Kararehe Kino - Animal Pest Research Issue 32
![Kararehe Kino Issue 32 banner](https://oldwww.landcareresearch.co.nz/__data/assets/image/0004/180598/kk-banner-32-web.jpg)
This issue of Kararehe Kino presents a sample of quantitative modelling methods and how they can be applied to various wildlife management issues.
Kararehe Kino is also available in print. Please email the editor, Morgan Coleman colemanm@landcareresearch.co.nz, if you would like to receive printed copies of this newsletter.
In this issue
![Andrew Gormley Andrew Gormley](https://oldwww.landcareresearch.co.nz/__data/assets/image/0019/180082/varieties/thumb200.jpg)
Editorial: Using quantitative models to gain insights in ecology
It is probably a fair assumption that people who are interested in the life sciences are not secretly yearning to learn and apply quantitative methods. Indeed, for many professional ecologists, mathematics and statistics were their least favoured subject areas during their training. However, because ecology typically involves trying to make sense of a complex system, we often require quantitative models to help us in that endeavour.
![Figure 1. Figure 1. A hypothetical example of using network connectivity as a basis for pest control. A series of localised populations of an invasive pest species connected via dispersal pathways that form a network of populations across a landscape is illustrated above. If the connections are known or can be predicted, then a network connectivity metric, such as ‘betweeness centrality’, can be used to identify those localised populations that form critical junctions for dispersal around the network. Targeting such localised populations with higher betweeness centrality may break the network into smaller, isolated populations that are individually easier to control or eradicate.](https://oldwww.landcareresearch.co.nz/__data/assets/image/0005/179681/varieties/thumb200.png)
Prioritising pest control based on network connectivity
Resources for the control of invasive pests can be prioritised for certain sites in different ways, but one approach that has not received a lot of attention is prioritising sites based on landscape connectivity.
![650_2-Warburton-and-Anderson-figure-threeEsProb.png Results of three hypothetical management scenarios illustrating how the integration of 3E-component probabilities determines the overall probability of project success. In the upper panel of each scenario (A, B, and C), the probabilities of ecological, economic and ethical acceptance are decomposed into individual probability distributions. The product of these probabilities is shown in the corresponding lower panel and represents the overall probability of programme success.](https://oldwww.landcareresearch.co.nz/__data/assets/image/0007/179683/varieties/thumb200.png)
Ecology, economics and ethics: the three Es required for sustained and effective vertebrate pest management
In New Zealand some introduced vertebrates are managed to limit their impacts on indigenous biodiversity, agricultural production, and infrastructure, and others for commercial and recreational harvest. Most of this management requires the use of lethal tools and techniques, and as a result wildlife managers are often challenged to justify their policies and actions on the basis of pest ecology, population dynamics and ethical acceptability.
![Juvenile ferret Juvenile ferret. © Grant Morriss](https://oldwww.landcareresearch.co.nz/__data/assets/image/0003/179706/varieties/thumb200.jpg)
Using computer models to understand and forecast reinvasion by invasive mammals
Preventing and effectively managing reinvasions is essential for the long-term viability and success of invasive species eradication and control interventions. It is a particularly formidable challenge in mainland scenarios where there are no natural barriers to hamper the spread and movement of potential reinvaders.
![800_4-brown-kiwi_0236_rc_doc.jpg Brown kiwi. © Rogan Colbourne](https://oldwww.landcareresearch.co.nz/__data/assets/image/0011/179687/varieties/thumb200.jpg)
Modelling supports nimble predator management for increasing kiwi populations over large areas
The recovery of the five species of kiwi is a national conservation priority. The great spotted kiwi, tokoeka and brown kiwi live in large tracts of forest and are experiencing population declines due to invasive predators. While the little spotted kiwi and rowi have low populations, their numbers locally have stabilised or are increasing due to effective predator management.
![Rabbit Rabbit. © John Hunt](https://oldwww.landcareresearch.co.nz/__data/assets/image/0006/179817/varieties/thumb200.jpg)
Wielding power for pest control
Consider this scenario: introduced predators, like ship rats, are responsible for dwindling numbers of North Island robins at Hamburger Hill Scenic Reserve. An aerial poison operation reduces rat numbers by an estimated 95%, and managers want to determine the response of the robin population to reduced predation.
![Argentine ant. © Richard Toft, Entecol Argentine ant. © Richard Toft, Entecol](https://oldwww.landcareresearch.co.nz/__data/assets/image/0010/179695/varieties/thumb200.jpg)
Using surveillance models to provide confidence in the eradication of Argentine ants
Surveys undertaken near the end of an eradication programme will often not find any target pests and the search results will consist of many zeros. But how do we know those zeros are real and there really are no pests left? Maybe some individuals have survived control but haven’t been detected because they are so rare, and/or the search effort was insufficient to find them.
![650_7-20161203_123811.jpg DOC 200 predator trap at Mt Arthur, Kahurangi National Park. Image: Rachelle Binny](https://oldwww.landcareresearch.co.nz/__data/assets/image/0010/179704/varieties/thumb200.jpg)
How do behavioural differences in pests affect their trapability and eradication success?
New Zealand has a history of successful small mammal eradications from offshore islands. On the mainland, advances in pest-proof fencing technologies have made it possible to eradicate pests over relatively small areas and to protect against reinvasion. Since the announcement of the Predator Free 2050 goal in 2016 there has been increased interest in the development of new tools and strategies to improve the efficiency, effectiveness and scale of pest eradication operations.
![Using TrapSim Using TrapSim](https://oldwww.landcareresearch.co.nz/__data/assets/image/0005/180086/varieties/thumb200.jpg)
TrapSim: an online tool to help managers decide on a trapping regime
When faced with the task of managing predators at a landscape scale, there are a number of decisions land manager(s) must make. These include how many traps should be used, how far apart traps should be set, how often traps should be checked, and are traps needed that can catch/kill more than one animal before being reset?
![Red deer recovery Red deer recovery](https://oldwww.landcareresearch.co.nz/__data/assets/image/0007/179701/varieties/thumb200.jpg)
Economic aspects of New Zealand’s wild deer recovery industry
Red deer were introduced into New Zealand in the mid to late 1800s and are now almost ubiquitous across both the North and South Islands. The commercial recovery and export of venison from wild-caught deer began in about 1958, but the industry did not grow significantly until about 1963, when helicopters were first used to harvest deer carcasses from alpine grasslands.
![Recent publications](https://oldwww.landcareresearch.co.nz/__data/assets/image/0016/180106/varieties/thumb200.jpg)