Document ID: chunk:federal_register_of_legislation:F2017L01040:body:0:p10
Version: federal_register_of_legislation:F2017L01040
Segment Type: other
Provision Reference: 
Character Range: 26705–29571

giant freshwater crayfish over the five month study period (Webb & Richardson 2004). This species is also known to walk over land (Horwitz 1991).
The main food of the giant freshwater crayfish is decaying wood and its associated microbes, though its diet varies with age, and they also eat leaves and animal flesh, including small fish, when available (Forteath 1987; Hamr 1996; Lynch 1967).
Giant freshwater crayfish display differences in habitat preferences at different life stages. A study by Davies et al. (2005) found juvenile giant freshwater crayfish in streams at elevations ranging from 18-250 m ASL, channels ranging from 1-20 m bankfull width and catchments areas ranging in size from 0.4-240 km2. However, the study noted that densities were greatest in streams in catchments of intermediate size (typically 2-30 km2) within channels of 1-3 m wetted widths at base flow (Davies et al. 2005). Furthermore, juvenile abundance responded positively to lower levels of silt substrate (< 2 %) and higher proportions of moss cover (> 10 % stream bed area) and boulder substrate (10-30 % stream bed area), while no juveniles were detected in streams with channel slopes > 10 %, silt substrate levels > 5 % and baseflow conductivities > 160 µS/cm (Davies et al. 2005). Optimal habitat for juvenile giant freshwater crayfish may be considered to include shallow areas of streams with minimal silt substrate, high proportions of moss and boulder cover, and meso-habitat features including large rocks, cavities and in-stream logs, while class 4 streams with substantial, sustained groundwater input may also provide suitable habitat conditions (Davies et al. 2005). Class 4 streams (catchment size < 50 ha) are defined within the Forest Practices Code as watercourses carrying water for part or all of the year for most years, they are differentiated from a drainage depression by: having a gravelly, pebbly, rocky or sandy bed; and/or an obvious gully; and/or a short steep section of stream bank adjacent to the watercourse bed (FPA 2015), Conversely, preferred habitat for adult giant freshwater crayfish includes larger streams with deeper pools often associated with snags (Webb 2001).
While small headwater streams have been found to contain suitable habitat for juvenile giant freshwater crayfish, the species has typically been detected in lower densities in these streams compared to larger, higher-order streams within the same drainage (Davies et al. 2005). However, there are some examples of high densities of juveniles being found in smaller headwater streams, such as Coopers Creek which has a catchment area of 40 ha (Davies et al. 2005), and streams with sources rising adjacent to basalt-sedimentary geological contacts (Davies & Cook, unpublished data, cited in Davies et al. 2005). Streams within the Flowerdale-Hebe River catchment provide an