Ecological Archives E095-218-A4
Cristina E. Ramalho, Etienne Laliberté, Pieter Poot, and Richard J. Hobbs. 2014. Complex effects of fragmentation on remnant woodland plant communities of a rapidly urbanizing biodiversity hotspot. Ecology 95:2466–2478. http://dx.doi.org/10.1890/13-1239.1
Appendix D. Description of the semi-qualitative disturbance assessment used to quantify intensity of human activities and grazing in the study remnants.
The intensity of human activities (i.e., trampling, waste disposal, and soil physical disturbance) and grazing (by the native western grey kangaroo Macropus fuliginosus and non-native European rabbit Oryctolagus cuniculus) in the study remnants was systematically estimated using a semi-qualitative disturbance assessment. This was composed of a set of questions scored from 0 to 5 in ascending order of significance in the sampling plot (0 = absent; 1 = very low; 2 = low; 3 = intermediate; 4 = high; 5 = very high). Six final composite variables, measuring the intensity of trampling, waste disposal, soil physical disturbance, overall human activities, grazing by native and non-native herbivores, were calculated by summing the different scores and dividing by the total maximum value. The questions used to assess disturbance in the remnants were the following:
Trampling:
1) Are there diffuse, narrow, vegetated "goat" tracks?
2) Are there narrow cleared tracks?
Waste disposal:
3) Are there signs that the area was previously used for dumping (landfill)?
4) Are there signs that the area is currently used for dumping?
5) Are there signs of old infrastructures and construction material (e.g., bricks and metal scraps)?
6) Are there signs of rubbish (e.g., plastic bags and drink bottles)?
7) Are there signs of vegetative rubbish (e.g., palm fronds)?
Soil physical disturbance:
8) Are there signs of previous excavations or alteration of the soil surface (e.g., mounds of dumped sand)?
9) Does the area look like it was cleared and modified in the past (e.g., vegetation altered, irregular soil surface)?
10) Are there cleared areas with signs of recent disturbance?
11) Are there motor ramps and other signs of motorbike activity?
12) Are there old 4WD tracks?
Grazing by the native western grey kangaroo:
13) Are there tracks and resting areas?
14) Are there excrement?
Grazing intensity by non-native European rabbit:
15) Are there burrows?
16) Are there soil diggings and scratches?
17) Are there excrement?
Grazing intensity was also assessed by counting the number of excrements of each species in the four 1.5 m radius circles and averaging data to the sampling plot. The composite and counting variables were highly correlated and the first performed better during preliminary data analysis. Therefore, only the composite semi-qualitative variables were used on remaining data analysis.