Summary - City of Gosnells

Vegetation 69The multivariate analysis (Appendix C) conducted on the floristic data collected in the quadrats of theMKSEA in combination with the SCP dataset of Gibson et al. (1994) (‘the SCP dataset’), provided someobjective evidence of the occurrence of the three threatened FCTs 3a, 8 and 20a in the MKSEA (Table 5.5,Column 3). The classification dendrogram of the quadrat only data (‘DEN quads’) from the MKSEAprovided more unequivocal results than the Nearest Neighbour analysis (‘NNB’) (Table 5.5, Column 4). Therelationships between the relevés (that were surveyed in the more degraded areas of the MKSEA) and theSCP dataset in the ‘DEN all’ classification (Appendix C, Table 2) were less clear. The habitat data collectedin the current survey provided additional resources for dealing with some of the shortfalls in the purelyfloristic approach to vegetation classification that is often used to determine the conservation value ofvegetation on the SCP.The relevés (that were surveyed in the more weedy areas of the MKSEA) tended to group preferentially withquadrats of the MKSEA in the ‘DEN all’ classification rather than with SCP dataset sites (Appendix C,Table 2). This is a common occurrence that has been observed in such analyses that is consistent with thegeneral ecological relationship of distance decay. The similarity indices that were used in the analysis wereinfluenced by both presence and absence of species. Therefore, both a deficit in native species numbers and asurplus of weeds in the MKSEA relevés contributed to decreasing the similarity between MKSEA relevésand SCP dataset sites. The addition of relevé data to quadrat data in the MKSEA (the ‘DEN all’) analysisresulted in a disruption of the pattern observed between the quadrat data and the SCP data in the ‘DENquads’ analysis and did not provide additional insights. Thus, the discussion below is confined mainly to the‘DEN quads’ (Table 5.5, Column 3) and ‘NNB’ (Table 5.5, Column 4) results rather than the ‘DEN all’results.Quadrats 4, 6, 8, 10, 11, 12, 15, 16, 17, 19, 20, 22 and 28 of the MKSEA were sampled in the most speciesrichand undisturbed vegetation of the survey area, and Relevés 14, 24 and 26 were analysed with them, asquadrats. All of these quadrats (except 15, 16 and 27, the only three sites with affinities to FCT 11) clusteredin the classification of the quadrat data ‘DEN quads’ with three FCTs of the SCP that are ThreatenedEcological Communities (3a, 8 and 20a) (Table 5.5, Column 3). The nearest neighbours for the quadrats ofthe MKSEA in the NNB analysis were (as expected) other quadrats and relevés from the MKSEA, followedby sites of the SCP dataset from FCTs 3a, 8, 20a and other FCTs. Any ambiguities that were added to therelatively simple ‘DEN quads’ pattern by the NNB results provided further insights about the MKSEAquadrat sites.The multivariate analysis of the MKSEA sites against the SCP dataset produced ambiguous results withregard to all MKSEA sites where Muchea Limestone was identified in the stratigraphic or hydrologicalsurvey. This is significant as Gibson et al. (1994) (‘the SCP survey’) did not identify any vegetationinhabiting Muchea Limestone as a FCT. Firstly, the SCP survey was limited to publicly owned land andthere was no extant native vegetation on limestone outcrops within these lands on the eastern side of theSCP. Secondly, the SCP survey did not investigate habitat in sufficient detail to detect the potential presenceof calcareous sediments unless it was a surface outcrop. Thirdly, the SCP survey did not generally include avery representative sample of seasonal wetland sites. Fourthly, the SCP survey used only floristic data todetermine clusters of sites. The Muchea Limestone TEC as currently defined (Keighery and Keighery, 1995;English and Blyth, 2001) is not a Floristic Community Type. It is a heterogeneous suite of native vegetationtypes that inhabit a specific but rare habitat on the eastern SCP.Consideration of the multivariate analysis summary (Table 5.5, Column 5) with the ecological evidence fromthe MKSEA survey leads to the inference that six groups (A, B, C, D, E and F) of sites that correspond toFCT 3a, FCT 20a, FCTs 7/8/10a, ML, Degraded Sites and Unassigned Sites occur in the MKSEA. The 32MKSEA floristic sites and their groups and conservation values are listed in Columns 6a and 6b of Table 5.5,and the groups of FCTs and the sites assigned to them are discussed below.Tauss, C. and Weston, A.S. (2010). The flora, vegetation and wetlands of the Maddington-Kenwick Strategic Employment Area.A survey of the rural lands in the vicinity of the Greater Brixton Street Wetlands. Report to the City of Gosnells, W.A. Version 18.04.10