Research

As it expands every year Waiwhakareke is not just taking shape as a Natural Heritage Park, it is also a living example of restoration innovations and best practice. On this page you will find a selection of restoration research either complete or currently underway at Waiwhakareke.

Urban Planning Provides Potential for Lake Restoration Through Catchment Re-Vegetation - Abstract

Ian C. Duggan, 2012, Urban Forestry & Urban Greening 11:95– 99
 
Encroachment of urban areas into forest and farmland is typically considered to have detrimental effects on terrestrial and aquatic ecosystems. Most restoration strategies for lakes affected by urban development represent expensive short-term fixes requiring on-going management, with long-term restoration requiring external nutrient inputs (typically the major impact of urban development) to be significantly reduced. This study details, using a simple nutrient budget, the effects of the conversion of farmland to native forest in a lake catchment (Waiwhakareke/Horseshoe Lake in the Waiwhakareke Natural Heritage Park (WHNP), New Zealand) during urban encroachment. I show how far-sighted planning employed by management authorities can lead to urban growth being beneficial to aquatic systems. Even using this method, however, managers should not expect lakes to become immediately available as amenities. Although reduction in external nutrient loads brought about by the reforestation of lake catchments in urban areas will ultimately lead to phosphorus reduction and concomitant water quality improvements, such responses may take a number of years due a continued release of nutrients from bottom sediments if they are initially within rural catchments. Urban management authorities therefore need to possess a long-term outlook and commitment to such projects. Overall, the WHNP project acts as a model for future urban development and spread of cities, providing opportunities for the long term restoration and conservation of lakes.

Waiwhakareke: Monitoring Revegetation Success

Monica Peters and Bev Clarkson, 2010

Chapter 13 of the Wetland Restoration Handbook for New Zealand Freshwater Systems uses Waiwhakareke Natural Heritage Park as an example to illustrate successful revegetation monitoring methods.

To view the entire Handbook click here

Zoo and Aquarium Association Quarterly Newsletter - August 2011 edition

Waiwhakareke Restoration Establishment of Experimental Monitoring Plots

To determine suitable techniques for reconstructing ecosystems in urban areas at the scale of tens of hectares, we have established a randomised block design experiment at Waiwhakareke Natural Heritage Park. This tests the most effective way of reconstructing Dacrydium cupressinum (rimu) – Beilschmiedia tawa (tawa) dominated forest, and peatland basin Dacrycarpus dacrydioides (kahikatea) – Laurelia novae-zelandiae (pukatea) semi-swamp forest. Different treatments in replicate plots comprise the range of possibilities from direct succession (in which the characteristic dominants are planted directly into pasture) to establishment of a nurse crop followed by later enhancement planting, thus allowing us to determine rates and extent of return to a functioning ecosystem.

Waiwhakareke Restoration Plantings: Re-measurement of Monitoring Plots

In this report we present our assessment of vegetation growth in marked baseline monitoring plots, two years after establishment. Additionally, we have established a new monitoring plot in a previously unsampled vegetation type planted in 2006. These plots are sited randomly throughout planting zones and thus allow assessment of plant health and survivorship, animal browsing impacts, reproductive output of plants, groundcover composition and canopy closure and cover.

Waiwhakareke Restiad Peat Bog Re-creation Guidelines

Restiad peat bogs dominated by Sporadanthus ferrugineus (cane rush) and Empodisma minus (wire rush) are unique to New Zealand. They are very different from the more typical Sphagnum moss bogs that are widespread in the Northern Hemisphere and elsewhere in the world.  The Sporadanthus-Empodisma bog type was once common throughout the northern North Island from near Kaitaia to Te Awamutu but, because of widespread drainage, is now restricted to three sites in the Waikato region; Kopuatai, Torehape, and Moanatuatua. Around Hamilton City, Sporadanthus once dominated former bogs at Rukuhia ‘Swamp’ to the south and Komakorau/ Gordonton Bog to the north.  At Waiwhakareke, the Sporadanthus bog types probably also occurred on the flat peat land immediately north of the lake.  

Urban Restoration Abstract

Are current restoration practices capturing levels of genetic diversity observed in the wild?
The use of locally eco-sourced seeds and plants is becoming common practice in a range of restoration projects. Along with the usual primary criterion of locality of collection, knowledge of genetic variation in wild in situ populations and resulting restored populations should be considered; application of population genetic theory can contribute to maximizing genetic variation in ex situ collections and therefore the long term persistence and evolutionary potential of these populations. We undertook population-level genetic analyses (ISSRs) of two plants commonly used in restorations, mahoe and kahikatea, to determine if the genetic variation in an ex situ “restored” population reflects the genetic variation in local, natural in situ populations. This knowledge will contribute novel genetic data to our research programme on evaluating eco-sourcing at an urban restoration site, Waiwhakareke Natural Heritage Park. Overall, this research will provide estimates of genetic variation over geographic distance (how local is local?), and, in conjunction with logistical considerations, will help determine how best wild seeds are used for the purpose of restoration/rehabilitation and delimiting seed provenance. This abstract was prepared for a workshop on urban restoration.