Forestry and land clearingForestry and land clearing

Forestry and land clearing

Loss of potential breeding habitat in Tasmania via clearance for conversion to agriculture, native forest logging and intensive native forest silviculture practices continues to reduce the amount of available Swift Parrot nesting and foraging habitat and it therefore remains a significant threat to the continued persistence of the species (Saunders et al. 2007, Saunders and Tzaros 2011, Webb et al. 2017, Webb et al. 2019).

There are no comprehensive estimates assessing loss of potential breeding habitat through forest harvesting or land clearing in recent years across the species breeding range. However one case study using the Southern Forests Swift Parrot Important Breeding Area (SPIBA) (one of 15 key breeding regions delineated for management purposes, Forest Practices Authority, 2010) estimated that forest harvesting between 1997 and 2016 had resulted in as much as 23 per cent of identified potential nesting habitat being lost in this time, noting that prior to 2007, this region was not recognised as supporting Swift Parrot breeding (Webb et al. 2019).

Much of the Swift Parrot potential breeding habitat in Tasmania is on private and public land that is subject to management arrangements under the Tasmanian Forest Management System.

The process of adaptive management and continuous improvement is built into the Tasmanian Forest Management System, and specific management arrangements for Swift Parrots have continued to evolve since 1996 to account for new knowledge (e.g. Forest Practices Authority 2010; Munks et al. 2004). However there remains an ongoing need for continual monitoring, evaluation and adaptive improvement in management approaches, particularly with regards to measures addressing habitat recruitment, the refinement of knowledge including in regards to nesting and foraging habitat requirements and their spatial and temporal availability.

Harvesting operations and land clearing of foraging habitat on the Australian mainland also remains a substantial threat. Impacts on Swift Parrot habitat in NSW have been so severe that only 5 to 30 per cent of the original vegetation now remains, such as for Grey Box and Grassy White Box woodland, and what is left is often degraded (Saunders and Russell 2016). With such extensive losses of habitat there is an increased risk that the remaining areas fail to produce the necessary food resources in one year. Before such extensive habitat losses occurred, the birds had a much greater chance of locating the food resources they needed each year (Saunders and Russell 2016).

The loss of mature box-ironbark woodlands of central Victoria and coastal forests of New South Wales, including Spotted Gum forests on the south coast, reduces the suitability of these habitats for this species by removing mature trees which are preferred by Swift Parrots. Larger trees typically provide more reliable, greater quantity and quality of food resources than younger trees (Wilson and Bennett 1999; Kennedy and Overs 2001; Kennedy and Tzaros 2005). However, the extent of forest loss over Swift Parrot foraging habitat on the mainland has not been quantified, and the impacts from urban and agricultural land clearing and commercial harvesting operations on the mainland remain uncertain.