WC2NH Giant Barred Frog Population Monitoring 2017/2018 - Year 3
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Annual Report WC2NH Giant Barred Frog Population Monitoring 2017/2018 - Year 3 PO Box 119 Lennox Head NSW 2478 T 02 6687 7666 PO Box 1446 Coffs Harbour NSW 2450 T 02 6651 7666 PO Box 1267 Armidale NSW 2350 T 02 6772 0454 PO Box 229 Lismore NSW 2480 T 02 6621 6677 [email protected] Prepared for: PACIFICO © GeoLINK, 2018 UPR Description Date Issued Issued By 2378-1421 First issue 06/03/2018 Jessica O’Leary 2378-1432 Second issue 09/03/2018 Jessica O’Leary 2378-1433 Third issue 12/03/2018 Jessica O’Leary Table of Contents 1. Introduction 1 1.1 Project Overview 1 1.2 Giant Barred Frog Habitat 2 1.3 Giant Barred Frog Description 2 1.4 Purpose of this Report 3 2. Methodology 6 2.1 Timing of Surveys 6 2.2 Frog Surveys 7 2.3 Swabbing for Chytrid Fungus 9 2.4 Tadpole Surveys 10 2.5 Abiotic Data 10 2.6 Habitat Data 10 2.7 Water Quality Data 11 3. Results 12 3.1 Abiotic Data 12 3.2 Giant Barred Frog Demography 14 3.2.1 Summary of Summer 2018 GBF Population and Habitat Monitoring 14 3.2.2 Year 3 Seasonal Monitoring Captures and Age Classes 17 3.2.3 Calculating Population Size 20 3.2.4 Sex Classes 23 3.3 Presence of Chytrid Fungus 24 3.4 Habitat Use 25 3.4.1 Frog Distribution along the Transect 25 3.4.2 Distance between GBF location and the stream edge 25 3.4.3 Position within the microhabitat 26 3.4.4 Movements of recaptured frogs within the habitat 26 3.4.5 Habitat Condition 26 3.4.6 Water Quality Monitoring 27 3.4.7 The Addition of Butchers Creek GBF Management Zone 29 4. Discussion 30 4.1 Capture and Age Class 30 4.1.1 Recaptured Frogs 30 4.1.2 Decrease in GBF recorded at UWC since baseline monitoring 31 4.1.3 Butchers Creek Potential GBF Habitat 31 4.2 Habitat Use 32 4.2.1 GBF habitat rehabilitation and landscaping once construction is complete 33 4.3 Recaptured Frogs 33 Annual Report - WC2NH Giant Barred Frog Population Monitoring 2017/2018 - Year 3 i 2378-1433 5. Recommendations 35 6. Objectives and Performance Measures 36 7. References 38 Illustrations Illustration 1.1 Site Context 4 Illustration 1.2 Butchers Creek GBF Management Zones 5 Illustration 2.1 Upper Warrell Creek GBF Management Zones and GPS Capture Locations 8 Illustration 3.1 Giant Barred Frog Movements within the Habitat 28 Tables Table 2.1 Key for Determining Reproductive Condition in Male GBF 9 Table 3.1 Abiotic Conditions during Giant Barred Frog Population Monitoring 2017/ 2018 13 Table 3.2 Rainfall Data During Nocturnal Giant Barred Frog Population Monitoring 2017/ 2018 13 Table 3.3 Monthly Rainfall Data (mm) 23 January 2015 – 7 February 2018 (source: WC2NH southern weather station, data from weathermation.net.au) 14 Table 3.4 Average Monthly Rainfall Data (mm) Smoky Cape, NSW (source: BOM, 2018) 14 Table 3.5 Records of Recaptured Frogs Overtime – Years 1 and 3 of Construction Monitoring 15 Table 3.6 Summary of Giant Barred Frog capture/ record data during seasonal population monitoring for Years 1 and 3 of construction 18 Table 3.7 Data input and Results of the Lincoln-Peterson Population Size Estimate Calculation for Year 1 and 3 of Construction Monitoring 20 Table 3.8 Results of the Lincoln-Peterson Population Size Estimate Calculation for Baseline, Year 1 and 3 of Construction Monitoring 22 Table 3.9 Chytrid Swab analysis results 24 Table 6.1 Summary of Key Performance Criteria for Giant Barred Frog Population Monitoring (Construction Phase) 37 Plates Plate 3.1 Frog 00078ABC66 (new capture) measured 95 mm snout to vent length and 130 grams 15 Plate 3.2 Frog 00078ABBF2 (new capture) was the longest frog measured at 100 mm snout to vent length and 152 grams 15 Plate 3.3 00078ABBF2 (new capture) photo of nuptial pads recorded as moderately grey (note this frog was recorded as female) 16 Plate 3.4 Frog 00077E9014 (recapture) is the heaviest frog captured weighing 159 grams and has been captured four times over Years 1 and 3, first in spring 2015 16 Plate 3.5 Butchers Creek water level between Zones 5 and 6 autumn 2017 17 Plate 3.6 Butchers Creek water level between Zones 5 and 6 summer 2018 17 Plate 3.7 Mixophyes fasciolatus (Great Barred Frog) tadpole, top/side view - Butchers Creek – Zone 7 23 Plate 3.8 Mixophyes fasciolatus (Great Barred Frog) tadpole, ventral view - Butchers Creek – Zone 7 23 Plate 4.1 UWC construction area through Zones 9 and 10 view to the north 32 Plate 4.2 UWC construction area through Zones 9 and 10 view to the south 32 Plate 4.3 Western side of UWC causeway view to the north through Zone 8 32 Annual Report - WC2NH Giant Barred Frog Population Monitoring 2017/2018 - Year 3 ii 2378-1433 Figures Figure 3.1 Giant Barred Frog records over six seasonal monitoring events during Years 1 and 3 of construction 18 Figure 3.2 The Lincoln-Peterson Equation to calculate population size (excerpt from page 8 of Baseline Monitoring Report within the GBFMS (Lewis Ecological, 2014)) 22 Figure 3.3 Mean distance of Giant Barred Frogs captured in proximity to the stream edge over six seasonal monitoring periods during Years 1 and 3 of construction 25 Appendices Appendix A GBF Population Monitoring (Raw Data) - Summer 2018 Appendix B Water Quality Results Compared Against ANZECC Trigger Values Appendix C Water Quality Laboratory Results – Autumn, Spring and Summer – Year 3 Appendix D Chytrid Results Analysis and Discussion Annual Report - WC2NH Giant Barred Frog Population Monitoring 2017/2018 - Year 3 iii 2378-1433 Executive Summary A population of Giant Barred Frogs (GBF) (Mixophyes iteratus) inhabit the Upper Warrell Creek (UWC) system which intercepts the Warrell Creek to Nambucca Heads (WC2NH) Pacific Highway Upgrade route alignment. As such, this population of GBF and construction works are required to be managed in accordance with the WC2NH Giant Barred Frog Management Strategy (Lewis Ecological, 2014). GeoLINK have been engaged by PACIFICO to undertake seasonal monitoring of two GBF management zones within the Project alignment. UWC has a resident population of GBF which has been previously studied by Lewis Ecological (2013/2014) to establish a population baseline. A total of 47 GBF were recorded, including records of juveniles and sub-adults (and recaptures). Since the unexpected find of GBF tadpoles within Butchers Creek, a new GBF management area was established with eight survey zones created for monitoring. No GBF have been recorded within the Butchers Creek survey zones during seasonal population monitoring for Years 1 or 3 of construction. Population monitoring undertaken in 2015/2016 (Year 1) returned fewer records of GBF across the three monitoring periods of autumn, spring and summer, with a total of 16 frogs captured at UWC. No sub-adults or juveniles were recorded during this survey period. Population monitoring undertaken in 2017/2018 (Year 3) returned again fewer records of GBF across the three monitoring periods of autumn, spring and summer, with a total of 14 frogs captured at UWC. Only one sub-adult was recorded during the Year 3 during monitoring. No juveniles were recorded during any survey periods. No GBF tagged in the baseline population monitoring of 2013/2014 have been recaptured during seasonal monitoring for Years 1 or 3 of construction. It can be reasonably expected that a reduced number of GBF have been recorded during construction phase monitoring as a result of an area of high GBF activity (and breeding habitat) has now been fully or partially impacted by construction works. During baseline population monitoring these areas recorded the highest number of frog captures with 21 records in Zones 8 and 9 and six in Zone 10 (i.e. a total of 27 GBF). Prior to construction works, pre-clearing surveys resulted in the capture and relocation of three GBF to outside of the works footprint; no other GBF were accounted for. Despite meeting the mitigation measure requirements via pre-clearing surveys, spotter/catcher presence during clearing works and installation of exclusion fencing, it appears GBF within the construction zone have been substantially affected and this population has declined. Other factors which may explain the considerable reduction in GBF records and no further recaptures since baseline population monitoring may include: ■ Non-favourable survey conditions due to lower than usual rainfall, particularly in the lead up to spring 2017 monitoring. ■ Lower than average monthly rainfall records and smaller than usual flood events. ■ The apparent lack of successful breeding events during the years between monitoring (and therefore no recruitment of juveniles). ■ GBF previously captured or recorded in baseline studies have moved out of the survey area seeking better dispersal or breeding opportunities. Annual Report - WC2NH Giant Barred Frog Population Monitoring 2017/2018 - Year 3 iv 2378-1433 Section 7.0 of the Giant Barred Frog Management Strategy (GBFMS) states that the objectives of the GBF monitoring program are as follows: ■ To demonstrate through the life of the Project that mitigation has maintained or improved population sizes and habitat of the Giant Barred Frog. The use of preconstruction, during construction and post construction monitoring to measure both frog distribution, abundance and habitat quality with defined thresholds will used to measure the overall performance of the mitigation; and ■ To ensure that mitigation measures are effective in maintaining Giant Barred Frog connectivity near the Project. Based on the results to date, the UWC GBF population has not been maintained or improved, but has declined.