Management of invasive mammal pests plays an integral role in the conservation of New Zealand’s native flora and fauna. Models fitted to pest capture data can guide conservation managers by providing estimates of pest densities within a management area, or probabilities of absence for declaring local eradication. A key parameter of these models is the detectability, i.e. the probability of an animal being detected by a surveillance device for a given amount of survey effort.
We review the recent rise to prominence in Aotearoa New Zealand of predation-focused conservation management, critically assessing the likelihood that this will deliver outcomes consistent with national biodiversity goals. Using a review of literature describing the impacts and control of three groups of introduced mammals (wild ungulates, brushtail possums, and predators), we identify shifts in management emphasis over a century of conservation decision-making in Aotearoa.
In the past few years genetic technologies springing from advances in DNA sequencing (so-called high-throughput sequencing), and/or from CRISPR/Cas9 gene editing, have been proposed as being useful in bioheritage research. The potential scope for the use of these genetic technologies in bioheritage is vast, including enabling the recovery of threatened species, engineering proxies of extinct species and genetically controlling pests.
Simple grazing models with two herbivores are used to assess the effects of pasture pests on stability and productivity of continously-growing pastures. Algebraic and graphical methods are also presented for estimating losses from pasture pests at different stocking rates directly, from data on productivity/stocking rate relationships. Pests are considered as competing grazing herbivores and denuders of pasture area. Denuding pests have no effect on stability but grazing pests increase the likelihood of discontinuous stability.
It is usually uncertain when to declare success and stop control in pest eradication operations that rely on successive reductions of the population. We used the data collected during a project to eradicate feral cats from San Nicolas Island, California to estimate both the number of cats remaining towards the end of the project, and the amount and type of surveillance effort required to declare successful eradication after the last known cat was removed.