Forest structure

Those sections of forest along the Te Anau lake shore, resting on unconsolidated material and within ca. 3m of the maximum natural lake level (204.3m above mean sea level), could be threatened by the predicted water table effects (Mark et al. 1972) of lake manipulation required for hydroelectric development. The floristics and structure of this forest were investigated. Five forest associations have been recognised, apparently related to differences in soil moisture conditions.

Plotless methods were used to sample four forest stands situated at different altitudes on Mount Colenso, Ruahine mountain range, North Island, New Zealand. The altitudinal distributions of the main woody species are described graphically. All species have overlapping altitudinal ranges, so that no clear altitudinal 'belts' can be distinguished. The forest composition is regarded as a continuum showing gradual variation from diverse mixed (podocarp-beach) forest on the terraces of the Kawhatau river (c. 2000 ft.

Designing robust monitoring programmes for cryptic species is particularly difficult. Not detecting a species does not necessarily mean that it is absent from the sampling area. A conclusion of absence made in error can lead to misguided inferences about distribution, colonisation and local extinction estimates, which in turn affects where and how conservation actions are undertaken. It is therefore important to investigate monitoring techniques that reduce the non-detection rate of cryptic species.

The forests of Rangatira Island (218 ha) in the Chatham Islands are a critical breeding site for a number of rare and threatened forest bird species, but are also home to more than three million seabirds, which could significantly affect forest regeneration processes. We surveyed the forests of Rangatira Island by establishing 40 permanent forest plots, estimated seabird density through burrow counts, and analysed soil properties.