Byron Flora and Fauna Study 1999 - Byron Shire Council

A GREENPRINT FOR A SUSTAINABLE FUTURE
7
Threats and amelioration
7.1 VEGETATION CLEARING
This study has indicated the extent of past vegetation clearance in the Shire (Section 4.6.1), although the
current vegetation cover includes substantial areas of regrowth and so underestimates the extent of past
clearing. Some kinds of vegetation have been cleared more than others, because vegetation growing on
prime agricultural land, and land favoured for settlement and coastal development, has been targeted to a
greater extent than soils of low fertility, slopes and hinterland situations. As a result, vegetation types such as
lowland rainforest are now scarce in the Shire and regionally.
Land clearing has obvious consequences for the biomass and area of vegetation. The number of individual
plants and animals present is directly reduced. As a result, threshold densities necessary for demographic
processes to operate may be reached, and the effectiveness and operation of other biotic and abiotic
interactions may be reduced. Some animals require large home ranges or territories (Terborgh 1992).
Longer term losses may occur as a result of inbreeding depression (Ralls et al. 1986). Whenever plant and
animal numbers and the area they occupy is reduced, there is an increased probability that chance events
will further reduce numbers below critical levels, and local extinction will result. The impact of removal of
any vegetation may thus be substantial, though it will always be difficult to predict precisely. Some of the
indirect effects of land clearing take place over long time frames, so that degradation resulting from historical
clearing may still be in progress.
As vegetation cover is already severely depleted in the Shire, it is now essential to retain and restore the
remaining vegetation, and revegetate to the extent that other land uses and available resources will allow.
Measures required, individually or in combination, will include:
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• Protection of remaining vegetation
• Rehabilitation of degraded vegetation
• Enrichment of species-poor regrowth
• Natural regeneration, with management where necessary
• Direct seeding
• Planting
A body of expertise in the planting and rehabilitation of local rainforest communities has accumulated
particularly over the last decade. The principles and techniques are embodied in two recent publications
(Kooyman 1996, Big Scrub Rainforest Landcare Group 1998a). Further detail about the identification and
control of environmental weeds is given by the Big Scrub Rainforest Landcare Group (1998b). Comprehensive
horticultural advice at the level of the individual species is also available (Nicholson and Nicholson 1985,
1988, 1991, 1994). Much material from these sources will be also be relevant to wet sclerophyll communities.