The role of crop diversity in climate change adaptation: insights from local observations to inform decision making in agriculture

https://doi.org/10.1016/j.cosust.2021.01.006Get rights and content

Highlights

  • We review climate-driven changes in crop portfolios reported by farmers.

  • We discuss the implications for local calories and nutrient production.

  • We document increased cultivation of water-demanding horticultural crops.

  • These crops contain less energy but more vitamins than abandoned ones, mainly cereals.

  • Farmers’ knowledge is an untapped source of information for climate decision making.

Homogenization of crop portfolios from the field to the global scale is raising concerns about agricultural adaptation to climate change. Assessing whether such trends threaten farmers’ long-term adaptive capacity requires a thorough understanding of changes in their crop portfolios, identification of the drivers of change, and the implications such changes have for local nutrition and food production. We reviewed the available literature on farmers’ reports of climate-driven crop changes. Small-scale farmers tend to adopt water-demanding crops, even in areas where models predict that reduced rainfall will reduce yields. The adoption of horticultural cash-crops combined with the abandonment of subsistence cereals modifies farmers’ nutritional inputs in terms of calories and nutrients, potentially undermining their food security. Farmers’ knowledge contributes to understand trends in crop diversity and support the design of strategies for adaptation to climate change.

Introduction

Diversification and modification of crop species and variety portfolios are widespread strategies used by farmers to cope with environmental and socio-economic variability and to adapt to change [1] including climate change [2]. Despite the significance of crop diversity for the ability of agroecosystems to adapt to climate change, existing public policies and development interventions provide limited support for crop diversification [3]. Rather, development policies combined with market demand over the last forty years have led to the general homogenization of crop species and varieties across regions [4], as well as of national and global food supplies [5]. Now, in the face of climate change, crop homogenization is jeopardizing global food security [5] and weakening farmers’ adaptive capacity [2]. The impacts of climate change on agriculture are expected to be particularly strong in Africa, Southeast Asia, Central America, the Pacific, and the Caribbean [6], where small-scale farmers are already facing pressure due to increasing market globalization, urbanization, and population shifts, all of which impact farmers’ crop portfolios [7, 8, 9] and household nutrition [10].

Several studies report a global reduction in crop diversity [4,5], but a thorough understanding is needed of how changes in farmers’ crop portfolios are linked to global trends and of the combined effects of climatic and socio-economic factors on these changes. Understanding changes in farmers’ crop portfolios, the interplay between climate and other drivers of change, and the implications for farmers’ food security, nutrition, and income is crucial to inform agricultural decision making, particularly to design viable strategies for long-term adaptation in a rapidly changing world.

Local knowledge is a relatively untapped source of information on the impacts of climate change on local communities and their adaptation strategies [11]. Here, drawing on farmers’ reports of observed changes in crop abundance and/or diversity at the level of the species or variety, we describe patterns of climate-related changes in crop diversity and the potential impacts of such changes on farmer’s nutrition. Finally, we discuss how studies on local farmers’ knowledge contribute to crop diversity research and agricultural decision-making in the face of climate change.

Section snippets

Methods

We searched scientific literature databases covering the semantic fields of local knowledge and observations, crops, and climate change. We selected 95 articles published in English up to and including 2019, that documented changes in crop diversity reported by farmers and explicitly linked to medium-term to long-term climate change (see SI 1 for details). For each reported change, we (i) recorded the geographical location, the corresponding climate zone according to the Köppen–Geiger

Geographic and climatic distribution of observations

The 95 studies reporting farmers’ observations of climate-related changes in crops we reviewed were conducted in 34 countries, 87% of which were in small-scale farming systems. Only 14% of the studies focused specifically on the impacts of climate change on crops, while the majority (86%) mentioned impacts on crops among other elements affected by climate change (e.g. water availability, natural ecosystems, forests). Our results reveal very uneven geographic and climatic distribution of

Discussion

Our findings suggest that farmers’ observations are a valuable source of information on climate-related changes in local crop diversity. However, to understand global trends, research should aim to fill two important gaps, namely the strong geographical clustering of studies and the strong focus on small-scale farming systems. Our review showed that available literature is focused on a small number of regions in Asia and Africa where climate change is particularly obvious (e.g. in the

Conclusion

Farmers across the world are reacting to the combined effects of climate and non-climate drivers of change by adjusting their crop portfolios. While such adjustments involve both the adoption and the abandonment of certain crops or landraces, we identified a general trend involving the adoption of water-demanding horticultural crops with little energy content. We argue that this trend may threatens the resilience of local cultivation systems and livelihoods. Our review calls for coordinated

Conflict of interest statement

Nothing declared.

References and recommended reading

Papers of particular interest, published within the period of review, have been highlighted as:

  • • of special interest

CRediT authorship contribution statement

Vanesse Labeyrie: Conceptualization, Funding acquisition, Data curation, Methodology, Formal analysis, Visualization, Writing - original draft, Writing - review & editing. Delphine Renard: Conceptualization, Funding acquisition, Data curation, Methodology, Formal analysis, Visualization, Writing - original draft, Writing - review & editing. Yildiz Aumeeruddy-Thomas: Methodology, Writing - review & editing. Petra Benyei: Data curation, Methodology, Writing - review & editing. Sophie Caillon:

Acknowledgements

This work was conducted in the framework of NetDivA project (ID 1702-022), which was publicly funded through ANR (the French National Research Agency) under the ‘Programme d’Investissements d’Avenir’ reference ANR-10-LABX-001-01 Labex Agro and coordinated by Agropolis Fondation in the frame of I-SITE MUSE (ANR-16-IDEX-0006). Research leading to this paper has also received funding from the European Research Council under an ERC Consolidator Grant (FP7-771056-LICCI) and from another ‘Programme

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