Edge effects on ant community structure and species
richness in an agricultural landscape
JENS DAUBER and VOLKMAR WOLTERS
Department of Animal Ecology
Justus-Liebig-University of Giessen
Author for correspondence
Received 4 June 2002; accepted in revised form 14 March 2003
Key words: Agroecosystems, Ecotones, Edge-mediated effects, Formicidae, Neighbourhood effects,
Abstract. The effect of sharp edges between three different types of land use on the species richness and
structure of ant communities was examined in an agricultural landscape within Central Hesse, Germany.
Species richness and nest densities of ants at the centres and the edges of meadows, crop ﬁelds, and
fallow land were recorded by hand sampling during 1997 and 1998. Edges between different land-use
types did not increase ant species richness at the landscape scale, nor were they unique habitats for a
specialised ant fauna. Nonetheless, most species shared ‘ecotonal effects’ in the way that their relative
abundance either decreased (e.g. Myrmica scabrinodis) or increased (e.g. Lasius niger, Lasius ﬂavus)at
the edges, resulting in different community structure between edges and centres of the land-use types.
This was inﬂuenced by two major factors: (i) the boundary contrast between the neighbouring habitats
(i.e. in terms of disturbance caused by agricultural practices), and (ii) the response of different species to
changing abiotic conditions. High nest densities of aggressive species with large colonies occurred along
edges. We hypothesise that this can signiﬁcantly reduce edge permeability for surface-dwelling ar-
Abbreviations: AC – Arable land centre, AF – arable land–fallow land edge, AM – arable land–
meadow edge, a.s.l. – above sea level, D – nest density of individual species, D – nest density of all
species, FA – fallow land–arable land edge, FC – fallow land centre, FM – fallow land–meadow edge,
MA – meadow–arable land edge, MC – meadow centre, MF – meadow–fallow land edge, S9 – number
of species corrected by sample based rarefaction.
The term ‘edge effect’ was originally coined to describe the increase of species
richness in the area between two adjoining habitats (see an overview in Angelstam
1992). A convenient explanation for this phenomenon is that edges share charac-
teristics of the two neighbouring habitats as well as distinctive features found only in
the intermediate area (Risser 1995). The current theory on biodiversity at ecotones
predicts higher, intermediate, or lesser levels of diversity in patch boundaries
(Hansen et al. 1988). In more recent studies, the focus has shifted from traditional
edge-effect patterns to the mechanisms through which edges inﬂuence ecological
processes, called ‘edge-mediated effects’ (Fagan et al. 1999).
2004 Kluwer Academic Publishers. Printed in the Netherlands.
Biodiversity and Conservation 13: 901–915, 2004.