Abstract
[Truncated] The extraction of minerals has the potential to bring about drastic transformations to topography, soil physical and chemical properties, hydrology, and biological assemblages. The science of restoration ecology aims to facilitate the reassembly of plant communities in these highly altered environments to resemble a target or reference state in a timeframe that is acceptable to stakeholders and policy makers. The outcomes of restoration practices are the product of interactions between environmental drivers and management intervention techniques through time, yet the long term effects of these interactions have rarely be quantified and may provide valuable implications for leading-practice in ecological restoration. This thesis examines a 19 year-old, post-mining Banksia woodland restoration chronosequence in order to further current understanding of how ecosystems develop in restored sites, in terms of three major ecosystem attributes; 1) plant community composition (species richness and abundance); 2) ecosystem function, and; 3) vegetation structure.
The development of plant community composition through time, and the effects thereon of environmental drivers (rainfall regimes during the establishment phase, site aspect, slope) and management intervention techniques (substrate ripping and properties of reconstruction materials) were assessed in terms of four commonly employed restoration criteria; species richness, plant density, vegetation cover, and similarity to reference sites. Irrespective of environmental drivers or management intervention techniques, vegetation cover increased through time, while plant density and species richness declined. Compositional similarity to reference communities remained relatively unchanged. Within the confines of these trends, rainfall and ripping treatments interacted to significantly affect restoration criteria; species richness and plant density were greatest when rainfall in the first winter immediately following site restoration was low, and then followed by a high summer rainfall. The most effective ripping depth was dependent on rainfall, with deep-ripped sites performing best when rainfall was high, and shallow ripped sites performing best under low-mean rainfall conditions.
The development of plant community composition through time, and the effects thereon of environmental drivers (rainfall regimes during the establishment phase, site aspect, slope) and management intervention techniques (substrate ripping and properties of reconstruction materials) were assessed in terms of four commonly employed restoration criteria; species richness, plant density, vegetation cover, and similarity to reference sites. Irrespective of environmental drivers or management intervention techniques, vegetation cover increased through time, while plant density and species richness declined. Compositional similarity to reference communities remained relatively unchanged. Within the confines of these trends, rainfall and ripping treatments interacted to significantly affect restoration criteria; species richness and plant density were greatest when rainfall in the first winter immediately following site restoration was low, and then followed by a high summer rainfall. The most effective ripping depth was dependent on rainfall, with deep-ripped sites performing best when rainfall was high, and shallow ripped sites performing best under low-mean rainfall conditions.
Original language | English |
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Qualification | Doctor of Philosophy |
Publication status | Unpublished - 2014 |