Some of the species associated with snags, logs and hollow living trees do not depend on dead wood as a source of nourishment. Instead, they use cavities and other dead-wood microhabitats for various purposes such as nesting, roosting, denning and hibernation. These species may be obligate saproxylics if the availability of dead wood is essential for their survival during some part of their life cycle. Many facultative saproxylic species use dead wood more opportunistically, without being dependent on it. In this chapter, we describe these uses of dead woody material, concentrating on saproxylic species that do not belong to the saproxylic food web described in Chapter 3.

Vertebrates

Nesting and roosting in cavities

Many forest-dwelling vertebrates utilize holes and cavities in trees. For instance, in Australia, over 300 vertebrate species are known to use cavities (which are generally referred to as hollows in the Australian literature). The list includes 83 mammals (31% of the total terrestrial mammal species in Australia), 114 birds (15%), 79 reptiles (10%) and 27 amphibians (13%) (Gibbons and Lindenmayer, 2002).