Comparison of microhabitat use in young regrowth and unlogged forest by the eastern pygmy-possum (Cercartetus nanus)

We describe microhabitat use and response to disturbance by the eastern pygmy-possum (Cercartetus nanus) in heathy dry sclerophyll forest using spool-and-line-tracking. We compared unlogged forest with forest regenerating four years after selective logging. Structural and floristic attributes were scored along spool lines and compared with a random line for each possum. We found that possums (n = 23) selected areas based on both structural and floristic attributes. Possums selected dense understorey, especially that comprising flowering hairpin banksia (Banksia spinulosa) and Gymea lily (Doryanthes excelsa). Fallen logs were not selected by nocturnally active possums. Spool lines in regrowth forest had less eucalypt cover and more understorey cover (e.g. D. excelsa and B. spinulosa) than unlogged forest. Conversely, cover of Banksia serrata was less in regrowth than unlogged forest. Spool lines were commonly found both at ground level (mean = 52–57% of lengths) and above the ground (43–48% of lengths). There was no difference in the mean spool height between the logging treatments (regrowth: 0.47 ± 0.14 m; unlogged: 0.49 ± 0.10 m; ± s.e.). Overall, our results suggest that the dense, flowering understorey that regenerates after selective logging is suitable for use and is the primary attribute selected by active pygmy-possums.

The importance of managing and conserving large old trees: a case study from Victorian Mountain Ash forests

Large old trees are critical structures in the Mountain Ash forests of the Central Highlands of Victoria. They perform many critical ecological and other roles. Populations of these trees are also in serious decline. A range of key management strategies is needed to arrest the decline of existing populations of large old trees and instigate population recovery. In particular all existing large old trees need to be properly protected with adequate buffers of uncut forest. In addition, all stands of old-growth forest, irrespective of their size, need to be protected to ensure they are not logged. The size of the old-growth estate also must be expanded so that it encompasses at least 30%‒50% of the distribution of Mountain Ash. Finally, the recruitment of new cohorts of large old trees is critically important to replace existing trees when they are lost. To achieve this, large areas of existing regrowth forest that regenerated after the 1939 fires need to be excluded from logging and grown through to an old-growth stage. Implementation of altered management in Mountain Ash forests is urgent, as delays in policies will exacerbate the decline of this significant population of large old trees in south-eastern Australia.

Canopy nectar production and the impact of logging and climate in Grey Ironbark Eucalyptus paniculata (Smith) forests

Nectar in tall forest canopies is a significant, but poorly quantified, resource for Australian fauna, as well as the European Honeybee Apis mellifera. We investigated the impact of logging on nectar production in the canopy of Grey Ironbark Eucalyptus paniculata (Smith) forests in southern Australia. Using cherry-pickers and cranes we measured nectar production in large and small trees in replicate sites in each of recently logged, young regrowth and old regrowth forest over three consecutive years (2004?2006). We focused on over-night nectar production, although nectar was produced during both the day and night. Logging history and tree size, when considered individually, had no significant effect on nectar production per flower, although the two factors showed a significant interaction. However, these differences were relatively minor in comparison to the negative relationship with drought. Little nectar was produced per flower under any logging history in drought. During good conditions nectar production varied depending on logging history. When scaled up to the forest stand, logging history had a marked effect on nectar production with old regrowth forest producing seven times as much sugar per ha as recently logged forest. Young regrowth forest 15?20 years old produced nectar quantities intermediate between that of recently logged forest and regrowth forest. At the compartment scale, current practices require the retention of old forest and the typical extent of this retention reduced the difference between old regrowth forest and recently logged forest to a factor of two times. Nectar production per flower was low and a limited resource in autumn 2004 and late-winter 2005, but was copious and in surplus in early summer 2006. Nectar standing crops at the flower scale appeared to be determined by an interaction between environmental conditions (drought) that negatively influenced nectar production and the feeding activity of flower visitors at the time, which itself is affected by prevailing temperatures and nectar attributes, such as sugar concentration and regional nectar availability. We suggest that management actions should focus on minimising nectar depletion in poor flowering years when the nectar resource is limiting.