Department of Environment and Conservation Report for A Comparison of Compost Types and Plant Establishment Techniques Anstey Wetland April 2012 This Comparison of Compost Types and Plant Establishment Techniques(“Report”): 1. has been prepared by GHD Pty Ltd (“GHD”) for the Department of Environment and Conservation; 2. may only be used and relied on by the Department of Environment and Conservation; 3. must not be copied to, used by, or relied on by any person other than Department of Environment and Conservation without the prior written consent of GHD; 4. may only be used for the purpose of reporting on the trial of applying compost in the establishment of the Anstey Wetland on the Forrest Highway. GHD and its servants, employees and officers otherwise expressly disclaim responsibility to any person other than arising from or in the Department of Environment and Conservation connection with this Report. To the maximum extent permitted by law, all implied warranties and conditions in relation to the services provided by GHD and the Report are excluded unless they are expressly stated to apply in this Report. The services undertaken by GHD in connection with preparing this Report: x were limited to those specifically detailed in Section 3 of this Report. Subject to the paragraphs in this section of the Report, the opinions, conclusions and any recommendations in this Report are based on conditions encountered and information reviewed at the time of preparation and may be relied on until 12 months, after which time, GHD expressly disclaims responsibility for any error in, or omission from, this Report arising from or in connection with those opinions, conclusions and any recommendations. 61/22541/13642 A comparison of Compost Types and Plant Establishment Techniques Anstey Wetland Contents Executive Summary i 1. Introduction 2 1.1 Background 2 1.2 Revegetation of Road Reserves 3 1.3 The Wetland 4 2. Environmental Setting 5 2.1 Climate 5 2.2 Topography and Geology 6 2.3 Hydrology and Hydrogeology 6 2.4 Reserves and Conservation Areas 6 2.5 Environmentally Sensitive Areas 6 2.6 Vegetation 6 2.7 Land Use 7 3. Methodology 8 3.2 Soil Amendments 9 3.3 Application Method 10 3.4 Site Revegetation 10 4. Data Collection and Analysis 11 4.1 Compost Assessment 11 4.2 Plant Germination 11 4.3 Threats to Plant Establishment 12 4.4 Soil and Water Quality 13 5. Results 15 5.1 Compost Assessment 15 5.2 Plant Establishment 17 5.3 Heath Plots 17 5.4 Dryland Plots 20 5.5 Soil Monitoring 24 5.6 Water Monitoring 33 6. Economic Implications 41 61/22541/13642 A comparison of Compost Types and Plant Establishment Techniques Anstey Wetland 6.1 Site Preparation 41 6.2 Soil Amendments 41 6.3 Site Establishment 41 7. Discussion 44 8. Conclusion 46 9. References 47 Table Index Table 1 Climatic data recorded at the medina Research Centre meteorological station 5 Table 2 Heath plot application details 9 Table 3 Dryland (Tuart) plot application details 10 Table 4 Data sheet for analysis 12 Table 5 Data sheet for seedling plots 12 Table 6 Analysis of compost product used on wetlands 16 Table 7 Soil testing results from the July 2008 samples for the 40 mm treatment plots 25 Table 8 Soil testing results from the August 2008 samples for the 40 mm treatment plots 26 Table 9 Soil testing results from the August 2009 samples for the 40 mm treatment plots 27 Table 10 Water monitoring results for metals and metalloids from the NW and BQ bores 35 Table 11 Water testing results (physical) from the NW and BQ groundwater well 38 Table 12 Initial site preparation costs for the wetland 41 Table 13 Costs for soil amendments 42 Table 14 Site establishment costs for the wetland 42 Table 14 Costs associated with applying compost and mulch to the site 43 Figure Index Figure 1: Locality map for the Wetland (SGA, 2007) 2 Figure 2: Average native species counts per plot for heath plots during each trial recording period 17 61/22541/13642 A comparison of Compost Types and Plant Establishment Techniques Anstey Wetland Figure 3: Average number of species in heath plots by treatment per recording period 18 Figure 4: Native plant species prevalence data for heath plots by treatment type for the August 2009 and September 2010 trial recording periods 18 Figure 5: Native plant species prevalence data for heath plots by replicate section for the August 2009 and September 2010 trial recording periods 19 Figure 6: Percentage cover of weeds and native plants in heath plots 20 Figure 7: Average native plant numbers per plot for dryland plots during each recording period of the trial 21 Figure 8: Percentage cover of weeds and native plants in dryland plots 22 Figure 9: Average number of species in dryland plots by treatment type for each recording period 22 Figure 10: Species recorded at the first and final count across the dryland plots 23 Figure 11: Average plant counts per plot according to the treatment type 24 Figure 12: Soil pH readings from samples collected at the heath plots during the trial 28 Figure 13: EC Readings from soil samples collected at heath plots during the trial 29 Figure 14: Moisture readings from soil samples collected at heath plots during the trial 30 Figure 15: Nitrite, nitrate, NOX, reactive phosphorus and organic carbon in the HR1 plots 31 Figure 16: Trends in nitrite, nitrate, NOX, reactive phosphorus and organic carbon in the HR2 plots 31 Figure 17: Trends in nitrite, nitrate, NOX, reactive phosphorus and organic carbon in the HR3 plots 32 Figure 18: Trends in nitrite, nitrate, NOX, reactive phosphorus and organic carbon in the dryland plots 33 Figure 19: Monthly rainfall totals for the 2008, 2009 and 2010 sample periods from the Hopelands BoM station (9253) 33 Figure 20: Metals and metalloids trends recorded for the NW bore 36 Figure 21: Metals and metalloids trends for the BQ bore, located to the east of the wetland 37 Figure 22: Major cation composition of the NW (2009 and 2010 ) and BQ (2009 and 2010) samples 37 61/22541/13642 A comparison of Compost Types and Plant Establishment Techniques Anstey Wetland Figure 23: Acidity levels of the NW and BQ bores (2008, 2009 and 2010) 39 Figure 24: Electrical Conductivity (EC) of water samples of the bores in 2008, 2009 and 2010 39 Figure 25: Sodium Adsorption Ratio (SAR) of water samples of the bores in 2008, 2009 and 2010 40 Appendices A Photographs B Species Used in Revegetation C Total Number of Germinates per Plot D Monitoring Sheets E Cost Breakdown 61/22541/13642 A comparison of Compost Types and Plant Establishment Techniques Anstey Wetland Executive Summary The Southern Gateway Alliance (SGA) and the Department of Environment and Conservation (DEC), in a joint arrangement, constructed a wetland (the Wetland) at Karnup, adjacent to the Forrest Highway, approximately 50 km south of Perth, Western Australia (the Project). With more than 30,000 vehicles expected to pass the Wetland each day, the DEC and SGA worked together to showcase plant establishment techniques, including soil amendments as part of a wetland establishment methodology. These soil amendments included compost, mulches and mulch compost blends. These amendments were incorporated into the soil profile at various depths. This wetland, known as the Anstey Wetland, is regarded as an environmental legacy of the construction of the Forrest Highway. Specifically, the assessment of the soil amendments considered: Changes to soil conditions during the trial period; The influence of the amendments in seed germination and tube stock plantation, establishment and growth; Weed germination and growth across the site; An assessment of soil and water quality from monitoring points associated with the wetland site; Cost analysis which looks at the cost effectiveness of mulch and compost in revegetation projects; and Visual changes to the site where compost has been applied as compared to plots where compost has not been applied. Analysis of sampled data was conducted using the Excel software program by Microsoft . The establishment of the site varied in part due to late seeding and plant establishment and that the winter season ended abruptly with warm, dry conditions dominating the plant establishment phase. In broad terms, the outcomes from the Project were: 1. Those sites which received compost showed greater rates of growth than the control plots where compost was not applied. 2. There was some response to the compost treatment and germination and plant establishment. Although further detailed work on treatment response characteristics and optimising application rates seems warranted, as the highest treatment application resulted in a slight lowering of germination rates. 3. Germination occurred over long periods of time (three years), highlighting the importance of having a mix of seed types with varying germination requirements. 4. Average native plant counts per plot were higher for the 20 mm and 30 mm compost treatments across both Heath and Dryland plots for most of the trial. This improvement is likely to relate to several factors which may include physical protection of germinates, improved soil temperature and soil moisture environment and the increase in plant available nutrients provided by compost. 61/22541/13642 A comparison of Compost Types and Plant Establishment Techniques Anstey Wetland 1. Introduction 1.1 Background Roadside rehabilitation, if done well, has the potential to support the protection and replacement of valuable remnant vegetation, wetlands and associated ecological systems in impacted sites. The construction, widening and upgrade of roads often presents the opportunity to establish or re-introduce flora and fauna systems that would ordinarily be lost as a result of any required clearing.