Analysis of techniques for mapping environments for fauna survey
Creators: name: Thackway, Richard Malcom
Publisher: name: The Australian National University
Year: 1985
Subjects: land system
unsupervised classification
Tianjara Army training Area
Morton National Park
pattern analysis
bird communities
bird survey
environmental classification
aerial photos
stratified representative sampling

description: A discussion of environmental land classification is presented for the purpose of surveying avifaunal communities. Surveying and mapping land uses the term environment in a special sense. Environment can be mapped into regions whose components are interacting climate terrain, geology, soils and biota. The problem of how to describe the environment for sampling fauna requires an approach which samples the inherent and known variability of all environmental regions present. Discovery of patterns between fauna and environment provide the basis for understanding species/habitat relationships and provides a valuable basis for management or more detailed studies. Two environmental mapping methods commonly employed in faunal survey and management are systematic grids and natural landscape patterns; these were compared to determine their effectiveness for classifying the environment for sampling avifaunal communities. A detailed study was undertaken between 1982-84 in a plot of 8km2 in the Tianjara area. The plot was chosen to encompass a representative sample of the wide range of environments described by Gunn (1985). Analysis of the systematic grids involved sampling a diverse set of environmental attributes into six different grid sizes, including 100m2, 200m2, 300m2, 400m2, 500m2 and 1000m2. Topographic maps and aerial photos provided the sources for measuring the attributes. Results of several analyses showed the 300m2 grid was the most appropriate for the Tianjara area. Analysis of natural landscape patterns involved adoption of the work done by Gunn et al (1984) and led to the preparation of a land unit map for the study plot. Detailed patterns were delineated in 1:27,000 scale air photos and described using the land unit descriptions in Gunn (1985). Results from ground site samples taken to verify the two mapping bases showed that the correspondence between map and ground data was better for sites in systematic grids than for natural landscape patterns. Notwithstanding this, a better understanding of the effects of sampling specific patches of environment was gained from examining sites in natural landscape patterns because it employed a stratified representative sampling strategy, while the systematic grids used a centric systematic sampling strategy. The effect of this was large uniform patches of habitat tended to be more oversampled by sites in systematic grids than was observed for sites in natural landscape patterns. Examination of the relationships between the sampling bases using analyses of environment was not possible because of the lack of sufficient sites in common between the two sampling bases. Comparison of the two sampling bases was, however, possible by using avifaunal data common to both sampling bases. Analysis of the relationships between avifaunal data and environmental groups showed only minor differences between the effectiveness of the two sampling bases to provide practical and realistic descriptions of environment for describing discrete assemblages of birds. The overall conclusion of this study is that any environmental classification, so long as it is based on relevant attributes known to be important for environmental structure and processes, will provide a valuable basis for sampling fauna. A number of points need to be stressed regarding analyses of this type; care needs to be exercised in choosing surrogate environmental attributes between the mapping and ground site data and caution is required when allocating sampling sites to avoid overemphasising area of environmental groups as more important than the inherent variability of the attributes within the environmental groups. An understanding of this problem will greatly improve the nature of sampling fauna in environmental regions.