Key Ecological Sites of Hamilton City Volume I CBER Contract Report 121 Client report prepared for Hamilton City Council by Toni S. Cornes, Rachel E. Thomson, Bruce D. Clarkson Centre for Biodiversity and Ecology Research Department of Biological Sciences Faculty of Science and Engineering The University of Waikato Private Bag 3105 Hamilton, New Zealand May 31st 2012 Email: [email protected] i ii Contents Executive Summary ........................................................................................................................ 1 Report Context and Overview...................................................................................................... 2 Overview .......................................................................................................................................... 2 Hamilton City Boundaries ................................................................................................................ 3 Ecology of Hamilton ......................................................................................................................... 4 Climate ......................................................................................................................................... 4 Geology ........................................................................................................................................ 4 Landforms and Vegetation Types ................................................................................................ 4 Fauna of Hamilton City ................................................................................................................ 5 Methodology .................................................................................................................................... 8 Identification of Potential Sites ........................................................................................................ 8 Field Survey ...................................................................................................................................... 8 General Information ..................................................................................................................... 8 Description of the Site .................................................................................................................. 9 Habitat and Vegetation Description ............................................................................................ 9 Flora and Fauna ......................................................................................................................... 10 Threats ....................................................................................................................................... 10 Human Associated Activities ...................................................................................................... 10 Climatic Conditions during Survey.............................................................................................. 10 Context/Nearby Site Information ............................................................................................... 10 Management Recommendations ............................................................................................... 10 Results .............................................................................................................................................. 12 City-wide Extent of Key Sites ......................................................................................................... 12 Extent of the Key Sites by Land Unit .............................................................................................. 12 Analysis of Representativeness ...................................................................................................... 13 Analysis of Ecological Rankings ...................................................................................................... 14 Spatial Distribution of Key Sites ..................................................................................................... 15 Discussion ........................................................................................................................................ 17 Overview ........................................................................................................................................ 17 Spatial Distribution of Key sites ..................................................................................................... 17 Gully Systems ............................................................................................................................. 17 iii Peat lakes ................................................................................................................................... 19 Riverbanks .................................................................................................................................. 20 Reduced Key sites .......................................................................................................................... 20 Nawton Wetland ........................................................................................................................ 20 Whyte St kahikatea .................................................................................................................... 20 Pukete Wetland .......................................................................................................................... 21 Results in a Regional Context ......................................................................................................... 21 Threats to the Key Sites ................................................................................................................. 22 Invasive Weeds ........................................................................................................................... 22 Vertebrate Pests ......................................................................................................................... 22 Surrounding Land Uses............................................................................................................... 22 Habitat Sustainability ................................................................................................................. 23 Threat Mitigation ........................................................................................................................... 23 Weed Control ............................................................................................................................. 23 Connectivity and Buffering ......................................................................................................... 23 Interactions with Landowners .................................................................................................... 24 Long Term Strategy .................................................................................................................... 24 Further Recommendations ......................................................................................................... 26 Monitoring ................................................................................................................................. 27 Conclusion ....................................................................................................................................... 27 Acknowledgements ...................................................................................................................... 28 References....................................................................................................................................... 28 Appendix one: SNA Review – Site Visit Assessment Form ................................................................ 32 Appendix two: Key Ecological Sites in Hamilton City …….……………………………………………………………..37 Appendix three: Ecological significance justification for key sites .................................................... 42 Appendix four: Species List ................................................................................................................ 47 Reviewed by: Approved for Release by: Kembley Pudney Daniel Laughlin Hamilton City Council University of Waikato iv Executive Summary Ecological sites of significance previously identified in 2000 were reviewed in 2011. Natural vegetation in areas acquired by the city since 2000 was also surveyed to identify any new key sites. In total seventy key sites that met the Waikato Regional Council Regional Policy Statement criteria for ecological significance were identified across Hamilton City. Of the original key sites, the total area covered by sites, average site size and overall quality of sites had increased between the 2000 and 2011 surveys. This was due to restoration efforts across the city by Hamilton City Council and the community. Vegetation restoration efforts have had other biodiversity and ecological benefits such as providing additional habitat for the city’s increasing tui population. Key sites are not spread evenly across the city or across landform types. Most key sites are either in gullies or adjoining the Waikato River. Less than 1% of urban alluvial plains and peat bogs are key sites. Two sites on private land have degraded and no longer meet the ecological significance criteria in 2011. The current survey utilised a