Conservation of maize landraces in the Mexico center of origin is critical for sustainable agriculture. However, farmers in many regions of Mexico are reducing landraces for more modern maize varieties, particularly hybrid maize. The reasons why farmers choose to maintain maize landraces have been recently recognized to be strongly linked to their specific values (i.e., intrinsic, instrumental, and relational values). However, there is a lack of studies that empirically investigate the nuances of farmers' specific values and how these values are adequately considered in broad agricultural policies. Using a mixed-methods case study based in indigenous and mestizo communities in Chiapas, Mexico, we analyzed farmers' maize production strategies, how those strategies connect to farmers’ value orientations, and the limitations that they confront in enacting such values. We found that households within both indigenous and mestizo communities fell into one of three categories regarding their maize production: 1) hybrid maize production for market sales, 2) landrace production for household consumption, and 3) a combination of these two strategies. All farmers hold a diversity of values in which mostly instrumental and relational values were mentioned among the three groups of farmers, who emphasized the livelihood and subsistence value of maize. Value differences for farmers who prioritize the cultivation of maize landraces were related to the strength of relational values, such as the biocultural diversity and heritage value of maize. In contrast, the farmers relying on hybrid varieties were the ones confronting the most limitations to their maize production, particularly economic limitations. Based on our empirical findings, we conclude that policies aimed at promoting the conservation of landraces must extend beyond a purely economic and market-oriented approach. The current policy emphasis on instrumental values is likely to fall short in achieving the desired outcomes since it does not sufficiently foster plural values that underpin the continued production of maize landraces.

Abstract Non-technical summary This article examines the challenges and opportunities to integrate diverse sources of evidence in assessments produced by international platforms working at the science–policy interface. Diversity (or pluralism) of sources of literature, both in terms of their geographic origin and disciplinary focus, is essential for assessments to inform decision-making across social–ecological contexts. Using the recently completed ‘Methodological Assessment of the Diverse Values and Valuation of Nature’ of the Intergovernmental Science–Policy Platform on Biodiversity and Ecosystem Services as a case, we find that significant effort has been dedicated to reviewing diverse literature. We discuss three strategies to expand pluralism in future assessments. Technical summary Representing plural views in science–policy platforms is essential to avoid reproducing geographic and epistemic biases that permeate contemporary scientific knowledge production and synthesis. The Intergovernmental Science–Policy Platform on Biodiversity and Ecosystem Services (IPBES) has strived to produce assessments that incorporate information from diverse regions and knowledge systems. We explore the geographic and epistemic pluralism of the literature included in the ‘Methodological Assessment of the Diverse Values and Valuation of Nature’ (VA), and the challenges and opportunities to achieve such knowledge pluralism. We applied a bibliometric analysis to the sources of evidence cited in the VA, and reflected on the assessment development process, in which we were directly involved. Our results highlight the success of different strategies developed by VA experts to engage with diverse sources of literature. Still, most evidence was English-language academic literature produced in Western Europe, Canada, and the United States, echoing the prominence of this literature in scientific publication in environmental disciplines. Reflecting on our experiences, we discuss strategies that could further enhance the geographic and epistemic pluralism in the information reviewed for future environmental assessments produced by IPBES and other international science–policy platforms. Social media summary Epistemic and geographic pluralism was partially achieved in IPBES Values Assessment, and can be further enhanced in future assessments.

Societal Impact Statement Agricultural sustainability depends on the adaptation of crops to their local environment. Smallholder farmers who save seed provide an essential “evosystem” service by growing locally adapted seed varieties that can recruit biodiversity to enhance their growth and defense. While professional plant breeding has diverted evolutionary processes away from local adaptation, smallholder farmers, particularly those in centers of origin for crops, benefit society by selecting and propagating diverse crop varieties that allow local adaptation processes to perpetuate. Given that smallholders support society through the generation of evosystem services, changes in policy and practice are needed to support the livelihoods of smallholder farmers in ways that mitigate risk and recognize their important contributions to agricultural sustainability. To enhance the reach of this work, a Spanish language version of the paper is available in the Supporting Information (see Translation_ES). [Correction added on 18 June 2024, after first online publication: The preceding sentence has been added in this version.] Summary Long‐term food security and agricultural sustainability depend on protecting the eco‐evolutionary processes that select for local adaptation in crops. Since seed systems structure how people acquire seed, institutional and social changes influence evolutionary processes within agroecosystems. Since World War II, the rise of professional breeding has bifurcated seed systems into traditional and formal systems, which has negatively affected agrobiodiversity, crop evolution, and agricultural sustainability. In traditional seed systems, farmers often save seed from plants that best provide desired qualities, selecting landrace crop varieties to adapt to local environmental conditions. In formal or centralized seed systems, farmers buy seeds bred primarily for maximizing yield under ideal conditions. When farmers source seeds externally, evolutionary processes underlying local adaptation are disrupted. Here, we argue that traditional seed systems provide important evosystem services , or the evolutionary processes resulting from the maintenance and use of genetic diversity that benefit society. We present a framework on how seed systems influence the evolutionary processes that enable local adaptation, which is necessary for sustainable agriculture. We discuss how changes in human values underlying traditional and formal seed systems can alter evolutionary processes that underlie local adaptation. We conclude that developing policies that support people in managing ecological and evolutionary processes within seed systems is needed to address current and future challenges of global food security and agricultural sustainability.

Twenty-five years since foundational publications on valuing ecosystem services for human well-being 1 , 2 , addressing the global biodiversity crisis 3 still implies confronting barriers to incorporating nature’s diverse values into decision-making. These barriers include powerful interests supported by current norms and legal rules such as property rights, which determine whose values and which values of nature are acted on. A better understanding of how and why nature is (under)valued is more urgent than ever 4 . Notwithstanding agreements to incorporate nature’s values into actions, including the Kunming-Montreal Global Biodiversity Framework (GBF) 5 and the UN Sustainable Development Goals 6 , predominant environmental and development policies still prioritize a subset of values, particularly those linked to markets, and ignore other ways people relate to and benefit from nature 7 . Arguably, a ‘values crisis’ underpins the intertwined crises of biodiversity loss and climate change 8 , pandemic emergence 9 and socio-environmental injustices 10 . On the basis of more than 50,000 scientific publications, policy documents and Indigenous and local knowledge sources, the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) assessed knowledge on nature’s diverse values and valuation methods to gain insights into their role in policymaking and fuller integration into decisions 7 , 11 . Applying this evidence, combinations of values-centred approaches are proposed to improve valuation and address barriers to uptake, ultimately leveraging transformative changes towards more just (that is, fair treatment of people and nature, including inter- and intragenerational equity) and sustainable futures.

In many cultures, interactions between humans and plants are rooted in what is called “relational values”—values that derive from relationships and entail reciprocity. In Mexico, biocultural diversity is mirrored in the knowledge and use of some 6500 plant species and the domestication of over 250 Mesoamerican native crop species. This research explores how different sets of values are attributed to plants and how these influence management strategies to maintain plant resources in wild and anthropogenic environments. We ran workshops in two communities (one Indigenous, the other non-Indigenous) in a highly biodiverse region in western Mexico, to ascertain the values and management activities related to important plant resources. The relationship between values attributed to plants and management activities was examined through redundancy analysis. A total of 180 plant resources were mentioned during the workshops, with a broad spectrum of values attributed to them, including material, non-material, and regulatory dimensions. We divided plant management strategies into three general categories of increasing intensity and complexity. We found that participants in the Indigenous community value and manage more wild plant resources than people in the non-Indigenous community. We also identified relationships between plant resource values and the type of management performed; for example, more intensive forms of management, such as sowing seeds, were used for seasonal plants that had a food value. By valuing and managing different sets of plant resources from forest, agricultural plots, and home gardens, people enabled multi-functional landscapes to form, illustrating a key feature of relational values in agroecosystems, which promotes both conservation and domestication of plants.

Recently, Mexico has launched policies of agroecological transition that seek to foster healthier agri-food systems. One of these policies is the reduction and eventual elimination of glyphosate by 2024. Despite being the most used herbicide in Mexico and the world, little information exists about what factors determine a greater or reduced use of glyphosate in different socio-ecological contexts. This study aimed to explore different agricultural management, biophysical and social variables and their effects on glyphosate use in maize crops by smallholders (<8 ha). A questionnaire and semi-structured interviews were performed with 142 farmer families in four regions of the state of Chiapas to document the use of herbicides and glyphosate. By using regression trees, we identified those variables that determine a greater or lesser use of glyphosate for each region and jointly. The average volume of glyphosate for the four regions during an agricultural cycle was 2.7 l/ha−1. Sets of variables were associated with syndromes of greater use of glyphosate and herbicides in general, such as small plots (<0.67 ha), indigenous population, younger farmers, fewer family members, rainfed conditions, and plots without mechanization. These results can help the design of contextualized and flexible policies of transition, consistent with the socio-ecological heterogeneity of Mexico.

The analysis of resource management strategies is considered to be relevant to the conservation and sustainable use of ecosystems. In Mexico, ejidos are the most important of the land tenure institutions that grant access to resources inside communities. Although it is recognized that an ejido’s internal structure creates different social groups, few studies have explored their resource management strategies. The aim of this study was to characterize natural resource management strategies in two ejidos in a highly biodiverse region on the southern coast of Jalisco, Mexico. We sought to identify differences in strategies and the variables that explain these differences. We took the household as the unit of analysis, and conducted 55 structured interviews that tackled different aspects of households’ productive activities and natural resource management. We used cluster and ordination analyses to generate a typology of natural resources management strategies, and linear models to identify the variables that differed among groups. The results show that four different natural resources management strategies were strongly associated with differences in land tenure and the type of ecosystem that a household manages. This information can help us to enhance and diversify strategies for sustaining both ecosystems and community livelihoods.

Values play an important role in farmers’ land management decisions, becoming increasingly relevant when designing environmental policy. One key element that influences farming decisions is the land tenure under which farmers and their land are embedded, which represents different sets of rights for farmers. Therefore, the aim of this study was to elicit farmers’ values regarding the social and ecological attributes of the landscape, and determine how these values vary according to differences in land rights. We performed this exercise in the two most important land tenure systems in rural Mexico. We carried out a choice experiment to understand preferences for different landscape attributes such as vegetation cover, surface water, terrain slope, and type of property. Then, we probed how these preferences change according to the land rights that farmers hold. We found that surface water was consistently the most important landscape attribute. However, there were clear differences that were related to land rights for some values, such as for example, vegetation cover. Institutional mechanisms such as boundary rules and conflicting values are part of the explanation of these differences. These results provide a bridge to understanding farmers’ management decisions, and in the future, improving sustainable development.

Analysis of social-ecological systems is becoming increasingly used since the framework provides a valuable set of variables for understanding relationships between people and ecosystems. This interaction focuses on the use and management of natural resources that, in many cases, are common-pool resources. In Mexico, common-pool resources have long been explored since at least 60% of the forested lands in the country are held under the legal figure of ‘ejidos’ and indigenous communities, which aimed at driving the collective use of lands and resources. However, few studies incorporate ecological processes for an integrated understanding of social-ecological systems. In this study, we seek to understand how ecological variability influences the creation and functioning of different rules and, consequently, institutions for forests management. Our case study was conducted in an ejido with high ecological variability located in Jalisco on the Pacific coast of Mexico. The research approach was interdisciplinary and combined qualitative and quantitative methods. We conducted participant observation and 23 semi-structured interviews; botanical collections were also carried out. We found that there is strong influence between ecological variables and the emergence of rules and collective action. The most important variables influencing these processes were the economic value of resource units, ecosystem services perceived by local people and location and size of the resource system (including area and number of species). Historical processes also play a part that generates knowledge of resource systems and the current social, economic and political settings at a larger scale. The establishment of relationships with variables that produce certain outcomes for the framework of the social-ecological system is an important challenge to be met in order to move forward in both theory and practice.