ArticlePDF Available

Abstract and Figures

Our understanding of arthropod responses to environmental pressures is limited, especially for the poorly studied Mediterranean region. In the light of likely further environmental change and the need for protocols for rapid biodiversity assessment, we measured how the abundance and species richness of two taxa, ground spiders and Orthoptera, belonging to different functional groups, fluctuates intra- seasonally (early-mid-late summer) and across habitat types (grasslands, maquis, forests). We also tested their surrogate value. Spiders were found to have higher species richness and abundance almost throughout the investigation. Orthoptera had lower species richness and abundance in forests compared to grasslands and maquis, while no significant difference between habitats was revealed for spiders. Early-summer was the richest period for spiders while mid-summer was the richest for Orthoptera. Canopy cover was found to significantly influence community composition of both groups, while herb height and cover of stones was a determinant factor for Orthoptera only. There was a significant congruence between the two groups and Orthoptera provided the best complementary network. Our results show that diversity patterns of both spiders and Orthoptera are sensitive to environmental changes even over short time-scales (e.g. within the summer period) and space (e.g. across different habitat types), suggesting that small inexpensive experimental designs may still reveal community dynamics. For conservation purposes, we advise a focus on variables regulating habitat heterogeneity and microhabitat characteristics. We provide a list of the most influential species and propose the most effective network for obtaining information on the local fauna.
This content is subject to copyright. Terms and conditions apply.
1 23
Journal of Insect Conservation
An international journal devoted to
the conservation of insects and related
ISSN 1366-638X
J Insect Conserv
DOI 10.1007/s10841-017-9993-z
Diversity of spiders and orthopterans
respond to intra-seasonal and spatial
environmental changes
Konstantina Zografou, George
C.Adamidis, Marjan Komnenov,
Vassiliki Kati, Pavlos Sotirakopoulos,
Eva Pitta & Maria Chatzaki
1 23
Your article is protected by copyright and
all rights are held exclusively by Springer
International Publishing Switzerland. This e-
offprint is for personal use only and shall not
be self-archived in electronic repositories. If
you wish to self-archive your article, please
use the accepted manuscript version for
posting on your own website. You may
further deposit the accepted manuscript
version in any repository, provided it is only
made publicly available 12 months after
official publication or later and provided
acknowledgement is given to the original
source of publication and a link is inserted
to the published article on Springer's
website. The link must be accompanied by
the following text: "The final publication is
available at”.
1 3
J Insect Conserv
DOI 10.1007/s10841-017-9993-z
Diversity ofspiders andorthopterans respond tointra-seasonal
andspatial environmental changes
KonstantinaZografou1 · GeorgeC.Adamidis2· MarjanKomnenov1·
VassilikiKati3· PavlosSotirakopoulos1· EvaPitta1· MariaChatzaki1
Received: 5 May 2016 / Accepted: 22 May 2017
© Springer International Publishing Switzerland 2017
and cover of stones was a determinant factor for Orthop-
tera only. There was a significant congruence between the
two groups and Orthoptera provided the best complemen-
tary network. Our results show that diversity patterns of
both spiders and Orthoptera are sensitive to environmental
changes even over short time-scales (e.g. within the sum-
mer period) and space (e.g. across different habitat types),
suggesting that small inexpensive experimental designs
may still reveal community dynamics. For conservation
purposes, we advise a focus on variables regulating habitat
heterogeneity and microhabitat characteristics. We provide
a list of the most influential species and propose the most
effective network for obtaining information on the local
Keywords Arthropods· Canopy· Grasshoppers·
Spiders· Diversity· Mediterranean· Seasonality·
Functional groups· Conservation
Despite the fact that 85% of all animal species are arthro-
pods, studies examining diversity shifts in ground-dwelling
arthropods are less common than those examining shifts in
vertebrates or charismatic arthropod taxa such as butter-
flies and moths (Chen etal. 2011). In the Mediterranean,
and especially in Greece, arthropod surveys are scarce
and our taxonomic knowledge is still limited, mainly due
to the extreme diversity of the fauna and the relatively few
taxonomists that specialize on this group (Behan-Pelletier
and Newton 1999). Additionally, practical difficulties for
their collection (e.g. cryptic lives, inaccessible microhabi-
tats, short biological cycles) make primary data difficult to
obtain. The lack of basic knowledge on their diversity in an
Abstract Our understanding of arthropod responses to
environmental pressures is limited, especially for the poorly
studied Mediterranean region. In the light of likely fur-
ther environmental change and the need for protocols for
rapid biodiversity assessment, we measured how the abun-
dance and species richness of two taxa, ground spiders and
Orthoptera, belonging to different functional groups, fluc-
tuates intra- seasonally (early-mid-late summer) and across
habitat types (grasslands, maquis, forests). We also tested
their surrogate value. Spiders were found to have higher
species richness and abundance almost throughout the
investigation. Orthoptera had lower species richness and
abundance in forests compared to grasslands and maquis,
while no significant difference between habitats was
revealed for spiders. Early-summer was the richest period
for spiders while mid-summer was the richest for Orthop-
tera. Canopy cover was found to significantly influence
community composition of both groups, while herb height
Electronic supplementary material The online version of this
article (doi:10.1007/s10841-017-9993-z) contains supplementary
material, which is available to authorized users.
* Konstantina Zografou
1 Department ofMolecular Biology andGenetics, Democritus
University ofThrace, Dragana, 68100Alexandroupoli,
2 Biodiversity Conservation Laboratory, Department
ofEnvironment, University oftheAegean, 81100Mytilene,
Lesbos, Greece
3 Department ofBiological Applications andTechnology,
University ofIoannina, 45110Ioannina, Greece
4 Present Address: Temple University, 1900 North 12th Street,
19122Philadelphia, PA, USA
Author's personal copy
J Insect Conserv
1 3
area hinders ecological research or conservation (Agnars-
son and Kuntner 2007). This explains the almost complete
absence of arthropods from conservation planning at a
national level (Sfenthourakis and Legakis 2001).
Functional groups of species (i.e. sets of species encom-
passing a variety of similar functional attributes) (Díaz
and Cabido 1997) contribute in a similar way to ecosystem
services and properties and thus permit generalizations on
species responses to environmental change (Wilson 1999).
The use of systems of interacting functional groups that
reflect environmental change differently (rather than indi-
vidual species) is an effective way of organizing empirical
research in ecology, thus increasing the value of monitor-
ing (Barton 2011). Investigating changes in arthropod func-
tional groups is a very efficient biodiversity shortcut that
could improve understanding of their ability to respond
to environmental change and provide a useful gateway to
more efficient conservation planning.
This has led us to focus on understanding the environ-
mental factors influencing diversity patterns of arthropods
in the Mediterranean region by combining data on two
different functional groups in different habitats. We chose
ground dwelling spiders (predators) and Orthoptera (herbi-
vores) in one of the most diverse areas in N.E. Greece, the
Dadia-Leukimi-Soufli National Park (Dadia NP hereafter).
Our aim was also to provide conservation biologists with
a tool to help develop effective strategies for conservation
planning in Dadia NP, focusing specifically on arthropods.
Spiders are among the most abundant predators of inver-
tebrates in terrestrial ecosystems (Symondson etal. 2002).
They are significant predators of many herbivore species
and also provide food for other canopy foragers, such as
ants and birds (Halaj etal. 1997). They also contribute to
many ecosystem processes (e.g. nutrient cycling (Lawrence
and Wise 2000)). The high taxonomic and functional diver-
sity of spiders justifies their use as a model group for study-
ing large-scale ecological patterns (Birkhofer and Wolters
2012; Cardoso et al. 2011). Orthopterans are apparently
under threat as their diversity declines in many temperate
regions (Marini etal. 2010), and in Europe 50% are consid-
ered endangered (Hochkirch etal. 2016). In addition, they
are important primary and secondary consumers in grass-
land ecosystems, and they provide an abundant source of
prey for many predators (e.g. insectivorous birds, spiders).
For several regions and biomes Orthoptera have been sug-
gested as appropriate bioindicators (Báldi and Kisbenedek
1997) due to their sensitivity to microclimatic conditions
(Zografou etal. 2009).
Thermal conditions are known to greatly affect all
arthropods because increased ambient temperatures have a
direct effect on their metabolic rates, activity patterns and
developmental rates. For Orthoptera, thermal conditions
might even determine their ability to avoid predators (Pitt
1999). For spiders, different climatic conditions between
early and late spring were found to affect their activity and
density patterns (Öberg et al. 2008). Given that climatic
variability operates over all time scales, even very short
ones (Ghil 2002), different thermal conditions within sea-
sons may control species activity patterns (e.g. within sea-
son abundance shifts), leading to sizeable effects at the
community level.
Another factor that is known to drive diversity patterns
of both ground spiders and Orthoptera is vegetation com-
position and structural characteristics including herb cover
and height, bare ground, and cover of stones (Standish
2004; Stromberg and Tellman 2012). Structural differences
can modify temperature, light intensity, and soil moisture,
which in turn can determine the distribution and diversity
patterns of arthropods (Guido and Gianelle 2001; Nufio
etal. 2010). An example of changes in vegetation structure
is forest re-establishment at the expense of open areas (Bar-
bero etal. 1990; Debussche etal. 1999) due to the reduction
of human densities in many rural areas in the Mediterra-
nean. This, in turn, has led to reduced species richness and
diversity of ground spiders (Zakkak etal. 2014). Likewise,
vegetation coverage and habitat desiccation were found to
constrain the distribution of spiders (Lambeets etal. 2008;
Perner and Malt 2003). Changes in other habitat-specific
variables such as the cover of flower-heads, presence of
shrubs or altitudinal changes were shown to greatly influ-
ence the Orthoptera community (Zografou etal. 2009).
The northern part of Greece was recently found to have
the most prominent seasonal trend in terms of temperature
alterations during the summer as opposed to the winter or
autumn period (Mamara et al. 2016). Given that weather
conditions from June to August are clearly distinct, Dadia
NP provides an excellent opportunity to study the intra-
seasonal activity of arthropods over a short time span i.e.
within summer.
Recent studies in Dadia NP showed that changes in tem-
perature have already impacted diversity patterns, commu-
nity composition and phenological patterns of butterflies
and orthopterans (Zografou et al. 2014, 2015). Further
climate warming (IPCC 2013) is likely to affect spiders
and orthopterans differently (Barton 2010, 2011), and also
cause changes in vegetation structure (Debussche et al.
1999). We adopted this combined approach of time- and
habitat-dependent structure and we documented the differ-
ences on diversity patterns of these two functional groups.
Specifically, we addressed the following questions: (a)
is there a significant difference in abundance and richness
of spiders and orthopterans intra-seasonally? (b) is there a
consistent effect of habitat type on diversity of spiders and
orthopterans? (c) are there any common habitat-specific
variables shaping spider and orthopteran community com-
position? and (d) which species are responsible for possible
Author's personal copy
J Insect Conserv
1 3
differences in the community structure intra-seasonally and
between habitats? Since each taxon displays an individual-
istic response to current pressures, dictated by its specific
ecological demands (Peñuelas et al. 2013; Rapacciuolo
etal. 2014) we expected to find significant differences in
activity patterns of the study organisms. In particular, we
expected that microhabitat characteristics (e.g. flower-
heads, shrubs, stones) will have a significant impact on
Orthoptera (Kati etal. 2004; Zografou etal. 2009), while
habitat characteristics such as openness (e.g. grasslands)
or closeness (e.g. forests) would affect spiders (Buchholz
2010; Zakkak etal. 2014). For spiders, we expected to find
increased activity in grasslands or maquis in the early-sum-
mer period, as spiders are known to populate open areas
during that time, after leaving their overwintering sites
(Bertrand etal. 2016). Previous studies on the phenology
of ground spiders in other Mediterranean areas (i.e. Maja-
das and Urones 2002; Jiménez-Valverde and Lobo 2006;
Cardoso etal. 2007) or in Greece (i.e. Chatzaki etal. 1998,
2005) confirm that late spring to early autumn is the period
of maximum activity, with variations depending on local
climate fluctuations. Our previous studies of Orthoptera in
the study area (Kati etal. 2004) and elsewhere (Kati etal.
2012; Zografou etal. 2009) showed that peak abundance
occurs in mid-summer, i.e. the hottest period of the sea-
son. Finally, we explored the value of ground spiders and
Orthoptera as biodiversity surrogates as well as their com-
plementarity. When data availability and funds are limited
but diversity is high, it is suggested to rely on few biodi-
versity surrogates for data acquisition, suitable for proper
prioritization of conservation efforts.
Materials andmethods
Study area andsites
The study area was Dadia NP in N.E. Greece
(41°07–41°15N, 26°19–26°36E) (Fig. 1). It is a hilly
area extending over 43,000ha, with altitudes ranging from
20 to 650m. It includes two strictly protected core areas
(7290 ha), where only low-intensity activities such as
extensive grazing and selective wood cutting are allowed
on a periodical basis. The climate is sub-Mediterra-
nean, with a mean annual rainfall of 653mm and a mean
annual temperature of 14.3 °C, (min in January and max
in July–August), while the hot and arid summer season
extends from July to September (mean temperature 25 °C,
mean rainfall 210mm) (Maris and Vasileiou 2010). Along
with the dry and hot summers that characterise Dadia NP,
a significant increase in average temperature of 0.95 °C has
been documented in a 22 year-period (1990–2012) (Zogra-
fou et al. 2014). Seventy-five percent of the reserve is
covered by pinewoods (Pinus nigra, Pinus brutia), broad-
leaved woods (Quercus frainetto, Quercus cerris, Quercus
pubescens), mixed pine-oak woods and maquis, whilst
Fig. 1 Map of Greece showing
the location of Evros prefec-
ture (left figures), the area of
Dadia-Lefkimi-Soufli National
Park (right figure) with the core
areas (polygons in dotted lines)
and the 12 sites where sampling
took place. Two out of the
twelve sites are located outside
the borders of the National Park
Author's personal copy
J Insect Conserv
1 3
the semi-open forested zone covers 5%, agricultural fields
cover 16% and grasslands and open habitats cover only 4%
(Poirazidis etal. 2002). Both pine and oak habitats reflect
the original Mediterranean vegetation at low altitudes. We
recognised three dominant habitat types: forests, grass-
lands and maquis and we located four sampling sites in
each, resulting to a total of 12 sites (Supplementary Online
Material, TableS1). The mean distance between sites was
1.2 km ± 0.5 (SE) so that each site represented an inde-
pendent sample in which diversity measures depend much
more on local activity of organisms than on immigration
from neighbouring sites.
Arthropod sampling
On the basis of a significant intra-seasonal variation of
mean temperature values from early to late summer (June
has significantly lower temperature from July and July
greater than August) sampling was conducted during the
extended summer period from late May to early Septem-
ber 2011. Orthoptera sampling was conducted along two
transects of 30m length and 2m width in each sampling
site, with a minimum distance of 100 m between the 24
transects. Adult specimens of Orthoptera were caught in a
sweep net, counted, and identified ex situ using the Greek
Orthoptera guide (Willemse 1985). Ground dwelling spi-
ders were sampled using pitfall traps. Five traps were
located at 10m intervals along every orthopteran transect,
(5 traps/transect and 10 traps/site) resulting in a total of 120
traps. The traps remained active for 94 (± 6) days on aver-
age from late May to early September and were emptied
three times. The three sampling periods were: 20. 5–25. 6.
2011 (early-summer), 25. 6–27. 7. 2011 (mid-summer) and
27. 7–3. 9. 2011 (late-summer). On average only nine (± 1)
traps were active per site due to losses from animal interfer-
ence and heavy rain. Each trap was filled with 200ml of
ethylene glycol (preservative) and was covered with a stone
roof for protection against rain. Samples were transferred
to 95% isopropyl-alcohol and subsequently sorted. As there
are no extensive keys available for Greek spiders, identifi-
cation was from existing literature related to the region and
the online database for European spiders (http://www.ara- Our taxonomic results were presented in a
separate paper (Komnenov etal. 2016). Species names fol-
low the nomenclature of the World Spider Catalog (Catalog
2016). The material is deposited in the Araneae collection
of the Natural History Museum of the University of Crete.
Habitat-specific variables
We recorded ten habitat-specific variables for orthopterans
and spiders in standard plots (5 ×2m2) by systematically
locating four orthopteran plots along each transect (every
10m: 96 plots) and one spider plot around every pitfall trap
(120 plots). Using a hand GPS we took the coordinates and
recorded the altitude (1). To estimate the temperature (2)
and soil humidity (3) at each site, we extracted data from
a Hobo data logger (U12) that was placed at the beginning
of each orthopteran transect and remained there for as long
as the sampling was conducted (15min with one record per
minute). In addition, we estimated the average percentage
canopy cover (4) per plot using a spherical densiometer
(measures at four cardinal directions in July 2011), as well
as the cover of herbs (5), shrubs (6), bare ground (7) and
stones (8) using the Braun–Blanquet scale (5: 75–100%,
4:50–75%, 3: 25–50,% 2: 5–25%, and 1: 0–5%). Finally,
we estimated mean herb height (9) as the average of four
measures corresponding to four dominant herb species as
well as the number of flower-heads (10) in May (2011)
using a five grade scale (1 ≤ 10, 2 > 10, 3 > 50, 4 > 100,
5 > 200).
Data analysis
Our dataset consisted of 12 sites and three samples (early-
mid-late summer period). In order to standardize sampling
effort in the whole experiment, for each sample in each site,
we estimated spider abundance as the total number of indi-
viduals caught in all pitfall traps, divided by the number of
active traps and the number of active sampling days, multi-
plied by 1000 thus rendering it to a standardised measure of
number of individuals per 1000 trap-days. For Orthoptera,
we considered both transects in each site as one sample
and we estimated a mean value of Orthoptera abundance in
terms of the number of individuals counted per site. Beta-
diversity was also used to quantify species turnover within
the summer period and across the habitat types using Whit-
taker’s formula for beta diversity (bw = S/ā 1), where S
is the total number of species in that period or habitat and
ā the average number of species in these periods or habi-
tats (Whittaker 1960). We calculated the proportion of spe-
cies exclusively found in only one repetition for each target
group separately.
The time andhabitat effect indiversity patterns
We used general linear models to investigate differences
in ground spider and Orthoptera species (a) richness
and (b) abundance in time and habitat types. In particu-
lar, each model described the response variable (species
richness or species abundance) as a function of the fac-
tors “taxon”, “intra-season”, “habitat type”, “site” and the
interactions of “taxon×intra-season” and “taxon×habi-
tat type”. The response variables were normalized using
log-transformation allowing the specification of a normal
error distribution. Models were validated by checking for
Author's personal copy
J Insect Conserv
1 3
homoscedasticity and normality of the residuals (Zuur
etal. 2009), and in all cases, diagnostic graphs showed that
model assumptions were met. Post-hoc tests (Tukey) were
conducted to further explore the interaction terms. Statis-
tical analyses were performed in R (R Core Team 2014)
using library faraway for lm () function, and library esti-
mability for lsmeans () function for post hoc tests (Lenth
The effect ofhabitat-specific variables incommunity
In order to explore the effect of habitat-specific variables
(ten in total) on species composition, we conducted Redun-
dancy Analysis (RDA) using CANOCO software (ter Braak
and Smilauer 2002). Preliminary analyses were made
using Detrended Correspondence Analysis [DCA, Hill and
Gauch (1980)] to check the magnitude of change in spe-
cies composition along the first ordination axis. Since the
gradient length was found to be smaller than 4 SD-units
(gradient length in standard deviation (SD) units, RDA
was the appropriate ordination method to perform analysis
and determine how much of the variation in species data
is accounted for by the environmental data (Ter Braak and
Prentice 1988). The RDA method extracts the major gra-
dients in the data that are accounted for by the measured
environmental parameters. The position of a species in the
resulting diagram indicates the degree of dependence on
the closest environmental parameters (arrows). The dia-
gram shows only the species sufficiently influenced by the
parameters (fit > 10%), and only the significant (P < 0.05)
environmental variables that did not show collinearity
(1,000 iterations of the Monte–Carlo test).
The most influential species
To pinpoint the most influential spider and orthopteran spe-
cies that contributed most to the observed differences dur-
ing the three summer periods and between open and closed
canopy cover areas, we used the SIMPER (Similarity
Percentage) method and the Bray-Curtis similarity meas-
ure (Clarke 1993). The classification between open and
closed areas was done on the basis of canopy cover per-
centage (%): sites with >50% of canopy cover were clas-
sified as closed and sites with <50% as open. In addition,
each species was given a vulnerability index from one (the
least vulnerable) to three (the most vulnerable). An index
of “one” was attributed to species that were found to be
the most influential during the mid-summer period. This
is because they are expected to be better synchronized to
their food resources compared to species represented ear-
lier or later (Donoso etal. 2016). An index of “two” was
given to species that increased their influential role in
late-summer, but for which the open/closed areas did not
seem to be effective. An index of “three” was given to spe-
cies that were found to be most influential both in the early-
or late-summer period and in open habitats. One of the best
studied species responses to climate change is the advanced
appearance. The response is more pronounced for species
that appear early or late in the season (McKinney et al.
2012). Therefore, species that will be found to be the most
influential in terms of the early- or late-summer period are
expected to have a higher vulnerability in the light of cli-
mate warming. Also, as the open areas are known to posi-
tively affect arthropod communities, if these areas are lost
or decreased at the expense of forests, this might present a
possible threat to these arthropods. We used PAST version
2.17c for SIMPER analysis (Hammer etal. 2001).
Surrogate value
We tested the surrogate value of (a) ground spiders and
(b) Orthoptera by comparing the congruence of their spe-
cies richness patterns using the Spearman rank correlation
coefficient. Using one group as the surrogate group and the
other as the target group, we formed the complementary
network after the surrogate group, starting with the most
species-rich site and adding those sites progressively con-
tributing more new species, until all species were included
in the network (Cardoso etal. 2004; Zografou etal. 2009).
By calculating the proportion of species in every group
included in each step of the networking procedure, we were
able to assess the most efficient complementary network,
thus eliminating the bias of the different number of sites
forming the network.
Single taxon diversity
Our dataset consisted of 136 spider species (22 fami-
lies, 2,403 individuals) out of which 12 species are new
records for Greece and seven species are new for science
(Komnenov etal. 2016) (Supplementary Online Material,
Table S2). The most abundant families were Gnaphosi-
dae (36.5%; 878 ind.), Dysderidae (20.6%; 496 ind.) and
Lycosidae (16%; 392 ind.). More spider species (26%)
were encountered exclusively in early summer and fewer in
mid (13%) and late summer (12.5%). Species turnover was
lower from the first to the second period (bw = 0.36) and
second to third (bw = 0.48) than first to third (bw = 0.54).
Accordingly, species turnover was greater between forests
and maquis (b
w = 0.67), and between forests and grass-
lands (b
w = 0.6) than grasslands and maquis (bw = 0.34).
We recorded 39 species of orthopterans (five families,
Author's personal copy
J Insect Conserv
1 3
2,628 individuals), with Acrididae (57%; 1,497 ind.) and
Tettigoniidae (34%; 893 ind.) being the most abundant
families (TableS2). The most important species in terms
of conservation, listed as endangered in the IUCN 2016
list (Hochkirch etal. 2016) is Paranocarodes chopardi, an
apterous pamphagid, with low dispersal ability that renders
it prone to extinction if its habitat changes (Kati and Wil-
lemse 2001). Most orthopteran species were encountered
exclusively in mid-summer (20.5%), fewer in early summer
(15.4%) and the least in late summer (8%). Species turno-
ver was higher from the first to the second period (bw=0.7)
and first to third (bw=0.6) than second to third (bw=0.37).
Species turnover across habitat types was higher between
forests and grasslands or maquis (bw = 0.5) than between
grasslands and maquis (bw =0.38).
The effect oftime andhabitat type ondiversity patterns
The main effects of “taxon”, “habitat type” and “site” on
abundance were significant, while no significant main
effect of “intra-season” was revealed (Table 1). The post-
hoc Tukey test for the factor “taxon” showed a significantly
higher abundance for spiders than Orthoptera (P < 0.001).
Forests had significantly lower abundance than both grass-
lands and maquis habitats (Tukey: P = 0.003 and P = 0.038
respectively), while grasslands and maquis had similar
abundance (Tukey: P = 0.61). The two interactions included
in the model were found to be significant at the 0.05 level
(Table1) indicating that differences between both habitat
types and intra-seasonally affected the response of abun-
dance to taxon. The post-hoc Tukey tests revealed that
spiders always had higher abundance than Orthoptera
(Fig.2a, b) except in the maquis habitats (P = 0.07; Fig.2a)
and in the mid-summer period which were marginally
significantly different in abundance (P = 0.056; Fig. 2b).
Orthoptera were significantly less abundant in forests
than in grasslands (Tukey: P = 0.005; Fig.2a) and maquis
habitats (Tukey: P = 0.007; Fig. 2a). However, the abun-
dance of orthopterans was similar in grasslands and maquis
(Tukey: P = 0.062; Fig.2a). Interestingly, spider abundance
did not significantly differ in the different habitat types
(Tukey: P > 0.05 in all cases; Fig.2a). Finally, there was no
Table 1 Effect of habitat
type and intra-seasonal
differentiation between the
two taxa (ground spiders,
Orthoptera) in terms of species
richness and abundance
Response Predictors df F value P value Tukey post hoc tests
Abundance Habitat type 3 586.63 *** Grassland > forest
Taxon 1 80.68 *** Spiders > Orthoptera
Intra-season 2 0.23 ns
Sites 9 2.87 **
Habitat type × taxon 2 6.93 ** (See Fig.2a)
Intra-season × taxon 2 8.00 *** (See Fig.2b)
Species richness Habitat type 3 435.12 *** Grassland, maquis > forest
Taxon 1 114.27 *** Spiders > Orthoptera
Intra-season 2 0.59 ns
Sites 9 1.29 ns
Habitat type × taxon 2 0.51 ns (See Fig.3a)
Intra-season × taxon 2 12.31 *** (See Fig.3b)
Fig. 2 Abundance of Orthoptera and spiders across a different habi-
tat types and b intra-seasonally. Different lower case letters indicate
significant differences (at P < 0.05) among the two taxa, by Tukey
post-hoc tests. All results are means of original data ± SE
Author's personal copy
J Insect Conserv
1 3
significant difference in abundance of either taxa intra-sea-
sonally (Tukey: P > 0.05 in all cases; Fig.2b).
The second model, with species richness as the response
variable, showed that the main effects of the factors
“taxon” and “habitat type” were significant, but not signifi-
cant was the effect of “intra-season” and “site” (Table1).
Species richness was significantly higher for spiders than
for Orthoptera (Tukey: P < 0.001). In addition, grass-
lands and maquis had higher species richness than forests
(Tukey: P < 0.001 in both cases; Fig.3a), while grasslands
and maquis had similar species richness (Tukey: P = 0.82;
Fig. 3a). The only significant interaction “taxon × habitat
type” indicates that differences between habitat types did
not affect the response of species richness to taxon. Spiders
had significantly higher species richness than Orthoptera,
across all different habitat types (Fig.3a) and intra-season-
ally (Fig. 3b). Orthoptera had significantly lower species
richness in forests than in grasslands (Tukey: P = 0.005;
Fig. 3a) and maquis habitats (Tukey: P = 0.006; Fig.3a).
However, orthopterans had similar species richness in
grasslands and maquis (Tukey: P > 0.05; Fig. 3a). The
species richness of spiders was not significantly different
across the different habitat types (Tukey: P > 0.05 in all
cases; Fig. 3a). Orthoptera presented significantly lower
species richness values in the early-summer than in the two
following periods (Tukey: P = 0.002 and P = 0.001 respec-
tively; Fig.3b), while the mid and late-summer had simi-
lar species richness (Tukey: P > 0.05 in all cases; Fig.3b).
On the contrary, spiders had significantly higher species
richness in early-summer than in the late-summer (Tukey:
P = 0.04; Fig.3b), while the mid-summer period had simi-
lar species richness to all other periods (Tukey: P > 0.05 in
all cases, Fig.3b).
Environmental factors shaping community composition
Among habitat-specific variables, increased canopy cover
was found to be the most influential factor for spider com-
munities, negatively affecting 72% of the species (61%
of the total variance explained, Fig. 4). Among newly
described spider species, some (Dysdera kati, Dysdera
krisis and Harpactea wolfgangi) were positively affected
by increased canopy cover, while others (Harpactea ice,
Phrurolithus thracia and Zodarion beroni) were nega-
tively affected (Fig. 4, Table S2). In addition to canopy
cover, herb height and cover of stones were found to sig-
nificantly influence the Orthoptera community. Increased
canopy cover negatively affected 74% of species, while
P. chopardi, a typical species for semi-shaded oak woods
with Mediterranean scrub undergrowth and leaf litter (Kati
etal. 2010), was positively affected by this factor. Increased
herb height and cover of stones positively affected 59 and
64% of species respectively (46.5% of the total variance
explained, Fig.4, TableS2).
Most influential species
Nine spider species belonging to six families were respon-
sible for more than 50% of the intra-seasonal differences,
while six species were responsible for the differences
between open and closed canopy areas; six species were
common in both cases (Table2). For Orthoptera, SIMPER
analysis indicated seven species that explained more than
50% of the differences intra-seasonally and between closed
and open canopy areas (Table2).
Surrogate value
We found significant congruence between patterns of
species richness of spiders and Orthoptera (rho = 0.73,
P = 0.007). Orthoptera served as the best surrogate group
where complementarity is concerned. Their network
included nine sites as opposed to twelve sites of the spider
Fig. 3 Species richness of Orthoptera and spiders across a differ-
ent habitat types and b intra-seasonally. Different lower case letters
indicate significant differences (at P < 0.05) among the two taxa, by
Tukey post-hoc tests. All results are means of original data ± SE
Author's personal copy
J Insect Conserv
1 3
network, which, basically, corresponded to the whole study
system (12 sites). The Orthoptera network conserved 88.9%
of the ground spider species and when comparing the aver-
age species richness included in each step of the comple-
mentary network selection, it succeeded in conserving
even more orthopterans (13%) and lost only 6.6% of spider
Time andhabitat effect
In this study, we found both season and habitat type sig-
nificantly influenced the arthropod assemblages in the
Dadia NP. As expected, responses were not consistent
between Orthoptera and spiders and their diversity meas-
ures. Regarding the within-season results, patterns of
variation in both species richness and abundance between
the two groups were different. Also, ground spiders were
always more abundant and rich in species than Orthop-
tera, except during the mid-summer period where differ-
ences in abundance of the two groups were not signifi-
cant. The species turnover analysis showed that many of
the spider species that are highly active in the early-sum-
mer period, also persist into mid-summer, but then they
are replaced by a few other species that are only highly
active in late summer. This phenological pattern has been
reported for Mediterranean Gnaphosidae before (Chat-
zaki etal. 2005). The analysis of the most influential spe-
cies showed that there are two highly influential spider
species with maximum activity in the early summer (Har-
pactea babori and Pardosa alacris) and two in the late
summer (Scytodes thoracica and Zelotes erebeus), but
only one in mid-summer (Civizelotes caucasius). These
observations, in conjunction with the short life cycle of
Orthoptera with peak activity in mid-summer (Kati etal.
2004) could explain the reduced differentiation between
the two groups during this period. The higher species
richness of spiders in the early-summer period indicates
the importance of this season for local biodiversity sug-
gesting it is the optimal time for sampling spiders in case
of low duration/budget inventories.
The results showed that grasslands and maquis hosted
more species than forests in both taxa examined. Habi-
tat openness, therefore, is the main driver of spider and
Orthoptera species richness in Dadia NP (Kati etal. 2004).
In fact, the positive effect of the open habitat structure
explains the lack of any significant interaction between the
factors “taxon” and “habitat type” in our models. How-
ever, for spider abundance, the pattern is not repeated since
both forests and grasslands host an equally high number of
individuals, resulting in non-significant variation among
habitat types (Fig.2a). Five out of the six most important
spider species that affect differences between open and
closed canopy cover areas had maximum activity in closed
forest habitats. Species turnover analysis, however, showed
that species inhabiting forests differed from those of grass-
lands or maquis, clearly demonstrating niche separation of
ground spiders. Given the lower species richness in forests,
a lessened inter-species competition may be expected and
hence an increase in the numbers of individuals of the spe-
cies that persist there. The preference of some of the spe-
cies for closed habitats has been previously documented, as
in the case of P. alacris which is known to prefer deciduous
oak and beech woods (Töpfer-Hofmann etal. 2000). How-
ever in most cases this study is the first to demonstrate clear
ecological preferences of the spider species recorded.
Fig. 4 Redundancy analysis diagram (RDA) presenting the signifi-
cant (P = 0.05) environmental factors affecting the community of spi-
ders and Orthoptera. Only species with a fit of more than 10% are
shown. Full names of the newly described spider species (>10% fit)
are given on the plots while all others are symbolized with a num-
ber (for corresponding species numbers and names see TableS2). For
Orthoptera, only the name of the most important species in terms of
conservation concern is provided
Author's personal copy
J Insect Conserv
1 3
Table 2 Species responsible for the observed differences intra-seasonally and between open versus closed areas using the Bray–Curtis similarity measure
According to this index, species having their maximum abundance in the start or in the end of the summer period and indicative for open areas will take the highest index number (i.e. “three”)
O orthopteran, S spiders, Intra-seasonal maximum abundance in early-mid-late summer, Canopy maximum abundance in open or closed canopy cover areas, Summer contr% ranked percentage
abundance per species considering the summer period, Early-Mid-Late summer contr% percentage of abundance per species considering early-mid-late summer period, Canopy contr% percent-
age of abundance per species considering the whole study area (all 12 sites), Close–open contr% percentage of abundance per species considering either open or closed canopy cover areas, Vul.
Ind the vulnerability index for each species based on climate sensibility and vegetation alterations scenarios (further details in the main text)
Taxon Species name Intra-seasonal Canopy Summer contr% Early sum-
mer contr%
Mid sum-
mer contr%
Late sum-
mer contr%
Canopy contr % Close contr% Open contr% Vul. Ind
OChorthippus bornhalmi Late Open 12.44 0.792 0.417 1.79 7.80 2 3.5 3
OTylopsis lilifolia Mid Open 8.44 0.667 1.67 0.25 9.31 0.75 3.5 1
OPoecilimon brunneri Early Open 7.51 1.42 0 0 5.73 0.25 2 3
OCalliptamus italicus Mid Open 6.98 0 1.79 0.167 8.79 0 2.94 1
OAcrida ungarica Mid Open 6.92 0 1.46 0.375 7.84 0 2.75 1
OOedipoda caerulescens Mid Open 6.44 0 1.17 0.667 7.41 0.125 2.69 1
OPezotettix giornae Mid Open 5.51 0.25 0.875 0.458 5.83 1 1.88 1
SHarpactea babori Early Closed 14.25 23.2 4.42 5.83 23.82 88.30 6.00 3
SCivizelotes caucasius Mid Open 8.95 2.33 11.9 4.5 7.86 0.00 28.10 1
SScytodes thoracica Late Closed 6.63 1.5 3.25 7.92 6.31 19.80 9.13 3
SAlopecosa albofasciata Early Ineffective 4.82 7.17 0.417 0.167 3
SZodarion morosum Late Ineffective 4.71 2.25 3.17 4.33 2
SHogna cf. radiata Late Ineffective 4.05 0 2.42 3.83 2
SPardosa alacris Early Closed 4.05 10.5 1.92 0.333 6.93 37.50 0.38 2
SZelotes erebeus Late Closed 3.48 0 0 6.33 4.16 19.00 0.00 3
SDrassyllus praeficus Early Ineffective 2.04 4.5 1 0 2
Author's personal copy
J Insect Conserv
1 3
Orthoptera showed a consistent pattern of preference
for open canopy cover areas. As found in previous stud-
ies in Dadia NP (Kati etal. 2004) and elsewhere (Kati
etal. 2012; Zografou etal. 2009), our results for Orthop-
tera demonstrated the importance of open habitats for
the conservation of this group. The conservation value
of open habitats, and the importance of habitat-specific
variables (e.g. shade, herb height, stones) at a com-
munity level are discussed below (Guido and Gianelle
2001; Zografou etal. 2009).
Habitat-specific variables shaping community
Both spider and orthopteran communities were negatively
affected by canopy cover (72 and 74% respectively). In
a recent review of biodiversity indicators for forest eco-
systems in Europe, the authors found that there is strong
evidence for a negative correlation between tree canopy
cover and spider species richness (Gao etal. 2014). Simi-
larly, a study conducted in the Greek mountains of Pindos
(Zakkak etal. 2014) showed that community composition
of ground spiders of the family Gnaphosidae is signifi-
cantly affected by land-abandonment with their diversity
and species richness being negatively correlated with for-
est cover. Orthoptera are well known to prefer open, dry
and warm habitats with short vegetation (Uvarov 1966),
although there are a few exceptions such as P. chopardi,
a species typical to oak woodlands with a very narrow
distribution restricted to Dadia NP and few localities in
Bulgaria (Kati etal. 2004).
The Orthoptera community was also found to be
greatly affected by herb height and concomitant changes
in rock cover. As herbs are the main food source for all
orthopterans, although bush-crickets have a mixed diet
consisting of other insects and flower parts, it seems rea-
sonable that increased herb cover positively affected 59%
of the species. With a range of more than half a meter,
herb height creates multiple microhabitats that can sup-
port a great variety of species with different ecological
requirements, providing also shelter from predators and
extreme climatic conditions (Kemp etal. 1990). However,
tall herbs might be an indication of increased shading or
lack of grazing that are well-known to negatively affect
egg and nymph development of some orthopteran species
(van Wingerden etal. 1991). The second element, rock
cover, seems to have an even greater positive influence
on Orthoptera (64%). It is known that rocks are important
structures, aiding in orthopteran thermoregulation as well
as providing shelter (Chappell 1983) and their positive
correlation to species richness has been previously dem-
onstrated (Crous etal. 2013).
The most influential species
Another interesting finding of this study is the list with
the most influential species (Table2). As climate warm-
ing is linked to a changing onset of phenological events
for a variety of taxonomic groups (Menzel et al. 2006;
Parmesan 2007; Primack etal. 2009) we expect that spe-
cies most abundant in early or late summer (e.g. Chorthip-
pus bornhalmi, Poecilimon brunneri, H. babori) will be
strongly influenced by climate warming. It is also plausi-
ble to assume that species that are most abundant in open
areas (e.g. Tylopsis lilifolia, Civizelotes caucasius) might
be seriously threatened by shifts in vegetation structure
such as, for example, forest encroachment on open habi-
tats (Debussche etal. 1999; IPCC 2013). On the basis of
anticipated further changes in climate and landscape, we
proposed a “vulnerability index” for each of the most influ-
ential species so that conservation efforts could be prior-
itized accordingly.
Surrogate value
Spiders and Orthoptera share no similar traits in their life
history and ecology (Barton 2011). However, our results
reveal a strong congruence in their species richness pat-
terns, suggesting the possible use of each taxon as a good
surrogate for the other. Although Orthoptera have been
previously tested for their surrogate value (Bazelet and
Samways 2012; Zografou et al. 2009), fewer studies can
be found on the surrogate value of spiders (but see Car-
doso etal. 2004), and none, to our knowledge, that inves-
tigates the surrogate value of spiders for Orthoptera and
vice versa. Given that, only recently, the rich spider fauna
of Dadia NP started to be investigated or described (Kom-
nenov etal. 2016), the identification of shortcuts such as
Orthoptera species network is expected to provide cost- and
time-effective monitoring schemes improving our ability
to better conserve the local fauna (Margules and Pressey
Seasonal variation in species activity is a normal event
in temperate ecosystems. However, our results demon-
strated that significant differentiation of species richness
and abundance can occur even within a season, such as
the summer period. Our findings highlight the value of
low-cost, short-term inventories for revealing commu-
nity dynamics and confirming that the choice of sampling
period is highly taxon-specific. Our study also suggests
the importance of open habitats for the conservation of
both herbivores and predators. However, some influen-
tial spiders’ species seem to benefit from closed habitats.
Author's personal copy
J Insect Conserv
1 3
Therefore, although the presence of grasslands or maquis
would greatly favour herbivores, forests too play a ben-
eficial role for spiders. It is suggested that for predators
and especially for spiders, preservation of landscape het-
erogeneity rather than openness is the most crucial factor
for their diversity as has been proposed in previous stud-
ies (Zakkak etal. 2014). In addition, the different effects
of other environmental factors we studied, showed that
arthropods do not respond in the same way, emphasizing
the need for multi-taxa approaches in ecological studies.
In the light of future land-use changes in the Medi-
terranean (Barbero et al. 1990; Debussche et al. 1999;
Gerard etal. 2010), we identified a pool of nine spiders
and seven orthopterans that drives community patterns
and can be a useful tool for conservation biologists.
Apart from its conservation value, this analysis offers a
well-documented observational framework of species
activity in the Mediterranean region, contributing to the
otherwise limited knowledge about their ecological pref-
erences. Finally, the proposal of the Orthoptera species
network as the best surrogate group in terms of comple-
mentarity accentuates the important role of biodiversity
studies in high biodiversity areas such as Greece. The
importance of spider and orthopteran diversity in the
Dadia NP, merits further ecological study and monitoring
in order to obtain detailed information on their popula-
tion trends.
To conclude, analysing summer samplings that incor-
porate both open and closed canopy sites with a high var-
iability of habitat-specific variables seems necessary to
better assess how time and habitat structure affect groups
with different ecological attributes. Conservation man-
agers should prioritize their conservation efforts in the
light of the most influential/vulnerable species but also
consider the complementarity value of Orthoptera when
planning future conservation actions.
Acknowledgements This project was co-funded by the European
Union (European Social Fund) and National Resources under the
Operational Programme “Education and Lifelong Learning” Action
81324 - SPIDOnetGR, ARISTEIA II Programme, NSRF 2007–2013.
In addition, it has been co-financed by the European Union (European
Social Fund - ESF) and Greek national funds through the Operational
Program “Education and Lifelong Learning” of the National Strategic
Reference Framework (NSRF) - Research Funding Program: Hera-
cleitus II. Investing in knowledge society through the European Social
Fund. We are grateful to the Forestry Department of Dadia NP, and
WWF for supporting the field research. Finally we wish to thank the
two anonymous reviewers for their valuable help in improving the
manuscript analyses and structure. We are deeply grateful to Dr A.
Russell-Smith who -as a native speaker – performed a thorough lin-
guistic revision of the last version of the manuscript.
Agnarsson I, Kuntner M (2007) Taxonomy in a changing world:
seeking solutions for a science in crisis. Syst Biol 56:531–539.
Báldi A, Kisbenedek T (1997) Orthopteran assemblages as indica-
tors of grassland naturalness in Hungary. Agric Ecosyst Envi-
ron 66:121–129. doi:10.1016/S0167-8809(97)00068-6
Barbero M, Bonin G, Loisel R, Quézel P (1990) Changes and dis-
turbances of forest ecosystems caused by human activities in
the western part of the mediterranean basin. Vegetatio 87:151–
173. doi:10.1007/bf00042952
Barton BT (2010) Climate warming and predation risk during herbi-
vore ontogeny. Ecology 91:2811–2818. doi:10.1890/09-2278.1
Barton BT (2011) Local adaptation to temperature conserves
top-down control in a grassland food web. Proc R Soc B
278:3102–3107. doi:10.1098/rspb.2011.0030
Bazelet CS, Samways MJ (2012) Grasshopper and butterfly local
congruency in grassland remnants. J Insect Conserv 16:71–85.
Behan-Pelletier V, Newton G (1999) Computers in biology: link-
ing soil biodiversity and ecosystem function - the taxonomic
dilemma. Bioscience 49:149–153
Bertrand C, Baudry J, Burel F (2016) Seasonal variation in the
effect of landscape structure on ground-dwelling arthropods
and biological control potential. Basic Appl Ecol 17:678–687.
Birkhofer K, Wolters V (2012) The global relation-
ship between climate, net primary production and the
diet of spiders. Global Ecol Biogeogr 21:100–108.
Buchholz S (2010) Ground spider assemblages as indicators for
habitat structure in inland sand ecosystems. Biodivers Conserv
19:2565–2595. doi:10.1007/s10531-010-9860-7
Cardoso P, Silva I, De Oliveira NG, Serrano ARM (2004) Indi-
cator taxa of spider (Araneae) diversity and their efficiency
in conservation. Biol Conserv 120:517–524. doi:10.1016/j.
Cardoso P, Silva I, Oliveira NG, Serrano ARM (2007) Seasonality of
spiders (Araneae) in Mediterranean ecosystems and its implica-
tions in the optimum sampling period. Ecol Entomol 32:516–526
Cardoso P, Pekár S, Jocqué R, Coddington JA (2011) Global pat-
terns of guild composition and functional diversity of spiders.
PLoS ONE. doi:10.1371/journal.pone.0021710
Catalog WS (2016) World Spider Catalog. Natural History Museum
Bern, online at, version 17.0, (Accessed on
30 Jan 2016)
Chappell MA (1983) Thermal limitations to escape responses in
desert grasshoppers. Anim Behav 31:1088–1093. doi:10.1016/
Chatzaki M, Trichas A, Markakis G, Mylonas M (1998) Seasonal
activity of the ground spider fauna in a Mediterranean ecosystem
(Mt. Youchtas, Crete, Greece). Proceedings of the 17th European
Colloquium of Arachnology, Edinburgh 1997: 235–243
Chatzaki M, Mylonas M, Markakis G (2005) Phenological patterns
of ground spiders (Araneae, Gnaphosidae) on Crete, Greece.
Ecol Mediterr, 31:33–53
Chen I-C, Hill JK, Ohlemüller R, Roy DB, Thomas CD (2011) Rapid
range shifts of species associated with high levels of climate
warming. Science 333:1024–1026. doi:10.1126/science.1206432
Clarke KR (1993) Non-parametric multivariate analyses of changes
in community structure. Aust J Ecol 18:117–143
Crous CJ, Samways MJ, Pryke JS (2013) Exploring the mesofilter
as a novel operational scale in conservation planning. J Appl
Ecol 50:205–214. doi:10.1111/1365-2664.12012
Author's personal copy
J Insect Conserv
1 3
Debussche M, Lepart J, Dervieux A (1999) Mediterranean land-
scape changes: Evidence from old postcards. Global Ecol Bio-
geogr 8:3–15
Díaz S, Cabido M (1997) Plant functional types and ecosystem
function in relation to global change. J Veg Sci 8:463–474
Donoso I, Stefanescu C, Martínez-Abraín A, Traveset A (2016)
Phenological asynchrony in plant–butterfly interactions asso-
ciated with climate: a community-wide perspective. Oikos
125:1434–1444. doi:10.1111/oik.03053
Gao T, Hedblom M, Emilsson T, Nielsen AB (2014) The role of
forest stand structure as biodiversity indicator. For Ecol Man-
age 330:82–93. doi:10.1016/j.foreco.2014.07.007
Gerard F etal (2010) Land cover change in Europe between 1950
and 2000 determined employing aerial photography. Prog Phys
Geogr 34:183–205. doi:10.1177/0309133309360141
Ghil M (2002) Natural climate variability. In: MacCracken MC,
Perry JS (eds). Encyclopedia of global environmental change,
vol1. Wiley, New York, pp544–549
Guido M, Gianelle D (2001) Distribution patterns of four orthop-
tera species in relation to microhabitat heterogeneity in
an ecotonal area. Acta Oecol 22:175–185. doi:10.1016/
Halaj J, Ross DW, Moldenke AR (1997) Negative effects of ant for-
aging on spiders in Douglas-fir canopies. Oecologia 109:313–
322. doi:10.1007/s004420050089
Hammer Ø, Harper DAT, Ryan PD (2001) Past: paleontological sta-
tistics software package for education and data analysis. Palae-
ontol Electron 4:XIX–XX
Hill MO, Gauch HG (1980) Detrended correspondence analy-
sis: an improved ordination technique. Vegetatio 42:47–58.
Hochkirch A, Nieto A, Garcνa Criado M, Cαlix M, Braud Y, Buz-
zetti FM, Chobanov D, Odι B, Presa Asensio JJ, Willemse L,
Zuna-Kratky T, Barranco Vega P, Bushell M, Clemente ME,
Correas JR, Dusoulier F, Ferreira S, Fontana P, Garcνa MD,
Heller K-G, Iorgu I.Ș., Ivković S, Kati V, Kleukers R, Krištνn
A, Lemonnier-Darcemont M, Lemos P, Massa B, Monnerat C,
Papapavlou KP, Prunier F, Pushkar T, Roesti C, Rutschmann
F, Şirin D, Skejo J, Szφvιnyi G, Tzirkalli E, Vedenina V, Barat
Domenech J, Barros F, Cordero Tapia PJ, Defaut B, Fartmann
T, Gomboc S, Gutiιrrez-Rodrνguez J, Holuša J, Illich I, Kar-
jalainen S, Kočαrek P, Korsunovskaya O, Liana A, Lσpez H,
Morin D, Olmo-Vidal JM, Puskαs G, Savitsky V, Stalling T,
Tumbrinck J (2016) European red list of grasshoppers, crickets
and bush-crickets. Publications Office of the European Union,
IPCC (2013) Summary for Policymakers. In: Climate Change 2013:
The Physical Science Basis. Contribution of Working Group I
to the Fifth Assessment Report of the Intergovernmental Panel
on Climate Change [Stocker TF, Qin D, Plattner G-K, Tignor M,
Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM
(eds) Cambridge University Press, Cambridge
Jiménez-Valverde A, Lobo JM (2006) Establishing reliable spider
(Araneae, Araneidae and Thomisidae) assemblage sampling
protocols: estimation of species richness, seasonal coverage and
contribution of juvenile data to species richness and composi-
tion. Acta Oecol 30:21–32
Kati V, Willemse F (2001) The grasshoppers and crickets of the Dadia
Forest Reserve (Thraki, Greece) with a new record to the Greek
fauna: Paranocarodes chopardi Pechev 1965 (Orthoptera, Pam-
phagidae). Articulata 16:11–19
Kati V, Dufrêne M, Legakis A, Grill A, Lebrun P (2004) Conserva-
tion management for Orthoptera in the Dadia reserve, Greece.
Biol Conserv 115:33–44. doi:10.1016/s0006-3207(03)00091-0
Kati V, Zografou K, Tzirkalli E, Chitos T, Willemse L (2012) But-
terfly and grasshopper diversity patterns in humid Mediterranean
grasslands: The roles of disturbance and environmental factors. J
Insect Conserv 16:807–818. doi:10.1007/s10841-012-9467-2
Kemp WP, Harvey SJ, O’Neill KM (1990) Patterns of vegetation and
grasshopper community composition. Oecologia 83:299–308.
Komnenov M, Pitta E, Zografou K, Chatzaki M (2016) Discovering
the still unexplored arachnofauna of the National Park of Dadia-
Lefkimi-Soufli, NE Greece: a taxonomic review with description
of new species. Zootaxa 0:000–000
Lambeets K, Hendrickx F, Vanacker S, Van Looy K, Maelfait
JP, Bonte D (2008) Assemblage structure and conservation
value of spiders and carabid beetles from restored lowland
river banks. Biodivers Conserv 17:3133–3148. doi:10.1007/
Lawrence KL, Wise DH (2000) Spider predation on forest-floor Col-
lembola and evidence for indirect effects on decomposition.
Pedobiologia 44:33–39. doi:10.1078/S0031-4056(04)70026-8
Lenth RV (2016) Least-squares means: the R package lsmeans. J Stat
Softw 69:33. doi:10.18637/jss.v069.i01
Majadas A, Urones C (2002) Communauté d’araignées des maquis
méditerranéens de Cyticus oromediterraneus Rivas Mart. et al.
Rev Arachnol 14:31–48
Mamara A, Argiriou AΑ, Anadranistakis M (2016) Recent trend
analysis of mean air temperature in Greece based on homog-
enized data. Theoret Appl Climatol 126:543–573. doi:10.1007/
Margules CR, Pressey RL (2000) Systematic conservation planning.
Nature 405:243–253. doi:10.1038/35012251
Marini L, Bommarco R, Fontana P, Battisti A (2010) Disentan-
gling effects of habitat diversity and area on orthopteran spe-
cies with contrasting mobility. Biol Conserv 143:2164–2171.
Maris F, Vasileiou A (2010) Hydrology and torrential environment.
In: Catsadorakis G, KÓ“lander H (eds) The Dadia-Lefkimi-Sou-
fli forest national park, Greece: biodiversity, management and
conservation. WWF Greece, Athens, pp41–45
McKinney AM, Caradonna PJ, Inouye DW, Barr B, Bertelsen
CD, Waser NM, Irwin RE (2012) Asynchronous changes
in phenology of migrating Broad-tailed Hummingbirds and
their early-season nectar resources. Ecology 93:1987–1993.
Menzel A et al (2006) European phenological response to climate
change matches the warming pattern. Global Change Biol
12:1969–1976. doi:10.1111/j.1365-2486.2006.01193.x
Nufio CR, McGuire CR, Bowers MD, Guralnick RP (2010) Grass-
hopper community response to climatic change: variation
along an elevational gradient. PLoS ONE. doi:10.1371/journal.
Öberg S, Mayr S, Dauber J (2008) Landscape effects on recoloni-
sation patterns of spiders in arable fields. Agric Ecosyst Envi-
ron123:211–218. doi:10.1016/j.agee.2007.06.005
Parmesan C (2007) Influences of species, latitudes and meth-
odologies on estimates of phenological response to
global warming. Global Change Biol 13:1860–1872.
Peñuelas J etal (2013) Evidence of current impact of climate change
on life: a walk from genes to the biosphere. Global Change Biol
19:2303–2338. doi:10.1111/gcb.12143
Perner J, Malt S (2003) Assessment of changing agricultural land use:
Response of vegetation, ground-dwelling spiders and beetles to
the conversion of arable land into grassland. Agric Ecosyst Envi-
ron 98:169–181. doi:10.1016/s0167-8809(03)00079-3
Pitt WC (1999) Effects of multiple vertebrate predators on grasshop-
per habitat selection: trade-offs due to predation risk, forag-
ing, and thermoregulation. Evol Ecol 13:499–515. doi:10.102
Author's personal copy
J Insect Conserv
1 3
Poirazidis K, Skartsi T, Katsadorakis G (2002) Monitoring plan for
the protected area of Dadia-Lefkimi-Soufli forest. WWF-Greece,
Primack RB, Ibáñez I, Higuchi H, Lee SD, Miller-Rushing AJ, Wil-
son AM, Silander JA Jr (2009) Spatial and interspecific varia-
bility in phenological responses to warming temperatures. Biol
Conserv 142:2569–2577. doi:10.1016/j.biocon.2009.06.003
Rapacciuolo G etal (2014) Beyond a warming fingerprint: individu-
alistic biogeographic responses to heterogeneous climate change
in California. Global Change Biol 20:2841–2855. doi:10.1111/
R Core Team (2014) R: a language and environment for statistical
computing. R Foundation for Statistical Computing, Vienna.
Sfenthourakis S, Legakis A (2001) Hotspots of endemic terrestrial
invertebrates in southern Greece. Biodivers Conserv 10:1387–
1417. doi:10.1023/a:1016672415953
Standish RJ (2004) Impact of an invasive clonal herb on epigaeic
invertebrates in forest remnants in New Zealand. Biol Conserv
116:49–58. doi:10.1016/s0006-3207(03)00172-1
Stromberg JC, Tellman B (2012) Ecology and conservation of the san
pedro river. The University of Arizona Press, Tuscon
Symondson WOC, Sunderland KD, Greenstone MH (2002) Can gen-
eralist predators be effective biocontrol agents? Annu Rev Ento-
mol 47:561–594. doi:10.1146/annurev.ento.47.091201.145240
TerBraak CJF, Prentice IC (1988) A theory of gradient analysis. Adv
Ecol Res doi:10.1016/s0065-2504(08)60183-x
TerBraak CJF, Smilauer P (2002) CANOCO reference manual and
canoco draw for windows user’s guide: software for canoni-
cal community ordination. (version 4.5) Microcomputer power,
Ithaca, New York
Töpfer-Hofmann G, Cordes D, von Helversen O (2000) Cryptic spe-
cies and behavioural isolation in the Pardosa lugubris group
(Araneae, Lycosidae), with description of two new species. Bull
Br Arachnol Soc 11:257–274
Uvarov B (1966) Grasshoppers and locusts: a handbook of general
acridology. Vol.1. Cambridge University Press, Cambridge
van Wingerden WKRE, Musters JCM, Maaskamp FIM (1991) The
influence of temperature on the duration of egg development in
West European grasshoppers (Orthoptera: Acrididae). Oecologia
87:417–423. doi:10.1007/bf00634600
Whittaker RH (1960) Vegetation of the Siskiyou Mountains, Oregon
and California. Ecol Monogr 30:279–338. doi:10.2307/1943563
Willemse F (1985) A key to the orthoptera species of Greece. Hel-
lenic Zoological Society, Athens
Wilson JB (1999) Guilds, functional types and ecological groups.
Oikos 86:507–522
Zakkak S, Chatzaki M, Karamalis N, Kati V (2014) Spiders in the
context of agricultural land abandonment in Greek Mountains:
species responses, community structure and the need to preserve
traditional agricultural landscapes. J Insect Conserv 18:599–611.
Zografou K, Sfenthourakis S, Pullin A, Kati V (2009) On the surro-
gate value of red-listed butterflies for butterflies and grasshop-
pers: a case study in Grammos site of Natura 2000, Greece. J
Insect Conserv 13:505–514. doi:10.1007/s10841-008-9198-6
Zografou K, Kati V, Grill A, Wilson RJ, Tzirkalli E, Pamperis LN,
Halley JM (2014) Signals of climate change in butterfly com-
munities in a mediterranean protected area. PLoS ONE.
Zografou K, Adamidis GC, Grill A, Kati V, Wilson RJ, Halley JM
(2015) Who flies first?—habitat-specific phenological shifts of
butterflies and orthopterans in the light of climate change: a case
study from the south-east Mediterranean. Ecol Entomol 40:562–
574. doi:10.1111/een.12220
Zuur AF, Ieno EN, Walker NJ, Saveliev AA, Smith GM (2009) Mixed
effects models and extensions in ecology with R. Springer, New
Author's personal copy
... insect-plant interactions) (Aishah et al., 2016;Wu et al., 2019;Silva et al., 2020). Insects can be applied for monitoring purposes in the recovery processes of degraded areas for their great diversity of species and habitats, and quick response to environmental changes (Pearce and Venier, 2006;Zografou et al., 2017;Silva et al., 2020). ...
... T. collaris). Spiders were also prominent, due to their numbers and predations of defoliating insects on A. mangium and C. brasiliense trees, in the Brazilian cerrado (Leite et al., 2012;Silva et al., 2020), and on pastures and forests in Greece, being directly correlated with Orthoptera (Zografou et al., 2017). ...
Full-text available
Fertilization with dehydrated sewage sludge can speed up the recovery process of degraded areas due to nutrients concentration, favoring the development of pioneer plants such as Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) and the emergence of insects. This study aimed the evaluation of chewing, pollinating insects, predators, their ecological indices and relationships on A. auriculiformis plants fertilized with dehydrated sewage sludge. The experimental design was completely randomized with two treatments (with and without dehydrated sewage sludge) and 24 repetitions. The prevalence of chewing insects Parasyphraea sp. (Coleoptera: Chrysomelidae), Nasutitermes sp. (Blattodea: Termitidae), and Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae), defoliation, and ecological indices of abundance of Coleoptera and Orthoptera were observed on fertilized A. auriculiformis. Acacia auriculiformis plants, with a superior number of branches/tree, revealed greater abundance of Coleoptera and Orthoptera, species richness of pollinating insects, defoliation, numbers of Parasyphraea sp. and T. collaris. The ones with larger leaves/branches displayed greater abundance of species richness of Coleoptera and Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae). Therefore, the use of A. auriculiformis plants, fertilized with dehydrated sewage sludge, is promising in the recovery of degraded areas due to the ecological indices increase of chewing and pollinators insects and spiders in the analyzed area.
... In Mexican tropical mountain cloud forests, strong seasonal variability in understory dwelling spider abundance, community structure, and diversity were detected; however, little seasonal variability was detected in ground spiders (Campuzano et al., 2020). In temperate forests of Greece, seasonal differences were found in ground spider species richness, but not in abundance (Zografou et al., 2017). Tasmania has a cool temperate climate with low seasonal variation in rainfall and temperature. ...
Full-text available
Seabirds influence island ecosystems through nutrient additions and physical disturbance. These influences can have opposing effects on an island's invertebrate predator populations. Spiders (order: Araneae) are an important predator in many terrestrial island ecosystems, yet little is known about how seabird presence influences spider communities at the intraisland scale, or how they respond to seasonality in seabird colony attendance.We investigated the effects of seabird presence and seasonality on ground-active spider community structure (activity-density, family-level richness, age class, and sex structure) and composition at the family-level across five short-tailed shearwater breeding islands around south-eastern Tasmania, Australia. Using 75 pitfall traps (15 per island), spiders were collected inside, near, and outside seabird colonies on each island, at five different stages of the short-tailed shearwater breeding cycle over a year. Pitfall traps were deployed for a total of 2674 days, capturing 1592 spiders from 26 families with Linyphiidae and Lycosidae the most common. Spider activity-density was generally greater inside than outside seabird colonies, while family-level richness was generally higher outside seabird colonies. For these islands, seabird breeding stage did not affect activity-densities, but there were some seasonal changes in age class and sex structures with more adult males captured during winter. Our results provide some of the first insights into the spatial and temporal influences seabirds have on spider communities. We also provide some of the first records of spider family occurrences for south-eastern Tasmanian islands, which will provide an important baseline for assessing future change.
... The snow period in Djurdjura National Park lasts for about 6 months, which might explain the single peak of activity. According to Bayram and Varol (2000) and Zografou et al. (2017), environmental changes can affect both spider activity duration and the activity peak. Vanin and Turchetto (2007) declare also that the mating period of species whom are adults in the winter is not determined genetically but can be adapted to climatic conditions of each habitat or even every year. ...
The ecology and phenology of the Dysderidae (Araneae) were investigated in two different sites (Tala‐Guilef and Tikjda), located at opposite slopes of the Djurdjura National Park in Algeria. The following questions were investigated: Are there any endemic species in the studied area? Do the slopes' orientation influence the abundance, richness and diversity of these spider communities? Are the activity and the vital cycle of the three most abundant species different in the two different plant physiognomies (cedar forests and alpine grasslands)? The Dysderidae were collected monthly for 2 years using pitfall traps. In total, 1532 specimens were collected: 333 males, 389 females and 381 juveniles in Tala‐Guilef and 230 males, 66 females and 133 juveniles in Tikjda. Among the total of 10 species sampled, three species belonging to three genera in Tala‐Guilef, 10 species belonging to four genera in Tikdja and four endemic species was recorded. The slope orientation influence the abundance and the species richness. The activity and the vital cycle of the three most abundant species were not different in the cedar forests and alpine grasslands. For these species, no relationship was found between the activity cycle and the vegetation physiognomy. Les études sur l'écologie et la phénologie des Dysderidae (Araneae) ont été menées dans deux sites différents (Tala‐Guilef et Tikjda), situés sur des versants opposés du Parc National du Djurdjura en Algérie. Les points suivants ont été examinés: Y a‐t‐il des espèces endémiques dans la zone étudiée ? Est‐ce que l'orientation des pentes influence l'abondance, la richesse et la diversité de ces communautés d'araignées? Est‐ce que les activités et le cycle vital des trois espèces les plus abondantes sont aussi différents dans les deux physionomies végétales respectives (forêts de cèdres et prairies alpines)? La collecte des Dysderidae a été effectuée mensuellement pendant 2 ans à l'aide de pièges à fosse. En tout, 1532 spécimens ont été collectés: 333 mâles, 389 femelles et 381 juvéniles à Tala‐Guilef et 230 mâles, 66 femelles et 133 juvéniles à Tikjda. Sur un total de 10 espèces échantillonnées, trois espèces appartenant à trois genres à Tala‐Guilef, 10 espèces appartenant à quatre genres à Tikdja et quatre espèces endémiques ont été enregistrées. Le sens de la pente influence l'abondance et la richesse des espèces. Les trois espèces les plus abondantes avaient une activité et un cycle vital identiques dans les forêts de cèdres et les prairies alpines. Concernant ces espèces, aucune relation n'a été trouvée entre le cycle d'activité et la physionomie de la végétation.
... When a S.S. operates in more than one L.S., that caused damage, its ks are summed. E.S.. = 0 when Da. by L.S. or E.S. non-significant for damage by L.S. or reduced L.S. by S.S. 2020); on pastures and forests in Greece, and in A. auriculiformis saplings in a degraded area in Brazil, being directly correlated with Orthoptera (Zografou et al., 2017;Mota et al., 2023); in many agroecosystems in the USA (Landis et al., 2000) and Italy (Venturino et al., 2008); and in 12 agricultural landscapes in the low mountain ranges of Central Hesse (Germany) (Öberg et al., 2008). Moreover, ants can reduce defoliation and fruit-boring insect populations (e.g., Coleoptera and Lepidoptera) (Leite et al., 2012a;Gonthier et al., 2013;Fagundes et al., 2017, Dassou et al. 2019) besides, they are bioindicators of the recovery of degraded areas (Sanchez, 2015). ...
Full-text available
Indices are used to help on decision-making. This study aims to develop and test an index, which can determine the loss (e.g., herbivorous insects) and solution (e.g., natural enemies) sources. They will be classified according to their importance regarding the ability to damage or to reduce the source of damage to the system when the final production is unknown. Acacia auriculiformis (Fabales: Fabaceae), a non-native pioneer species in Brazil with fast growth and rusticity, is used in restoration programs, and it is adequate to evaluate a new index. The formula was: Percentage of the Importance Indice-Production Unknown (% I.I.-PU) = [(ks1 x c1 x ds1)/Σ (ks1 x c1 x ds1) + (ks2 x c2 x ds2) + (ksn x cn x dsn)] x 100. The loss sources Aethalion reticulatum L., 1767 (Hemiptera: Aethalionidae), Aleyrodidae (Hemiptera), Stereoma anchoralis Lacordaire, 1848 (Coleoptera: Chrysomelidae), and Tettigoniidae, and solution sources Uspachus sp. (Araneae: Salticidae), Salticidae (Araneae), and Pseudomyrmex termitarius (Smith, 1877) (Hymenoptera: Formicidae) showed the highest % I.I.-PU on leaves of A. auriculiformis saplings. The number of Diabrotica speciosa Germar, 1824 (Coleoptera: Chrysomelidae) was reduced per number of Salticidae; that of A. reticulatum that of Uspachus sp.; and that of Cephalocoema sp. (Orthoptera: Proscopiidae) that of P. termitarius on A. auriculiformis saplings. However, the number of Aleyrodidae was increased per number of Cephalotes sp. (Hymenoptera: Formicidae) and that of A. reticulatum that of Brachymyrmex sp. (Hymenoptera: Formicidae) on A. auriculiformis saplings. The A. reticulatum damage was reduced per number of Uspachus sp., but the Aleyrodidae damage was increased per number of Cephalotes sp., totaling 23.81% of increase by insect damages on A. auriculiformis saplings. Here I show and test the % I.I.-PU. It is an new index that can detect the loss or solution sources on a system when production is unknown. It can be applied in some knowledge areas.
Full-text available
The abundance, dominance and diversity of the arachnid population are influenced by their habitat’s microclimate and environmental variables. Here we evaluated a seasonal dominance, diversity and richness pattern of the arachnid population and their guild composition in the Muthupet mangrove forest. Most of the spiders were aggregated from specific mangrove plants such as Avicennia and Rhizophora species by adopting standard hand-picking and net-sweeping methods and employing bark traps, pitfall traps and leaf litter traps. A total of 14 families, 29 genera and 47 species of arachnids were recorded. The sequence of the abundance of the families was: Araneidae > Tetragnathidae > Lycosidae > Salticidae > Oxyopidae > Eresidae > Liniphidae > Clubionidae > Sparassidae > Uloboridae > Hersilidae > Gnaphosidae = Thomisidae > Miturgidae. The annual average population density of spiders was maximum (36.13%) during the post-monsoon (January, February, and March) and summer seasons. The minimum seasonal mean population density was during the pre-monsoon and monsoon periods, attributed to the changes in temperature, relative humidity and rainfall. The Muthupet mangrove forest registered six types of guilds. The dominant group was orb-weavers (62.44%), followed by foliage runners (15.11%). The rest of the guilds were represented by tunnel web builders (15.78%), ground runners (2.23%), communal web weavers (4.41%), and ambushers (0.03%). Thus, changes in environmental parameters produced alterations in arachnid abundance and diversity. Moreover, the predatory potential of the arachnids relies chiefly on the composition of spider assemblages, which in turn, gets impacted by abiotic factors of its environment.
Full-text available
The dataset contains records of spiders collected in the northeast of Luhansk Oblast in the periods 1982-1989, 2009-2011 and 2021. It aimed at the inventory of spider fauna of the Striltsivskyi Steppe Nature Reserve and species distribution in the main grassland and forest habitats of the region. The research was also concerned with the impact of conservation management ‒ hay mowing or strict protection and man-induced steppe fire on spider communities. The dataset includes records from seven geographical localities in the northeast of Luhansk Oblast with 1,955 occurrences of 6662 individuals. For the first time, it provides detailed information about spider species composition, phenology and habitat distiribution within the study area, including two conservation areas and the primary material on the studies on the impact of hay making and steppe fire on spider communities. All the records of 246 spider species with georeferencing were published in GBIF.
Arthropods can be loss and solution sources for Platycyamus regnellii saplings. This study aims to evaluate the herbivorous insects and their natural enemies on 48 P. regnellii saplings. They were classified according to their ability to damage or reduce the source of damage on these saplings using the percentage of the Importance Index-Production Unknown (% I.I.-PU). The loss sources Aleyrodidae, Tettigoniidae, Tropidacris collaris, and Phenacoccus sp., showed the highest % I.I.-PU on leaves of P. regnellii saplings. Araneidae was the only solution source, showing the highest % I.I.-PU on leaves of P. regnellii saplings.
Herbivorous insect communities are structured by multiple processes operating locally (e.g. bottom–up effects of plants) and regionally (e.g. dispersal limitation). Although the relative strength of these processes has been well documented, how it varies in time is less understood, especially in relation with the temporal dynamics of plant communities. If temporal turnover of local plant species composition is too rapid for insect community assembly to keep up with, bottom–up effects are expected to be weak. Here, in plant and herbivorous insect communities in Japanese grasslands, we studied how the relative importance of local (bottom–up effects of plants, structures of plant communities and top–down effects of predators) and regional (dispersal limitation) processes varies over the growing season. In addition, we tested the hypothesis that larger temporal turnover of plant species composition is related to the weaker bottom–up effects, that is, the lower explanation power of plant communities for insect communities. We found that, throughout the growing season, the insect species composition was mainly explained by local variables (plant species composition, vegetation height and predator abundance), and their explanation power was higher during later phases of the season (late summer). Furthermore, the variation not explained by plant species composition was correlated with the degree of temporal turnover of plants, suggesting that insect communities failed to track the temporal turnover of plant species. These results were pronounced when we focused on leaf sucker insects, whose host plant range is presumably more limited. We conclude that herbivorous insect communities are mainly regulated by local processes, especially bottom–up effects from plants, while stochasticity may have played a role in early phases of the season. Furthermore, we underscore the importance of considering relative time scale of community assembly and environmental shifts, especially in systems characterized by dynamic changes.
Full-text available
Spiders have been increasingly used as environmental and ecological indicators in conservation and ecosystem management. In the Neotropics, there is a shortage of information regarding spiders’ taxonomies and ecological responses to anthropogenic disturbances. To unravel these hitches, we tested the possibility of using high-level diversity and high-level functionality indicators to evaluate spider assemblages’ sensitivity to landscape changes. This approach, if proven informative, might overcome the relevant limitations of taxonomic derived indexes, which are considered time-consuming, cost-demanding and dependent on the (few) expert taxonomists’ availability. Our results highlight the pertinence of both indicators’ responses to the structural changes induced by increasing anthropogenic disturbance, and are associated with reductions in ecosystem complexity, microclimates, and microhabitats. Overall, both indicators were sensitive to structural changes induced by anthropogenic disturbance and should be considered a useful resource for assessing the extent of ecosystems’ disruptions in the Neotropics, and also to guide managers in landscapes’ restoration.
Full-text available
Landscape ecology has highlighted the role of the surrounding landscape in structuring arthropod communities at a given place. Previous studies have confirmed that non-crop habitats in agricultural landscapes increase the abundance and diversity of natural enemies in crop fields, which can generate a positive impact on pest control. However, landscape structure may differentially affect generalist predator communities within a year. Our knowledge about how such intra-annual variation affects the biological control of pests is still scarce. In this study, we surveyed predator carabid and spider assemblages and estimated biological control potential using experimentally added aphids in 21 winter wheat fields from mid-March until harvest. We investigated whether landscape structure differentially affected predator activity density, species richness and species composition across months, as well as how the relationship between biological control potential and landscape structure changed over time. We also investigated whether different time steps (15-day sampling period vs. whole sampling season) influenced the detection and significance of landscape effects. Spider assemblages benefit from fine-grained landscapes in spring, but this effect disappeared later in summer. For carabids, species richness was the only biodiversity measure related to grain size, and the relationship was strongest when considering the whole sampling season. No relationship was found between landscape structure and biological control potential. Our study showed that the influence of landscape structure can be inconsistent across taxa, biodiversity measures and time. The results demonstrate the importance of time steps and seasonality in the relationship between landscape structure and biodiversity.
Full-text available
The National Park of Dadia in NE Greece (Thrace) was established as a nature reserve in 1980, mainly due to its great diversity in birds of prey. Since then many studies have taken place, focusing on other birds, reptiles, amphibians and some invertebrates (grasshoppers, beetles and butterflies), but up to now none was conducted on spiders. The aim of the present paper was to create the first extensive checklist on the spiders of this important natural reserve. For this purpose, pitfall traps were set in 15 sites located in and around the National Park, resulting in a large spider collection. The results of the taxonomical revision of this collection are here presented, giving rise to 132 species in total, which belong to 24 families. Of them, 11 species (Centromerus valkanovi Deltshev, 1983, Crosbyarachne silvestris (Georgescu, 1973), Ipa terrenus (L. Koch, 1879), Sintula spiniger (Balogh, 1935), Tenuiphantes floriana (van Helsdingen, 1977), Alopecosa taeniopus (Kulczyñski, 1895), Liocranum rupicola (Walckenaer, 1830), Zodarion turcicum Wunderlich, 1980, Gnaphosa modestior Kulczyñski, 1897, Philodromus krausi Muster & Thaler, 2004, Cozyptila thaleri Marusik & Kovblyuk, 2005) are new records for the Greek territory. Seven species (Dysdera kati sp. n., Dysdera krisis sp. n., Harpactea ice sp. n., Harpactea wolfgangi sp. n.—Dysderidae, Phrurolithus thracia sp. n.—Phrurolithidae, Zodarion beroni sp. n.—Zodariidae, Drassyllus dadia sp. n.—Gnaphosidae) are here proposed as new species for science.
Full-text available
Least-squares means are predictions from a linear model, or averages thereof. They are useful in the analysis of experimental data for summarizing the effects of factors, and for testing linear contrasts among predictions. The lsmeans package (Lenth 2016) provides a simple way of obtaining least-squares means and contrasts thereof. It supports many models fitted by R (R Core Team 2015) core packages (as well as a few key contributed ones) that fit linear or mixed models, and provides a simple way of extending it to cover more model classes.
Full-text available
Although much information has been accumulated on the effects of climate change on particular species worldwide, research aimed at assessing how such change influences biotic interactions from a community-wide perspective is still in its infancy. We contribute to filling in this gap by analyzing a 17-year (1996–2012) dataset that includes records of flower-visitation interactions between 12 butterfly species and 17 plant species in a coastal wetland area in northeastern Iberian Peninsula. We assessed the extent to which temporal asynchronies between plants and adult butterflies are influenced by different climatic variables that affect both plant and insect phenologies. Temperature and degree of aridity at various monthly summaries were used as predictors of the plant–butterfly phenological asynchrony. We identified the seasonal window with the greatest effect on asynchronies for two butterfly generations (spring and summer), and assessed whether the magnitude of asynchrony is associated with the level of butterfly specialization. We used generalized linear mixed models considering a total of 39 plant-butterfly interactions. Average asynchrony was higher in the spring generation and dry conditions during winter lead to decreased temporal overlap with flowers in this butterfly generation, whereas dry conditions in the spring lead to decreased temporal overlap in the summer butterfly generation. The magnitude of the effect was consistently small at the community level (all interactions pooled). Moreover, no clear climatic trend over the study time frame was detected. Finally, specialized and generalized butterflies in their resource use as adults were similarly vulnerable to asynchronies, in contrast to previous predictions of greater mutualistic disruptions in species with narrower niches. We conclude that a least in the Mediterranean region, phenological asynchronies might be more affected by aridity level than by temperature itself, and thus the former can be a key climatic trait to make better predictions in this region. This article is protected by copyright. All rights reserved.