Vertebrate Ecology

An introduction to tetrapod feeding

by Kurt Schwenk

Diversity of vertebrate feeding systems

by Kurt Schwenk

When Does an Alien Become a Native Species? A Vulnerable Native Mammal Recognizes and Responds to Its Long-Term Alien Predator

by Alex Carthey

Co-authored with Peter B Banks
Published in PLoS ONE

The impact of alien predators on native prey populations is often attributed to prey naiveté towards a novel threat.... more The impact of alien predators on native prey populations is often attributed to prey naiveté towards a novel threat. Yet evolutionary theory predicts that alien predators cannot remain eternally novel; prey species must either become extinct or learn and adapt to the new threat. As local enemies lose their naiveté and coexistence becomes possible, an introduced species must eventually become ‘native’. But when exactly does an alien become a native species? The dingo (Canis lupus dingo) was introduced to Australia about 4000 years ago, yet its native status remains disputed. To determine whether a vulnerable native mammal (Perameles nasuta) recognizes the close relative of the dingo, the domestic dog (Canis lupus familiaris), we surveyed local residents to determine levels of bandicoot visitation to yards with and without resident dogs. Bandicoots in this area regularly emerge from bushland to forage in residential yards at night, leaving behind tell-tale deep, conical diggings in lawns and garden beds. These diggings were less likely to appear at all, and appeared less frequently and in smaller quantities in yards with dogs than in yards with either resident cats (Felis catus) or no pets. Most dogs were kept indoors at night, meaning that bandicoots were not simply chased out of the yards or killed before they could leave diggings, but rather they recognized the threat posed by dogs and avoided those yards. Native Australian mammals have had thousands of years experience with wild dingoes, which are very closely related to domestic dogs. Our study suggests that these bandicoots may no longer be naïve towards dogs. We argue that the logical criterion for determining native status of a long-term alien species must be once its native enemies are no longer naïve.

TURNER, S. 1974. Sunfish and Moonfish. Transactions Natural History Society of Northumberland, Durham and Newcastle upon Tyne, 41 (3): 241 242.

by Susan Turner

TURNER, S. and BAMBER, R. 1977. A rare fish in the North Sea. Transactions Natural History Society Northumberland, Durham and Newcastle upon Tyne, 42 (6): 136.

by Susan Turner

co-authored with Roger Bamber

Horned Lizards (Phrynosoma) Incapacitate Dangerous Ant Prey With Mucus

by Kurt Schwenk

Recovery from the most profound mass extinction of all time

by Sarda Sahney

Sahney, S. and M.J. Benton 2008. Recovery from the most profound mass extinction of all time. Proceedings of The Royal Society of London. Series B, Biological Sciences 275:759-765.

The end-Permian mass extinction, 251 million years (Myr) ago, was the most devastating ecological event of all time,... more The end-Permian mass extinction, 251 million years (Myr) ago, was the most devastating ecological event of all time, and it was exacerbated by two earlier events at the beginning and end of the Guadalupian, 270 and 260 Myr ago. Ecosystems were destroyed worldwide, communities were restructured and organisms were left struggling to recover. Disaster taxa, such as Lystrosaurus, insinuated themselves into almost every corner of the sparsely populated landscape in the earliest Triassic, and a quick taxonomic recovery apparently occurred on a global scale. However, close study of ecosystem evolution shows that true ecological recovery was slower. After the end-Guadalupian event, faunas began rebuilding complex trophic structures and refilling guilds, but were hit again by the end-Permian event. Taxonomic diversity at the alpha (community) level did not recover to pre-extinction levels; it reached only a low plateau after each pulse and continued low into the Late Triassic. Our data showed that though there was an initial rise in cosmopolitanism after the extinction pulses, large drops subsequently occurred and, counter-intuitively, a surprisingly low level of cosmopolitanism was sustained through the Early and Middle Triassic.