1 a Survey of the Flora of Remnants Within the Waddy
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1 A SURVEY OF THE FLORA OF REMNANTS WITHIN THE WADDY FOREST LAND CONSERVATION DISTRICT Stephen Davies and Phil Ladd for the Waddy Forest Land Conservation District Committee March 2000 2 CONTENTS INTRODUCTION 1 METHODS 3 RESULTS 4 DISCUSSION 56 ACKNOWLEDGEMENTS 59 REFERENCES 60 Appendix 1 - Composite plant list 60 Appendix 2 - Plants found outside the sample sites 67 Appendix 3 - Composite bird list 67 3 INTRODUCTION The Waddy Forest Land Conservation District is about 41,000 hectares and contains 23 substantial land holdings. In 1999 the District received a grant from the National Heritage Trust to survey the flora of its remnant vegetation. Much of this is on private property and the District Committee selected thirty three plots of remnant bushland on private farms to be included in flora survey. The present report is based on visits to these thirty three remnants that lie on 14 of the 23 farms in the district. The surveys are intended to provide information about the biodiversity of the various remnants with the aim of establishing the priority for preservation, by fencing, of the remnants and to determine the value of linking some of them by the planting of corridors of vegetation. At each site the local landholder(s) joined the survey and provided invaluable background information about the history of the remnants. The vegetation of this part of the northern wheatbelt is known to be very diverse. The Marchagee Nature Reserve, lying north west of the District, was surveyed between 1975 and 1977 (Dell et al. 1979). The area was covered by Beard in his vegetation mapping project (Beard 1976), and part of the south of the District was covered in a report on Koobabbie Farm in 1990 (Davies 1990). Other less formal surveys have been conducted and the results of these have been consulted where possible. The Waddy Forest Land Conservation District is near the western edge of the Yilgarn Block, at an altitude of between 250 and 300 m above sea level. The streams in the catchment drain into an extensive system of salt creeks, lakes and pans, that flow through the catchment as a S-shaped ephemeral watercourse. This rises in the north-east of the District and flows south westerly to leave the catchment in the south west. Many of the remnants are on the upper slopes and rocky watersheds of the landscape, but efforts were made to cover some run-on sites as well. The salt creek system provides an existing, continuous corridor of remnant vegetation that will be of great value in the rehabilitation programme. The climate is a Mediterranean one, of cool wet winters and hot, dry summers. Rainfall is about 400 mm per year, of which about two thirds falls from May to August. Only three months, June, July and August, have a mean relative humidity above 50%, with an annual mean of about 35%. Evaporation at Carnamah (35 km north west) is 2125 mm per year. Mean maximum temperature Figure 1: Map of the Waddy Forest Land Conservation District, showing the vegetation associations and the positions of the site of the remnants at which the flora was sampled during the survey. 4 for the hottest month at Carnamah is 35.8oC and mean minimum temperature for the coolest month is 18.0oC. Extreme temperatures are 45.7oC and 0oC. Frosts are rare, occurring on average three days a year. Prevailing winds are from the south east in summer and the north west in winter, and are light, except when the area receives the impact of a cyclonic disturbance. Waddy Forest Land Conservation District lies within the Irwin district of the South Western Botanical Province of Gardner and Bennetts (1956). Figure 1 shows the classification of vegetation of Beard (1976) and the location of the remnants surveyed. The abbreviations on the map are: anSc Acacia thicket of shrubs >1 m tall with Allocasuarina c3Sc Shrubland with scattered trees (Allocasuarina campestris thicket on stoney and lateritic ground) c3Sc/xZi Thicket with patches of heath on sandplain (Allocasuarina campestris thicket on stoney and lateritic ground with shrubs >1 m tall, an incomplete canopy, projective foliage cover 10-30% and, on sandplain, mixed vegetation of dwarf shrubs <1 m tall with Allocasuarina) 6 e 8Mi Sclerophyll woodland (Eucalyptus loxophleba/E. salmonophloia of 10-25 m with an incomplete canopy, projective foliage cover 10-30%) e6Mi Sclerophyll woodland (Eucalyptus loxophleba of 10-25 m with an incomplete canopy, projective foliage cover 10-30%) e8Mi Sclerophyll woodland (Eucalyptus salmonophloia of 10-25 m with an incomplete canopy, projective foliage cover 10-30%) m5Sc.k3Ci Salt Country - Teatree thickets and samphire (Melaleuca thyoides as shrubs >1 m tall, with Casuarina, succulents and halophytes; canopy incomplete 10-30% projective foliage cover) x7SZc Scrub heath - Actinostrobus - Banksia alliance on sandhills (shrubs >1 m tall and dwarf shrubs <1 m tall with Allocasuarina) x8SZc Scrub heath - Banksia - Xylomelon alliance on sandplain (mixed vegetation of shrubs >1 m tall and dwarf shrubs <1 m tall with Allocasuarina) METHODS Two visits were made to the District to conduct the flora survey. These took place in September 1999. Rainfall had been heavy during the winter and the flowering of daisies (Asteraceae) and orchids (Orchidaceae) was particularly good. At each site plant taxa were identified and listed during a prolonged walk through the remnant. Specimens of plants that could not be immediately identified were collected (under CALM licence No. SW005713), dried and later identified from keys and by checking against material at the WA Herbarium. The Waddy Forest Land Conservation District has its own small herbarium collection, which was often very helpful. Introduced plants were not systematically recorded but are marked with an asterix (*) in the lists. 5 The condition of each site was assessed on a scale from 1 - 5, following the methods of Perth's Bushplan Directory; the criteria for each category are given below: (1) Pristine. Pristine or nearly so, no obvious signs of disturbance. The Blue Green algal mat intact. (2) Excellent. Vegetation structure intact, disturbance affecting individual species and weeds are non-aggressive species. The Blue Green algal mat still widespread. (3) Very Good. Vegetation structure altered, obvious signs of disturbance. For example, disturbance to vegetation structure caused by the presence of aggressive weed species, grazing by stock, and/or kangaroos and rabbits. The Blue Green algal mat severly damaged, occurring as isolated patches. (4) Good. Vegetation structure significantly altered by very obvious signs of multiple disturbance. Retains basic vegetation structure or ability to regenerate it. For example disturbance to vegetation structure caused by the presence of aggressive weed species at high density, partial clearing, grazing by stock, and/or kangaroos and rabbits. The Blue Green algal mat absent. (5) Degraded. Basic vegetation structure severely impacted by disturbance. Scope for regeneration but not to a state approaching good condition without intensive management. For example disturbance to vegetation structure caused by the presence of very aggressive weed species, salting, heavy grazing by stock, and/or kangaroos and rabbits. The Blue Green algal mat absent. Where available soil information is given from the survey coordinated by Agriculture WA (1999). RESULTS The present section gives a brief description of each site, numbered from 1 to 33, and a list of the plant taxa found at that site. Introduced plants were not systematically recorded but are marked with an asterix (*). A composite list of the 329 native plant taxa found in the sample sites within the whole District is given in Appendix 1. Nine other native plant taxa, not found in the sites, but recorded within the District, are listed in Appendix 2, making a final total of 338 taxa. Nine of these were listed Priority Flora. There is great local variation within taxa and, especially in the Orchidaceae, determinations do not precisely fit current keys or herbarium specimens. For this reason the symbol "?" has been used to indicate the closest fit to the particular specimen. A complete set of specimens will be offered to the WA Herbarium. For each site the species of birds recorded there during the survey are also given. Appendix 3 gives a composite list of birds recorded in the District. Site W1 Gabriella and Richard Hyde House Remnant Sclerophyll woodland (Eucalyptus loxophleba/E. salmonophloia of 10-25 m with an incomplete canopy, projective foliage cover 10-30% and some understorey). The site contained many weeds and the understorey was degraded. It was classed as condition (5). 24 taxa of native plants were identified at this site. CHENOPODIACEAE Rhagodia preissii Sclerolaena diacantha 6 AMARANTHACEAE Ptilotus obovatus SURIANACEAE Stylobasium australe MIMOSACEAE Acacia acuminata Acacia aestivalis Acacia andrewsii Acacia hemiteles MYRTACEAE Eucalyptus loxophleba Eucalyptus salmonophloia Eucalyptus salubris Melaleuca acuminata Melaleuca lateriflora Melaleuca uncinata SANTALACEAE Santalum acuminatum EUPHORBIACEAE Euphorbia drummondii MYOPORACEAE Eremophila drummondii GOODENIACEAE Scaevola spinescens ASTERACEAE Cephalipterum drummondii Chthonocephalus pseudovex Gilruthia osbornei Hyalosperma glutinosum POACEAE Austradanthonia caespitosa Austrostipa nitida Birds recorded Emu Dromaius novaehollandiae Australian Shelduck Tadorna tadornoides Nankeen Kestrel Falco cenchroides Crested Pigeon Ocyphaps lophotes Short-billed Black-Cockatoo Calyptorhynchus latirostris Galah Cacatua