Dead standing trees contribute to the conservation of arthropods in burnt woodland of Kings Park, Western Australia

Abstract

Dead, standing trees, commonly referred to as stags in Australia and as snags in North America, are a regular feature of forests and woodlands. Although previously regarded as useless, often meriting removal, stags are now recognized as important for wildlife. We quantified the abundance of arthropods that visited or used the trunks of stags in Kings Park, an inner-city woodland park in Perth, Western Australia. Stags ranging from around 4 to 11 years since death were compared with live trees of the same species; Jarrah Eucalyptus marginata, Tuart E. gomphocephala, and Fraser's Sheoak Allocasuarina fraseriana. At the ordinal level, stags were visited or used by almost as many taxa of arthropods as live trees. One group, the beetles (Coleoptera), when considered at the morphospecies level, was found to be only slightly less diverse on Eucalyptus stags than on live trees and was more diverse on sheoak stags than live sheoaks. A large proportion of the beetle species was specific to either live trees or stags, suggesting that the existence of stags enriches the diversity of arthropods in forests and woodlands. In addition to contributing to arthropod diversity and conservation, these organisms provide a food source for insectivorous vertebrates, as well as contributing to core ecosystem functions, such as nutrient cycling. Retention of stags therefore has important conservation benefits and, other than when there is a risk to public safety, stags should be protected and allowed to fall naturally in the course of time.