multivariate analysis

Cyathea medullaris (Cyatheaceae) is a frequent pioneer of disturbed areas (e.g. landslides) or edge environments, sometimes forming near continuous canopies. We test the hypothesis that colonisation by this species as a pioneer alters the seedling assemblage to favour more shade-tolerant broadleaved trees than that beneath another common native pioneer (Kunzea robusta, Myrtaceae) in the same landscapes. We compared vegetation and abiotic characteristics of 166 sites across the Auckland region where C. medullaris or K.

The effects of environment and management on the composition of short-tussock grasslands and the abundance of the invasive weed Hieracium pilosella were investigated in two small catchments. Species composition and site factors were recorded on a total of 182 plots and the management history of each catchment was reviewed. H. pilosella was present on >80% of all plots, but was at an early stage of invasion in one catchment (<5% cover) and dominant in the other (25% cover).

A plant sociological survey of tall-tussock grasslands in the Mackenzie country was repeated after an interval of 26-28 years. Changes in physiognomy of the grasslands which have been inferred from earlier studies have been found to be continuing on many sites. A noteworthy feature of most sites has been a reduction in number of indigenous species found. An increase in abundance of Hieracium pilosella or H. praealtum has occurred at most sites.

The distribution of banded rail habitat use in a saltmarsh was measured by recording the rate at which their footprints accumulated. The relationships between habitat use, time of day, state of the tide, and 15 environmental parameters, were investigated using multivariate analysis. Banded rails were most active in the morning and evening and immediately after a tide. They did not venture far from cover and their activity was greatest at low levels on the shore, and amongst certain vegetation types.

Fire has been a major driver of forest loss in New Zealand. A conceptual model has been proposed in which positive feedbacks between vegetation, fire and soils can arrest regeneration of recurrently burned wet forest landscapes. We used vegetation data collected across three topographically similar landscapes – Awana, Glenfern and Windy Hill – on Great Barrier Island to (1) describe current vegetation composition and structure and predict future change in composition and (2) assess evidence for interactions between fire and soils slowing regeneration in these landscapes.