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ŠUMARSKI LIST 9-10/2010 str. 38     <-- 38 -->        PDF

L. Šerić Jelaska,A. Ješovnik, S. D. Jelaska,A. Pirnat, M. Kučinić, P. Durbešić: VARIATIONS OF CARABID ... Šumarski list br. 9–10, CXXXIV (2010), 475-486


in Hodkinson 2005). The physical structure of the


environment, mediated by plant communities, can inf


luence the distribution and interactions of species (review
in Lawton 1983). “Structural heterogeneity
hypothesis” assumes that structurally complex habitats
may provide more niches and environmental resources
for exploitation and thus increase species diversity, although
empirical support for this relationship is biased
towards studies of vertebrates and habitats under anthropogenic
influence (Tews et al. 2004). Lassau and
Hochuli (2004) and Lassau et al. (2005) showed
that habitat complexity in forests may affect the composition
of ant and beetles assemblages.Brose (2003b)
showed that effects of habitat heterogeneity on ground
beetle assemblages were positive on the micro- and


2


meso-scale (0.25 and 500–1000 m, respectively), and


2


were not significant on a macro-scale (10 km).
In “taxonomic diversity hypothesis” plant taxonomic
diversity is positively correlated with the diversity of
herbivore insects (Murdoch etal. 1972,Root1973),
and thus with predator diversity (Hunter and Price
1992). The importance of floristic richness for the
ground beetle abundance was also reported by Baguette(
1993).
Ants and ground beetles have been widely recommended
as environmental, ecological and biodiversity
indicators (e.g. Altegrim et al. 1997, Andersen
1997, Niemelä 2000, Szyszko et al. 2000, Andersen
et al. 2002,Antonova and Penev 2006,
Pearce and Venier 2006, Šerić Jelaska et al.
2007,Šerić Jelaska and Durbešić 2009). They
respond well to natural and anthropogenic disturbances.
Microhabitat characteristics, i.e. litter type, organic
matter content, insolation, temperature fluctuation,
are important for providing hunting, foraging niches
and for protection of beetles from predators, ovipositioning,
larval development, over wintering etc.


(Thiele 1977,Pearce and Venier 2006). Theuse
of carabids morpho-ecological traits like wing morphology,
body size or diet are recommended in the evaluation
of habitat quality (Blake etal. 1994,Gutiérrez
et al. 2004,Gobbi andFontaneto 2008).Brose
(2003a) found that large carabids, as more preferable
prey because of their higher nutritive value and reduced
foraging time required, prefer dense vegetation
plots as enemy-free spaces.According toAndersen
et al. (2002), ant functional groups can be used as
indicators of habitat quality and forest health under different
management (Stephens and Wagner2006).


Lassau andHochuli (2004) suggested measurement
of habitat complexity as a surrogate for the diversity
of a range of arthropods including ants.Very often,
different taxonomic groups indicate certain areas as important
for protection or nature conservation, showing
mutual positive correlations. Based on the existence of
these correlations, the use of “surrogate species groups”
for estimation of overall biodiversity has been reported
(Garson etal. 2002;Satersdal etal. 2003); being
particularly useful where limited biodiversity data exist.
Vascular plants have been reported bySatersdal et
al. (2003) as a good surrogate group, which also works
for estimation of ground beetle diversity. Although,
some habitat preferences are known for many species of
ants and ground beetles, it is not always evident which
environmental factors are the most responsible for species
assemblage and distribution.


The aim of this study was to analyze ants and carabid
species richness and abundance, carabids body size
and ants functional groups, in different habitats within
natural temperate mature forests, and to test whether
higher habitat complexity and plant species richness
support higher insect diversity along vertical gradient
in Mt. Medvednica.


MATERIALAND METHODS – Materijal i metode


Study Area – Područje istraživanja


Mount Medvednica is part of the Croatian continental
karst, located north of Zagreb, the capital of Croatia.
The great floristic diversity (Dobrović et al. 2006),
due to the mosaic structure of forest communities, geographical
position and geological structure make this
area very interesting for biodiversity investigations.
Dobrović etal. (2006) reported that the floristic richness
and diversity of the mountain was higher than similar
regions in Croatia and several European countries
(Italy,Austria, Slovakia, Poland and Serbia). For protection
of its valuable forest areas, the western part of Mt.


2


Medvednica (228 km) was proclaimed a nature park by
the Nature ProtectionAct in1981. Thehighestpeak of


the mountain, named Sljeme, is placed 1035 m above sea


level. Despite protection, anthropogenic pressures on


Med vednica are constantly increasing (road construction,
recreation, ski trails, logging, etc.), mainly at its
upper elevations, changing the habitat quality.This can
change structural complexity of forests, especially where
trees and shrubs form part of the natural landscape.


Surveyed forests are natural temperate ones on
brown acid soil with silicate parent rocks (Basch
1995). For this investigation, six plots (50 x 50 m) were
selected along the central profile of Mt. Medvednica
across a vertical gradient on both slopes of the mountain
(Figure 1).They were placed in mature stands of
five different forest communities, that account for 78%
of the total forest cover of the nature park:Querco–Castaneetum
sativaeHt. 1938, (plot 1);Luzulo–Fagetum
sylvaticaeMausel 1937, (plot 2);Lamio orvale–Fage