“Are some of science’s most important questions simply unanswerable without redefining how research is done?” (sensu Coles et al., 2022). We argue that for conservation science the answer is a resounding “yes,” and an effective process increasingly involves working through a broad network of interdisciplinary decision makers, stakeholders, and scientists to coproduce actionable science designed to guide resource management and policy decisions. While many papers on the science of teams have been published, few case studies exist (Henson et al., 2020), especially for big teams working on conservation-oriented problems. As such, we describe a salient example of big-team conservation science focused on the monarch butterfly (Danaus plexippus), drawing from the literature of big-team science and our collective experiences, and offer recommendations for advancing big-team science approaches for solving some of the most important conservation problems.

We begin by summarizing published descriptions of effective science teams, highlighting the benefits of big-team science, elements of success, effective implementation approaches, and barriers or pitfalls. “Big-team science” has been described as a broad movement towards large-scale grass-roots science collaborations, self-organizing to align intellectual and technical capacity in pursuit of a common goal (Coles et al., 2022). Whereas traditional research teams tend to be smaller in scope, institutionally more isolated and competitive, big-team science is based on networks of collaborators coordinating across institutions—in our case, an international team aligned across federal and state agencies, non-governmental organizations, and academia. The size of these teams may be quite variable; what distinguishes “big-team” science is not necessarily the number of partners but rather the scope and scale of the problem, the dispersed and interdisciplinary nature of the participants, and a highly collaborative spirit driven by mutual interests and/or practical necessity.

The terminology used to describe or classify collaborative science endeavors varies by context, somewhat dependent on whether the framing centers on process, functions, structure, or outcomes. For example, Coles et al. (2022) distinguish “grassroots” big-teams from those developed with formal top-down funding (e.g., Human Genome Project). We view funding streams and the “top-down” vs. “bottom-up” organization of teams as a continuum of approaches to organize and fund big-team science. We recognize the overlap between conceptualizations of, and products stemming from, ideas called “big-team science” in conservation, “co-produced science,” and “translational ecology” (Enquist et al., 2017) and intermix these terms when appropriate, but primarily we focus on team science, recognizing such teams will likely co-produce science and/or perform translational ecology when working on conservation problems.

We offer recent efforts for the monarch butterfly in North America as a proof of concept, an example of the effectiveness and challenges of applying big-team conservation science to a highly complex, and consequential, conservation problem. This narrative includes a description of the species’ status and trend, the complex and diverse set of conservation actions and policies across Mexico, the United States, and Canada, the new conservation actions and policies that occurred in response to monarch declines, and the formation of the US-based and Trinational Monarch Conservation Science Partnerships (MCSP and Tri-MCSP) as team efforts for determining imperilment status and recovery options. We couch these science efforts in the framework of Strategic Habitat Conservation, the business model for conservation employed by the US Fish and Wildlife Service (USFWS) to meet conservation science goals identified by stakeholders from Canada, the United States, and Mexico.

The science of big-team science is an active area of discovery with recent work focusing on how interdisciplinary science teams function and can better deliver information that policymakers and stakeholders require. The primary benefit of big teams is their ability to solve difficult scientific problems emerging from complex systems, requiring diverse skills and perspectives and involving highly dynamic physical and/or political environments. Many conservation science problems meet these criteria, suggesting that conservation science (and desired conservation outcomes) may benefit greatly from big-team approaches.

Some of the reasons big-teams are well-suited to tackle complex problems include: 1) enhanced technical capacity for translational science (Vogel et al., 2014; Lotrecchiano et al., 2021), 2) leadership and coordination functions resulting in a holistic and strategic organizational alignment (Beier et al., 2017), 3) adaptive and interactive connections between researchers, managers, and applied policy decision-making contexts (Saunders et al., 2021; Chambers et al., 2022), 4) potential to leverage resources for added efficiencies and collective benefits, 5) momentum and positive feedback loops that may increase the relevance/utility of products and thereby the likelihood of diversified funding opportunities, 6) increased diversity, interdisciplinary or transdisciplinary thinking, and inclusivity among participants resulting in shared learning and novel ways of thinking (Vogel et al., 2014; Jagannathan et al., 2020).

However, not all conservation science problems demand big-teams. There is inherent power in such an approach, but there are also well-documented challenges accompanying large and dispersed science teams. The National Research Council book (National Research Council, 2015) remains an excellent distillation of the literature on team science, identifying 7 features of team science that can generate challenges and recommendations to overcome them. These features overlap with issues and challenges identified before (Pooley et al., 2014; Vogel et al., 2014) and after the NRC book (Baron et al., 2017; Saunders et al., 2021; Coles et al., 2022). Across these 5 studies, we classified the assorted challenges into 5 general themes: Funding, Team management, Team structure, Interdisciplinary effectiveness, and Credit/rewards (Figure 1).

These 5 themes cover a wide swath of issues affecting science teams. However, big-teams working on conservation-oriented problems have additional, perhaps unique, issues to consider. First, conservation or wildlife management science teams are, by design, formed to solve real-world problems. Given the urgency of the conservation mission, conservation science teams are often time limited, attempting to deliver science to meet a legal or politically determined timelines (Laurance et al., 2012). Whereas traditional research may rely on controlled or relatively stable experimental systems, conservation problems are inherently novel situations often associated with limited observational data and wickedly complex dynamic socio-ecological systems. Conservation science often happens simultaneously with large-scale planning, ongoing interventions, and environmental change. Furthermore, the conservation issue may be contentious, have numerous stakeholders with differing opinions, including legal actions, and these issues may affect the framing of the science that will or can be accomplished. Finally, conservation science teams may be organized such that scientists and non-scientists (stakeholders and decision makers) coproduce science by jointly framing research questions, the methods used to address them, and the interpretation of the results to inform natural resource management and environmental policy decision making (Beier et al., 2017; Saunders et al., 2021).

The monarch butterfly, as one of the most-studied insects in the world, offers an important case study in big-team conservation science. Whereas many conservation problems suffer from a dearth of information about extremely rare or obscure species, there are hundreds (if not thousands) of relevant publications focused on monarch biology and ecology spanning numerous decades. Thus, the challenge for monarch conservation is a matter of synthesis, new science directed at strategic gaps or sensitive assumptions, and adaptive application.

Decades of research completed since Dr. Fred Urquhart’s announcement of the overwintering sites in Mexico (Urquhart, 1976) offers a foundational understanding of natural history, physiology, behavior, and other aspects of monarch biology. However, the conservation problem is a more recent phenomenon where population declines occur against a backdrop of unprecedented environmental conditions and a highly dynamic interplay between landcover and climate change, threats, and multiple conservation interventions across three countries. For many scientists the most important questions for monarch conservation science became: “What is the risk of extinction?,” “what is an adequate population level?,” “what are the threats and which ones can be/should be addressed?” and “how much conservation effort is enough?.” These questions are inherently interdependent, informed (but not answered) by past research—indicating a prime situation where a big-team approach offers the necessary platform for multi-faceted integration. In sections 3–5 below, we provide an overview of monarch biology, recent declines, and the complex array of conservation actions to better frame the case study as an example of big-team science in conservation.

The multi-generational, multi-population continental-scale monarch migration phenomenon is extremely complex. In North America, monarch butterflies have two populations differentiated by the location of overwintering and breeding habitats (Figure 2). The much larger eastern population overwinters in oyamel fir (Abies religiosa) forests in the mountains of central Mexico, and migrates northward each spring, via 4 or 5 successive generations, from Texas and into the midwestern and eastern United States and Canada. The western population overwinters in forested groves along the California coast and northern Baja California, and moves north and east each spring, breeding throughout the region west of the Rocky Mountains. These populations are not isolated genetically but show some phenotypic differences (Freedman et al., 2021). Tagged monarchs show animals in Arizona can migrate to either Mexico or California (Billings, 2019). After multiple generations of breeding and successive expansion from overwintering areas, environmental cues (Goehring and Oberhauser, 2002) result in reproductive diapause and the final generation of animals migrate south, returning to the overwintering locations. Monarchs lay eggs on a wide variety of milkweed species (genus Asclepias), which act as host plants for developing larvae. Adults require nectar from flowering plants during breeding and migration.

Both eastern and western monarch populations have declined in overwintering abundance (Figure 3). Area occupied by overwintering clusters in Mexico (Figure 3A) has varied considerably (Rendón-Salinas et al., 2020), but generally declined from the winter of 1996–97 to a low in 2013–2014 (Vidal and Rendón-Salinas, 2014; Semmens et al., 2016). The mean overwintering area from 1993 to 2008 was 7.6 ha, and from 2009 to 2021, 2.7 ha. In the West, sporadic sampling prior to 1997 suggests populations were highest in the mid-1980’s at approximately 4.5 million butterflies and experienced a multiyear decline until 1994 (Schultz et al., 2017). Sampling by the Xerces society (Figure 3B) indicated populations peaked again in 1997 at approximately 1.2 million butterflies then declined to a relatively stable low from 1999 to 2017. In 2018, the population crashed to ∼30,000 individuals (Pelton et al., 2019) and continued to decline until 2021, when it increased to ∼200,000 individuals.

The causes of both annual variation and the longer-term declines have been extensively studied in both populations. For eastern monarchs, a leading hypothesis for long-term declines involves changing agricultural practices and associated landuse/landcover change, though other factors such as disease, predation, and toxicity from pesticides may play a roll. The adoption of genetically modified, herbicidally resistant corn and soybeans led to large losses of milkweed in agricultural fields (Pleasants and Oberhauser, 2013; Zaya et al., 2017) and is associated with declining population trends in Mexico (Thogmartin et al., 2017c; Saunders et al., 2018; Zylstra et al., 2021). This loss of milkweed could limit populations in more than one way–first, by reducing the total amount of breeding habitat and, second, by limiting the ability of females to find milkweed and lay eggs before they die (Zalucki et al., 2016; Crone and Schultz, 2022). In the west, habitat loss or degradation of overwintering areas and pesticide use in the California Central Valley has been associated with declines (Espeset et al., 2016; Crone et al., 2019; Pelton et al., 2019). Climate, primarily temperature and precipitation at various stages of the life cycle, has also been linked to annual population dynamics and to longer-term declines (Espeset et al., 2016; Zylstra et al., 2021). The loss of overwintering habitat remains a key threat for both western and eastern monarch populations. In Mexico, though forest loss has occurred (Vidal et al., 2014), Flores-Martínez et al. (2020) found that current rates of deforestation are low and that there is no evidence linking forest loss to eastern population declines since monitoring began in 1993–1994. In summary, with respect to monarch biology and population trends, the declining trends are well-documented but the cause-effect relationships associated with specific threats or drivers remain difficult to pinpoint due to limited data, correlated explanatory variables, and the observational nature of much of the data.

Numerous conservation efforts focused on monarchs exist across North America and were in place before data showing declines in the eastern and western wintering grounds were available. Shahani et al. (2015) provided detailed examples of these activities and organizations in all three countries. We provide an overview below, intended to convey the complexity and magnitude of conservation occurring across North America and the regulatory mechanisms engaged.

In Mexico, efforts to protect the fir forests where monarchs overwinter began in the 1980’s based on the research initiated by Dr. Lincoln Brower, a founding proponent of monarchs and the conservation of their overwintering forests. Complex and difficult negotiations between World Wildlife Fund (WWF), landowners, and the federal government through the late 1990’s resulted in the establishment of the Monarch Butterfly Biosphere Reserve (MBBR) in 2000. Economic incentives to landowners in the core zone of the MBBR who meet conservation commitments are facilitated by the Monarch Butterfly Fund (MBF, Fondo Mariposa Monarca; https://fmcn.org/es/proyectos/fondo-monarca; Honey-Rosés et al., 2009). In addition, the Alliance Initiative (https://www.wwf.org.mx/quienes_somos/nuestras_alianzas2/alianza_wwf_telcel/) provides financial support for overwintering population monitoring, environmental education, and reforestation (Semarnat y Conanp, 2018). Collectively, these programs have greatly reduced logging (Flores-Martínez et al., 2019; Flores-Martínez et al., 2020), and are a critical element of monarch conservation in North America.

In Canada, the monarch butterfly’s breeding range extends across 10 provinces. At the federal level, the monarch butterfly is listed as a Species of Special Concern under Canada’s Species at Risk Act (SARA) and is currently being considered for up-listing to Endangered. Legal protections under SARA usually only apply to federal lands. At the provincial level, monarchs are listed as Special Concern in Ontario and New Brunswick and Endangered in Nova Scotia under their respective species at risk legislations. However, only the latter listing affords the monarch protection by prohibiting killing, injuring, disturbing, taking or interfering with the species. Canada is actively working with the United States and Mexico to improve monitoring efforts in Canada using a trinationally adopted survey protocol (see Cariveau et al., 2019) through its main community science monitoring program Mission Monarch (www.mission-monarch.org).

In the United States, numerous monarch conservation (Shahani et al., 2015) and community science programs (Oberhauser et al., 2015) have protected and restored habitat and added to our knowledge of monarch breeding biology and migration over the last ∼30 years. Projects such as Monarch Watch (www.monarchwatch.org), the Monarch Larva Monitoring Project (www.monarchnet.org/monarch-larva-monitoring-project), Journey North (journeynorth.org), and the Western Monarch Count (westernmonarchcount.org) have been collecting data on monarchs since the late 1990’s. The multi-agency Monarch Joint Venture formed in 2008 and coordinates and implements education and conservation actions. In the western United States, protection and management of overwintering sites is a high priority (Pelton et al., 2016). The top 50 overwintering sites occur on both public and privately owned lands. Land ownership, in addition to state and local laws restricting development, creates different levels of protection across the sites.

International efforts to conserve monarchs include the North American Monarch Conservation Plan (NAMCP) (Oberhauser et al., 2008), developed after 3 international meetings of monarch biologists, NGOs, and decision makers in 2006 and 2007. The NAMCP outlined key trinational conservation objectives and outcomes to ensure that 1) sufficient overwintering habitat is available in Mexico and the United States; and 2) sufficient breeding and migrating habitat is available in Mexico, the United States, and Canada to maintain the overall North American population.

In response to the population declines described above, monarch conservation efforts have increased substantially. Viewed against a backdrop of habitat loss and a multitude of growing threats, these conservation efforts add another layer of dynamic complexity (and applied relevance) to the conservation problem.

Following two decades of observed population declines, eastern monarch overwintering levels in Mexico hit a historic low during the winter of 2013–2014 (Rendon-Salinas et al., 2020; Figure 3A). The alarming possibility of losing the migration phenomenon for the iconic monarch butterfly set into motion continental-scale efforts to mobilize conservation actions (Figure 4). At the North American Leaders Summit in Mexico, February 2014, Presidents of the US and MX and the Prime Minister of Canada responded with a shared commitment “to work on the preservation of the monarch butterfly as an emblematic species of North America which unites our three countries.” Prior to the meeting, the USFWS received a petition to list the monarch as a threatened species under the Endangered Species Act (US Fish and Wildlife Service, 2014).

The trinational agreement resulted in the development of multi-faceted federal policies and legal strategies across Mexico, Canada, and the United States. As part of these strategies, or in parallel, a wide network of partners rallied nationally and internationally to advance monarch conservation efforts. Mexico developed a comprehensive action plan for monarch butterflies aligned with trinational efforts (Semarnat y Conanp, 2018). In addition, WWF coordinated the formation of the Red Nacional de Monitoreo de la Mariposa Monarca en México (Working Group for the Conservation and Monitoring of the Monarch Butterfly Flyway), a forum for collaboration and coordination of efforts, capacities, and resources to conserve the Mexican flyway, which now includes over 43,000 butterfly sightings. In the United States, the USFWS began its species status assessment for monarchs (US Fish and Wildlife Service, 2020) and a landmark Candidate Conservation Agreement with Assurances (CCAA) for the Monarch Butterfly–the largest CCAA ever implemented–was signed (University of Illinois Chicago, 2020). Participating energy and transportation companies across the contiguous United States and authorities agreed to restore and maintain monarch-friendly habitat. Regional state-led monarch conservation plans were developed (Midwest Association of Fish Agencies, 2018; Western Association of Fish and Wildlife Agencies, 2019). In Canada, ECCC published a management plan for the monarch (Environment and Climate Change Canada, 2016) and as described above, the conservation status of monarchs was recommended to change from Special Concern to Endangered (COSEWIC, 2016) which is currently under review by ECCC. Since 2015, ECCC has funded over 108 projects related to monarchs and formed strategic partnerships to develop national level monitoring for milkweed and monarchs, to restore breeding and nectar habitat, and to develop a native seed strategy for restoration projects.

In 2022, the International Union for the Conservation of Nature (IUCN) evaluated and listed the North American monarch butterfly population as Endangered, indicating that the species faces a very high risk of extinction in the wild. While affording the monarch no legal protection in North America, the IUCN listing decision brings increased global attention to the eastern and western migratory monarch population declines and may serve as an additional catalyst for future conservation actions.

The response to monarch declines by the scientific community followed similar timelines, as an international scientific collaboration formed to help guide strategic conservation efforts and fill critical information gaps. A big-team approach emerged from a workshop in October 2014, where a group of conservation scientists initially focused on population modeling and geospatial priorities. This initial technical workshop coalesced a broader network of scientists from federal and state government, academia and non-governmental organizations, across Mexico, Canada, and the United States. This paper focuses on this extended group that would later be known as the “Trinational Monarch Conservation Science Partnership-Tri-MCSP”, its evolution, structure and function, and how it coproduced science to meet information needs related to monarch conservation and management.

In this section, we reflect on the MCSP relative to existing literature on science teams. We describe the 5 general elements we derived from literature (Figure 1) relative to the Tri-MCSP and give associated recommendations.

Why are big science teams beneficial to conservation? While reading the literature about big-team science we were surprised by the lack of papers focusing on benefits. Many papers never mentioned benefits and focused solely on challenges. To this end, we felt a list of benefits would contribute to the broader understanding of why big-team science in conservation can be useful and adopted and supported when possible. As noted by Beier et al. (2017) our brief bullets “gloss over many of the complexities.” The following benefits stem from both literature (a citation is provided) and our experience with the MCSP.

Big-team science in conservation…

• Increases the ability to tackle complex, long-term conservation challenges, including those that entail landscape change and dynamic environmental conditions across international borders.

Given the current pace of changes to the environment and coincident declines in biodiversity, there is a strong need for both more big-team science in conservation and examples of what makes conservation science teams effective. In our collective experiences, we have routinely seen scientists engage with decision makers and groups performing restoration and management, have participated in such groups, and noted varying levels of success. We were motivated to develop this paper because the MCSP was successful–and because these successes can likely be replicated to tackle other conservation science problems. Key takeaways from our experience suggest big-teams in conservation science must be funded, structured and managed to deliver actionable science for decision makers. This applied focus permeates decisions regarding team structure and leadership, prioritizes the order science products are delivered to meet decision making timelines, and requires intimate coproduction of science. Furthermore, effective conservation science teams require individuals who act as translators, facilitating two-way communication between scientists and policy makers and/or individuals who implement management activities. With technology allowing us to enter a new paradigm of science characterized by large amounts of open access data and synthesis (Hey et al., 2009), big-team science is more viable than ever, and as our case study shows, has high potential to solve conservation problems. Big-team science may become increasingly necessary to tackle the complex conservation challenges of the future.