Biology Reference
In-Depth Information
Box 2.6. The growth stages of woodland remnants and the
importance of woodland regrowth for biodiversity
The terms 'old growth' and 'regrowth' are often thought of in the context of tall wet
forests and their management. But our recent work has indicated that different
growth stages are also critical in temperate woodland vegetation. This is because
growth stages significantly influence the presence and abundance of many species
of woodland animals. Three broad growth stages of woodland remnants which have
proven significant in our studies of reptiles, possums and gliders are old growth,
coppice regrowth and seedling regrowth. 7 Old-growth woodland is dominated by
large trees that are generally more than 100 years old. Coppice regrowth is multi-
stemmed regrowth from existing living trees recovering after fire, logging or both.
Seedling regrowth is natural regrowth originating from seeds germinating after being
dropped by overstorey trees.
In our large study on the South West Slopes of New South Wales, the Common
Brushtail Possum and the Common Ringtail Possum were most often recorded in
old-growth woodland. 7 In contrast, the Wall Skink was more often found in coppice
regrowth and old growth than in seedling regrowth. The Marbled Gecko was more
likely to be detected in seedling regrowth than coppice regrowth.
One of our major studies of birds on the South West Slopes of New South
Wales showed that nine species of declining and/or threatened woodland birds
were more likely to occur in regrowth woodland (coppice or seedling) than old-
growth woodland. 4 These included the Black-chinned Honeyeater, Crested
Shrike-tit, Diamond Firetail, Eastern Yellow Robin, Jacky Winter, Restless Fly-
catcher and the Dusky Woodswallow. Other work on woodland birds in the
Australian Capital Territory region has also highlighted the importance of eucalypt
regrowth for a range of birds including the Brown Thornbill and Buff-rumped
Thornbill. 5
Recognition of the value of different growth stages in woodlands is important for
several reasons. A critical one is that areas of regrowth woodland have often been
regarded as 'rubbish' country in the past and of limited value for biodiversity. This
is clearly not the case. Some species exhibit a stronger preference for regrowth
woodland than old growth. Second, because different species select different
growth stages as habitat, the conservation of these different kinds of vegetation
should be part of any strategy aimed at maintaining populations of the full range of
species that might occur on a farm. Third, the different kinds of growth stages of
remnant native vegetation form part of the portfolio of vegetation assets that under-
pin farm-level biodiversity conservation. Finally, vegetation development is a
dynamic process: stands that are currently regrowth can, with appropriate manage-
ment and an absence of intensive disturbances, eventually become old-growth
stands. Therefore, the long-term maintenance of old-growth woodland requires the
maintenance of existing areas of regrowth that can be recruited to an old-growth
stage over time. 7
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