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1. Environmental context and herbivore traits mediate the strength of associational effects in a meta‐analysis of crop diversity

   https://doi.org/10.1111/1365-2664.14382  

   Hahn, Philip G.; Cammarano, Joseph H. (April 2023, Journal of Applied Ecology)

   Abstract Crop diversification offers a promising solution to meet expanding global food demands while maintaining ecosystem services. Diversification strategies that use mixed planting to reduce pest damage (e.g. intercropping), termed ‘associational effects’ (AE) in the ecological literature, can decrease (associational resistance) or increase (associational susceptibility) herbivore abundance on a focal plant. While application of AE to agroecosystems typically reduces pest abundance, the range of outcomes varies widely.We conducted a meta‐analysis using 272 estimates of insect herbivore abundance on crops neighbored by a conspecific or heterospecific from 44 studies undertaken on six continents. We focus on four agricultural crops well represented from sites across the globe to test hypotheses related to understanding how herbivore traits (diet breadth, feeding guild, origin), plant traits (crop type, phylogenetic distance to neighbour) and environmental context (climate, experimental design) contribute to variation in the outcomes of AE.Overall, bicultures provided a strong reduction of insect abundance on the focal crop. Climate and interactions between herbivore traits, particularly diet breadth and origin, and plant traits or environmental context mediated the strength of AE.Bicultures provided the strongest reductions in insect abundance at low latitudes, and this effect decreased at higher latitudes but only for insects with certain traits. Abundance of generalist herbivores and globally distributed pests tended to be most strongly negatively affected by bicultures, under certain contexts, whereas specialist herbivores and native pests were less affected by neighbours.Synthesis and application. This meta‐analysis highlights that crop diversification schemes have an overall strongly beneficial effect of reducing pest abundance. However, there was also variability in the outcomes that is determined in part by the interactive effects of herbivore traits and environmental context. The results provide guidance for incorporating beneficial ecological interactions into integrated pest management strategies. 

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2. Narrow and Brittle or Broad and Nimble? Comparing Adaptive Capacity in Simplifying and Diversifying Farming Systems

   https://doi.org/10.3389/fsufs.2021.564900  

   Petersen-Rockney, Margiana; Baur, Patrick; Guzman, Aidee; Bender, S. Franz; Calo, Adam; Castillo, Federico; De Master, Kathryn; Dumont, Antoinette; Esquivel, Kenzo; Kremen, Claire; et al (March 2021, Frontiers in Sustainable Food Systems)

   null (Ed.)

   Humanity faces a triple threat of climate change, biodiversity loss, and global food insecurity. In response, increasing the general adaptive capacity of farming systems is essential. We identify two divergent strategies for building adaptive capacity. Simplifying processes seek to narrowly maximize production by shifting the basis of agricultural production toward centralized control of socially and ecologically homogenized systems. Diversifying processes cultivate social-ecological complexity in order to provide multiple ecosystem services, maintain management flexibility, and promote coordinated adaptation across levels. Through five primarily United States focused cases of distinct agricultural challenges—foodborne pathogens, drought, marginal lands, labor availability, and land access and tenure—we compare simplifying and diversifying responses to assess how these pathways differentially enhance or degrade the adaptive capacity of farming systems in the context of the triple threat. These cases show that diversifying processes can weave a form of broad and nimble adaptive capacity that is fundamentally distinct from the narrow and brittle adaptive capacity produced through simplification. We find that while there are structural limitations and tradeoffs to diversifying processes, adaptive capacity can be facilitated by empowering people and enhancing ecosystem functionality to proactively distribute resources and knowledge where needed and to nimbly respond to changing circumstances. Our cases suggest that, in order to garner the most adaptive benefits from diversification, farming systems should balance the pursuit of multiple goals, which in turn requires an inclusive process for active dialogue and negotiation among diverse perspectives. Instead of locking farming systems into pernicious cycles that reproduce social and ecological externalities, diversification processes can enable nimble responses to a broad spectrum of possible stressors and shocks, while also promoting social equity and ecological sustainability. 

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3. Forgotten forests: expanding potential land use in traditional Hawaiian agroecosystems, and the social-ecological implications

   https://doi.org/10.5751/ES-14656-280421  

   Lee, Tiffany; Lincoln, Noa (January 2023, Ecology and Society)

   The development of agricultural systems is a fundamental component of social-ecological transformation and a predominant factor influencing social behavior and structuring. However, oversimplification of traditional agricultural production often occurs and limits the understanding of past populations’ abilities to mitigate potential risks and enhance food security through effective land management strategies. The social-ecological traits that characterize the Hawaiian Islands provides a unique vantage to explore human ecodynamics over the longue durée and assess how these systems can be used to inform current and future land-use strategies, both locally and globally. Using the Hawaiian archipelago as a case study, digitized historical maps depicting a range of crop species and cropping systems were georeferenced to assess previous estimates of land use by early island populations and demonstrate the limitations of narratives constructed from previously modeled extents of land-use activity that rely solely on the preservation of archaeological remnants. The results of our mapped vegetation correspond well with the more intensive forms of agriculture that were included in previous models, but overall indicate that previous models do not fully represent the extent of land use by early island populations, missing vast applications of agroforestry and arboriculture. Based on our findings, we argue that the omission of cultivation systems not associated with physical infrastructure has vastly limited the comprehension of land use by early island populations and driven narratives in social-ecological dynamics that underestimate the extent of agricultural production while inferring sociopolitical outcomes based on the prevailing agricultural dichotomy. To remedy this limitation, we suggest a multimethods approach that integrates diverse data sets for an agricultural model that is more inclusive of all agricultural forms implemented by early Native Hawaiian populations and, therefore, is more representative of the extents of land use by island populations. 

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4. Understanding How Smallholders Integrated into Pericoupled and Telecoupled Systems

   https://doi.org/10.3390/su12041596  

   Dou, Yue; da Silva, Ramon; McCord, Paul; Zaehringer, Julie; Yang, Hongbo; Furumo, Paul; Zhang, Jian; Pizarro, J.; Liu, Jianguo (February 2020, Sustainability)

   Increasing connections and influences from near to far have changed social structures, access to natural resources, and essential livelihoods of smallholders (i.e., those with incomes generated primarily from natural resources on small rural properties). However, the potential benefits and negative impacts from these connections to smallholders’ livelihoods and social-ecological effects remain understudied. In this paper, we applied the frameworks of pericoupling and telecoupling (human-nature interactions between adjacent and distant systems, respectively) to systematically investigate how the flows linking smallholder systems to other systems affect their livelihoods, and causing varying economic, social, and environmental effects from case to case. We synthesized 12 cases of smallholder systems around the world that are linked to adjacent and distant systems through flows of goods, people, resources, and/or information. In each case, we summarized smallholders’ agency, i.e., capability on the formation or operation of these flows, and the changes on livelihoods on the economic, social, and environment effects. Results suggest that strong smallholder agency is associated more with positive than negative effects. Smallholders with medium to high agency have greater overall well-being within the area of interest. Smallholders integrated in pericoupled systems often have strong agency. Being spillover systems in an intercoupled system (e.g., large-scale agricultural investments) can often cause negative outcomes unless smallholders have additional pericoupling flows. Our findings suggest one potential approach to ending poverty and increasing well-being for smallholders is creating and increasing pericoupling flows to empower smallholders for desired livelihood and social-ecological outcomes. 

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5. Buffering new risks? Environmental, social and economic changes in the Turkana Basin during and after the African Humid Period

   https://doi.org/10.1177/09596836221121766  

   Hildebrand, Elisabeth; Grillo, Katherine M.; Chritz, Kendra L.; Fischer, Markus L.; Goldstein, Steven T.; Janzen, Anneke; Junginger, Annett; Kinyanjui, Rahab N.; Ndiema, Emmanuel; Sawchuk, Elizabeth; et al (October 2022, The Holocene)

   This paper evaluates risk-oriented frameworks for explaining environmental, social, and economic changes faced by fishing and herding communities in the Turkana Basin during and after the African Humid Period (AHP, 15–5 ka). The orbitally-forced AHP created moist conditions, high lake levels, and unusual hydrological connections across much of northern and eastern Africa. As arid conditions set in and rainfall decreased between 5.3 and 3.9 ka in eastern Africa, Lake Turkana (NW Kenya) shrank dramatically. Shoreline retreat coincided with an expansion of open plains, creating new ecological conditions and potential opportunities for early herders in the basin. In this changing landscape, economies shifted from food procurement (fishing/hunting aquatic resources) to food production (herding), likely through both in-migration by pastoralists and adoption of herding by local fishers. Early pastoralists also built at least seven megalithic pillar sites that served as communal cemeteries during this time. Recent research has shown that local environmental dynamics – both during and after the AHP – were complex, demanding a more careful interrogation of the notion that post-AHP life entailed new and/or heightened risks. Risk-buffering strategies might include mobility, diversification, physical storage, and exchange. Archaeologists working around Lake Turkana have proposed that economic shifts from fishing to pastoralism entailed increased mobility as a risk-buffering strategy to deal with aridity and resource unpredictability, and that pillar sites – as fixed landmarks in an unstable landscape – provided settings for congregation and exchange amongst increasingly mobile herding communities. However, recent research has shown that local environmental dynamics in the Lake Turkana basin – both during and after the AHP – were more complex than previously thought, necessitating re-evaluation of the notion that post-AHP life entailed new and/or heightened risks. Here, we explore risk buffering strategies (e.g. mobility, diversification, physical storage and/or exchange) as only one category of potential explanation for the new social practices observed in the region at this time. Gauging their applicability requires us to (a) assess the spatial mobility of communities and individuals interred at pillar sites; (b) evaluate whether and how mobility strategies may have changed as pastoralism supplanted fishing; and (c) examine alternative explanations for social and economic changes. 

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