Riparian vegetation mapping


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Monitoring network
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Surface water quality in Tasman District
In-stream habitat assessment
Stream productivity
Fish distribution
Trout assessment by drift diving
Trout numbers in the Motueka River
Riparian classification
Riparian vegetation mapping
Riparian vegetation trials in the Sherry River
Riparian plants - stability
Cow crossings & water quality
Campylobacter - Motueka River

Introduction

One of the important aspects of riparian management to aid improvement in freshwater habitat is to assess the nature of the existing riparian vegetation and explore opportunities for vegetation enhancement - particularly with native vegetation.

A pilot catchment, the Sherry River, was chosen to explore ways of mapping current vegetation and identify where the best places might be for native vegetation enhancement.

A method was designed to classify riparian vegetation using the Tasman District Council colour orthophotographs to describe riparian vegetation in seven broad classes. Ground truthing corrected misinterpretations. The vegetation in the non-pasture classes was assessed to provide a description of the vegetation and an understanding of the opportunities for enhancement.

Results

11% of the length of the Sherry River is pasture and has no woody riparian vegetation. Over a third of the riparian vegetation has been classified Deciduous hardwood. Deciduous hardwood vegetation is generally about 5 m wide and consists mainly of crack willow trees draped in old man’s beard.

It often has a thick ground cover of blackberry. Weed management is essential if more desirable riparian
vegetation to be established.

The mixed Indigenous shrubland vegetation is in the upper part of the catchment, and contains some native
species such as kanuka and Coprosmas.

Indigenous forest exists along about 17% of the length of the river and consists of beech and podocarp trees, some native understory species, with few weeds present. This vegetation has an average width of 6 m. Individual beech trees also occur intermittently along the length of the river. These areas offer good opportunities for riparian enhancement with native species. Weed management will be less difficult, and a native seed source already exists.

 

Riparian enhancement considerations

  • Adjoining land management objectives

  • Potential riparian values

  • Proximity to native vegetation

  • Stock exclusion

  • Weed and pest management

  • Willow management/removal

  • Use of nurse crops

  • Planting/seeding of natives

  • Community motivation.

Poster presented at AGM 2003 on this work. ( 3120 KB)

Contact Lisa Langer for more information.


Page last updated 24 July 2006