Multi-stakeholder working groups to improve rodent management outcomes in agricultural systems

Abstract

Rodent pests pose significant impacts to agricultural systems and public health globally. Effective strategies for sustainable management while minimizing environmental impacts are crucial. To address the multifaceted nature of rodent impacts, well-coordinated initiatives are necessary to support control strategies, raise awareness among authorities, and inform the public. There is increasing global evidence of Working Groups delivering successful management of a range of natural resource management issues. We outline three case study working groups to tackle rodent pests: (1) National Mouse Group in Australia to manage mouse plague impacts, (2) Working Group Common Vole Management in Germany to manage common vole impacts, and (3) FREDON network for vole management in France. Each working group evolved independently, but all have remarkably similar structures, including monitoring, modelling/forecasting, regular stakeholder meetings (including producers, researchers, government agency staff and others), developing advice for management and identifying research priorities. The success of these working groups was related to: (1) broad stakeholder engagement (particularly farmers/producers), (2) dedicated funding to conduct direct research to inform control strategies, (3) maintained momentum through all phases of rodent population cycles, and (4) benefit for all stakeholders. As rodenticides are increasingly restricted, such working groups will become more important in the future, because stakeholder engagement is necessary to develop rodent management “toolboxes”.

Keywords:

• Damage
• house mice
• impacts
• outbreaks
• stakeholders
• voles

Introduction

Rodents are the most diverse mammal group in the world, with an estimated 2,277 species (Carleton & Musser, 2005), and are keystone species or ecosystem engineers in most of the ecosystems in which they are found (Delibes-Mateos et al., 2011). However, the populations of some species have global impacts and cause damage in all countries where arable crops are grown (particularly in simplified ecosystems such as agroecosystems, but also in more diversified urban systems). Such populations can infect humans and livestock with pathogens, cause structural damage and spoilage and have significant negative impacts on those ecosystems (Capizzi et al., 2014; Harris, 2009; Jacob et al., 2020; Jacob & Tkadlec, 2010; John, 2014; Meerburg et al., 2009a; 2009b; Singleton et al., 2010). In addition, invasive rodents can cause serious negative effects on native flora and fauna. Worldwide, the economic impact of invasive rodents has been estimated at US$3.6 billion annually (Diagne et al., 2023), and is increasing over time. Pre-harvest crop losses are reasonably well studied, with most losses around 5–15%, but can be up to 100% in some situations (Brown, Douangboupha et al., 2017; John, 2014; Singleton et al., 2010). This is particularly important because cereal production has to increase globally by 50-70% in order to meet the growing population and enable household and national food security (FAO, 2022), with climate change further exacerbating the problem (van Dijk et al., 2021). The people most affected by rodents include farmers, households and vulnerable people in both developed and developing countries (Meerburg et al., 2009b), especially when rodent outbreaks or disease outbreaks occur (Jacob et al., 2020). Many rodent species are the carriers of pathogens of human diseases such as the plague, hantavirus diseases, leptospirosis, rat-borne typhus and arenavirus infections (Meerburg et al., 2009a; Mills, 1999; Tangkanakul et al., 2005), with rodent-related diseases in humans costing billions of dollars worldwide (Budke et al., 2006; Carabin et al., 2005). For effective management, understanding when and where rodents will be a problem is critical, as well as having effective strategies for sustainable control avoiding unintended effects on non-targeted populations and other deleterious effects on the ecosystems (Giraudoux, 2022). Because of the multi-faceted nature of rodent impacts, there are calls for well-coordinated initiatives to support control strategies, to raise awareness among the public and authorities, and involve a range of stakeholders (Colombe et al., 2019; Scobie et al., 2023).

A strategy that was employed in Australia in the 1980s to manage the impacts of mouse plagues, was to use the PICA strategy (Redhead & Singleton, 1988b) – a four-step strategy encompassing: (1) Prediction of the mouse plague, (2) Informing governments, farmers and other managers, (3) Control using a tactical, prophylactic approach to prevent mouse abundance from reaching plague proportions; and (4) Assessing the effectiveness of the control operation (Redhead & Singleton, 1988b). While this approach was well founded, it has not been followed largely because there was no central agency responsible for coordinating all the different elements, nor any empowerment of a formal group to oversee a response. Therefore, management of large-scale rodent outbreaks often remains ad hoc, leading to delayed management after damage has already occurred leading to poor benefit-cost outcomes (Redhead & Singleton, 1988a) (although, see below).

A critical component for the management of pests is to engage with a range of people (likely with different views and attitudes and different roles and responsibilities), because it is people that decide what is a “pest” and community engagement is key (Braysher, 2017). One way to engage with people and affected communities is through “working groups” or “multi-stakeholder platforms”. These have been created and used to manage a range of pest and natural resource management problems, including environmental management problems in Australia (Hajkowicz, 2008), water reforms in Bolivia and South Africa (Faysse, 2006), pest species in South Africa (Davies et al., 2020), and for conservation of pangolins in Singapore (Nash et al., 2020). Common across many of these groups is the desire to link research with policy and management implementation, but there is also a strong need to ensure that stakeholders are engaged and work for co-production of knowledge that is meaningful and accessible to a broad range of stakeholders (Davies et al., 2020). In many cases, the coordination of applied research seems to occur with little input from stakeholders in terms of detailed research questions and rarely includes stakeholder feedback in the process of research. If conducted at all the approach is usually conducted informally and intuitively without a formal process. Conversely, often there are agreed strategies used to disseminate knowledge generated to stakeholders.

We are therefore interested in determining how such working groups have informed improved management outcomes for rodent pests. As such, the purpose of this paper is to describe the path to establishment and the importance of these multi-stakeholder working groups in the management of a range of rodent pests, through case studies in Australia, Germany and France, and consider their limitations. We frame this review in the hope that there might be valuable lessons for others to follow and build on.

The need for coordination and stakeholder engagement

Farmers and people in urban, semi-urban and rural environments bear the brunt of rodent impacts through damage to crops, and disease transfer to humans causing health problems (Caughley et al., 1994; Meerburg et al., 2009b). However, to minimise these impacts, input is required from a range of critical stakeholders. Stakeholders have been defined as “Anyone who has an interest in an issue, whether that interest is financial, moral, legal, personal, community-based, direct or indirect” (Aslin & Brown, 2004). In the context of managing rodent pests in agriculture to reduce crop damage and disease impacts, relevant stakeholders would include government, farmers and other managers (Redhead & Singleton, 1988b), but could include regulators, industry bodies, health departments, environmentalists, animal welfare groups etc. Stakeholders were identified as key to facilitating participatory approaches in managing rodent pests in Madagascar, with interests identified around the dimensions of people, resources, knowledge and power (Scobie et al., 2023).

Multi-stakeholder platforms have been defined as: “[D]ecision-making bodies (voluntary or statutory) comprising different stakeholders who perceive the same resource management problem, realise their interdependence for solving it, and come together to agree on action strategies for solving the problem” (Steins & Edwards, 1999). Faysse (2006) suggests the objective of multi-stakeholder platforms is “To enable the empowered and active participation of stakeholders in the search for solutions to a common problem.” Multi-stakeholder working groups can deal with specific or cross-cutting issues (Davies et al., 2020), however there is often a “knowing-doing gap”, thus the need for ongoing engagement with researchers including social scientists to understand how to bridge this gap.

Multi-stakeholder groups have been created for a variety of reasons. They have been established to help support 48 stakeholders with decisions for environmental management problems in Queensland, Australia (Hajkowicz, 2008), where they used multiple criteria analysis (MCA) to provide a framework for a transparent and informative decision process. Faysse (2006) reported on the establishment of multi-stakeholder platforms dealing with water reforms in Bolivia and conflicts over water and sanitation projects in South Africa, and where some were more successful than others. Faysse (2006) identified some issues that governed the success of multi-stakeholder platforms as: (1) power relationships, (2) platform composition, (3) stakeholder representation and capacity to participate meaningfully in the debates, (4) decision-making power and mechanisms, and (5) cost of setting up a multi-stakeholder platform. In countries where an enabling environment supports these multi-stakeholder platforms, it is more likely they will be successful. Davies et al. (2020) reported on the formation and continuation of a working group established to provide science and evidence-based decision-making support to the management of alien species in the Cape region of South Africa. The key issues identified were: enabling continuous, long-term or time-bound funding, importance of stakeholder identification and engagement should be conducted early, importance of ethical and animal welfare factors in design phases of projects, and ensuring stability of working group membership (organisational and individual). A successful working group must have benefits for all parties involved. The Singapore Pangolin Working Group (SPWG) was established in 2014 to advise on research and conservation, engage with developers and policy makers, and raise public awareness of pangolins and the threats they face in Singapore (Nash et al., 2020). The SPWG forged strong relationships with a diverse range of stakeholders and developed a robust population estimate for pangolins in Singapore through standardisation of methods and data sharing. The SPWG co-hosted the development of a Conservation Strategy and Action Plan for Pangolins, and enabled a move away from short-term projects to larger-scale, multi-stakeholder projects. The success of the SPWG was attributed to the good morale among stakeholders and having a diverse team to motivate stakeholders and other people (Nash et al., 2020). Coordinated management is therefore required to bring together a range of diverse stakeholders to guide relevant management strategies to address specific problems. Multi-stakeholder platforms have been borne out of an adaptive management paradigm, which is an approach for simultaneously managing and learning about natural resources, or through “learning by doing” and by involving stakeholders (Walters & Holling, 1990; Williams, 2011).

Case studies

The National Mouse Group to manage mouse plagues in Australia

Mouse plagues are a unique feature of Australian cropping systems. House mice (Mus musculus L.) were introduced to Australia by early European explorers and settlers, and have taken advantage of the highly modified agricultural systems (Redhead et al., 1991). Mouse plagues have occurred in Australia since the early 1900s, and occur roughly every 4 years (Singleton et al., 2005). When mouse numbers are moderate to high in grain cropping systems, farmers need to undertake control measures to reduce crop damage, especially when densities exceed 200 mice/ha (Brown et al., 2007), but mouse densities can exceed well over 1,000 mice/ha (Singleton et al., 2005). A recent mouse plague in New South Wales in 2021 was estimated to cause AUD$1 billion in damage (NSW Farmers, 2021), with losses from the 1993 mouse plague being conservatively estimated at AUD$64.5 million (Caughley et al., 1994). Despite attempts at developing a range of best farm management practices to reduce damage (Brown et al., 2004), farmers tend to rely solely on the application of rodenticides, but with variable effectiveness (50-95% efficacy in reducing mouse abundance) (Brown, 2006; Brown et al., 2002; Mutze & Sinclair, 2004; Twigg et al., 2002).

In Australia, the house mouse is considered exotic/introduced species, however, there is no state or federal government legislation requiring that landholders control mice (unlike for other declared pests where all land owners are legally required to manage pest animals on their land, including European red fox, European rabbits, wild dogs, feral pigs, etc). For example, in South Australia, rural landholders “Are responsible for the control of mice on their land as part of their normal management practices, including paddock hygiene measures to minimize build-up of mouse populations” (https://pir.sa.gov.au/__data/assets/pdf_file/0016/232045/declared-animal-policy-house-mouse.pdf).

In Australia, most funding for mouse plague research has been provided by the Grains Research and Development Corporation (GRDC), the purpose of which is “To invest in research, development and extension to create enduring profitability for Australian grain growers” (https://rdeplan.grdc.com.au/strategic-investment). Funds for research come from levies paid by grain growers and contributions made by the Australian Government.

At the end of the Millennium drought (from 2001 to 2009; https://www.environment.sa.gov.au/topics/river-murray/current-dry-conditions/millennium-drought), there was a large and widespread mouse plague that resulted in high mouse numbers over much of the grain-growing regions of southeastern Australia in 2010/11. The increase in mouse activity led to calls to develop a South Australian Mouse Working Party in June 2011, with the group officially formed in August 2012 (https://www.abc.net.au/news/2010-06-25/mouse-plague-policy-issues-under-review/880962). This was further refined to establish a National Mouse Management Working Group (NMMWG) to help coordinate mouse monitoring and management strategies, so that the grain growers and the grain industry could be better prepared and aware of impending mouse damage issues ahead of future mouse plagues. It was also important to better understand and promote mouse management practices to counter the threat posed by mice. This group was initially coordinated through the Invasive Animals Cooperative Research Centre, who engaged Landcare Research (in New Zealand) because of their expertise in ecology and knowledge of the mouse forecast models. CSIRO took over the coordination of the NMMWG in 2018 (as part of a GRDC-funded project on “Improved surveillance and management options for mice in crops”). The initial NMMWG was established with some farmer representation and state government agencies but driven by Grain Producers Australia (a national farmer advocacy group). The NMMWG grew and evolved, such that in 2020, it was re-named the National Mouse Group (NMG).

The Terms of Reference for the NMG are provided in Appendix 1. In essence, the key attributes of the NMG are:

• Membership: consisting of

  • Chair(farmer representative),

  • Secretary (to assist with organising meeting and minutes),

  • Rodent ecologist representatives from research institution (CSIRO),

  • State and federal government agency staff relevant to the management of mouse plagues and pesticide registration, and

  • Producer representatives (at least two farmers per state, who receive sitting fees).

• Regular meetings: hold regular teleconferences and face-to-face meetings (3x a year)

• Main discussion points:

  • Current mouse situation across five states (Western Australia, South Australia, Victoria, New South Wales and Queensland),

  • Agree on key management strategies and communication, and

  • Identify future research priorities for mice.

The timing of the NMG teleconferences is linked to the monitoring that is undertaken by CSIRO (Brown et al., 2022), collaborators and anecdotal observations by state government representatives and farmers. Based on these observations, outputs from forecast models (Kenney et al., 2003; Pech et al., 1999) and feedback from the NMG, Mouse Updates are prepared and sent out to an email distribution list, posted on various websites (e.g. https://research.csiro.au/rm/mouse-activity-updates/) and form the basis of media releases. The aim is to provide timely advice to Australian grain growers about the current mouse situation (low, medium or high), and relevant management practices depending on the main crop stage.

One specific example of the benefit of the NMG has been to solve problems with zinc phosphide (ZnP) rodenticide baits. ZnP is coated on wheat grains (25 g ZnP/kg bait) and is distributed by ground-based spreaders on farm vehicles or aerially applied at the label rate of 1 kg/ha (the label contains approved directions for use). It is the only registered product available for broadacre use in Australia to protect crops from rodent damage. Label conditions include: that bait is not applied to bare ground; there is a buffer area of 50 m around the edge of crops and native vegetation to reduce risk to birds/non-target animals; and that monitoring confirms sufficient mouse numbers for the potential for crop damage. Many reports were received and discussed by the NMG that the registered ZnP baits were not performing satisfactorily (baits worked in some situations, but not others). Through the NMG, and with support from GRDC, CSIRO embarked on a series of studies to understand issues around acceptability of bait substrate and behavioural issues (Henry et al., 2022), amount of toxin on the bait (Hinds et al., 2023), along with a field evaluation (Ruscoe et al., 2022) of a revised ZnP bait. Additional work also determined the significant role that background food plays in mortality (Brown et al., 2024). Throughout this period, the research work was incrementally presented and endorsed by the NMG. Through this research, a new strength of zinc phosphide bait (50 g ZnP/kg bait) was developed and received Emergency Permit status during the mouse plague that affected the state of New South Wales in 2021, and was found to provide far superior efficacy than the original approved rate of 25 g/kg bait (label rate) (Ruscoe et al., 2022).

Another major outcome is that there is now a whole industry approach to managing mice as it brings together all the disparate parts for a united approach to the problem to identify and fill research gaps to improve management outcomes for farmers. There is strong interest in keeping the NMG going, because it enables communication and coordination more than direct management success, but it is dependent on continuity of funding to enable central coordination and support for a Secretariat.

The Working Group Common Vole Management in Germany

Common voles (Microtus arvalis) are the most abundant mammals in Europe (Mitchell-Jones et al., 1999). They provide important ecosystem services but are a highly relevant pest species during population outbreaks that occur about every 3-5 years (Cornulier et al., 2013). These outbreaks can be largely synchronised across Europe (Jacob et al., 2020) and can result in several thousand individuals per ha, up to a maximum of 10,000 voles per ha (estimated from counts of active tunnel entrances, S. Krüssel pers. comm.). During outbreaks, damage to crops is massive, causing financial losses of up to €450/ha (Lauenstein & Barten, 2011), and requiring treatment of 300,000 ha with rodenticides (Barten, 2009). This option leads to >€120 million pre-harvest losses in Germany alone, while there is spoilage, destruction of infrastructure and machinery (Jacob et al., 2014) as well as the risk of transmission of pathogens from common voles to humans and livestock (Jeske et al., 2019; 2021). In addition, there can be conservation issues when voles predate nests of endangered ground-nesting birds (Bures, 1997), and, as predator populations thrive for a period during common vole outbreaks, they may subsequently seek alternative prey, potentially targeting animal species of high conservation importance once the common vole population declines (Panek, 2009).

The underlying mechanisms that regulate common vole population dynamics are not well understood (Andreassen et al., 2021; Cornulier et al., 2013). It seems likely that there is no single driver. Landscape parameters and weather conditions are related to general outbreak risk (Blank et al., 2011; Imholt et al., 2011). The latter was used to develop a forecast system to predict outbreak risk of central German common vole populations (Esther et al., 2014).

Management of common voles in Germany and in other countries of the European Union (EU) relies on the use of ZnP. The substance is approved under Regulation (EC) Number 1107/2009 (https://food.ec.europa.eu/plants/pesticides/eu-pesticides-database_en) in the EU and there are multiple national product authorisations. In some countries, restrictions imposed by national authorities on the use of ZnP have led to a situation where it is impossible to apply ZnP in many regions regularly affected by common vole outbreaks (Jacob et al., 2020). In Germany, there are three options for ZnP bait application in agriculture: (1) application in tunnel entrances with a commercially available applicator gun, (2) application with a machine that creates an artificial tunnel and places bait at the required rate directly in the tunnel – with machinery that is certified by the Federal Government, and (3) bait boxes. In all cases no bait is allowed to be present at the surface, the maximum application rate of ZnP bait is 2 kg/ha and bait can be applied once a year. Presently, six products are registered with ZnP concentrations of 0.08 or 2.5% (https://apps2.bvl.bund.de/psm/jsp/index.jsp?modul=form).

Products can only be applied when:

• it was demonstrated and documented that the infestation justifies rodenticide use

• dead and dying voles are removed

• prior to application in Natura 2000 sites (flora and fauna habitat sites, bird protection areas; https://ec.europa.eu/environment/nature/natura2000/index_en.htm) it is documented that it is guaranteed that the protection goal of relevant elements of the site is not considerably negatively affected

• it is checked daily for three days and documented before application that the site is not used for resting by migratory birds (goose species, cranes).

Products cannot be applied between 1 March and 31 October if there is recent verified occurrence of common hamster (Cricetus cricetus), northern birch mouse (Sicista betulina), or hazel dormouse (Muscardinus avellanarius) in a radius of 25 m around trees, woods or hedges.

Alternatives to the use of ZnP are rare and mostly restricted to small-scale crops such as vegetables (carrots) and fruit trees (Leukers et al., 2014). They include the use of barriers, trapping, wire netting around root ball when young trees are planted, repellents and diversionary feeding. Generally, these methods are conditionally effective, sometimes lack practicability and may not always be environmentally safe. Bio-control via the promotion of terrestrial and especially avian predators has been discussed extensively as a means to manage pest rodents (Luna et al., 2020; Mougeot et al., 2019). However, there is very little evidence that this approach is successful in reducing plant damage, let al.one increasing yield (Labuschagne et al., 2016).

For large-scale field rodent management, agro-technical measures such as ploughing, extended fallow periods and swift removal of stubble are suitable tools. In particular circumstances, flooding fields is possible and effective (Jacob, 2003). These methods as well as keeping short vegetation at field margins and burning fields are in conflict with strategies to conserve soil, water retention and biodiversity (García-Orenes et al., 2009). New concepts such as fertility control (Jacoblinnert et al., 2022; Massei et al., 2023) and gene drive (Campbell et al., 2019; Grunwald et al., 2022) are interesting concepts but far from having demonstrated effectiveness or having gained regulatory approval. Fertility control products to manage overabundant rodent populations are available in China, Tanzania and the USA (Massei et al., 2023), but there are no registered products available in the EU.

After a massive outbreak in Germany in 2012 (Jacob et al., 2014), the German Federal Ministry of Agriculture through its institutional research facility Julius Kühn-Institut (JKI; Federal Research Centre for Cultivated Plants) founded the Working Group Common Vole Management (WGCVM). It presently consists of representatives of the plant protection agencies of 13 Federal States (not included are the three States that are cities: Berlin, Bremen, Hamburg). Additional members are from the Federal Ministry of Food and Agriculture; the Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection; the Federal Office of Consumer Protection and Food Safety and the Federal Institute for Risk Assessment. Institutional representatives (authorities, academia, industry, NGOs) and individuals including farmer representatives are invited to participate in the annual/biannual meetings as required.

The WGCVM is primarily a body for coordination between Federal and State Agencies on common vole management and the development of sustainable management techniques. Population management and damage prevention are taken into account as well as the overall context of the protection of crops, environment, livestock, and health in the context of common vole activity. Furthermore, the group serves to discuss urgent research questions and occasionally publishes general positions (Götz & Wolff, 2015) and group activities (Jacob et al., 2018).

Through the group, a harmonised system for monitoring common voles in relevant crops was developed and data were exchanged. Damage is evaluated on the basis of current economic condition for cost-benefit analyses, damage thresholds and control thresholds regarding integrated crop protection. The group coordinates research questions and formulates common goals such as long-term monitoring and large-scale population management. Results are centrally collated and distributed to stakeholders. The latter is primarily done by the plant protection agencies as their extension staff are closely linked to farmers and farmer associations.

Procedures for alternative and chemical management measures are coordinated and exemptions for management measures on cultivated land (tillage, crop rotation, etc) or management measures on adjacent non-cultivated land are exchanged. Optimising the application of rodenticides is discussed and if necessary, the applications for emergency permits are jointly prepared for submission.

Recent results of the activities of the WGCVM include the listing/registration of the device that creates and baits artificial tunnels mentioned above. This is the only means of a mechanised bait application in Germany and has been readily adopted by farmers. In addition, several restrictions for the use of ZnP have been amended and clarified with the relevant authorities leading to officially updated versions. The updated versions are now well defined for practitioners and a more harmonised approach to the translation into practice among states was accomplished.

The political and public interest in common vole associated problems fluctuates as much as the common vole outbreaks themselves. In outbreak years or shortly after, tax funded research programs are granted with the usual project duration of 2-3 years. During that time population abundance of voles is often low, which makes it difficult to conduct studies. Long-term funding, be it for monitoring or research, is needed to achieve a more sustainable approach that considers the multi-annual nature of the problem. The lack of such funding has led to abandoning regular systematic updates of forecasts of common vole outbreak risk.

The WGCVM does not receive any dedicated funding for monitoring, research or its members whose duties go far beyond common vole related topics. However, within 10 years, the WGCVM has developed into an important instrument for authorities, research institutions and farmers to jointly strive for a science-founded, minimally invasive and more sustainable common vole management.

FREDON network for vole management in France

In Metropolitan France, three vole species are pests on farmland during population outbreaks. The common vole, Microtus arvalis, exhibits various population dynamic patterns. Although multiannual trends and sometimes population peaks can be synchronized on a continental scale (Jacob et al., 2020), cycle durations and amplitudes can vary according to landscape composition and structure (Delattre et al., 1992; 1999) and populations can even be non-cyclic (Giraudoux et al., 2019). The importance of damage has not been evaluated for the country, but depending on the crop considered, can be devastating as in Central Europe (Jacob & Tkadlec, 2010). The montane water vole, Arvicola amphibius (Chevret et al., 2020), causes severe damage to orchards and to permanent grasslands of mid-altitude mountains specialized in milk production (Giraudoux, 2022). In the Jura Massif for the latter, the costs were estimated between €9,000-25,000 for a 70 ha farm in a year of population peak (Schouwey et al., 2014). There, populations have 5-7 year cycles and spread in travelling waves over large areas of thousands of square kilometres (Berthier et al., 2014). The Mediterranean pine vole, Microtus duodecimcostatus, is limited to the southern part of the country. Damage occurs mostly in orchard, vegetables, seed crops, etc. In young orchards (1-7 years) debarking and root consumption can cause 5-12% of total losses (€500-1500/ha, not including replanting labour and subsequent delay in setting up a productive orchard). In older orchards, the reduction in yield due to the weakening of the trees can reach 40% of the orchard's yield potential, hence a loss between €7,500 and €10,000/ha/year (Sevely, 2016).

The management of those three species in France is regulated under the European law, with a national list specific in the Code rural et de la pêche maritime where they are listed as species “for which it may be necessary, in the public interest, to implement preventive, monitoring or control measures”. This permits the Ministry of Agriculture and Food to recognize action plans prepared by technical NGOs called Organisme à vocation sanitaire pour le végétal, OVS (Plant Protection Organization) in each region (administrative division of 8,700-84,000 km²)

With regard to voles, regional FREDONs (FREDON Bourgogne Franche-Comté, FREDON Rhônes-Alpes, etc; https://fredon.fr/), which are actually technical associations of farmers, are attributed the OVS label under legal terms of reference (including impartiality) for 5 years and are in charge of organizing surveillance, prevention and control, and to advise their regional subunits called Groupements de défense (Defence collective) and to coordinate actions. Each Groupement de défense, a farmer group, can cover at the minimum a commune (administrative unit of some tens of km²) or more frequently a canton or even larger (cluster of several communes up to some hundreds of km²). Regional FREDONs are federated in FREDON France, a national association with a national specialist for “vertebrate pests” coordinating the network.

Each action plan, here called Programme d'action régional campagnols, PARC (vole regional action plan) is presented for discussion to the Conseil régional d'orientation de la politique sanitaire animale et végétale (CROPSAV, Regional council for the orientation of the animal and plant sanitary policy), a committee chaired by the Regional Prefect who is the validation authority. The committee includes the prefects of the departments within the region, representatives of territorial authorities, the regional health agency, recognised agricultural and veterinary organisations, hunting associations and approved analysis laboratories. For instance, the PARC in Bourgogne Franche-Comté organises vole control by permanent monitoring of vole populations, by training and advising farmers with a particular attention on non-intentional effects on non-target fauna, by informing about the actions undertaken, by validating actions and evaluating and taking stock of experiences.

Following the banning of bromadiolone (an anticoagulant rodenticide) from January 2021 (Marketing Authority 9800525 was withdrawn by ANSES France), vole control, as everywhere else in the European Union, largely relies on the use of ZnP. Poisoned baits must be delivered in natural or artificial galleries underground or in bait stations (Table 1) exclusively, “in order to protect birds and wild mammals” (e.g. AMM n°2170698: https://ephy.anses.fr/ppp/ratron-gw).

Table 1. Zinc phosphide (ZnP) preparation types and usage limitations in France (each category corresponds to one or several registered trademarks).

		Maximum quantity/year
Bait type	ZnP concentration	Burrow	Bait station
Wheat bait	25 g/kg	2 kg/ha	–
Artificial lens bait	8 g/kg	2 kg/ha	2.5 kg/ha
Stick bait	8 g/kg	5 kg/ha	–

However, it is largely acknowledged that chemical control, as any lethal control alone does not result in long-term control of vole populations (Hein & Jacob, 2019). PARCs strongly encourage regional surveillance of vole populations and early control at low population density based on a set of tools (toolbox; a set of interventions that vary over time and adaptive, depending on vole population dynamics, Figure 1) including mole control (aluminium phosphide or trapping) for the montane water vole (Delattre et al., 2006), targeted ploughing and crop rotation, plant cover management, alternating mowing/grazing, favouring predation (hedges, perches, etc) etc. (Delattre & Giraudoux, 2005; 2009; Michelin et al., 2014). By law, on a national level, it includes a population density threshold as measured by activity index transects (Giraudoux et al., 1995; Quéré et al., 2000) above which chemical control is forbidden to minimize non-intentional effects on non-target fauna (Légifrance, 2014). Although this restriction was designed when anticoagulants were used, the same process applies with the use of ZnP to protect nontarget fauna and encourage early control. Regional surveillance is organized by FREDONs and, for instance in Bourgogne Franche-Comté, warnings and recommendations to farmers are delivered through a quarterly Bulletin de santé du végétal (Plant Health bulletin). The general strategy for control has been largely inspired at national level by research carried out with stakeholders in the 1990s-2000s about the control of montane water vole populations (Figure 1). Collaboration between FREDONs and researchers has been (and still is) strongly encouraged by the Ministry of Agriculture and Food (Giraudoux, 2022) however it can vary between regions according to the availability of human resources and funding. For instance, the national specialist of FREDON France is also staff of the FREDON Bourgogne Franche-Comté. Since 2013, he has a part-time delegation at the Chrono-environment research lab of the University of Franche-Comté/CNRS which assists with updating and distributing scientific papers, common research programmes, and stakeholder feedback. This strong structural permeability between research and technical bodies has led to increased collaboration with other stakeholders such as naturalists and hunters for specific issues (https://zaaj.univ-fcomte.fr/spip.php?article115&lang=en) (Figure 2), and to publish a large number of scientific and technical articles and media co-authored between stakeholders (Giraudoux, 2022; Giraudoux et al., 2017).

Figure 1. Example of control strategy carried out by farmer collectives (Groupements de défense) for the montane water vole in grassland (after Couval & Truchetet, 2014). Early surveillance at low population density is promoted and a set of actions can be carried out below a density threshold above which chemical control is prohibited to prevent secondary poisoning of vole predators (Coeurdassier et al., 2014) and encourage early control. Surveillance, early intervention, toolbox providing tools that can be adapted to local contexts are general principles applied also for other species as recommended by law, even after the prohibition of anticoagulant rodenticides in plant protection since December 2020 (Légifrance, 2014). Grass refusal cutting refers to mowing clumps of grass that cattle have refused to eat and therefore provide refuges for vole colonies.

Figure 2. Research and subsequent control strategies (here in Franche-Comté) involve multiple stakeholders at various levels (after Giraudoux, 2022).

On a national level, annual consultation between stakeholders (FREDONs, researchers, administrations, etc) is organized additionally by Végéphyl (https://www.vegephyl.fr), a NGO whose aim is to “bring together all those involved in plant health, to encourage exchanges between them and to share experience and to help improve plant protection”.

General discussion

There is increasing evidence of the usefulness of using Working Groups to manage a range of natural resource management issues. These approaches have proven effective in tackling environmental issues in Australia (Hajkowicz, 2008), implementing water reforms in Bolivia and South Africa (Faysse, 2006), combatting pest species in South Africa (Davies et al., 2020), and safeguarding pangolin populations in Singapore (Nash et al., 2020). Through the three case studies, this paper has demonstrated that Working Groups can provide an important process for enabling a range of input from stakeholders to reduce the multi-faceted impacts of rodents, and that it is possible to move beyond local-scale issues to effectively function at a national level.

These Working Groups have come a long way from the strategies envisioned in the 1980s to manage mouse plagues in Australia (Redhead & Singleton, 1988a; 1988b). Firstly, broad stakeholder engagement has been pivotal in driving the success of these Working Groups, by involving experts, government agencies, and local communities to gain a diverse range of perspectives and expertise to address the challenges posed by rodent outbreaks. Secondly, dedicated funding has been instrumental in facilitating the implementation of effective measures to combat rodent population outbreaks. Adequate financial resources are needed to allow the Working Groups to function and to assist with directing research and promoting well-founded control methods. Moreover, the formal establishment of these Working Groups has proven crucial in maintaining momentum. Unlike the past approach of only addressing the issue during peak rodent phases, the formal Working Group can help to ensure ongoing efforts and coordinated actions especially during the low-density phase when preventive and early control measures are essential. Working Groups also enhance communication between farmers and scientists enabling effective identification of key issues.

It is currently impossible to measure the economic benefit of these Working Groups. One key issue is that damage is high when outbreaks occur. Outbreaks cannot be entirely prevented because they are widespread and all farmers can do is minimise damage as best they can. The benefit of these Working Groups is that farmers and industry are better prepared to undertake early management at scale (using appropriate tools/toolboxes) rather than having an ad hoc approach (or after damage has occurred, as described by Redhead and Singleton (1988a)). Another key issue is that the economic impact of outbreaks is borne “pre-farm gate”, and because outbreaks occur when crop yields are high (i.e. in good years because mice are responding to favourable conditions) (Singleton et al., 2005), the impact does not show up in secondary statistics (national grain production statistics etc). Research is required to gain more insights into the economic impacts of these outbreaks and the benefits of these Working Groups. However, Giraudoux et al. (2017), comparing the area where a working group is active with the surroundings where farmers have a non-collective approach to control, show a clear effect on dampening population density fluctuations of A. terrestris over two cycles (12 years).

It is interesting to note the coevolution of Working Groups to manage rodent pests in three different countries. Essentially, these Working Groups all came about because of the ongoing impact that the rodent species were causing and the uncoordinated responses to management of damage, for human health impacts and/or for unintended effects on the environment including non-target species. There are many similarities between the different Working Groups (Table 2), where there are strong links and feedback loops between the different components, building on monitoring and forecasting (modelling), to consider the development and testing of management practices and future research needs (Figure 3). In each country, the Working Groups meet reasonably regularly and involve a range of stakeholders. They have all been operational for ten years or more, so could therefore be viewed as a successful approach.

Figure 3. Basic inputs, activities, outputs and outcomes of Working Groups for rodent management.

Table 2. Similarities and differences between the different Working Groups in Australia, Germany and France.

Activity	Australia National Mouse Group	Germany Working Group Common Vole Management	France FREDON network for vole management
Monitoring	Monitoring conducted 3x per year from ∼150 sites, plus incidental observations	Monitoring conducted 2x per year in several German States in key crops using several methods, plus incidental observations	Depending on the species and region; in Franche-Comté and Auvergne for A. amphibius, 2x per year in each relevant commune
Modelling/Forecasting	Mouse forecast models run once/year	Occasional forecast depending on the availability of funding	Mapping of population densities and knowledge of travelling waves (A. amphibius) can predict population evolution one year in advance
Format of advice	Mouse Updates issued 3x per year, plus development of media releases	Newsletters of the States' extension services and direct advice to farmers in farmer schools	Quarterly Bulletin de santé du vegetal and direct advice to farmer groups (contrats de lutte)
Development and testing of management practices	Ongoing agenda item for meetings	Ongoing agenda item for meetings, research being conducted by some of the Working Group members	Experimental areas designed and monitored with farmers and researchers and with the participation of other stakeholders
Identification of future research needs	Ongoing agenda item for meetings	Ongoing agenda item for meetings	Ongoing agenda for meetings
Frequency of meetings	3x per year, linked to timing of monitoring (2x teleconferences and 1x face-to-face meeting)	At least 1x per year	Variable according to needs; general assemblies of “groupement de défense” and Végéphyl meeting yearly
Stakeholders involved	Farmers, rodent ecologists, state and federal government agency staff, Chair (farmer) and Secretary	State and federal government agency staff and academia, industry, environmentalists, NGOs, farmer groups by invitation	Farmers, rodent ecologists, health services, environmentalists, hunter associations, government agency staff

Borrowing a framework from Davies et al. (2020), we are able to compare some important characteristics of successful Working Groups (Table 3), including (1) continuous, long-term or time-bound funding, (2) early stakeholder identification and engagement, (3) consideration of ethical and animal welfare factors in design phases of projects, (4) involvement of ecologists/environmentalists (5) stable working group membership (organisational and individual), and (6) benefits for all parties involved. While there are some differences between the Working Groups from Australia, Germany and France, these characteristics appear to be critical in enabling successful outcomes, and should be considered as a minimum set of characteristics if new Working Groups should be developed.

Table 3. A comparative assessment of the attributes for successful Working Groups, based on the framework of Davies et al. (2020), and applied to the National Mouse Group in Australia, the Working Group Common Vole Management in Germany, and the FREDON network for vole management in France.

Characteristic	Australia National Mouse Group	Germany Working Group Common Vole Management	France FREDON network for vole management
Continuous, long-term or time-bound funding	Funded by industry since 2012 Ongoing funding to be negotiated every ∼3 years	No dedicated funding, participation as part of work duty	Funded by the Ministry of Agriculture, negotiated every year
Early stakeholder identification and engagement	Producer representatives (farmers) Rodent ecologists State and Federal government agency staff	Farmers Rodent ecologists State and Federal government agency staff	Producer representatives (farmers) Rodent ecologists Government agency staff
Consideration of ethical and animal welfare factors in design phases of projects	All aspects of work approved by institutional Animal Ethics Committee	All relevant aspects of work approved by State and District authorities	All aspects of work approved by institutional Animal Ethics Committee
Stable working group membership (organisational and individual)	A farmer representative is the long-term Chair of the NMG Continued funding enables stability of Group	Shared chairing by a research institution of the Federal Ministry of Agriculture and a representative of a State Plant Protection authority	Staff of the FREDON and of the Ministry of Agriculture specifically in charge Continued funding enables stability of monitoring and collaborations
Benefits for all parties involved	All members actively engaged	All members actively engaged and benefit from shared up to date knowledge and insider information	All members actively engaged

Successful Working Groups is just one aspect of good rodent management. Ecologically-Based Rodent Management (EBRM) relies on a series of principles being met, namely, (1) the management actions are environmentally sound, (2) they are cost effective, (3) the actions are sustainable, (4) they are applied on a large scale, (5) they are politically advantageous, and (6) they are socially acceptable (Brown et al., 2006; Jacob et al., 2010; Singleton, 1997; Singleton et al., 1999; Singleton & Brown, 1999). Brown, Aplin et al. (2017) compared these principles between Southeast Asia, where research and development work was conducted over a 10-15 year period, and the Pacific, where only a small amount of research had been conducted. For each of the case studies being considered in this paper, we could easily state a “yes” for each of these principles, although we have not assessed whether these working groups would be considered cost-effective, which could be an area of future research. An additional set of attributes of successful EBRM was proposed by Brown, Aplin et al. (2017), including (1) understanding of the taxonomy, biology and ecology (behaviour and life-history characteristics) of the pest species within the agricultural system, (2) monitoring systems to determine thresholds for management (linked to socioeconomic thresholds), (3) having practicing rodent biologists in the region, (4) experimental field studies used to evaluate management strategies and test hypotheses about rodent population dynamics, and (5) consideration of a range of management strategies; do not rely on rodenticides alone. All of these attributes hold true for the successful Working Groups presented in this paper, thus confirming the importance of having well-understood systems with adequate support.

In the future, it will be increasingly important to further refine and continue to develop these Working Groups. We contend that Working Groups should be developed for other rodent pests in other contexts around the world, particularly to build on participatory approaches such as found in Madagascar (Scobie et al., 2023). It would also be highly appropriate to adapt these Working Groups for use in non-cyclic rodent problems, such as found with rodents in urban environments or in the tropics. Furthermore, there are several changes occurring with tighter regulations around the use of rodenticides (e.g. in the EU, but elsewhere too). Rodenticides have been a global cornerstone for rodent control, especially in extensive cropping systems, due to their effectiveness, user-friendly application, relative safety for human handlers, and cost-effectiveness (Jacob & Buckle, 2018). However, there is a growing trend of legislative regulations on the use of anticoagulant rodenticides resulting in products for plant protection having been phased out in the European Union and increasing restrictions on their use as biocides. This is driven by concerns surrounding their persistence, bioaccumulation, potential secondary exposure, and animal welfare implications (Coeurdassier et al., 2014; Fisher et al., 2019; Mason & Littin, 2003). In addition, there is an increasing trend towards restricting products based on acute compounds such as ZnP in the plant protection sector. In light of these concerns, it becomes crucial to have well-regulated yet effective control options that have minimal environmental impact. This way, we can ensure that the benefits of using rodenticides are maximized while mitigating associated risks. Striking this balance is essential to maintaining successful rodent control strategies. The implications of these restrictions need ongoing discussion within the Working Groups given the prominence of rodenticides in the “toolbox” of rodent management. It also emphasises the role of considering a range of other management strategies that might be added to the toolbox in the future such as farm management, fertility control and gene drive (for example, in France: Delattre & Giraudoux, 2009; Giraudoux, 2022; Giraudoux et al., 2017; Michelin et al., 2014).

We conclude by reinforcing the benefits and outcomes of having dedicated Working Groups to manage the impacts of rodent pests. We concur with Faysse (2006) in that Working Groups (or multi-stakeholder platforms) need to be well managed, and need to overcome a series of challenges including (1) issues around power relationships and decision-making power, (2) platform composition, (3) stakeholder representation and capacity to participate meaningfully in the debates, and finally (4) cost of setting up a multi-stakeholder platform. To enable sustainability of the groups, they must also have benefits for all stakeholders. We hope that the learning from these three case studies will help inform the development of similar Working Groups in other countries with other rodent pests.

Author contributions

PRB conceived the idea for this paper in discussion with JJ and PG. All authors were involved in revising the paper for intellectual content.

Acknowledgements

We are grateful to the organisers of the 17^th Rodent et Spatium conference who held a Round Table conference session on “Rodent-human conflicts in the XXI century: crop protection and public health” which sparked the idea for this paper. This review article did not receive specific funding. PRB gratefully acknowledges the support of CSIRO and GRDC for continued support. We thank Steve Henry for comments that improved the manuscript, and the reviewers for their constructive comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

All data available in the manuscript.

Additional information

Funding

This work was supported by Commonwealth Scientific and Industrial Research Organisation.

Appendix 1

National Mouse Group (NMG)

Terms of Reference (Updated February 2021)

Purpose

These Terms of Reference set out the membership and responsibilities of the NMG.

The NMG is a stakeholder working group that was initiated within an emergency context. It now operates as a standing stakeholder liaison group for the GRDC funding CSIRO Mouse Management Project.

The role of the NMG is to:

1. Provide an opportunity for stakeholders to draw together available information about mouse activity, damage and management options to bring to the attention of other members and regulators

2. Provide a forum for the CSIRO to seek feedback on research outcomes and proposed mouse management options

3. Provide a forum for the CSIRO and GRDC to seek feedback on proposed mouse management communications

4. Encourage stakeholders to be actively involved and have agency with regards to the mouse related research being undertaken by CSIRO

Scope of the role of the NMG

• The NMG is an advisory group whose role is to support the CSIRO in the running of the mouse management projects and provides an opportunity for the exchange of information with other members, and where appropriate the regulators.

Out of scope of the role of the NMG

• Advocacy or lobbying

Operation of the NMG

• Members must bring whole-of-organisational views.

• Members must recognise their roles and responsibilities as defined by legislation.

• Individual members are asked to respect the confidentiality of the discussions and to only communicate using the official communiqué and update documents released following the meetings.

• Members will be asked to assist the distribution of key messages back to their stakeholders.

• The NMG is independent of commercial interests.

Conflict of interest

All NMG members attend/participate in NMG meetings as stakeholder representatives for their nominating organisation only.

Membership

The NMG will comprise members including:

• An independent Chair (independent is defined as not being conflicted in any way as to adversely impact on the working group's operation or aims);

• A skills-based selection of stakeholder members with expertise in;

• mouse ecology;

• rodent and rodenticide research;

• state and federal agency staff relevant to the management of mouse plagues including pesticide registration;

• producer representative organisations (the preference is for at least two farmers per state at minimum to ensure ability to collect broad anecdotal mouse numbers and management options information)

Secretariat

The Secretary to the NMG is appointed by the CSIRO. Currently the secretary is an independent contractor employed on an as needs basis to assist with the management of the working group meetings.

Funding

The NMG will be funded through the Mouse Management Project (funded by GRDC).

Meetings

The Chair of the NMG will be responsible for determining the timing, frequency and location of all meetings in consultation with the CSIRO project leaders in order to carry out its responsibilities. However, the NMG shall aim to meet face-to-face at least once per year.

A quorum for a meeting is 70% of membership organisations. Decisions must be consensus based. Members should, to the extent practicable, make themselves available to attend meetings. If members forego three consecutive meetings, membership may lapse and an alternative member may be considered.

Records of all meetings must be approved by the NMG and kept by the Secretariat.

Remuneration

Travelling, expense and sitting fee allowances for Farmer Members of the NMG for face-to-face meetings and teleconferences will be paid by the NMG. This is in recognition of the costs involved in leaving their farms to attend the meetings.