View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by ResearchArchive at Victoria University of Wellington EVALUATING BIOLOGICAL CHANGE IN NEW ZEALAND MARINE RESERVES By Anjali Pande A thesis Submitted to the Victoria University of Wellington in fulfilment of the requirements for the degree of Doctor of Philosophy in Zoology Victoria University of Wellington 2001 i Abstract This study illustrates the importance of baseline surveys, why they are necessary and how best to conduct them. A proposed marine reserve site (the south coast of Wellington) was monitored for three years to establish a comprehensive baseline study. The results were used to recommend appropriate methodology for sampling in this area and also to establish which species are the best to use as indicator species to detect any possible change occurring in this area due to future reservation status. The 11 km stretch of coast surveyed, which included future reserve and control sites, was tested for heterogeneity, to prevent any future differences in sites being attributed to reservation status as opposed to natural variation. It was determined that an environmental gradient exists along the south coast, from east to west, most likely due to increasing wave exposure and increasingly strong tides and currents towards the west. An established marine reserve (Kapiti Marine Reserve) was also monitored over the same period of time to establish what differences existed in size and abundance of key species between reserve and control sites. The data collected in this investigation were also compared to data collected immediately prior to reserve establishment to determine what changes had occurred over time. Results showed that sites inside the marine reserve supported a greater species abundance, and in some cases, larger size classes. There was some evidence for a general shift in the community structure particularly in algal plants. However, these results may have been confounded by the effect of one site that appeared to have a very high natural species diversity and abundance (even before reservation status). It was concluded that the one-off survey conducted before establishment of this reserve was inadequate to use as a baseline against which to detect changes. No changes were found between the present study and the preliminary survey, although specific data analysis indicated a reserve effect. Continued sampling methodology for Kapiti Marine Reserve area was suggested. Raw data, on two key species (blue cod and rock lobster) from six marine reserves in New Zealand were investigated in an attempt to perform a statistical “meta-analysis” of the effects of marine reserves in New Zealand. A meta-analysis is different from a narrative review as it uses statistical methods to compare results across studies. This methodology has not been applied to studies of marine reserves before. The meta analysis conducted in the present investigation showed that generally marine reserves in New ii Zealand are having a positive effect, in terms of increasing size and abundance of individual species, as compared to control areas. There is some evidence for a latitudinal trend influencing the “effect size” (a statistical term indicating the magnitude of the treatment tested – in this case, reservation) of the reserves. iii Acknowledgements I could not have produced this thesis without the help of many people. Acknowledging them here hardly begins to express my gratitude to them. Thank you to my supervisor Dr. Jonathan Gardner, for setting up this project, convincing me to apply for it and then doing all that a supervisor is supposed to do. Thanks to the late Andy Ritchie for helping to organise funding for this thesis and thanks to Kathy Walls for organising the funding from DOC (Department of Conservation). Thanks go to Victoria University of Wellington for providing the scholarship that enabled me to complete this thesis. Field work would have been even more impossible than it was, without the expert knowledge and boat driving skills of our skipper Robert Williamson. Thanks too, to Graham Weakley and Ollie Moeller for filling in when Robert was unavailable. I could never have collected all my data without all those volunteer divers who gave up their free time to help me. Some who deserve a special mention are: definitely Trevor Willis and Justine Saunders who came all the way down from Auckland to help me learn the ropes. When they left, Andy Maloney and Vicky Froude dived with me almost from day one to day end, and also thanks to Sri Lloyd, Dave Payne and Dave Shanks who during the time that they were available were almost always there too. My import crew from the UK- Rick, Dan and Dave – you guys were great! To all the others, thank you again – it never would have happened without you. Thank you to the team at Splash Gordon’s dive shop, for letting me into the shop at silly hours to fill tanks and borrow gear and sending volunteer divers my way. It would have been a nightmare if you hadn’t been so accommodating! Jeff – without your computer expertise, I would have been struggling to keep my data in line and would probably have resorted to pen and paper!!!! You taught me a lot. Thanks too for all those last minute weather forecasts – it would have been great had you been able to control the weather too!! iv Huge thank you’s to Rob Davidson, for giving me faith in my project, letting me bounce ideas off him and for all the millions of proof reads! I really appreciate it. Special thanks to Ali MacDiarmid for helping me formulate the idea of a meta-analysis and for being the first to provide me with data to carry it out. Thanks to Clinton Duffy, Debbie Freeman, Russell Cole and Rob Davidson also for providing me with much needed data. I must thank Charlie Daugherty and Helen Neil for convincing me not to quit, when I got to that phase that apparently most PhD students go through…. Not being a mathematical genius I am very grateful to Edith Hodgen and Peter Smith for all their help with the statistics I had to wade through! The list goes on – I must thank my flatmates for their support, especially Tom who let me whinge and cry on his shoulder when the going got tough. Thank you to George Gibbs and Bruce Dix for your comments on the manuscript, and many many thanks especially to Kerstin, but also Brent and Rhys for all the last minute proof reads and excellent suggestions!!! Finally, thanks to my father for keeping me on the straight and narrow during the three years I was working on this thesis, always hassling me to do my schoolwork….I hope I make you proud. N.B. Maps are reproduced from Department of Conservation discussion documents, The Taputeranga Marine Reserve application document by the Royal Forest and Bird Society and Battershill et al. (1993). Thank You! v TABLE OF CONTENTS ABSTRACT......................................................................................................................I ACKNOWLEDGEMENTS......................................................................................... III LIST OF TABLES .....................................................................................................VIII LIST OF FIGURES ....................................................................................................XII CHAPTER 1 - INTRODUCTION............................................................................... 1 1.1 General Introduction.............................................................................................2 1.2 Study aims ............................................................................................................ 12 1.3 The layout of this thesis.......................................................................................13 CHAPTER 2 – METHODS.......................................................................................... 15 2.1 Site Selection – South Coast................................................................................16 2.2. Site Selection – Kapiti Marine Reserve............................................................. 20 2.3. Species surveyed.................................................................................................. 23 2.3.1. Algae .............................................................................................................. 23 2.3.2. Invertebrates ................................................................................................... 23 2.3.3. Fish ................................................................................................................. 24 2.4. Survey Methods................................................................................................... 27 2.4.2 Fish .................................................................................................................. 29 2.4.3. Invertebrates ................................................................................................... 30 2.4.4. Algae .............................................................................................................. 30 2.5. Statistical analysis............................................................................................... 32 2.5.1. Kruskal-Wallis Tests ......................................................................................32 2.5.2. Analysis of Variance tests ..............................................................................33 2.5.3. Power analysis...............................................................................................