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Providing evidence to improve practice

Individual study: Temporal trends in use of fauna-friendly underpasses and overpasses

Published source details

Bond A.R. & Jones N.J. (2008) Temporal trends in use of fauna-friendly underpasses and overpasses. Wildlife Research, 35, 103–112


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Install overpasses over roads/railways Terrestrial Mammal Conservation

A study in 2004–2007 in eucalypt woodland in Queensland, Australia (Bond & Jones 2008) found that a wildlife bridge was used by mammals. A total of 1,240 herbivore scats were recorded on the bridge. Brown hare Lepus capensis scats were the most common (78%), followed by red-necked wallaby Macropus rufogriseus (15%), eastern grey kangaroo Macropus giganteus (5%), swamp wallaby Wallabia bicolor (1%), possum (1%) and short-beaked echidna Tachyglossus aculeatus (1%). Six mammals were killed on the road before construction and one afterwards. In 2004, a 1.3-km section of highway was upgraded to four lanes and a variety of wildlife crossings constructed, with barrier fencing (2.5 m high) between. Use of a large overpass (15–20 m wide, 70 m long, planted with grass, shrubs and trees) was monitored from six months after completion. Scats were recorded weekly from August 2005–February 2006 and for two weeks in June 2007. Road-kill was monitored twice weekly before construction (April–July 2004) and weekly afterwards, until June 2007.

(Summarised by Rebecca K. Smith)

Install barrier fencing and underpasses along roads Terrestrial Mammal Conservation

A before-and-after study in 2004–2007 along a highway through eucalypt woodland in Queensland, Australia (Bond & Jones 2008) found that two underpasses, in areas with roadside barrier fencing, were used by mammals and the mammal road casualty rate fell after construction. There were three wild mammal road casualties over 29 months post-construction and six during four months pre-construction. This comparison was not tested for statistical significance. Tracks detected in underpasses were from rodents (370 tracks), house mice Mus musculus (115), Dasyurid sp. (most likely Common dunnart Sminthopsis murina) (17), northern brown bandicoots Isoodon macrourus (179), possums (16), red-necked wallabies Macropus rufogriseus (3), short-beaked echidnas Tachyglossus aculeatus (2) and from feral cats Felis catus, dogs Canis lupus familiaris and brown hares Lepus europaeus. Proportions of tracks representing full crossings varied by species with the highest figure for wild mammals being for possums (18–40% of records). In 2004, a 1.3-km section of highway was upgraded to four lanes and a variety of wildlife crossings constructed, linked by barrier fencing (2.5 m high). Use of two underpasses (2.4 m high, 2.5 m wide, 48 m long) with water flowing through and ledges attached to side walls, was monitored, starting six months after construction. Tracks were counted on sand within each entrance, twice weekly from August 2005–February 2006 and monthly from June 2006–June 2007. Road-kill was monitored twice weekly before (April–July 2004) and weekly after construction until June 2007.

(Summarised by Rebecca K. Smith)