A Synthesis of Geophysical and Biological Assessment to Determine Restoration Priorities

How can geomorphology inform ecological restoration? A synthesis of geophysical and biological assessment to determine restoration priorities A thesis submitted in partial fulfilment of the requirements for the Master of Science Degree in Physical Geography By Leicester Cooper School of Geography, Environment and Earth Sciences Victoria University Wellington 2012 _________________________________________________________________________________________________________________ Acknowledgements Many thanks and much appreciation go to my supervisors Dr Bethanna Jackson and Dr Paul Blaschke, whose sage advice improved this study. Thanks for stepping into the breach; I hope you didn’t regret it. Thanks to the Scholarships Office for the Victoria Master’s (by thesis) Scholarship Support award which has made the progression of the study much less stressful. Thanks go to the various agencies that have provided assistance including; Stefan Ziajia from Kapiti Coast District Council, Nick Page from Greater Wellington Regional Council, Eric Stone from Department of Conservation, Kapiti office. Appreciation and thanks go to Will van Cruchten, for stoically putting up with my frequent calls requesting access to Whareroa Farm. Also, many thanks to Prof. Shirley Pledger for advice and guidance in relation to the statistical methods and analysis without whom I might still be working on the study. Any and all mistakes contained within I claim sole ownership of. Thanks to the generous technicians in the Geography department, Andrew Rae and Hamish McKoy and fellow students, including William Ries, for assistance with procurement of aerial images and Katrin Sattler for advice in image processing. To Dr Murray Williams, without whose sudden burst at one undergraduate lecture I would not have strayed down the path of ecological restoration. A better thing I can’t think of. And thanks for financial assistance without which this would be a very different thesis. Thanks also to other lecturers within the geography department that have given support. I would particularly like to mention Emeritus Professor Mike Crozier as a wonderfully inspiring keeper and communicator of geomorphological knowledge. A without whom is required for the late Dr Nick Preston whose spirit I carry as I walk the hills and to whom I turn to provide inspiration for answers about the landforms that I appraise. To family and friends; thanks for your patience and understanding. There is now a chance that I may return to some form of human normality in the not too distant future. _________________________________________________________________________________________________________________ i _________________________________________________________________________________________________________________ Preface Each summer my parents took me from my state house in a state house suburb on a charmed, but often bumpy, journey to some distant corner of New Zealand. Those times sitting in the back of the upright Prefect, then the newer little box Prefect, Anglia or Cortina (yes we were upwardly mobile, in today’s jargon) found me gazing at every nook and cranny of New Zealand, save for a few extremities such as the Catlins or East Cape. Leaving behind the experience and the wonderment of all the majesty that a child could perceive in the landscape of New Zealand and returning to Wellington was always depressing. Possibly the thought that summer was ending and school was the next port of call had something to do with it. In adulthood most of my life has been spent away from these magical islands but the long white cloud never left the periphery of my vision. A strong connection to the shape of the land and its forest complexity may be explained by my upbringing; but it is hard to say. Possibly it is due to my (childhood) habit of eating soil from my father’s garden, making me one with the land. Don’t worry, I spat the worms out, I must have known that I would become a vegan. What is easy to say is that I am deeply saddened by the general loss of a clean healthy environment, the pressure on biodiversity, and the struggle to maintain the integrity of what little is left of an ark that can never be replaced. Along the way, here and elsewhere, small battles have been won (but never permanently, for example, propositions to mine national parks); however, sadly, the war is being lost. Yes, larger and more emphatic change occurred following the dual discoveries, firstly by Polynesians and secondly by Europeans. Yes, I know that the cycles of natural change with glaciation have occurred, but these are not changes imposed by a species alone. With increased affluence, education and understanding it might be expected that we would appreciate the environment upon which we depend for our wellbeing, instead of increasing our impact, vis á vis dairying dry country or damming wild rivers. We continue to enlarge our footprint whilst reducing that of the species that we share this wonderful ball of sediment with; the unprecedented speed of species extinction a marker of the impact. Though little is spoken of it, the impact of our society really is a serious ethical issue (see Cairns, 2003). It would seem that such an attitude to our environment can only be explained by the increasing distance, in fact divorce, of humans from nature and the role it has in providing for the very society we live in. Possibly we have lost touch with our hearts. But not totally, as there are many people that are in touch with the natural world and attempting to stem the tide in the conservation movement. Additionally, there are those that are prepared not just to stem the tide but wish to turn it back; bringing together the conservation ethic and an ecological restoration ethic. Such people are committed passionate people who approach the restoration endeavour from a myriad of backgrounds; lay and scientific. _________________________________________________________________________________________________________________ ii _________________________________________________________________________________________________________________ My love of the landform and deep sense of compassion for other species is the underlying foundation for this study. Such a foundation has its roots in the heart and in culture, but is still reasoned with the head. Van Diggelen et al. (2001) pondered ecological restoration’s scientific relevancy querying the “the state of the art” or “state of the science”. Although science may inform ecological restoration, alone it cannot achieve it. To achieve restoration requires ownership by society and a sense of connection to the land. It seems that in practice ecological restoration is in part art and in part science, placed within a societal construct. Possibly van Diggelen et al. should have rephrased the question, swapping “or” for “and”. It is evident from the published work that science has a fundamental role to play in ecological restoration. That this knowledge is not perfect is also apparent. Given the precarious nature of the world’s ecosystems there doesn’t seem we have the time to wait until the complexity of ecosystems are well enough understood before restoration work begins. I see people who are very committed to caring for the environment and living harmoniously with the ecosystem, who do not require detailed scientific understanding, simply a connection. These people are achieving to some degree what scientists theorise about. (In a parallel universe) my artistic creation comes from the heart with a strong, in fact, visceral sense of connection to materials and forms, and to the natural world around me which informs my output. I think that ecological restoration is about a visceral, cultural connection to place, and it is very much an art; drawing together the biotic, geographical and the sociological elements. Without full knowledge it will always be so. Since there isn’t time to wait for full knowledge restoration needs to proceed with management adapting as our knowledge increases; but also riding on heartfelt passion. What this thesis is about is adding to the knowledge base and hence advancing the success of restoration projects and so helping to maintain society’s enthusiasm for the project. ___________________________________________________________________________ _____________________________________ iii _________________________________________________________________________________________________________________ Summary The central concern that this study addresses is how an understanding of geomorphological processes and forms may inform ecological restoration; particularly practical restoration prioritisation. The setting is that of a hill country gully system covered in grazing pasture which historically would have been cloaked in indigenous forest. The study examines theory in conjunction with an application using a case study centred on Whareroa Farm (the restoration site) and Paraparaumu Scenic Reserve (the reference site) on the southern Kapiti Coast, north of Wellington. The impact that the change of land use has had on the soil and geomorphic condition of Whareroa and the influence the changes may have on the sites restoration is investigated. The thesis demonstrates a method of choosing reference sites to be used as templates for rehabilitating the restoration site. Geographical Information Systems and national databases are used and supplemented with site inspection. The reference site chosen, Paraparaumu Scenic Reserve, proved to be a good template for the

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