ORIGINAL PAPER The enduring toxicity of road-killed cane toads (Rhinella marina) Michael Crossland • Gregory Brown • Richard Shine Received: 1 December 2010 / Accepted: 25 May 2011 / Published online: 10 June 2011 Ó Springer Science+Business Media B.V. 2011 Abstract The primary ecological impact of inva- sive cane toads (Rhinella marina) in Australia is mediated by their powerful toxins, which are fatal to many native species. Toads use roads as invasion corridors and feeding sites, resulting in frequent road- kills. The flattened, desiccated toad carcasses remain highly toxic despite being heated daily to [ 40°C for many months during the tropical dry-season. In controlled laboratory experiments, native tadpoles (Cyclorana australis, Litoria rothii), fishes (Mog- urnda mogurnda) and leeches (Family Erpobdellidae) died rapidly when we added fragments of sun-dried toad to their water, even if the native animals had no physical access to the carcass. Given the opportunity, native tadpoles and fishes strongly avoided the vicinity of dried toad fragments. Hence, long-dead toads may contaminate roadside ponds formed by early wet-season rains and induce avoidance and/or mortality of native anuran larvae, fishes and inverte- brates. Our studies show that the toxicity of this invasive species does not end with the toad’s death, and that methods for disposing of toad carcasses (e.g., after culling operations) need to recognize the persistent danger posed by those carcasses. Keywords Ecological impact Á Fishes Á Invasive species Á Leeches Á Poisoning Á Tadpoles Introduction Understanding the mechanisms by which invasive species influence ecosystems is a critical first step towards ameliorating impacts on biodiversity and ecosystem function. However, the task is a complex one, because invaders affect native taxa by a diversity of pathways including predation, competition, path- ogen transfer and alteration of structural components of the habitat (Parker et al. 1999; Mack et al. 2000; Snyder and Evans 2006; White et al. 2006). In the vast majority of cases, impacts involve live invaders, but we describe a case where long-dead individuals of the invasive taxon have the potential to continue to affect native species. The cane toad (Bufo marinus, or Rhinella marina under an alternative nomenclatural scheme—Pramuk 2006) is a large anuran native to Central and South America, but introduced to many countries worldwide as a biocontrol agent (Lever 2001). Since its intro- duction to northeastern Australia in 1935, the cane toad has spread through more than a million square kilometers of the wet-dry tropics and associated regions (Urban et al. 2007). Because Australia has no native toads, its predators have little evolutionary history of exposure to the distinctive toxins of bufonid species (Lever 2001). The defensive arsenal of the M. Crossland Á G. Brown Á R. Shine (&) School of Biological Sciences A08, University of Sydney, Sydney, NSW 2006, Australia e-mail: rick.shine@sydney.edu.au 123 Biol Invasions (2011) 13:2135–2145 DOI 10.1007/s10530-011-0031-x