BEE‐STEWARD: A research and decision‐support software for effective land management to promote bumblebee populations

The demand for agent‐based models to explore the effects of environmental change on pollinator population dynamics is growing. However, models need a simple yet flexible interface to enable adoption by a wide range of stakeholders. We introduce BEE‐STEWARD: a research and decision‐support software tool, enabling researchers, policymakers, land management advisors and practitioners to predict and compare the effects of bee‐friendly management interventions on bumblebee populations over several years. BEE‐STEWARD integrates the BEESCOUT and Bumble‐BEEHAVE agent‐based models of bumblebee behaviour, colony growth and landscape exploration into a user‐friendly interface, with reconstructed code, and expanded functionality. Bespoke automatic reports can be created to illustrate how different land management interventions can affect the densities of bumblebees and their colonies over time. BEE‐STEWARD could be an important virtual test bed for scientists exploring the impacts of different stressors on bumblebees and used by those with little or no modelling experience, enabling a shared methodology between research, policy and practice.

The demand for agent-based models to explore the effects of environmental change on pollinator population dynamics is growing, and mechanistic models can be used to simulate long-term population trends and the impact of stressors and mitigation measures (Becher et al., 2013;EFSA, 2015;E.P.A., 2015;Henry et al., 2017).
With Bumble-BEEHAVE (Becher et al., 2018) and its landscape module BEESCOUT (Becher et al., 2016), powerful agent-based models exist to predict the impact of land use on bumblebee behaviour, colony growth and population dynamics. However, these models were built for researchers, so interpretation and implementation of results for decision-making is limited (Kerr, 2004). Models need a simple yet flexible interface to enable adoption by a wide range of research, policy and practice users. It is only through stakeholder consultation during model development (Rossi et al., 2014) that this implementation barrier to evidence-based land management could be overcome (Dicks et al., 2014).
We have therefore, created BEE-STEWARD (Figure 1), integrating Bumble-BEEHAVE and BEESCOUT into a research and decisionsupport software tool, enabling researchers, land management advisors and practitioners to predict and compare the effects of bee-friendly interventions on bumblebee populations (colony sizes, numbers and survival) over several years. While the underlying model processes are validated and unchanged (Becher et al., 2016(Becher et al., , 2018, the code has been reconstructed, some previous limitations removed, new functionality created and a user-friendly interface has been redesigned.

| Development
Stakeholder consultation is an essential practice in developing decision-support tools (Rossi et al., 2014). Therefore, BEE-STEWARD functionality and interface have been co-designed and refined through workshops and pilots with bumblebee researchers and key land advisory and management stakeholders to widen the potential end-users beyond academia.
Our stakeholder consultation process highlighted that to guide decision-making, a software tool needed to be (a) user-friendly and straightforward whilst (b) also reflecting realistic landscape management options process; findings also supported by Rose et al. (2016).
We, therefore, firstly integrated the landscape exploration module of BEESCOUT into Bumble-BEEHAVE for ease of loading, creating, A bespoke map representing habitats and crops in a landscape (symbolised by default pixel colours, for example, purple is semi-improved pasture) can be created, imported and modified. This map shows bumblebee colonies establishing in an example farm. In the SETUP & RUN section, select 'SETUP' to load the Default map and then 'Run' to start a simulation. The user can define how long the simulation will run for. Simulation results will appear in the RESULTS section. Select 'Run' again to stop the simulation function provided a simple alternative to assess intervention options' impact without applying more advanced model analysis tools (e.g. NetLogo's 'BehaviorSpace' or statistical software, which are still researcher options).

| COMPARING B EE-S TE WARD WITH B EE SCOUT (2 .0) AND B u mble-B EEHAVE
By integrating the BEESCOUT and Bumble-BEEHAVE agent-based models, the new BEE-STEWARD software tool is easier to use whilst capable of producing the same results (SI.8) and having increased features (Table 1).
User-friendly features: • The number of interface inputs, buttons and monitors etc., reduced to those associated with land management.
• A step-by-step approach guides the user through the control panel and the user messages.
F I G U R E 2 Model structure and relationship between user actions, input files and model processes of the BEE-STEWARD software tool. Model processes ANALYSIS, SETUP and GO, enable users to create and set up a map, run it with the bumblebee behaviour, colony growth and population model, and gain results using one tool • One interface to input, create and modify resource maps, run the bumblebee behaviour, colony growth and population model, and compare results between two maps representing land management scenarios.
Additional functionality: • Unlimited habitat or crop types. The restriction of nine habitat types in BEESCOUT (2.0) has been removed. Habitats can be defined by any of the NetLogo 'color swatches' as a decimal number between 0 and 139.9 via the 'HabitatsFile'.
• Unlimited bumblebee species. New bumblebee species can be defined via the 'BeespeciesFile' without modifying the code. • Creating an automatic report. A simple option has been added to quickly compare two landscapes representing different management options and the relative number of bumblebee colonies and individual adult bees they support. This option can be selected from the interface and is for users not familiar with the analysis of computer models.

| Example setup
We provide a simple example of how BEE-STEWARD could be applied using a map of a realistic farmed area with and without intervention options to predict its suitability to support bumblebee populations.
The default BEE-STEWARD model settings were used (unless stated otherwise) starting on 1st January with 8 hr of foraging time per day.

F I G U R E 3
The automatic report (PDF) generated by the BEE-STEWARD tool comparing the max and mean relative number of bumblebee colonies and adult workers (pollinators) over 5 years (n = 20) from two simulations representing different management scenarios of a baseline (Example_Farm_Baseline) and adding a 0.5 ha flower-rich plot (Example_Farm_plot) As the example map was small (1.5 km by 1 km), the initial number of Bombus terrestris queens was set to 100.

| CON CLUS IONS
BEE-STEWARD is a decision-support tool for researchers, policymakers and practitioners to predict the impact of land-use change on bumblebee colony and population dynamics. The user-friendly interface and additional functionality have been co-developed with and for researchers, land advisors and land managers through stakeholder consultation to increase the likelihood of uptake (Rose et al., 2016;Rossi et al., 2014). As a result, BEE-STEWARD is already being used by researchers and conservation organisations, which are adapting the default input options to reflect bespoke land management scenarios (Bumblebee Conservation Trust, 2020; Knapp et al., 2019;Roberts, 2019 Agri-environment schemes.
5. Compare predictions of the relative bumblebee colony densities between landscape management scenarios to aid robust decisionmaking for land management to support bumblebee populations.
The BEE-STEWARD tool illustrates how complex systems models can be re-engineered and expanded through stakeholder con- sultation into an open-source, user-friendly, decision-support tool enabling a shared methodology between research, policy and practice in support of bumblebee survival.

ACK N OWLED G EM ENTS
The creation and piloting of BEE-STEWARD were supported by

PE E R R E V I E W
The peer review history for this article is available at https://publo ns.com/publo n/10.1111/2041-210X.13673.