Document ID: chunk:federal_register_of_legislation:F2017L01040:body:0:p15
Version: federal_register_of_legislation:F2017L01040
Segment Type: other
Provision Reference: 
Character Range: 42828–45902

forestry operations impacts can include changes to stream flows, geomorphology, nutrient dynamics, carbon budgets and impacts to in-stream habitat (Thompson et al. 2009). These threats were known to occur in Tasmanian catchments (Jackson & Blühdorn 1999). Impacts on stream condition can vary in relation to the location, extent and duration of forestry operations within a catchment (Smith et al. 2009; Johnson & Host 2010), in addition to the nature of the forestry operations being undertaken. The giant freshwater crayfish is known to occur in streams in both plantations and native forest areas subject to production forestry activities (Pracejus 2016)
A recent study by Davies et al. (2016) examined the relationship between upstream forest management and the condition of mid-catchment streams in the north west of Tasmania. It aimed to investigate whether historical forestry operations (native forest harvesting and plantation management) in upper catchment areas have downstream effects on stream biota, including benthic macroinvertebrates, and threatened fauna (specifically giant freshwater crayfish). The study found that when > 40 % of the upstream catchment area had been harvested under clearfell, burn and sow (CBS) operations, levels of fine benthic sediments increased and the proportion of sensitive aquatic insect taxa decreased in relation to the proportion of upstream (headwater) land area under CBS. Increases in fine sediment loads were largely attributable to historic CBS operations, though increases in the area of unsealed roads in upstream CBS operations were also positively correlated with increases in fine sediment loads in downstream reaches. In catchments with non-basaltic geologies these impacts could extend up to 10 km downstream to mid-catchment regions. Fewer giant freshwater crayfish were found in catchments with a greater proportion of land harvested by CBS, however the results were only marginally statistically significant due to the small sample size (Davies et al. 2016). Furthermore, it was not possible to distinguish whether the impacts recorded were the result of current CBS operations or legacy impacts from historic CBS operations. Thus the extent to which forestry operations impact on juvenile giant freshwater crayfish habitat, and the effectiveness of current management actions to reduce impacts, remains unclear.
The work by Davies et al. (2016) also suggests that plantation forestry (hardwood Eucalyptus nitens) in Tasmania within predominantly basaltic catchments in north-west Tasmania appear significantly more benign in terms of downstream impacts on stream biota than CBS forestry operations and associated road construction occurring in other geological contexts. Nevertheless, harvest of plantation forests that were established on steep land prior to the implementation of the Forestry Practices Code (i.e. pre-1987), with no regard for streamside reserves, has affected the condition of Class 2 to Class 4 streams, particularly after heavy rainfall (McIntosh 2016; McIntosh et al. 2007, 2014). The