Please cite this article in press as: Yasuda, M., Koike, F., The contribution of the bark of isolated trees as habitat for ants in an urban landscape. Landscape Urban Plann. (2009), doi:10.1016/j.landurbplan.2009.05.008 ARTICLE IN PRESS G Model LAND-1713; No. of Pages 6 Landscape and Urban Planning xxx (2009) xxx–xxx Contents lists available at ScienceDirect Landscape and Urban Planning journal homepage: www.elsevier.com/locate/landurbplan The contribution of the bark of isolated trees as habitat for ants in an urban landscape Mika Yasuda ∗ , Fumito Koike Graduate School of Environmental Science and Technology, Yokohama National University, 79-7 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan article info Article history: Received 22 July 2008 Received in revised form 8 April 2009 Accepted 12 May 2009 Available online xxx Keywords: Host specificity Isolated trees Scattered trees Ants Arthropod community Urbanisation abstract Since urbanisation and fragmentation result in a decrease in larger forests, the importance of isolated trees as habitat in urban landscapes is increasing. This study investigated the contribution of trees in urban landscapes to the abundance and variety of arthropod taxa. Ants and other arthropods were surveyed on the bark of 341 trees in three types of arrangement: isolated trees, trees in linear corridors and trees in patches. Ant species and other arthropods were identified and the numbers on each tree were counted. In order to determine the effects of host tree properties (size and plant species) and the surrounding environment (arrangement of trees, surrounding land cover), an analysis of covariance was conducted. Tree species was the most important influence, followed by tree size, on ants and other arthropods in the urban landscape, with little effect from the arrangement of trees. Thus, in order to increase arthropod diversity in urban landscapes, it is important to select tree species that attract a large number of arthropod taxa. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Urban areas are expanding around the world (Botkin and Beveridge, 1997; Ozanne et al., 2000; Sudha and Ravindranath, 2000; Lumsden and Bennett, 2005). This reduces the amount of natural vegetation and fragments it into patches of various sizes and shapes, leaving trees as relatively isolated individuals in the urban matrix (Dickman, 1987; Fujiwara et al., 2002; Rickman and Connor, 2003). Associated with this fragmentation and loss of native vegetation are reductions in the complexity of microclimates and arthropod species richness, as well as a loss of native species and their replacement by exotics (Hashimoto et al., 1994; Gibb and Hochuli, 2002; McKinney, 2006). Vegetated areas within urban landscapes are increasingly seen as valuable refuges for local biota (Snep et al., 2006; von Haaren and Reich, 2006), and a number of studies have been conducted on arthropod communities in urban forest fragments (Hashimoto et al., 1994; Nuckols and Connor, 1995; Touyama and Nakagoshi, 1994; Yui et al., 2001; Rickman and Connor, 2003; Snep et al., 2006; Yasuda and Koike, 2006; Hodgkison et al., 2007), residential gar- dens (Majer and Brown, 1986), and clumps of trees in urban parks ∗ Corresponding author. Current address: Rice Bug Management Research Team, National Agriculture and Food Research Organization, 3-1-1 Kannondai, Tsukuba, Ibaraki, 305-8517, Japan. Tel.: +81 29 838 8838/45 339 4356; fax: +81 29 838 8837/45 339 4356. E-mail address: mica.yasuda@gmail.com (M. Yasuda). (Shimada and Maruta, 1988; Terayama, 2001; Kohno et al., 2003; Yamaguchi, 2004; McFrederick and LeBuhn, 2006). It is now recog- nized that planting trees might be the only option to conserve local biota in urban areas, but very few studies have examined arthropod communities on isolated trees planted in urban areas (Semlitsch and Bodie, 1998; McCoy and Mushinsky, 1999; Bhullar and Majer, 2000; Fischer and Lindenmayer, 2002). In this study, we surveyed ant and other arthropod species on the bark of trees in an urban area of temperate Japan. We focused on ants because they are functionally important and influence soils, plants and other animals (Read and Andersen, 2000). For instance, ants have evolved mutualisms with plants and confer primary services such as protection from predation and para- sitism, resulting in enhanced growth; in return, plants offer nectar and nesting spaces for ants (Oliveira, 1997; Bronstein, 1998; de la Fuente and Marquis, 1999; Blüthgen et al., 2000; Stuntz et al., 2003). There are also important mutualistic relationships between ants and homopterans (Bach, 1991; Gaume et al., 1998). Ants play an important role in the structuring of arboreal arthropod com- munities, as they exert a constant and high predation pressure (Stuntz et al., 2003). We focused on tree trunks because they are of special importance for some arthropods as sites for egg- laying, as pathways to the canopy and as resting places (Moeed and Meads, 1983; Nicolai, 1986; Hanula and Franzreb, 1998; Majer et al., 2003). The aim of the study was to investigate the contribution of urban trees, some of which were isolated, as habitat for ants and other arthropods in an urban landscape. We evaluated the effects of host 0169-2046/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.landurbplan.2009.05.008