Endangered Ecological Communities of the South East Corner
FACT SHEET 4
Brogo Wet Vine Forest and Dry Rainforest Management Issues
This Fact Sheet discusses some symptoms of declining condition in Brogo Wet Vine Forest and Dry Rainforest EEC remnants and
some remedial actions to improve their health.
Weeds
Weeds are the main threat in these two EECs, with control made difficult by the problems of access on the steep and rocky
slopes where they often occur. There are several native plants associated with these EECs which can form dense stands and
which have burrs or sticky seeds, and may be mistaken for weeds. The most obvious of these are hillside burr-grass (Cenchrus
caliculatus), Indian weed (Sigesbeckia orientalis) and native hound’s tongue (Cynoglossum australe). Weeds which seem to have a
particular affinity with these two EECs are the tall annual herb cobbler’s peg (Bidens pilosa) which can cover large areas, prickly
pears (Opuntia species, listed as noxious on the south coast), cotton bush (Gomphocarpus fruticosus) and the sky-blue flowered
small shrub Tweedia coerulea. Photos of these and other native and weed species can be found overleaf and on the website
www.thebegavalley.com/plants.html.
Livestock camping under figs may assist weeds to invade by opening up the edge of the fig canopy, admitting more light. Typical
invaders are woody weeds whose seed is packaged in a fleshy fruit and spread by birds, since birds visit Dry Rainforest to feed on
fig fruits. Blackberries, privet, pepper trees and lantana are all likely invaders of degraded Dry Rainforest patches.
It is most important that land managers become familiar with the local weeds and keep woody weeds and noxious weeds
controlled at all times. It is far easier to control weeds if they are removed when they first appear and before they set seed.
Waiting until infestations build up is a recipe for a long, costly and probably ultimately losing battle.
There are many methods for dealing with weeds besides spraying them with herbicide. In fact this can be counter-productive,
especially if non-selective types are used, as it creates bare ground, which many weeds love. Some broad-scale weed
management methods include avoiding over-grazing (many unpalatable weeds thrive when more palatable pasture is eaten down)
and using brief crash grazing to minimise seeding of some annual weeds. This has been reported to be effective in reducing
cobbler’s peg in Brogo Wet Vine Forest remnants. However, in these two EECs, leaving stock in for more than a few days would
probably do more harm than good.
Dieback
Tree dieback can affect trees of all ages, and is most often seen in eucalypts and rough-barked apple (angophora). Dieback usually
happens over a long period (as distinct from rapid death from drought), with branches progressively dying back from the tips,
and being replaced by new shoots further back on the branches. Dieback results from stress, which might originate from several
factors, or a combination of them, including insect attack, drought or waterlogging, soil salinity or acidity. Repeated insect attack
and drought are the most obvious immediate causes of episodes of poor tree condition on the south coast. Tree dieback is often
a landscape scale problem which is unlikely to be fixable at the single property level. The aggressive native birds, the noisy miner
and bell miner (not to be confused with the introduced Indian or common myna, gradually moving into the south coast from the
north) can contribute to poor tree health by driving out other birds which feed on insects. The bell miner prefers forest with a
dense shrub understorey and is the species more likely to be found in Brogo Wet Vine Forest remnants. Occasionally bell miner
colonies move on to new territory, allowing trees to recover, but sometimes they persist in a particular location until trees have
died.
The removal of dying or dead trees for firewood should be avoided. They are very important for providing nesting and shelter
sites for a wide range of native animals, including possums and gliders, small insect-eating bats, parrots, owls, kookaburras and
other kingfishers, dollarbirds, goannas and even tree-frogs. Many of these animals help control insects, which is beneficial for both
farmers and the remaining trees. Because tree density has been much reduced over most of the farming areas tree hollows are a
limiting factor for fauna populations.
Lack of eucalypt regeneration, understorey trees and shrubs
Lack of regeneration is seldom a problem in the larger Brogo Wet Vine Forest remnants of the Bega Valley since most such
remnants occur on steeper slopes which livestock tend to avoid. However, small remnants in less steep areas such as around
Moruya may have this problem, in which case fencing to exclude stock will probably help. However, kikuyu if present around
the remnant edges will discourage tree and shrub regeneration even if stock are removed, since ungrazed kikuyu forms a dense
mat which seedlings would have difficulty growing through. Rabbit control may also be important in Brogo Wet Vine Forest
remnants, and can present difficulties due to the rugged terrain and presence of large boulders which provide ideal warren sites.
For assistance with rabbit control methods consult the South Coast Rural Lands Protection Board. For a more detailed discussion
of assisting regeneration see Fact Sheet 2.
(continued overleaf)
In general it is preferable to exclude livestock altogether from Brogo Wet Vine Forest and Dry Rainforest. Most sites on which
these EECs occur are steep and vulnerable to erosion. Dry Rainforest patches are favoured stock camping sites, especially in
summer, because of the deep shade they provide but stock sheltering under them will usually destroy all understorey plants and
may compromise the health of the fig trees.
Too much tree or shrub regeneration
This can become a problem when grassy EEC remnants which have been grazed are de-stocked, potentially including Brogo
Wet Vine Forest. Problems with dense regrowth in this EEC are the loss of ease of access for management actions such as
weed control, rabbit and fox harbour and the fact that regenerating tree growth will be slow due to the intense competition for
resources among the saplings. Dense tree sapling stands will generally self-thin in time, while black wattle dies after 20 or 30
years. Some shrubs such as the dogwoods (Cassinia species) are also quite short-lived, but blackthorn is more persistent. Dense
shrub regrowth may also self-thin once a tree canopy develops. On the positive side, dense regrowth can provide habitat for
fauna, especially small bush birds.
Some active management may improve tree growth rates and selective thinning can improve species diversity. Management
options are more limited on steep sites than in most grassy forest remnants, but include use of selective woody weed herbicides
(non-residual) to thin regrowth, harvesting of larger saplings for firewood and use of fire. Fire is an effective tool in reducing
density of young regrowth, but of limited use in older regeneration which has usually suppressed the flammable grass beneath it.
Fire should be applied very carefully or not at all in Brogo Wet Vine Forest and Dry Rainforest, since it may be difficult to control
on steep slopes and would tend to remove the fire-sensitive species which make these two communities distinctive. Mature figs,
most vines and most of the relevant shrubs can resprout after fire, but young plants may be killed.
Some weeds of
Brogo Wet Vine Forest
Gomphocarpus fruticosus
Narrow leaf cotton bush
Bidens pilosa leaf
Cobbler’s peg leaves
Bidens pilosa fruit
Cobbler’s peg fruits
Tweedia coerulea
Opuntia aurantiaca
Tiger pear
Opuntia stricta
Common Pear
Lantana camara
Lantana
Ligustrum sinense
Large-leaf privet
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