Kererū declined rapidly following European settlement in New Zealand, and they remain at a reduced density. We assessed three sources of information to test the hypothesis that predation by introduced mammals and abundance of food resources are the two major factors determining kererū abundance across New Zealand. First, we reviewed the literature on factors affecting the vital rates of kererū. This analysis showed that predation is the cause of most nest failures and deaths in kererū.
Effective biodiversity conservation in lowland New Zealand requires an understanding of the relative benefits of managing impacts of native forest loss versus controlling invasive species. We used bird count data from 195 locations across mainland northern New Zealand to examine how the abundance and richness of native forest birds varied across wide gradients of native forest cover (c. 0–100%) and intensity of invasive species control (‘eradication’, ‘high-intensity rat and possum’, ‘low-intensity rat and possum’, ‘periodic possum’ and ‘none’).
Spatial pattern plays an influential role in the ecological processes of ecosystems, and landscape pattern metrics computed from remotely sensed data offer a way to quantify the correlation between pattern and process. However, the resolution of geographic data affects the landscape metrics obtained from a GIS, with consequent implications for the interpretation of biological effects studied at landscape scales.