The data set contains information on the Habitat structure of the Karawatha Peri-urban site, southeast Queensland. There are two data sets: 1) information on Canopy cover percentage from the study plots and 2) information on the Ground cover properties such as the number of hits/strikes of the 'bare ground', 'rock', 'herbs', 'grass', 'shrubs', 'trees' and 'cwd', along each transect in the core plot.
Credit
We at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging.
Lineage
Canopy cover and ground cover estimates for 33 one-hectare plots in Karawatha Forest Park. The plots are at 500 m intervals in a grid that covers the entire Park. Each plot follows the elevational contour and is 250 m long x 40 m wide. Canopy cover was measured using photographs taken at 50 m intervals along the 250 m mid-line of the plot. Ground cover was measured using the point-intercept method at 2 m intervals along the mid-line. Surveys were completed during the period October 2007 to February 2008.
1) Determination of canopy cover: Canopy cover can be defined as the extent of coverage of the forest floor by the vertical projection of tree crowns (Jennings et al., 1999). The percentage canopy cover was measured along a 250m transect located 5m to the left- hand side and parallel to the plot midline (ie. the same transect that lizard surveys are conducted on; from now on, referred to as the “vegetation transect”). A measure of canopy cover or CGF (Canopy Gap Fraction) was obtained using a modified method by Zancola et al. (2000). A Seimax Super 0.35X semi fisheye lens (MVC-FD73) was used with a Sony Digital “Mavica” camera to photograph the canopy every 50m, therefore giving six measures for each plot. The photographs were converted into black and white images using Paintshop Pro software, and then opened in Image Pro where the numbers of pixels were counted. An estimate of canopy cover for each image was reached by dividing the total number of pixels by the number of black pixels. Percentage canopy cover for the entire plot was then calculated by averaging the six estimates.
2) Determination of percentage ground cover: Ground substrate refers to shrubs (up to 2m), leaf litter, rock, bare ground, grasses, coarse woody debris (CWD) and herbs. The percentage cover of all ground substrates was calculated using the point- transect method (referred to as the “line- point transect method” in Bonham (1989)). A wooden dowel, 2m in length and 9.5mm diameter was used to probe the ground at 2m intervals along the 250m vegetation transect (a total of 125 points per plot) and all substrates that the pole intercepted were recorded. This included termite mounds and trees however these variables were removed from any analyses because they were recorded in very low numbers. Percentage cover of total ground substrates and the percentage cover of each individual component (eg. rock, shrub etc.), always summed to 100%. The frequency of touches for each component was also recorded.
3) Determination of leaf litter depth: Leaf litter depth was measured by using the same wooden dowel as above, which had markings in 1cm increments from the base. For the purpose of this study, leaf litter depth can be defined as the vertical distance from the highest dead particle in contact with the wooden dowel, to the bottom of the litter layer (Brown & Nelson, 1993). Litter depth measurements were taken every 2m along the 250m vegetation transect. A total of 125 measures per plot were recorded and these were averaged to obtain an estimate of litter depth for the plot.
References:
1) Jennings, S.B; Brown, N.D. and Sheill, D. (1999). Assessing forest canopies and understorey illumination: canopy closure, canopy cover and other measures. Forestry. 72: 59-73
2) Zancola, B. J., Wild, C.H. and Hero J.M. (2000). Inhibition of Ageratina riparia (Asteraceae) by native Australian Flora and fauna. Austral Ecology 25: 563-569.
3) Bonham, C.D. (1989). Measurements for Terrestrial Vegetation. John Wiley and Sons: New York, New York, USA.
4) Brown, G.W. and Nelson, J.L. (1993). Influence of successional stage of Eucalyptus regnans (Mountain Ash) on habitat use by reptiles in Central Highlands, Victoria. Australian Journal of Ecology. 18: 405- 417.
