PARENT SESSION
Oral Session 2: Avian Ecology I: Habitat and Disturbance.
Presiding: D Miles and C Lepczyk
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room A 106.
Experimental analysis of bird and mammal responses to variation of fallen-timber loads on forest floors.
Horrocks, Greg1, Mac Nally, Ralph1, 1 Australian Centre for Biodiversity, Monash University, Clayton, Victoria, Australia
ABSTRACT- Habitat structure long has been identified as a key factor influencing assemblage composition. Fallen timber (logs and large boughs) is one of few habitat elements in woodlands that is manipulable with high precision. We conducted an experiment in a river red gum (Eucalyptus camaldulensis) floodplain forest in southeastern Australia. Eight treatments were used, of which six were different fallen-timber loads (0 t/ha-80 t/ha) and two were controls (with/without disturbance). Surveys were conducted before and after the manipulation. The only terrestrial native mammal captured during the study, Antechinus flavipes (an insectivorous marsupial), showed greater relative increases in densities and activity at high fallen-timber loads than at lower ones. For birds, the most substantial increases were in the 80 t/ha and disturbed-control plots, while changes following manipulation in treatments with less than 40 t/ha differed little from zero. Three bird species increased substantially following manipulations: Lichenostomus penicillatus (a honeyeater), Climacteris picumnus (a treecreeper) and Platycercus elegans flaveolus (a parrot). The greatest mean increases following manipulation in any one treatment were 9.9 birds/ha for L. penicillatus, 6.4 birds/ha for C. picumnus and 6.2 birds/ha for P. e. flaveolus Given that average fallen-timber loads are less than 20 t/ha in most river red gum floodplain forests, the large increases, especially for the 80 t/ha treatments, suggest that substantial increases in fallen timber loads would be advantageous for both birds and Antechinus flavipes in these intensively managed forests.
Key words: fallen timber, floodplain, Antechinus flavipes, restoration