Technical report: effect of vegetation management on woodland communities in the Traprock region
Technical report
Title | Technical report: effect of vegetation management on woodland communities in the Traprock region |
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Report Type | Technical report |
Authors | Le Brocque, Andrew F. (Author), Goodhew, Kellie A. (Author) and Cockfield, Geoff (Author) |
Institution of Origin | University of Southern Queensland |
Number of Pages | 93 |
Year | 2005 |
Publisher | University of Southern Queensland |
Place of Publication | Toowoomba, Australia |
Abstract | [Summary]: The modification of natural woodland tree densities through tree removal or clearing is one management option used by landholders to increase native grass production for livestock grazing. These variegated landscapes are found in many eastern states where both livestock grazing and tree removal represent significant anthropogenic disturbances on natural woodlands. An understanding of the effects of vegetation management on native vegetation characteristics is an important first step to ensure appropriate management of woodland communities. The broad aim of this research project was to determine if vegetation management has an effect on floristic composition, species richness and plant cover in the Traprock wool-producing region of southern Queensland. The following specific questions were examined: Is there a difference in floristic composition, species richness and plant cover between mature tree density classes?; Do woody regrowth areas have a different floristic composition and lower species richness than areas without woody regrowth?; and Are there differences in vegetation responses across vegetation types? Forty-seven sites were sampled across the study area according to vegetation type (ironbark/gum woodland and box woodland), density of mature trees (low [<6 trees/ha], medium [6-20 trees/ha] and high [>20 trees/ha]), and the presence or absence of woody regrowth. Sample sites were established randomly within patches and the composition and relative abundance (frequency) of plant species were determined in a 500 m² quadrat. Stand structural characteristics, including foliage projective cover of distinct strata, and cover of litters, logs and rocks were also determined subjectively within each quadrat. Tree recruitment was determined by measuring the density of juvenile trees in three height classes < 1m, 1-3m and > 3m within each 500 m² quadrat. Management history (from landholder questionnaires), landscape context, the perimeter and area of sampled vegetation patches, and the level of disturbance at each site were also determined for all sites sampled. Patterns in floristic composition were determined using Indicator Species Analysis (ISA) and non-metric Multidimensional Scaling (nMDS). Analysis of Similarity (ANOSIM) determined whether there were significant differences in floristic composition between mature tree density classes, with or without woody regrowth. nMDS was also used to assess patterns in cover data for growth forms. The relationship between floristic composition and environment was examined by Canonical Correspondence Analysis (CCA). In addition, analysis of variance was used to determine if groups differed significantly for species richness, percentage cover of selected plant functional groups and tree and shrub recruitment. This research shows that retaining trees in variegated landscapes provides significant landscape heterogeneity and important habitats for plant species that may be largely excluded from open grassland habitats. Importantly, there is some support for maintaining a medium density of trees in box woodlands that can potentially provide both production and biodiversity benefits. Future studies should separate the effects of sheep grazing from that of tree density to increase understanding of the ecological changes undergone by vegetation in response to management. |
Keywords | tree density; woody regrowth; sheep grazing; production landscapes; paddock trees; biodiversity benefits; eucalypt woodlands |
ANZSRC Field of Research 2020 | 410206. Landscape ecology |
410401. Conservation and biodiversity | |
410406. Natural resource management | |
Public Notes | File reproduced in accordance with the copyright policy of the publisher/author. |
Byline Affiliations | Australian Centre for Sustainable Catchments |
Department of Biological and Physical Sciences |
https://research.usq.edu.au/item/9y1w1/technical-report-effect-of-vegetation-management-on-woodland-communities-in-the-traprock-region
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