A social practice perspective on environmental volunteering and pest management in Aotearoa New Zealand

Introduction

Environmental volunteers are playing an increasing role in conservation efforts across Aotearoa New Zealand (henceforth Aotearoa), with many participating in activities such as predator trapping, restoration plantings, weeding and environmental monitoring (Woolley et al. 2021; Gerolemou et al. 2022; Heimann and Medvecky 2022). With the announcement of Predator Free 2050 (PF2050) (New Zealand Government 2016), which aims to ‘[e]radicate the most damaging introduced predators (mustelids, rats and possums)¹ from all of Aotearoa New Zealand by 2050’ (Department of Conservation n.d.), the number of community environmental groups in Aotearoa has increased greatly in recent years (Leathwick and Byrom 2023). For example, in 2013, Peters et al. (2015) identified 540 community environmental groups through a search of publicly accessible website databases, compared to over 5000 groups in 2020 involved in predator trapping alone (Department of Conservation 2020a).

This significant increase in community environmental groups aligns with Aotearoa’s PF2050 Strategy ‘to mobilise, innovate and accelerate delivery of a predator free New Zealand by 2050’ (Department of Conservation 2020a, p. 17). Mobilising the support and commitment from people, communities and organisations is seen as key to achieving PF2050 (Department of Conservation n.d.). A critical aspect of this, according to the PF2050 Strategy ‘Towards a Predator Free New Zealand’ (Department of Conservation 2020a), is understanding what motivates people to actively engage with PF2050. Internationally, there has been a lot of attention on the reasons or motivations for volunteering (Forner et al. 2024), and this has also been addressed recently in the environmental volunteering literature in Aotearoa (e.g. Woolley et al. 2021; Heimann and Medvecky 2022). While it is important to understand what motivates people to engage with PF2050, how they are engaging is just as important to ensuring successful pest management. However, how they are engaging is not well documented in literature.

The goal of pest management is resource protection, not dead pests (Holloway 1993). Poorly delivered management can result in time and money being spent with little long-term effect and can be more damaging than no management at all. For a management program to be effective, it must maintain the pest population below a threshold level of ecosystem damage that allows the resource of interest to thrive. Otherwise, even though pests are being killed, this may be making no difference at all to the status of the resource (as the pest’s natural net population increase rate is higher than the rate that the pests are being killed. Therefore, the pressure on the resource being protected is never relieved, and the resource continues to decline) (Holloway 1993).

In a seminal assessment of pest management in Aotearoa, Holloway (1993, p.285) noted that a ‘widespread lack of understanding of the principles of pest management’ has meant that the many millions of dollars spent over 100 or more years on the management of introduced pests ‘…had little long-term effect, largely because of persistent failure to understand the biology of the target animals, to define objectives, and to apply effective and efficient control measures’ (Holloway 1993, p. 287). Drawing on expert scientific and technical knowledge, Holloway (1993) outlined the fundamental principles (e.g. that the goal is resource protection, not dead pests) and strategies (e.g. prevention, eradication, sustained control) of pest management,² which underpin publicly available ‘best practice’ pest management guidelines (e.g. Department of Conservation 2022a, 2023). Holloway (1993) contended that if the fundamental principles and strategies of pest management continued to be ignored, including controlling pests according to fashion or whim, then time and money would continue to be spent with little effect.

It is the goal of PF2050 to eradicate mustelids, rats and possums from all of Aotearoa by 2050 (Department of Conservation n.d.). Eradication means the complete removal of predators, and:

should be attempted only where no immigration is possible; where all of the pest animals can be placed at risk; and where the pest can be killed at a rate faster than its natural net population increase (Holloway 1993, p. 288).

All three conditions need to be satisfied for eradication to occur (Holloway 1993; Samaniego et al. 2021).

Preventing reinvasion of the predators targeted by PF2050 is not feasible with current tools, other than fences (Innes et al. 2024). However, developing novel approaches to address this aspect is part of the PF2050 strategy (Bell et al. 2019; Department of Conservation 2020a). The creation of virtual barriers, where multiple lines of closely spaced traps around the operational perimeter are deployed to exclude any pests from attempting to re-enter a protected area (Bell et al. 2019) is one example. Even if this condition can be addressed, the other two conditions noted by Holloway (1993) still must be satisfied to achieve eradication.

Thus, in addition to preventing reinvasion, PF2050 will also need to ensure every target pest across all of Aotearoa is put at risk, including those in cities and towns (Department of Conservation 2020a). Trapping is currently the most widely promoted and adopted control technique by the PF2050 movement, with over 5400 trapping projects across the country (Department of Conservation n.d.). Engaging large numbers of people in predator control is a key action of the PF2050 Strategy ‘Towards a Predator Free New Zealand’ (Department of Conservation 2020a). For example, it is the goal of the Towards Predator-Free Taranaki – Taranaki Taku Tūranga project to get one in five urban households trapping (Taranaki Regional Council n.d.). For a large provincial city such as New Plymouth, this would require around 7000 households (New Plymouth District Council 2023) voluntarily engaging in predator control on a continuous basis (until eradication is achieved), to a standard that is supportive of best practice for eradication (i.e. traps are set and maintained at a density that puts at least one trap in every home range of the target species).

In this research, we use Social Practice Theory (SPT) to investigate the practice of voluntary rat trapping in an urban environment to understand how people are engaging with the PF2050 movement. A SPT lens looks beyond what motivates people to include what people do, how they do it, why and with what (Shove 2010; Shove et al. 2012). Examining the practice of predator trapping can provide insight into the enablers and constraints that determine people’s commitment and participation in pest management programs. This knowledge can help develop and link policy interventions and management actions for achieving the management strategies of PF2050.

Social practice theory

A practice in SPT is broadly defined as:

a routinized type of behaviour which consists of several elements, interconnected to one other: forms of bodily activities, forms of mental activities, ‘things’ and their use, a background knowledge in the form of understanding, know-how, states of emotion and motivational knowledge (Reckwitz 2002, p. 249).

A practice consists of three connected elements: (1) meanings; (2) competencies; and (3) materials (Fig. 1) (Shove et al. 2012).

Fig. 1.

The three SPT elements and their links (adapted from Shove et al. 2012).

All three elements are required to perform a practice (Spurling et al. 2013). For example, the practice of rat trapping comprises a set of meanings (e.g. about the relative importance of rats versus the things that they are affecting, and the emotional engagement to take action), competencies (e.g. knowing how to set a trap and being physically able to do so), and materials (e.g. a rat trap). Each individual element can also influence how that practice is performed. For example, how well an individual traps rats can depend on how well a trap is maintained (materials, competencies), which type of trap/bait is used (materials) and the frequency with which the trap is checked and reset/rebaited (competencies).

Helpful to understanding practices is the distinction between practice-as-entity and practice-as-performance (Spurling et al. 2013; Kuijer 2014).

Practice-as-entity refers to practice as the generally understood ideal type of practice – what people usually recognize as a practice and what kinds of elements are connected to it. People can talk about and understand it, also without performing it. …Practice-as-performance… is the unique performance of a practice in a specific time/place setting. Although a performance will always differ somewhat from other performances of the same practice, it resembles the general doing of the practice enough to be recognized as the practice (Svennevik 2021, p. 3)

An important aspect of practice-as-performance is that each performance is slightly different each time. While the practice-as-entity forms a guiding structure, there is continuous internal variety within the practice-as-performance (Warde 2005; Kuijer 2014; Hui 2017). Practices contain the seeds of constant change and innovation (Warde 2005), They can emerge, persist, transform, or die out when links between the three elements are made, maintained or broken (Hargreaves 2011; Shove et al. 2012).

By examining the three elements and their interactions that generate, maintain, or transform practice, SPT provides insight and understanding of the way people engaging with predator control think, behave, and act.

Methods

We investigated the predator control practices of urban households in New Plymouth, Aotearoa New Zealand, which is a large provincial city (population approximately 80,000; New Plymouth District Council 2023) on the west coast of Aotearoa’s North Island. This research builds on previous research into people’s motivation to engage in urban predator control in New Plymouth (see Kaine and Stronge 2020; Kaine et al. 2024).

Participants for this study were recruited from the randomly selected group of New Plymouth adult residents who were involved in the Kaine and Stronge (2020) study (n = 436), and who had agreed to further interviews. These participants were contacted by email and/or phone and invited to participate in an interview. A total of 148 people had initially indicated that they would be willing to participate in further interviews; however, only 35 took up the invitation when approached. Approximately 66% of respondents were women. Eighty per cent of respondents were over the age of 50 years. Sixty eight per cent of respondent’s highest level of formal education was at the tertiary level.

Participants were interviewed about their experiences of trapping rats (n = 21). Interviews were also conducted with participants who did not trap (n = 14 – some used poison but most were not engaged in any control). Interviews followed a semi-structured approach and were conducted either via video conferencing platforms or by phone (see Supplementary material for the interview schedule). Interviews were approved by Manaaki Whenua – Landcare Research’s social research ethics process (approval number 1920/10). All interview participants received a Personal Information Sheet outlining the purpose of the research and information on the interview process. All the participants gave informed consent to participate in the research.

All interviews were recorded, and the recordings transcribed by a transcription services company. Transcripts were managed using the computer software NVivo 12. The interviews were analysed, using deductive thematic coding, into three broad themes drawn from SPT, (i.e. meanings, competencies, materials). We then inductively coded the responses within each category into further themes (Table 1).

Results

The following section looks at how people are engaging with the PF2050 movement by examining the three different elements of the practice-as-performance of having a rat trap that is set and maintained on a property.

Discussion

Aotearoa is seen as a world leader in pest management (Bell et al. 2019; Samaniego et al. 2021), an achievement that was built on decades of learning, adaptive management and a strict adherence to best practice. Key to this success are critical reflections and objective assessments of the factors that influence operational performance (Samaniego et al. 2021). Performance is linked to practice in and through the meanings, competencies, and materials that make up a practice (Shove et al. 2012). The constant reproduction of a practice through its performance creates a considerable inertia or persistence, reinforcing existing norms (Warde 2005; Alkemeyer and Buschmann 2017; Svennevik 2021). If the norm that is being reinforced is an inadequate or inappropriate pest management practice (i.e. it ignores the decades of learning, underpinned by the principles of pest management outlined by Holloway (1993)), then the failures of the past, which saw time and money being spent with little effect on Aotearoa’s declining biodiversity, will just be repeated.

It was evident from our findings that all three elements, either individually or in combination, influenced how the practice of trapping rats was performed. For example, while support (meanings) for reducing rat numbers was high among our interviewees, the motivation (also an aspect of meanings) to keep their traps set and maintained varied. This is consistent with Kaine et al. (2024) who found moderate-to-high support for reducing rat numbers but mostly moderate motivation to do so. This implies that while the desire was there, the disciplined effort required to undertake pest management to the high standards required by best practice (Samaniego et al. 2021; Innes et al. 2024) was not. Another example of how the elements combine to influence practice was demonstrated by how rat behaviour (materials) and lack of knowledge of that behaviour (competencies) combined to influence when traps were set or not. These examples highlight the importance of looking systematically across all three elements (meanings, competencies, and materials) and their interactions, to understand variations in the performance of a practice.

The variability in the performance of practices has important implications for PF2050’s goal of eradicating mustelids, rats and possums from all of Aotearoa New Zealand by 2050 (Department of Conservation n.d.). The PF2050 strategy of mobilising and accelerating delivery of pest management across Aotearoa (Department of Conservation 2020a) relies on engaging large numbers of volunteers on a continual basis to undertake pest management (until eradication is achieved). Forner et al. (2024, p. 454) contend that continual volunteer engagement with a project relies on providing ‘volunteers with an opportunity to contribute meaningfully and to have some autonomy in the way they carry out their work’. However, from a SPT perspective, providing volunteers with autonomy manifests as variations in practice, and some of these variations can jeopardise pest eradiation objectives (e.g. not having traps continuously set). It was evident from the trapping practices described by our interviewees that the variations in the way they carried out their predator control activities, did not place every target pest at risk. While this paper focuses on the trapping of rats in one urban location, Stronge and Hyslop (2024) identified similar practice variations by volunteers within a large rural predator control project in the Waikato region of Aotearoa; indicating that this is not an isolated occurrence.

Some PF2050 projects have changed the language (meanings) they use, using the terms elimination, suppression or zero-density, rather than eradication (Palmer and McLauchlan 2023; Innes et al. 2024). These terms equate to a pest management strategy of sustained control, not eradication. Sustained control requires a:

constant proportion of the population [to] be killed on a sufficiently regular basis to maintain a stable population below some threshold level of ecosystem damage (Holloway 1993, p. 288).

As Innes et al. (2024, p. 19) note, for numerous projects this threshold is not made clear and that terms such as suppression can act ‘as cover for vague objectives and poor pest control practices’. In addition to not resulting in significant ecological benefits ‘congruent with Aotearoa’s high level biodiversity goals’ (Leathwick and Byrom 2023, p. 10), such projects can also create a reputational risk for the Department of Conservation (DOC), as the lead agency responsible for Predator Free 2050 (Department of Conservation n.d.). While sustained control is a valid strategy in the management of pest species (Holloway 1993), sustained control masquerading under the banner of eradication has the potential to create a false sense of expectation and achievement within the public of Aotearoa (Palmer and McLauchlan 2023). This could affect DOC’s trustworthiness and social licence to operate (Stronge et al. 2024), when the sustained control outcomes fail to match the eradication narrative.

Decades of learning and implementation show that successful pest management requires a principle-based approach and strict adherence to best practice (Holloway 1993; Samaniego et al. 2021; Innes et al. 2024), regardless of whether that is for eradication or suppression. Regardless of the strategy (eradication or suppression), pest management practices need to be performed in a way that contributes to the protection of the resource. Pest management will only result in significant ecological benefits if the biology of the target animals is understood, resource protection objectives are defined, and effective and efficient control measures are applied to achieve those objectives (Holloway 1993). Anything less will just see the endless killing of pests for no biodiversity gain because: (1) non-targeted pests may also need to be controlled; (2) target pest populations are not reduced enough; or (3) recovery of Indigenous species and ecosystems is limited by factors other than pests, such as habitat availability (Innes et al. 2024).

The change in meaning away from resource protection to one of dead pests has implications for achieving the biodiversity outcomes stated in Te Mana o te Taiao – Aotearoa New Zealand Biodiversity Strategy 2020 (Department of Conservation 2020b, 2022b). The misconception ‘that every dead pest is a good pest’ assumes that any level of pest management results in positive biodiversity outcomes (Leathwick and Byrom 2023). This implicitly assumes a linear density-impact function. In other words, the impact on a valued resource and the density of a pest, changes in a consistent and incremental way (Yokomizo et al. 2009; Norbury et al. 2015). However, as Norbury et al. (2015) highlight, most pest density-impact functions from Aotearoa are non-linear. This means that the damage threshold (the point where the pest population causes unacceptable injury or harm to the valued resource) is not just density dependent, and may occur at any density, depending on multiple variables (e.g. spatial or temporal variability). Non-linear density-impact functions will see little return for effort until pest densities are reduced below a threshold level, otherwise money is wasted on ineffective management (Yokomizo et al. 2009).

Government agencies, in particular DOC as the lead agency for PF2050, have a critical role to play in normalising desirable practices. Igalla et al. (2020) argue that the performance of community-based initiatives is positively related to government support. As such, agencies have a pivotal role to play in how community groups are engaging with pest management, through the provision of strong leadership, logistics, tools and guidance (Leathwick and Byrom 2023) that identify, reinforce, and support the desired practice-as-performance. As Peters et al. (2015, pp. 186–187) note, ‘[t]he need for training (e.g. pest and weed control, outcome monitoring, group and volunteer management) forms a common thread through studies of community environmental groups in New Zealand’. Generating more desirable practices that overcome the inertia or persistence of existing undesirable norms requires the challenging and breaking of certain links and elements, which then need to be replaced and re-made to ensure the desired practice is sustained (Hargreaves 2011). There is a multiplicity of ways that this can be done, and while the full range of ways in which government agencies can do this is beyond the scope of this paper, SPT does provide the means of identifying effective intervention strategies to help government agencies accomplish this replacing/remaking process.

One approach is through re-crafting practices (Shove et al. 2012; Spurling et al. 2013). Re-crafting entails changing the elements that make up a practice by encouraging more sustainable variants of that practice. This approach uses intervention strategies such as information or education campaigns but looks at it systematically across the three elements (Spurling et al. 2013). Re-crafting focuses on phasing out or changing elements of unsustainable or undesirable practices with the aim of shifting the practice towards more desirable forms of performance. The practice of not having traps set all the time is an example of where elements can be re-crafted. Changes could be made to the competencies through improved training of volunteers, improved materials and through improved management of volunteers, to reinforce the importance of desirable volunteer practices. Development of training standards, audit, and compliance are roles that government agencies could potentially take.

While deficiencies in knowledge (competencies) can be addressed through re-crafting strategies such as information or education campaigns, our interviews highlighted that the comprehension, retention, and knowledge of these campaigns are highly variable, which supports findings in existing literature (e.g. O’Neill and Bardrick 2017). Therefore, the impact of these campaigns will be limited unless they also translate into an increase in motivation (meanings) towards best practice (Kaine et al. 2024). This highlights the importance of looking systematically across all three elements (meanings, competencies, and materials) and their interactions, when seeking to re-craft the performance of a practice.

A second approach is substituting practices (Spurling et al. 2013), i.e. replacing current practice with alternatives. For example, substituting practices may be effective when homeowners have unfavourable attitudes towards rats but for various reasons, are unable to devote sufficient personal time, effort, and resources to consistently trap to an appropriate standard. For example, having a trained and dedicated cadre of people manage rat trapping on private properties, as part of a wider neighbourhood program, may be an effective substitute practice. The advantage of this approach is that the different variations of the practice that currently exist across the community can be substituted with a desired, standardised version. There are economic costs associated with this approach, which is often an issue for volunteer groups (Peters et al. 2015). Holloway (1993, p. 287) notes that ‘sufficient funding is a necessary precondition for any control programme’ and that management programs should not be initiated if those funds cannot be reasonably guaranteed. Ensuring those groups undertaking control are adequately funded to meet the required practice-as-performance levels, both for on ground works and project administration, is a potential role for government agencies. If funding is an issue for volunteer groups (Peters et al. 2015) and agencies cannot reasonably guarantee those funds, then questions should be raised as to whether using volunteers is the right approach to achieve the PF2050 outcomes.

A third approach is to look at how practices interlock with each other and how interventions focused on those connections can cause change to ripple through those interconnected practices (Watson 2012; Spurling et al. 2013). For example, a primary motivation to reduce rat populations was due to their unfavourable impact on biodiversity. Policy interventions aimed at encouraging people to become involved in outcome monitoring can flow into trapping rats if people see the biodiversity benefits of sustaining that practice. Despite outcome monitoring being a key component to good pest management practice (Holloway 1993), outcome monitoring is lacking from many projects conducted under the umbrella of PF2050 (Leathwick and Byrom 2023; Innes et al. 2024). Promoting and supporting outcome monitoring by government agencies could help provide motivation to continue good trapping practice and encourage those not currently involved to begin trapping.

There is a place for all three of these policy intervention strategies in improving the pest management practice-as-performance levels for projects being conducted under the umbrella of PF2050. Failure to address the current variations in practice-as performance, and the norms that these variations are reinforcing (i.e. a focus on dead pests over resource protection), will compromise PF2050’s goal of eradicating mustelids, rats and possums from all of Aotearoa New Zealand by 2050.

Conclusion

While it is important to understand what motivates people to engage with PF2050, how they are engaging is just as critical to its success, and ultimately, the success of achieving the national biodiversity goals outlined in Te Mana o te Taiao. In this research we used SPT to look beyond what motivates people to engage with PF2050, to how they are performing the pest management practices associated with this initiative. Our research highlights the importance of looking systematically across all three elements (meanings, competencies, and materials) when considering the performance of a practice, such as the trapping of rats.

While environmental volunteers have achieved, and will continue to achieve, outstanding conservation work in Aotearoa, the recent mobilisation of large numbers of people to voluntarily engage in pest management is not meeting the recognised practice-as-performance standards needed for the protection and restoration of Aotearoa’s biodiversity. Furthermore, current practice-as-performance is reinforcing and normalising a focus on dead pests over resource protection. Achieving Aotearoa’s national biodiversity goals will require the generation of more desirable pest management practices that reinforce and normalise resource protection. Government agencies, in particular DOC as the lead agency for PF2050, have a critical role to play here.

Supplementary material

Supplementary material is available online.