Patchiness in distribution of rodents and mustelids in New Zealand forests.

摘要: Context. Relative density indices assuming uniform distribution of the target species are often only cost-effective method for monitoring a population over long term and at landscape scale, source valuable historical data. Yet, theoretical models emphasise dangers ignoring spatial heterogeneity, especially in short-term field Aims. To test whether Brown’s index patchiness (BIP) can offer simple means checking rodent mustelid survey data violations assumption distribution. Methods. We use BIP to interrogate long-term legacy collected by trapping mice (Mus musculus), rats (Rattus rattus R. norvegicus) stoats (Mustela erminea) New Zealand forests. Key results. found evidence moderately patchy distributions that were independent abundance all three species. In two South Island beech (Nothofagus) forest valleys, 19% (6 31) mouse samples 8% (3 36) stoat significantly patchy, correlated with seedfall event; mixed Pureora North Island, significant ship was recorded (16 84) Fenn trap 5% (2 42) samples. Conclusions. Moderate is common. The consequences any given study depend on purpose work, but may be more important practical management than modeling.