Authors: J Ogden Y Deng M Horrocks S Nichol S Anderson
Publish Date: 2006/02/10
Volume: 6, Issue: 1-2, Pages: 25-40
Abstract
Whangapoua Estuary Great Barrier Island New Zealand is central to a proposed Marine Reserve and is currently managed for conservation by the Department of Conservation This paper describes the sequential impacts of Maori and European people on the process of estuarine vegetation succession in time and space and the rate of estuarine sedimentation Multiple cores from one estuary gave confidence in assessing the temporal sequence of vegetation change but bioturbation and other disturbance factors made it difficult to interpret 14C dates from the estuarine environment The modern vegetation zonation pattern on the estuary is an active succession which has been generated by rapid estuary infilling probably initiated as a consequence of erosion following Maori burning of the adjacent forest European forest clearance for agriculture resulted in a further increase in estuarine sedimentation and may have reactivated earlier sediments trapped in adjacent swamps The combined effects of two phases of human exploitation have resulted in largescale loss of nutrients and topsoil from catchments throughout Great Barrier Island Conservation management of the estuary should take account of the anthropogenic impacts that have driven the plant succession and created the current vegetation zonation pattern This pattern is neither static nor ‘natural’ but rather an ongoing response to the changing human activities in the surrounding catchmentThe study was supported by funds from an Auckland University Doctoral Scholarship Deng and the Auckland University Research Committee Grant 3600222 Ogden Nichol Thanks to Jack GrantMackie Janet Wilmshurst and Rewi Newnham for critical discussion of the results Professor J A Dearing Dr A J Plater and an anonymous referee provided valuable criticism of an earlier draft
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