YURII V. KORNILEV, STEVEN J. PRICE and MICHAEL E. DORCAS

Department of Biology, Davidson College, Davidson, NC 28035, USA

Introduction
Human transportation infrastructures, such as roads, can adversely affect animal populations via fragmentation (Forman and Alexander 1998; Mader 1984) and habitat deterioration due to
construction (Ritters and Wickham 2003), changes in predator/prey concentrations (Dijak and Thompson 2000) and vegetation composition (Angold 1997), and the spread of invasive species (Tyser and Worley 1992) (for summary references see Forman et al. 2003). Direct mortality has been demonstrated for many animals, including mammals (Groot Bruinderink and Hazebroek 1996; Havlín 1987), and amphibians and reptiles (e.g., Ashley and Robinson 1996; Hels and Buchwald 2001; Smith and Dodd 2003). Other land transportation networks, such as railroads, can result in direct mortality due to collisions with trains, although this has been primarily documented for mammals (see Van Der Grift 1999 for review). Although some lizards may benefit from railroad structures (Blanke 1999), the railroad bed itself may be lethal for smaller animals that can become trapped between the rails, where they may be susceptible to predation or physiological stress. Railroads can also form barriers, either physically (inability to cross) or behaviorally (avoidance), that can result in fragmented populations (Groot Bruinderink and Hazebroek 1996). For example, Van Der Grift (1999) points out that few Hedgehogs (Erinaceus europaeus) are killed by trains, but the structure of the railroad may act as a barrier to movement.

e-mail (MED): midorcas@davidson.edu