Effective rabbit management in a post RHD environment in New Zealand

Abstract

Developing effective rabbit management in the post RHD environment in New Zealand is of paramount importance to land managers and government agencies. Historically rabbit management has lacked clear objectives and faced conflicting interests from various stakeholders. With the advent of RHD, rabbits at some sites were reduced by up to 90%. However, the ad-hoc style of release meant there was no coordinated approach or collective action to maintain these gains through secondary control such as shooting and fumigation to remove surviving rabbits. Soon rabbits again reached high levels in many areas that necessitated a return to primary control using toxin application. Many landholders are locked in a model of periodic reactive control, still with no clear objective to permanently reduced rabbit numbers. A model of strategic sustained management (SSM) offers an alternative solution for effective rabbit management in the post RHD environment. SSM has a clear objective to permanently reduce rabbit numbers. It is one of the best methods to ensure the efficacy of RHD is maintained by removing immune survivors, thereby mitigating the potential of heritable immunity. It is anticipated under a model of SSM, that regular repetition of secondary control methods will reduce rabbit numbers and lead to declining efforts and costs concurrently. Striking the correct balance between costs and repeat applications is important and this will largely depend on the rabbits reproductive capacity at a site, RHD dynamics and environmental parameters. Landholders frequently implement wasteful rabbit control practices because they rely heavily on one technique, often inefficiently, and fail to follow up with maintenance control that may have sustained the initial level of control achieved. This represents a model of crisis management which lacks a clear long term objective. Implementing a program of strategic sustained management will avoid this pitfall. A thorough knowledge of factors that impede a rabbit’s chance of survival is needed to enable the manager to systematically create an environment that is non-conducive to the rabbit’s success. Combined with secondary control, this will create systematic sustained management and long-term benefits with reduced long term costs. Landholders need to take ownership of the rabbit problem but landholder and community attitudes to rabbit management is complex. There is often a lack of technical rigour and best practice is poorly understood in many cases. Government agencies have a regulatory compliance role which often lacks a strategic approach and is more of a command and control model than being supportive of long term objectives. Maniototo Pest Management Ltd (MPM) based in Otago has successfully implemented a model of SSM and operates an audited self-management program. It has successfully maintained rabbits at low levels and has shown that frequency of treatment can be extended once low levels of rabbit infestation are achieved. Ownership of the rabbit problem while divested in the pest management company is still squarely with the landholders who hold shares in MPM. This model has proven successful and holds merit for other areas wishing to implement a program of strategic sustained management and maintain the efficacy of RHD.