Introductionfrog

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1.0 Introduction

This study of Leiopelma hochstetteri was undertaken as a student research project as part of the Northland Polytechnic's Environmental Management Diploma programme.

L.hochstetteri is one of four extant endemic frog species in New Zealand. Although it is the most widely spread of the four species, it is the only one to be found in Northland. The populations in the Waipu and Mareretu areas, of which the Brynderwyn Hills population is one, are the most northern populations so far identified in New Zealand.

The species has a catergory B conservation status, and it has been suggested that (Bell 1994) that using the ICUN Red Data Book catergories, that appropriate classification for L.hochstetteri would be low risk.

The princpiple threat to the species has been identified as predominantly that of loss or deterioration of habitat, in Northland (Ogle 1982, Newman 1996). Ogl's surveys revealed "critical loss and deterioration of habitat" in Northland, with the greatest being in the Brynderwyn Hills.

The Department of Conservation's native frog recovery plan (Newman 1996) identifies the Waipu populations of L.hochstetteri as the most threatened of the North Island populations. Further, Newman (1996) suggests that because the populations are small and localised, they may be even more at risk by environmental disturbances such as floods or siltation caused by for example, ground disturbance.

This area is heavily impacted upon by human activities, egmajor roads, quarrying and exotic afforrestation. Heavy rainfall in the area often causes slips on State Highway 1 through the hills, the clay and silt from which often ends up in the adjacent streams.

This species was thus chosen as a research topic because of the identified threats to its long term survival. The management of this species in exotic forests is currently very topical.

Contrary to earlier beliefs, L.hochstetteri has been found in isolated enclaves (eg waterfalls and rock fissures) in established exotic forest. This has prompted CHH to implement a management strategy for their Mahurangi Forest near Warkworth, as a mitigation measure for forthcoming logging near the species' habitats.

this study aimed to investigate and compare the habitat parameters and demographic features of populations established in pine and native forests. It was hoped that the resulting information would then be of use for effective management of the species and its habitat in the future.

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