Hunua Ranges and Waharau Regional Park

Structure of invertebrate communities (ground & arboreal); Community structure of vegetation, and Flowering & fruiting phenology in the Kokako Management Area in the Hunua Ranges

Structure of invertebrate and plant communities was compared between three areas with different pest and predator control regimes and histories. Intermittent control of large mammalian pests such as goats and pigs is carried out in all three areas; in two of the areas, seasonal control of predators such as possums, rats and stoats is carried out, but one area has a history of 10 years of such control measures, while the other has been subject to this regime for only one year. Permanent transects and vegetation plots, as well as invertebrate sample sites were established. Baseline data was collected on both arboreal and ground dwelling invertebrate communities, and on diversity, abundance and structure of vegetation communities. Fruiting and flowering phenology was part of this suite of projects also. These are long-term studies, which will be expanded and repeated.

Surveys of trial plantings using native timber species
Although growth rates of native trees are generally considered slow when compared to growth rates the introduced Pinus radiata, the use of native timber for production forestry is increasingly gaining popularity in New Zealand. Already 20 years ago, plantings of native species were trailed in the Hunua ranges. These plantations were intensively managed for the first 5-10 years, little monitoring has been carried out in the past 10 years. Over the past 3 years, students have been involved in a number of studies in the trial plots in the Hunua Ranges. Students have investigated and documented a variety of topics, including: growth rates of the different native species; impacts of soil characteristics on growth rates of kauri (Agathis australis); analysis of stem spatial distribution and stem diameter; natural regeneration of understorey species; invasion of weeds into the trial plantings; spread of native species from the trial plantings; and the role of birds in the dispersal of seeds of native and introduced plants from the trial planting blocks

Frog surveys in the Hunua Ranges

In 2005, new projects in the Hunua Ranges included surveys for the native Hochstetter's frogs in three areas subject to three different predator control regimes. This project will be repeated in 2006, after which it becomes part of a long-term monitoring regime.

Fishes and invertebrates of Waihihi Stream

The lower reaches of the Waihihi Stream, just below Waharau Regional Park, were first surveyed by students in 2002. During the fall 2004 semester, students investigated the effects of barriers to fish passage in Waihihi stream in Waharau Regional Park. Students fished the stream (catch and release) 100m below and above each of seven structures in the stream that were considered (potential) barriers to fish passage. In-stream and riparian habitats were described and characterised. As part of this study, effectiveness of methods for catching freshwater fishes was investigated, comparing the use of fyke nets and minnow traps, and three different baits. Each method can be used to target different species of fish, and to assess diversity, a combination of methods is recommended.

Diversity and abundance of macro-invertebrates was also studied in the Waihihi Stream. Seven sites were sampled in the Waihihi Stream and two of its tributaries. Site-specific conditions, and habitat quality were taken into account. Macroinvertebrate Community Indicies (MCI) suggested that water quality was overall high.

Riparian management for Whakatiwai Stream
The lower reaches of the Whakatiwai Stream form the northern boundary of the EcoQuest Campus. Land use up stream is part agriculture (cattle) and part forested (Regional park). The margins of the stream and its banks, as well as the stopbanks are overgrown with introduced weeds.

In the spring 2004 semester, a team of students set out to survey the vegetation on the stream banks. They created a detailed map, and wrote a proposal for systematic removal of the weeds and revegetation of the stream banks. Management issues included: The fact that parts of the area on both sides of the stream are waahi tapu (sacred sites) requires close consultation with the local iwi, and digging the large weeds and weed-trees out is not always an option; the integrity of the stopbanks needs to be safeguarded at all times; and use of herbicides next to a waterway is not desirable.