vege-
tation height and P. australis significantly correlated with
each other (rS = 0.680; p value = 0.00006762).
Wind was chosen as an abiotic factor which may
potentially affect spiders because it is an independent
variable that is not associated with vegetation. We did not
choose abiotic factors such as temperature, moisture and
shading since they usually correlate with the architecture
of plants (Geiger 1950; Xu and Qi 2000). Wind speed
was measured before taking each sample so the effect of
wind on spiders can be estimated adequately. Results
showed highly negative correlation between the most
abundant species D. fimbriatus (Clerck, 1757) and wind
speed.
0
0.2
0.4
0.6
0.8
1
Rel
ativ
e ab
unda
nce
(%)
Engur
e
Kaier
is
Platen
eV
tii
Sl tere irb
aJe
i
Ap u
ciem
s
Active hunters
Sit-and-wait ambushers
Web spinners
Fig. 3 Guild composition of
grass-dwelling spider
communities from the eight
studied calcareous fens
Table 2 Diversity of vascular plants and spider species in eight studied fens
Fens Vascular plant diversity Spider diversity
S H D E S H D E
Apsuciems 22 1.675 ± 0.102 0.721 ± 0.039 0.662 ± 0.034 9 1.420 ± 0.066 0.737 ± 0.021 0.941 ± 0.017
Engure 37 1.301 ± 0.236 0.622 ± 0.055 0.466 ± 0.073 4 0.514 ± 0.192 0.333 ± 0.210 0.619 ± 0.122
Kanieris 33 1.283 ± 0.408 0.538 ± 0.131 0.428 ± 0.169 11 1.380 ± 0.208 0.702 ± 0.045 0.883 ± 0.048
Platene 28 1.201 ± 0.196 0.535 ± 0.057 0.425 ± 0.079 6 0.326 ± 0.326 0.171 ± 0.203 0.203 ± 0.171
Vıtini 25 1.615 ± 0.472 0.654 ± 0.142 0.545 ± 0.123 4 0.676 ± 0.676 0.367 ± 0.488 0.488 ± 0.367
Slıtere 24 1.767 ± 0.071 0.747 ± 0.010 0.639 ± 0.012 6 0.760 ± 0.173 0.472 ± 0.031 0.865 ± 0.076
Kirba 25 1.815 ± 0.115 0.797 ± 0.047 0.683 ± 0.017 8 1.279 ± 0.060 0.648 ± 0.076 0.810 ± 0.046
Jeci 12 0.486 ± 0.024 0.194 ± 0.026 0.236 ± 0.013 6 1.156 ± 0.151 0.589 ± 0.002 0.727 ± 0.029
Means are presented with their standard errors (mean ± s.e.)
S species richness, H Shannon-Wiener diversity index, D Simpson diversity index, E species evenness
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Tab
le3
Correlationsbetweengrass-dwellingspidersanddifferenthabitat
variables
Individual
plantspecies
Individual
spider
species
Spider
richnessanddiversity
Life-form
ofa
plant
Plantspecies
D.
fimbriatus
E.
arcuata
T. maritimus
P. spha
gnicola
M.
radiata
X.ulmi
Spider
abundance
in
total
Adultspider
abundance
Spider
species
richness
Shannon
index
Sim
pson
index
Species
evenness
Trees
Betulasp.
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Pinus
sylvestris
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Treesin
total
0.393*
ns
0.459*
ns
ns
0.435*
ns
0.421*
ns
ns
ns
ns
Shrubs
Frang
ulaalnu
sns
0.576**
0.366•
ns
ns
ns
ns
0.334•
0.453*
0.506**
0.423*
ns
Myricaga
lens
0.489**
0.327•
ns
ns
ns
ns
ns
0.442*
0.549**
0.464*
ns
Salix
sp.
ns
−0.574**
ns
ns
−0.337•
ns
ns
−0.405*
−0.346•
−0.323•
ns
ns
Shrubs
intotal
ns
ns
0.413*
ns
ns
ns
ns
ns
0.424*
0.476*
0.429*
ns
Evergreen
dwarfshrubs
A.po
lifolia,Empetrum
nigrum
andOxycoccus
sp.together
ns
−0.336•
ns
ns
−0.326•
ns
ns
ns
ns
ns
ns
ns
Graminoids
Carex
lasiocarpa
ns
−0.422*
ns
ns
ns
−0.319•
ns
ns
ns
ns
ns
ns
Carex
panicea
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Molinia
caerulea
ns
0.489**
0.503**
0.399*
ns
ns
ns
0.534**
0.559**
0.569**
0.479**
ns
P.au
stralis
ns
ns
ns
ns
ns
ns
−0.368•
ns
−0.376*
−0.460*
−0.486**
−0.405*
Schoenus
ferrugineus
ns
ns
ns
ns
ns
ns
ns
0.320•
ns
ns
ns
ns
Graminoids
intotal
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Forbs
C.pa
lustre
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Galium
uliginosum
ns
−0.382*
−0.358•
ns
ns
ns
ns
ns
ns
ns
ns
ns
Menyanthestrifo
liata
ns
−0.383*
ns
ns
−0.344•
ns
ns
ns
ns
−0.339•
−0.369•
ns
Peuceda
num
palustre
ns
−0.388*
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Potentilla
erecta
ns
0.425*
ns
ns
ns
ns
ns
0.321•
0.323•
0.473*
0.498**
0.324•
Forbs
intotal
ns
ns
ns
ns
−0.421*
ns
ns
ns
ns
ns
ns
ns
Non-vascular
plants
Bryophytes
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Other
factors
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Plantrichness
and
diversity
Plantspeciesrichness
ns
−0.354•
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Shannonindex
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Sim
psonindex
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Speciesevenness
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Vegetation
structure
Vegetationheight
ns
ns
ns
ns
ns
ns
−0.341•
−0.347•
−0.373•
−0.402*
−0.396*
ns
Abioticfactor
Windspeed
−0.633***
ns
ns
ns
ns
ns
−0.360•
−0.457*
ns
ns
ns
ns
Only
thestatisticallysignificant(indicated
bythestar(s))andmarginally
significant(indicated
bythepoint)Spearm
an’s
rankcorrelationcoefficientsr S
aregiven
Significance
codes:• —
0.1;*—
0.05;**—
0.01;***—
0.001;ns—
notsignificant
J Insect Conserv (2014) 18:757–769 763
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The results of the DCA are shown in Fig. 4. It can be seen
that there is some kind of gradient in the plant graph, and
differentiation in this graph is significantmainly along the first
axis, the eigenvalue of the second axis being lower (eigen-
values: axis 1 = 0.503; axis 2 = 0.381). In turn, if we take a
look on the DCA for spider data, it seems that the plot dis-
tribution along the axes cannot be attributed to any obvious
gradient—almost all plots are grouped at the one part of the
ordination diagram (eigenvalues of the first two axes are 0.416
and 0.235, respectively). Only two plots—one from Vıtini
(the open triangle) and the other from Platene (the filled tri-
angle)—are very distinct from the others. Overall, the
ordination of the spider dataset revealed differences in com-
munity structure between plots rather than between fens. In
addition, the first DCA axiswas positively associatedwith the
total cover of the great burnet Sanguisorba officinale, theBuxbaum’s sedge Carex buxbaumii and the gipsywort Lyc-opus europaeus but the cover of the bog rosemaryAndromedapolifolia and willow Salix sp. were positively correlated withthe second DCA axis. Negative correlation with the second
DCA axis was found for the marsh thistle Cirsium palustreand the mud sedge Carex limosa.
Discussion
Generally, the knowledge of spiders in fens (especially in
calcareous ones) is scarce, because only very few
investigations have been carried out in this mire habitat
type. More studies have been conducted in bogs. In this
research we have focused on grass-dwelling spiders so the
material was collected by using a sweep net. Overall, the
grass-dwelling spiders are less studied than ground-dwell-
ing ones, the same being applied to spiders inhabiting
calcareous fens (Bultman 1992; Stokmane et al. 2013). For
all these reasons it is hard to find investigations that can be
directly comparable to the present study. In Estonia, Vil-
baste (1980) has surveyed different mire types (including
fens, transitional mires and bogs) but these data are quite
old—materials were collected by a sweep net from 1947 to
1976. Nevertheless, if we compare our study with his
survey, it can be concluded that most spiders we have
detected in fens, were also found in Estonian fens. Only six
of all the species that we collected, were not found in
Estonian fens—two of them, i.e. A. diadematus (Clerck,
1757) and E. ovata (Clerck, 1757) were found by Vilbaste
in mire habitats other than fens (mainly in bog forests) but
the rest four species, i.e. A. bruennichi (Scopoli, 1772), D.plantarius (Clerck, 1757), L. cornutus (Clerck, 1757) and P.impressa (L. Koch, 1881) Vilbaste did not find in Estonian
mires at all. It can partly be explained by the fact that over
the past century there has been quite a rapid poleward
range expansion of numerous species due to climate
change. Since the data of Vilbaste are quite old, they do not
show those spider species that have recently spread
northwards. A very good example is A. bruennichi (Scopoli
Axis 1
Axi
s 2
Andr_pol
Car_buxb
Car_limo
Cirs_pal
Lyco_eur
Salix_sp
Sang_off
Axis 1
Axi
s 2
Fig. 4 DCA plot ordination diagrams for (a) vegetation data and for
(b) spider data environmental variables (arrows). Filled circlesApsuciems; open circles Engure; filled squares Kanieris; opensquares Slıtere; filled triangles Platene; open triangles Vıtini; filleddiamonds Kirba; open diamonds Jeci; Sang_off = S. officinale (the
great burnet); Lyco_eur = L. europaeus (the gipsywort); Car_-
buxb = C. buxbaumii (the Buxbaum’s sedge); Andr_pol = A.polifolia (the bog rosemary); Salix_sp = Salix sp. (a willow);
Cirs_pal = C. palustre (the marsh thistle); Car_limo = C. limosa (the
mud sedge)
764 J Insect Conserv (2014) 18:757–769
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1772). It is a thermophilic species that originally occurred
in the Mediterranean part of Europe but during the 20th
century has extended its range northwards (Kumschick
et al. 2011). In 2004 this spider species was detected in
Latvia for the first time (Spungis 2005). The study of Cera
et al. (2010) is another one we need to mention. This study
was conducted in Lake Engure Nature Park from 1997 to
2008, and the grass-dwelling spiders were collected in 12
different habitats including calcareous fens. Eight of spider
species that were collected in our study were also detected
in calcareous fens from Lake Engure Nature Park. These
species were: A. diadematus (Clerck, 1757), E. arcuata(Clerck, 1757), K. pullata (O.P.-Cambridge, 1863), L.cornutus (Clerck, 1757), M. radiata (Grube, 1859), T.maritimus (Menge, 1875) and X. ulmi (Hahn, 1831). Thedominant spider species in the calcareous fens of Lake
Engure Nature Park were T. maritimus (Menge, 1875), M.radiata (Grube, 1859), E. arcuata (Clerck, 1757) and L.cornutus (Clerck, 1757). The former three species were
also abundant in our study but the latter one we collected as
a singleton.
In general, two of the most abundant spider species in
the present study were D. fimbriatus (Clerck, 1757) and T.maritimus (Menge, 1875). It is quite logical for both of
these species to be found in a wetland habitat because they
are typical of moist habitats in general. D. fimbriatus(Clerck, 1757) is usually found in swamps which do not
dry up, because it needs permanent pools of water (Locket
and Millidge 1951). This spider can walk on the surface of
water where it hunts insects, tadpoles or sometimes even
small fish thus also being important predator in semi-
aquatic food webs (Foelix 1996; Roberts 1996). A bit less
abundant in our study was T. maritimus (Menge, 1875).
This species is found on coarse grasses, rushes, heather and
in similar situations. It usually inhabits damp places, for
example, raised bogs (Locket and Millidge 1951; Harvey
et al. 2002). It has also been recorded in calcareous fens
(Cera et al. 2010). The rest of the species accounted for less
than 30 % of all individuals.
In the present study both of the wandering spider guilds
—sit-and-wait ambushers and active hunters—were more
abundant than web builders. This result could suggest that
active wandering might be a more successful hunting
strategy than sedentary lifestyle. There are many reasons
supporting this assumption. Firstly, wandering spiders may
be more likely to find suitable food than web spinners
because while most species of wanderers are capable of
capturing a wide diversity of prey types, web spinners
exhibit considerable specialization on prey (Nentwig 1985,
1986). Secondly, the mobility of actively hunting spiders
provides them with greater flexibility to move readily to
areas with more favorable microclimate and resource val-
ues (Williams 1962; Samu et al. 1999); on the contrary, site
abandonment means a high energetic cost to sedentary
spiders because they must avoid predation during and after
relocation and build a new web (Tanaka 1989; Lubin et al.
1993). And thirdly, wanderers are less sensitive to local
changes in their habitat because they are capable of
exploiting larger areas, i.e. since microhabitat relocations
are part of the foraging strategy of wandering spiders, this
group of spiders uses not only their immediate surrounding
but also suitable habitats in the vicinity of their habitat
patch (Ford 1978; Ehmann and MacMahon 1996).
To evaluate spider diversity in the examined calcareous
fens, several diversity indices were calculated. Diversity
indices are often considered to be a more indicative
diversity measure than mere species richness (Magurran
2004). In all cases the Shannon diversity index of spider
communities was low but the Simpson diversity index—
quite high. It suggests that the grass-dwelling spider com-
munity is characterized by a few abundant species and
numerous rare species. As other authors have shown, this
pattern is actually expected for spider assemblages (Toti
et al. 2000; Bonaldo et al. 2007).
The number of correlations between spiders and differ-
ent habitat features was less than expected. For example,
no consistent relationship between increasing plant species
diversity and patterns of richness and diversity of spider
communities emerged. Nevertheless, there were quite a lot
of associations between spiders and individual plant spe-
cies. The DCA showed quite a similar pattern—some of the
individual plant species were fairly important for spider
communities. These results partly support research by other
authors (Uetz 1991; Pozzi et al. 1998; Jimenez-Valverde
and Lobo 2007; Hore and Uniyal 2008) who have found
that vegetation structure is one of the major habitat features
explaining spider species composition. It has been shown
that greater habitat complexity usually results in a higher
abundance and diversity of spiders (Langellotto and Denno
2004). It is in accordance with the habitat heterogeneity
hypothesis (Tews et al. 2004) which states that structurally
more diverse habitats provide more niches and different
potential ways of resource exploitation. Thus increased
vegetational complexity may provide a lot of benefits for
spiders: more web attachment points (for web spinners),
higher prey density, reduced intraguild predation, access to
alternative food sources and better protection from their
own predators (Uetz 1991; Gunnarsson 1996; McNett and
Rypstra 2000; Langellotto and Denno 2004; Rickers et al.
2006).
The results indicated that spiders were negatively cor-
related with the vegetation height. This observation is
apparently inconsistent with the numerous of other studies
(e.g., Mrzljak and Wiegleb 2000; Dennis et al. 2001; Harris
et al. 2003; Horvath et al. 2009) in which the height of the
vegetation is a habitat feature that positively affects
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spiders. It is associated with the fact that higher vegetation
is usually vertically more structured which increases spider
species richness (Horvath et al. 2009). Probably the main
reason why in the present study vegetation height had a
negative effect on the spider richness and diversity is that
the height of the vegetation in the fens was associated with
a high cover of the common reed P. australis. The corre-
lation analysis revealed that this plant species negatively
influenced spiders. The common reed is a typical expansive
plant which can replace other plant species. Moreover, by
forming very dense stands, this plant can create shading
(Aunins et al. 2010) due to which spider communities
could be affected. Photophilous spider species are espe-
cially negatively influenced. The common reed might have
a high importance for spiders only during the winter
because reed beds have been reported to be substantially
important overwintering places for spiders (Puhringer
1979).
Spiders were also negatively affected by the wind which
is in accordance with several other studies. The negative
effect of the wind is usually associated with the destruction
of spider webs. Spider webs are relatively weak so they can
be easily damaged by wind gusts (LeSar and Unzicker
1978; Hodge 1987; Szinetar 2000). In both the field
observations and in the laboratory experiments there have
been established that spiders tend to build their webs at
places where the influence of wind is smaller (Jocque
1973). Also, Wise (1995) proposed that the abundance of
spiders depends on three niche axes, one of which is wind
(the other two are temperature and moisture).
Calcareous fen conservation is one of the priorities in
the European Community. Although peatland ecosystems
(e.g. fens and bogs) are typical habitats in northern Europe,
nowadays they are endangered even in this region. As a
result many organisms, including spiders, living in peat-
lands are currently threatened. The worst thing is that
spider fauna and ecology are very poorly investigated in
peatland (especially fen) habitats. Spiders have been sug-
gested as good biodiversity indicators which is one of the
main reasons why it is so important to perform systematic
studies of spiders in rare and threatened habitats. In our
previous study we focused on ground-dwelling spiders of
calcareous fens (Stokmane et al. 2013) so this time we
were taking into account the grass-dwelling ones. Consid-
ering all possibilities and limitations, we chose to collect
the data in the mid-July. There are a couple of reasons why
we decided that this period of time would be the best for
the short-term intensive sampling. Firstly, some researchers
have found that spider species diversity and the number of
species positively correlate with mean weekly temperature
and thus reach maximum values during midsummer (Hat-
ley and Macmahon 1980). In Latvia July is the warmest
month of the year (LEGMC 2014), besides our personal
observations also indicate that it is usually the richest
period of the growing season when plant biomass and food
availability are at their peak. Since it is supposed that peaks
of herbivorous insect abundance correlate with flowering
and/or fruiting peaks (Buskirk and Buskirk 1976), it is
expected that the density of spiders will also increase
proportionally—Kiritani et al. 1972, for example, have
discovered that the peak of population density of spiders
coincides with an increase of insect pests. Secondly, it
should be noted that this study was restricted only to grass-
dwelling spiders (including flower-dwellers). If compared
to other spider groups (for instance, ground-dwelling spi-
ders), grass-dwellers is a group of spiders that may be
especially dependent on the presence of different plant
reproductive structures, i.e. buds, flowers and fruits. Grass-
dwellers are indirectly related to these structures, because
they are often dependent on phytophagous insects and
pollinators which usually visit these plant structures (Lo-
uda 1982; Souza and Martins 2004). During the season the
relative amount of plant reproductive elements is varying,
but the midsummer in Latvia is expected to be the hotspot
of the amount and diversity of these structures (personal
observation), so it was hoped that during this period
diversity of grass-dwelling spiders would be at its highest
point or near it. Of course, abundance of spiders varies
seasonally and certain species may dominate at different
times of the season (Robinson et al. 1974; Corey et al.
1998; Sudhikumar et al. 2005), but we need to emphasize
that our aim was to try to evaluate the overall spider
diversity and not the diversity of one or several particular
spider group(s). If our goal, for example, would be to study
a specific spider family, the optimum sampling period
might be very different.
Next, if speaking about the experimental design of this
study, the transect method and the sweep net were used to
collect the grass-dwelling spiders in the chosen fens. The
number of transects differed between fens—it was in
accordance with the vegetation types present in each par-
ticular fen. Since we wanted to focus on the typical
calcareous fen spider species it was supposed that no more
transects are necessary because it has been shown that an
increasing sampling effort results in a higher chance of
finding non-typical species, which have immigrated from
adjacent habitats, and that no typical species are caught
additionally (Bonte et al. 2003). Anyway, sampling over an
entire fen area is recommended to more accurately estimate
spider counts, and more intensive sampling would also be
useful because otherwise it is difficult to assess the habitat
affinities of rarely collected species.
Contrary to our expectations, the total number of adult
spiders collected was much lower than anticipated. In con-
trast, a greater number of juveniles were collected, which
could be explained by the fact that a large number of spider
766 J Insect Conserv (2014) 18:757–769
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species are giving birth to offspring during this time (Cum-
mins 2007). In any case, in the future research it is
recommended to choose some other sampling periods in the
growing season to more completely evaluate the spider
diversity of the calcareous fens. Also, since our sampling
method was restricted only to grass-layer inhabiting spiders,
other collection methods are required to be used in the future
studies to obtain a more complex overview of the spider
fauna of the studied habitats. In general, this research actu-
ally can be considered more like a preliminary assessment,
and the topic deserves future investigations because there is
still a lot to learn about spider fauna and ecology in these rare
and endangered habitats—calcareous fens.
Acknowledgments The authors would like to thank Andris Zie-
melis and Agnese Zukova for their help in collecting spiders. We also
wish to thank Inese Cera for checking spider identifications and for
the help with the identification of difficult spider specimens. This
study was supported by the project (No. 09.1589) “Factors limiting
diversity of animals in terrestrial ecosystems—interaction of natural
and anthropogenic factors” funded by the Latvian Council of Science,
as well as by the European Social Fund project (agreement No. 2009/
0162/1DP/1.1.2.1.1/09/IPIA/VIAA/004) “Support for the implemen-
tation of master studies at University of Latvia”.
References
Aunins A, Bambe B, Engele L, Ikauniece S, Kabucis I, Laime B,
Larmanis V, Reriha I, Rove I, Rusina S, Salmina L, Sniedze R
(2010) European Union protected habitats in Latvia: identifica-
tion handbook. Latvian Fund for Nature, Riga (in Latvian)
Barber KE (1993) Peatlands as scientific archives of past biodiversity.
Biodivers Conserv 2:474–489
Bonaldo AB, Marques MAL, Pinto-da-Rocha R, Gardner T (2007)
Species richness and community structure of arboreal spider
assemblages in fragments of three forest types at Banhado
Grande wet plain, Gravataı River, Rio Grande do Sul, Brazil.
Iheringia Ser Zool 97:143–151
Bonte D, Criel P, Van Thournout I, Maelfait JP (2003) Regional and
local variation of spider assemblages (Araneae) from coastal
grey dunes along the North Sea. J Biogeogr 30:901–911
Bultman TL (1992) Abundance and association of cursorial spiders
from calcareous fens in southern Missouri. J Arachnol 20:165–
172
Buskirk RE, Buskirk WH (1976) Changes in arthropod abundance in
a highland Costa Rican forest. Am Midl Nat 95:288–298
Canard A (1990) Heathland spider communities, a functional group
study. Acta Zool Fenn 190:45–50
Cera I, Spuņģis V, Melecis V (2010) Occurrence of grass-dwelling
spiders in habitats of Lake Engure Nature Park. Environ Exp
Biol 8:59–69
Chapman S, Buttler A, Francez AJ, Laggoun-Defarge F, Vasander H,
Schloter M, Combe J, Grosvernier P, Harms H, Epron D, Gilbert
D, Mitchell E (2003) Exploitation of northern peatlands and
biodiversity maintenance: a conflict between economy and
ecology. Front Ecol Environ 1:525–532
Churchill TB (1997) Spiders as ecological indicators: an overview for
Australia. Mem Mus Vict 56:331–337
Convention Ramsar (1971) Convention on wetlands of international
importance especially as waterfowl habitat. United Nations
Treaty Series, Ramsar
Corey DT, Stout IJ, Edwards GB (1998) Ground surface spider fauna
in Florida sandhill communities. J Arachnol 26:303–316
Cummins LG (2007) Spiders in Paint Creek, a local wetland: initial
findings in family composition and distribution. Sr Honors
Theses 137:1–19
Dennis P, Young MR, Bentley C (2001) The effects of varied grazing
management on epigeal spiders, harvestmen and pseudoscorpi-
ons of Nardus stricta grassland in upland Scotland. Agric
Ecosyst Environ 86:39–57
EC (1992) European Community Council Directive 92/43/EEC of 21
May 1992 on the conservation of natural habitats and of wild
fauna and flora. Official Journal of the European Communities,
Brussels
Ehmann WJ, MacMahon JA (1996) Initial tests for priority effects
among spiders that co-occur on sagebrush shrubs. J Arachnol
24:173–185
Foelix RF (1996) Biology of spiders. Oxford University Press, Oxford
Ford MJ (1978) Locomotory activity and predation strategy of the
wolf spider Pardosa amentata (Clerck) (Lycosidae). Anim
Behav 26:31–35
Fowler J, Cohen L, Jarvis P (1998) Practical statistics for field
biology. Wiley, New York
Geiger R (1950) The climate near the ground. Harvard University
Press, Cambridge
Gorham E (1991) Northern peatlands: role in the carbon cycle and
probable responses to climatic warming. Ecol Appl 1:182–195
Gravesen E (2000) Spiders (Araneae) and other invertebrate groups as
ecological indicators in wetland areas. Ekologia (Bratislava)
19:39–42
Gunnarsson B (1996) Bird predation and vegetation structure
affecting spruce-living arthropods in a temperate forest. J Anim
Ecol 65:389–397
Harris R, York A, Beattie AJ (2003) Impacts of grazing and burning
on spider assemblages in dry eucalypt forests of north-eastern
New South Wales, Australia. Aust J Ecol 28:526–538
Harvey PR, Nellist DR, Telfer MG (2002) Provisional atlas of British
spiders (Arachnida, Araneae), Volume 2. Biological Records
Centre—Centre for Ecology and Hydrology, Huntingdon
Hatley CL, Macmahon JA (1980) Spider community organization:
seasonal variation and the role of vegetation architecture.
Environ Entomol 9:632–639
Hodge MA (1987) Factors influencing web site residence time of the
orb weaving spider Microthena gracilis. Psyche 94:363–371
Hore U, Uniyal VP (2008) Influence of space, vegetation structure,
and microclimate on spider (Araneae) species composition in
Terai Conservation Area, India. Eur Arachnol 14:71–77
Horvath R, Magura T, Szinetar C, Tothmeresz B (2009) Spiders are
not less diverse in small and isolated grasslands, but less diverse
in overgrazed grasslands: a field study (East Hungary, Nyırseg).
Agric Ecosyst Environ 130:16–22
Jimenez-Valverde A, Lobo JM (2007) Determinants of local spider
(Araneidae and Thomisidae) species richness on a regional scale:
climate and altitude vs. habitat structure. Ecol Entomol 32:113–
122
Jocque R (1973) The spider-fauna of adjacent woodland areas with
different humus types. Biologisch Jaarboek (Dodonaea) 41:153–
178
Kiritani K, Kawahara S, Sasaba T, Nakasuji F (1972) Quantitative
evaluation of predation by spiders on the green rice leaf hopper,
Nephotettix cincticeps Uhler, by a sight count method. Res Popul
Ecol 13:187–200
Koponen S (2003) Ground-living spider communities (Araneae) on
boreal and hemiboreal peatbogs. Biodiversity and conservation
of boreal nature. Proceedings of the 10 years anniversary
symposium of the Nature Reserve Friendship. Finn Environ
485:212–215
J Insect Conserv (2014) 18:757–769 767
123
Author's personal copy
Kumschick S, Fronzek S, Entling MH, Nentwig W (2011) Rapid
spread of the wasp spider Argiope bruennichi across Europe: a
consequence of climate change? Clim Chang 109:319–329
Langellotto GA, Denno RF (2004) Responses of invertebrate natural
enemies to complex structured habitats: a meta-analytical
synthesis. Oecologia 139:1–10
LEGMC (2014) Latvian environment, geology and meteorology
centre. Available at: http://www.meteo.lv. Accessed 21 June
2014
LeSar CD, Unzicker JD (1978) Soybean spiders: species composition,
population densities and vertical distribution. Illinois Nat Hist
Surv Biol Notes 107:1–14
Locket GH, Millidge AF (1951) British spiders, vol 1. Metchim and
Son Ltd, London
Locket GH, Millidge AF (1953) British spiders, vol 2. Metchim and
Son Ltd, London
Louda SM (1982) Inflorescence spiders: a cost/benefit analysis for the
host plant, Haplopappus venetus Blake (Asteraceae). Oecologia
55:185–191
Lubin Y, Ellner S, Kotzman M (1993) Web relocation and habitat
selection in a desert widow spider. Ecology 74:1915–1928
Magurran AE (2004) Measuring biological diversity. Blackwell
Publishing, Oxford
Marc P, Canard A, Ysnel F (1999) Spiders (Araneae) useful for pest
limitation and bioindication. Agric Ecosyst Environ 74:229–273
McCune B, Mefford MJ (2006) PC-ORD. Multivariate analysis of
ecological data. Version 5.0. MjM Software Design, Gleneden
Beach
McNett BJ, Rypstra AL (2000) Habitat selection in a large orb-
weaving spider: vegetational complexity determines site selec-
tion and distribution. Ecol Entomol 25:423–432
Mrzljak J, Wiegleb G (2000) Spider colonization of former brown
coal mining areas—time or structure dependent? Landsc Urban
Plan 1:131–146
Mueller-Dombois D, Ellenberg H (1974) Aims and methods of
vegetation ecology. Wiley and Sons, New York
Nentwig W (1985) Prey analysis of four species of tropical orb
weaving spiders (Araneae: Araneidae) and a comparison with
araneids of the temperate zone. Oecologia 66:580–594
Nentwig W (1986) Non-web building spiders: prey specialists or
generalists? Oecologia 69:571–576
Nentwig W, Blick T, Gloor D, Hanggi A, Kropf C (2012) Spiders of
Europe. Available at: http://www.araneae.unibe.ch. Accessed 14
March 2013
Nyffeler M, Benz G (1987) Spiders in natural pest control: a review. J
Appl Entomol 103:321–339
Nyffeler M, Sterling WL, Dean DA (1994) How spiders make a
living. Environ Entomol 23:1357–1367
Oxbrough AG, Gittings T, O’Halloran J, Giller PS, Smith GF (2005)
Structural indicators of spider communities across the forest
plantation cycle. For Ecol Manage 212:171–183
Platnick NI (2013) The world spider catalog. Version 13.5. New
York: American Museum of Natural History. Available at: http://
research.amnh.org/iz/spiders/catalog. Accessed 08 May 2013
Pozzi S, Gonseth Y, Hanggi A (1998) Evaluation of dry grassland
management on the Swiss occidental plateau using spider commu-
nities (Arachnida: Araneae). Rev Suisse Zool 105:465–485
Puhringer G (1979) Productivity of spiders living in the reed belt of
lake “Neusiedler See” (Austria, Burgenland). Zool Jb Syst
106:500–528
R Development Core Team (2011) R: a language and environment for
statistical computing. Vienna: R Foundation for Statistical
Computing. Available at: http://www.r-project.org. Accessed
11 April 2013
Rickers S, Langel R, Scheu S (2006) Stable isotope analyses
document intraguild predation in wolf spiders (Araneae:
Lycosidae) and underline beneficial effects of alternative prey
and microhabitat structure on intraguild prey survival. Oikos
114:471–478
Roberts MJ (1996) Spiders of Britain and Northern Europe. Collins,
London
Robinson MH, Lubin YD, Robinson B (1974) Phenology, natural
history and species diversity of web building spiders on three
transects at Wau, New Guinea. Pac Insects 16:117–163
Rydin H, Jeglum J (2006) The biology of peatlands. Oxford
University Press, Oxford
Samu F, Sunderland KD, Szinetar C (1999) Scale-dependent dispersal
and distribution patterns of spiders in agricultural systems: a
review. J Arachnol 27:325–332
Saunders DA, Hobbs RJ, Margules CR (1991) Biological conse-
quences of ecosystem fragmentation: a review. Conserv Biol
5:18–32
Sefferova SV, Seffer J, Janak M (2008) Management of Natura 2000habitats: 7230 Alkaline fens. DAPHNE—Institute of Applied
Ecology, Slovakia
Southwood TRE, Henderson PA (2000) Ecological methods. Black-
well Science, Oxford
Souza ALT, Martins RP (2004) Distribution of plant-dwelling
spiders: inflorescences versus vegetative branches. Austral Ecol
29:342–349
Spunģis V (2005) Wasp spider Argiope bruennichi (Scopoli, 1772)(Aranea, Araneidae) in Latvia. Latvijas Entomologs 42:106–107
Stokmane M, Spungis V, Cera I (2013) Spider (Arachnida: Araneae)
species richness, community structure and ecological factors
influencing spider diversity in the calcareous fens of Latvia.
Proceedings of the 54th International Scientific Conference of
Daugavpils University. 45–55
Sudhikumar AV, MathewMJ, Sunish E, Sebastian PA (2005) Seasonal
variation in spider abundance in Kuttanad rice agroecosystem,
Kerala, India (Araneae). Eur Arachnol. 181–190
Szinetar C (2000) Data on the biology of Larinia jeskovi Marusik,
1986 (Araneae: Araneidae) from the reed belts of Lake Balaton.
Proceedings of the 18th European Colloquium of Arachnology,
Ekologia (Bratislava) 19:105–110
Tanaka K (1989) Energetic cost of web construction and its effect on
web relocation in the web building spider Agelena limbata.Oecologia 81:459–464
Tews J, Brose U, Grimm V, Tielborger K, Wichmann MC, Schwager
M, Jeltsch F (2004) Animal species diversity driven by habitat
heterogeneity/diversity: the importance of keystone structures. J
Biogeogr 31:79–92
Toti DS, Coyle FA, Miller JA (2000) A structured inventory of
Appalachian grass bald and heath bald spider assemblages and a
test of species richness estimator performance. J Arachnol
28:329–345
Uetz GW (1977) Coexistence in a guild of wandering spiders. J Anim
Ecol 46:531–541
Uetz GW (1991) Habitat structure and spider foraging. In: Bell SS,
McCoy ED, Mushinsky HR (eds) Habitat structure: the physical
arrangement of objects in space. Chapman and Hall, London, pp
325–348
Van Diggelen R, Middleton B, Bakker J, Grootjans A, Wassen M
(2006) Fens and floodplains of the temperate zone: present
status, threats, conservation and restoration. Appl Veg Sci
9:157–162
Vilbaste A (1980) The spider fauna of Estonian mires. Eesti NSV
Teaduste Akadeemia Toimetised, Koide Biologia 29:313–327
Whitcomb WH (1974) Natural populations of entomophagous
arthropods and their effect on the agroecosystem. In: Maxwell
FG, Harris FA (eds) Proceedings of the summer institute on
biological control of plant insects and diseases. University Press
of Mississippi, Jackson, pp 150–169
768 J Insect Conserv (2014) 18:757–769
123
Author's personal copy
Williams G (1962) Seasonal and diurnal activity of harvestmen
(Phalangida) and spiders (Araneida) in contrasted habitats. J
Anim Ecol 31:23–42
Wise DH (1995) Spiders in ecological webs. Cambridge University
Press, Cambridge
Xu M, Qi Y (2000) Effect of spatial scale on the relationship between
plant species richness and microclimate in a forested ecosystem.
Pol J Ecol 48:77–88
Young OP, Edwards GB (1990) Spiders in United States field crops
and their potential effect on crop pests. J Arachnol 18:1–27
Zedler JB, Kercher S (2005) Wetland resources: status, trends,
ecosystem services, and restorability. Annu Rev Env Resour
30:39–74
J Insect Conserv (2014) 18:757–769 769
123
Author's personal copy
