Elsevier

Biological Conservation

Volume 132, Issue 1, September 2006, Pages 98-108
Biological Conservation

Variation in wolf spider (Araneae: Lycosidae) distribution and abundance in response to the size and shape of woodland fragments

https://doi.org/10.1016/j.biocon.2006.03.017Get rights and content

Abstract

The wolf spider (Lycosidae) community of open paddocks and five different configurations of woodland habitat in the wheatbelt of New South Wales, Australia, was sampled by nocturnal spotlighting. A total of 16 species was detected amongst the 2769 individuals that were sufficiently mature to allow identification, and 80% of these individuals were accounted for by just three species. There were no significant differences in the spider community among any of the woodland configurations, but the community of all five configurations differed significantly from that of open paddocks. However, only three species differed significantly in abundance between paddocks and the woodland configurations. Two species, Venator spenceri and Sp. C appeared to be less common in paddocks than in the woodland habitats, while Sp. A was more abundant in the paddocks. The percentage cover of thistles, medium grass and high grass, as well as the total abundance of Callitris glaucophylla were the habitat variables that best explained variation in the wolf spider community between woodland sites. Of these, thistle cover had the strongest correlation suggesting that disturbance, rather than cover per se, might be an important determinant of wolf spider communities. This study indicates that habitat fragmentation, at the spatial scale associated with current agricultural practices, may not be presenting a threat to generalist ground predators such as wolf spiders.

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)

  • M. Abensperg-Traun et al.

    How small is too small for small animals? Four terrestrial arthropod species in different-sized remnant woodlands in agricultural Western Australia

    Biodivers. Conserv.

    (1999)
  • M. Abensperg-Traun et al.

    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.

    (1996)
  • J.E. Banks

    The scale of landscape fragmentation affects herbivore response to vegetation heterogeneity

    Oecologia

    (1998)
  • G.W. Barrett et al.

    Conservation of woodland birds in a fragmented rural landscape

    Pac. Conserv. Biol.

    (1994)
  • J. Chen et al.

    Growing-season microclimatic gradients from clearcut edges into old-growth Douglas-Fir forests

    Ecol. Appl.

    (1995)
  • K.R. Clarke et al.

    Change in Marine Communities: An Approach to Statistical Analysis and Interpretation

    (1994)
  • K.F. Davies et al.

    Effects of habitat fragmentation on carabid beetles: experimental evidence

    J. Anim. Ecol.

    (1998)
  • D.M. Debinski et al.

    A survey and overview of habitat fragmentation experiments

    Conserv. Biol.

    (2000)
  • C. Denys et al.

    Plant–insect communities and predator–prey ratios in field margin strips, adjacent crop fields and fallows

    Oecologia

    (2002)
  • H.H. de Vries et al.

    Ground beetle species in heathland fragments in relation to survival, dispersal, and habitat preference

    Oecologia

    (1996)
  • D.M. Golden et al.

    Experimental effects of habitat fragmentation on old-field canopy insects: community, guild and species responses

    Oecologia

    (1999)
  • Cited by (20)

    • Assessing the conservation and enhancement value of revegetated strips on arthropod assemblages in a pasture landscape

      2021, Journal of Environmental Management
      Citation Excerpt :

      The order classification may be too course a level to gain meaningful data on spiders. Lycosidae, wolf spiders, are key predators of pests in agroecosystems and have been found in both forested areas and agricultural landscapes (Lang et al., 1999; Major et al., 2006). They had no significant differences in abundance in early spring, but in mid-summer abundance was highest along the edge of revegetated strips and 20 m into adjacent pasture.

    • Do agricultural pesticides in streams influence riparian spiders?

      2019, Science of the Total Environment
      Citation Excerpt :

      For example, contaminants reduced aquatic insects and riparian spiders (Kraus et al., 2014; Paetzold et al., 2011). The taxonomic and trait composition of spider communities can be shaped in response to stressors, such as those related to agricultural land use (2005; Major et al., 2006; Schmidt et al., 2008). Those traits responding to a stressor (Violle et al., 2007), can be used to establish trait-stressor relationships.

    • Biodiversity analysis of natural arthropods enemies in vineyard agroecosystems in La Rioja, Spain

      2019, Journal of Asia-Pacific Entomology
      Citation Excerpt :

      However, in the family Lycosidae, a direct response at the habitat level with grasslands and proximity to other patches has been observed in the present work. This response was not directly related to fragmentation (Major et al., 2006). Our results were strongly limited by the taxonomic resolution that was possible.

    • Responses of ground-dwelling spiders (Araneae) to variable retention harvesting practices in the boreal forest

      2012, Forest Ecology and Management
      Citation Excerpt :

      ‘Ground runners’ showed a markedly decreasing pattern in importance as the prominence of ‘sheet/tangle weavers’ increases along this same gradient. It is well known that ‘Ground runners’ are the major component of these assemblages once the canopy of a forest opens after a large scale disturbance (Huhta, 1971; Buddle et al., 2000; Major et al., 2006), with the wolf spider P. moesta, being most common (Dondale and Redner, 1990; Buddle, 2000; Pickavance, 2001). In contrast, ‘sheet/tangle’ weavers represent the most significant element of spider assemblages in undisturbed areas (Huhta, 1965; Buddle and Draney, 2004; Peck and Niwa, 2004).

    • Integrating environmental conditions and functional life-history traits for riparian arthropod conservation planning

      2009, Biological Conservation
      Citation Excerpt :

      We used nMDS since it is an iterative ordination method that places sample units in a k-dimensional space using ranked distances between them (McCune and Grace, 2002). Because nMDS does not assume linearity or monotonicity of the underlying data structure, it is particularly appropriate for the kinds of ecological data in this study (Beals, 2006; Major et al., 2006), and provides a stress-factor which indicates the stability of the ordination. Similarity matrices were based on Bray–Curtis distance measures.

    View all citing articles on Scopus
    1

    Present address: University of Melbourne, School of Forest and Ecosystem Science, Water Street, Creswick, Vic. 3363, Australia.

    View full text