Variation in wolf spider (Araneae: Lycosidae) distribution and abundance in response to the size and shape of woodland fragments
Introduction
Land clearing and the associated fragmentation of natural habitats is considered to be the greatest threat to terrestrial biodiversity (United Nations Environment Program, 1995). Deleterious effects have been documented for a range of taxa around the globe, particularly vertebrates, but the extrapolation of the lessons from vertebrates to other groups is a large jump, given that invertebrates make up more than 75% of global species diversity (Hammond, 1992, Wilson, 1992). Furthermore, their generally small size presents different challenges, potentially at a different scale from those faced by the usually larger-bodied vertebrates (Russell, 1987, Soulé and Gilpin, 1991). Increasing understanding of the response of invertebrates to habitat fragmentation is clearly an important field of research for conservation biologists.
Amongst invertebrates, the deleterious effects of fragmentation have been particularly well documented for butterflies (Sutcliffe and Thomas, 1996, Haddad, 1999, Haddad and Baum, 1999) and a number of large, ground-living groups like beetles (Turin and den Boer, 1988, Klein, 1989, Davies and Margules, 1998) and scorpions (Margules and Milkovitis, 1994, Abensperg-Traun et al., 1996, de Vries et al., 1996, Debinski and Holt, 2000). Ground-living forms may be particularly vulnerable due to the compounding effect of altered habitat quality. Land-clearing is usually associated with activities such as cropping and grazing, that may have ongoing impacts at ground level. Deleterious effects are not so evident in arboreal invertebrates, and in fact, increased abundance and species richness have been detected in the edge habitats commonly associated with fragmented landscapes (Malcolm, 1997, Meiners et al., 2000, Major et al., 2003). The response of invertebrates appears to be highly variable, depending on habitat specificity, foraging substrate and foraging guild of the species (Banks, 1998, Zabel and Tscharntke, 1998, Golden and Crist, 1999, Denys and Tscharntke, 2002). Habitat density (i.e. canopy cover) and vegetation structure are also likely to be important determinants of the strength of response of forest fauna to edge-mediated effects of habitat fragmentation because many of the microclimatic effects of edges depend upon wind and light penetration (Matlack, 1993, Chen et al., 1995, Baldissera et al., 2004, Pywell et al., 2005).
Much of Australia’s agricultural production occurs on land that was once occupied by woodland. With a canopy cover of less than 30% (Pulsford, 1991), it is more open than many habitats, e.g., tropical rainforests, that have been the focus of fragmentation studies. Accordingly, Australian woodlands might be less subject to edge effects, resulting in a lesser fragmentation response. Nonetheless, fragmentation is believed to be a major cause of decline of birds in Australian woodlands (Saunders, 1989, Barrett et al., 1994, Robinson and Traill, 1996, Recher, 1999, Ford et al., 2001), due at least in part to inhibited dispersal and small population size. In contrast, investigations of edge effects on terrestrial wolf spiders failed to identify any difference in the wolf spider community between woodland interiors and the edge zone between large woodlands and paddocks (Martin and Major, 2001). The lack of an edge effect suggests that wolf spiders, and potentially other ground-dwelling arthropods, might not be particularly vulnerable to fragmentation. However before drawing this conclusion it is important to demonstrate that the spider communities of remnants are not changing due to small population size and isolation. It is conceivable that individual spiders recruited in habitat interiors might disperse to the edge, masking an edge effect, but be lacking from small remnants without the interior habitat necessary for population recruitment.
The aim of this study was to determine whether habitat fragmentation, at the scale resulting from historical agricultural practices, has had an impact on the community composition of wolf-spiders in White Cypress Pine (Callitris glaucophylla) woodlands of south-eastern Australia. Two main hypotheses were tested. Firstly, that the wolf spider community of woodland fragments with substantial tracts of interior habitat is not significantly different from that of configurations dominated by edge habitat. Secondly, that the wolf spider community of woodland fragments is not significantly different from that of the agricultural matrix. This second hypothesis provides information on the relative “hostility” of the agricultural matrix and therefore the limits to dispersal.
Section snippets
Experimental design
This study was conducted in fragmented White Cypress Pine Woodlands (Sivertsen and Metcalfe, 1995) in the central west of New South Wales, Australia (Fig. 1). A full description of the topography, vegetation, climate, land-use history and the specific location of the study sites is presented in Major et al. (2003).
Study sites were selected to allow comparison of six different habitat configurations replicated by six sub-regional blocks (Fig. 1). The different habitat configurations were
Description of the fauna
A total of 4522 spiders was collected during the study of which 2769 were sufficiently mature to have developed characters necessary to assign them to one of 16 species (Table 1). Of the remaining 1753 individuals, 164 could be identified to one of two species, and a further 1589 could not be identified with any confidence. None of these specimens are included in Table 1. Of the 16 species identified, seven have been named and three have been referred to in previous work as “Sp. A, Sp. B, Sp.
Wolf spider relationships with configuration
The wolf spider community was made up of sixteen species and it varied significantly in composition only between woodland remnants and the paddock matrix. One species (Sp. A) was significantly more common in the paddocks, and two species (Sp. C and V. spenceri) were less common. However, four other species, which were encountered sufficiently frequently to be analysed at the species level, did not discriminate between the matrix and the remnants composed of native vegetation. The remaining
Acknowledgments
We are grateful for the field assistance provided by Ricardo Aravena, Sarah Brown, Sam Burns, Laura Collins, Katie Crass, Sam Davis, John English, Belinda Fry, David Kingsland, Adam Lamont, Matthew Lindeyer, Steven Mannix, Tim Martin, Matthew McConnell, Graham Milledge, Natasha Mooney, Barry Nielson, Derek Smith, Helen Smith, Celia Symonds and Jaynia Tarnawski. Specialist taxonomic assistance was provided by Rolly McKay and Cor Vink, to whom we are most grateful. We are also grateful to Dr.
References (43)
- et al.
Web spider community response along an edge between pasture and Araucaria forest
Biol. Conserv.
(2004) - et al.
Distribution of arthropod species across the margins of farm woodlands
Agric. Ecosyst. Environ.
(1994) - et al.
Why have birds in the woodlands of Southern Australia declined?
Biol. Conserv.
(2001) - et al.
Influence of remnant and landscape attributes on Australian woodland bird communities
Biol. Conserv.
(2001) - et al.
The effect of habitat configuration on arboreal insects in fragmented woodlands of south-eastern Australia
Biol. Conserv.
(2003) Microenvironment variation within and among forest edge sites in the eastern United States
Biol. Conserv.
(1993)- et al.
Determinants of overwintering habitat quality for beetles and spiders on arable farmland
Biol. Conserv.
(2005) Changes in the avifauna of a region, district and remnant as a result of fragmentation of native vegetation: the wheatbelt of Western Australia. A case study
Biol. Conserv.
(1989)- et al.
Changes in the distribution of carabid beetles in The Netherlands since 1880: II. Isolation of habitats and long-term trends in the occurrence of carabid species with different powers of dispersal (Coleoptera, Carabidae)
Biol. Conserv.
(1988) In defence of small islands: termites (Isoptera) in the Western Australian central wheatbelt, and the importance of dispersal power in species occurrence
Pac. Conserv. Biol.
(2000)
How small is too small for small animals? Four terrestrial arthropod species in different-sized remnant woodlands in agricultural Western Australia
Biodivers. Conserv.
The effects of habitat fragmentation and livestock-grazing on animal communities in remnants of gimlet Eucalyptus salubris woodland in the Western Australian wheatbelt. I. Arthropods
J. Appl. Ecol.
The scale of landscape fragmentation affects herbivore response to vegetation heterogeneity
Oecologia
Conservation of woodland birds in a fragmented rural landscape
Pac. Conserv. Biol.
Growing-season microclimatic gradients from clearcut edges into old-growth Douglas-Fir forests
Ecol. Appl.
Change in Marine Communities: An Approach to Statistical Analysis and Interpretation
Effects of habitat fragmentation on carabid beetles: experimental evidence
J. Anim. Ecol.
A survey and overview of habitat fragmentation experiments
Conserv. Biol.
Plant–insect communities and predator–prey ratios in field margin strips, adjacent crop fields and fallows
Oecologia
Ground beetle species in heathland fragments in relation to survival, dispersal, and habitat preference
Oecologia
Experimental effects of habitat fragmentation on old-field canopy insects: community, guild and species responses
Oecologia
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Present address: University of Melbourne, School of Forest and Ecosystem Science, Water Street, Creswick, Vic. 3363, Australia.