publications
2024
- OneEarthHalting the expansion of pasture in the Brazilian AmazonErasmus K. H. J. zu Ermgassen, Marcos Adami, Michel E. D. Chaves, and 2 more authorsOne Earth, Nov 2024Publisher: Elsevier
There are growing hopes that improved supply chain traceability can break the link between pasture-based cattle ranching and deforestation in the Amazon. Here, we caution that supply chains are but one part of the puzzle—a combination of policies are needed to end the expansion of pasture.
- NatSustainCharacterizing culture’s influence in land systemsLeonie Hodel, Yann Waroux, and Rachael D GarrettNature Sustainability, Nov 2024
Group-shared attributes, coded in cultural systems, heavily influence how land is used. Despite recent advances in behavioural theory, the central role of culture in land-use decision-making and linked sustainability outcomes is underexplored. We expanded on institutional analysis and system-dynamics frameworks to analyse 66 studies that causally link culture to land use. We found that most studies focus on norms, practices, values or meanings. These can lead actors to maintain a particular land use, which is coded into cultural systems, adding to the land system’s resilience. Internal group events or changes in structural factors can also lead to shifting norms and values, changing land use or destabilizing systems, leading to new system dynamics or resistance to new feedbacks. Our findings further link cultural underpinnings of land systems to positive and negative sustainability outcomes. We call for further research on the role of culture in land-system dynamics.
2021
- ERLHave food supply chain policies improved forest conservation and rural livelihoods? A systematic reviewRachael D. Garrett, Samuel A. Levy, Florian Gollnow, and 2 more authorsEnvironmental Research Letters, Nov 2021
To address concerns about the negative impacts of food supply chains in forest regions, a growing number of companies have adopted policies to influence their suppliers’ behaviors. With a focus on forest-risk food supply chains, we provide a systematic review of the conservation and livelihood outcomes of the mechanisms that companies use to implement their forest-focused supply chain policies (FSPs)—certifications, codes of conduct, and market exclusion mechanisms. More than half of the 37 cases that rigorously measure the outcomes of FSP implementation mechanisms find additional conservation and livelihood benefits resulting from the policies. Positive livelihood outcomes are more common than conservation additionality and most often pertain to improvements in farm income through increases in crop yields on coffee and cocoa farms that have adopted certifications or codes of conduct. However, in some cases certifications lead to a reduction in net household income as farmers increasingly specialize in the certified commodity and spend more on food purchases. Among the five cases that examine conservation and livelihoods simultaneously, there is no evidence of tradeoffs or synergies—most often an improvement in one type of outcome is associated with no change in the other. Interactions with public conservation and agricultural policies influence the conservation gains achieved by all mechanisms, while the marketing attributes of cooperatives and buying companies play a large role in determining the livelihood outcomes associated with certification. Compliance with the forest requirements of FSP implementation mechanisms is high, but challenges to geospatial monitoring and land use related selection biases limit the overall benefits of these policies. Given the highly variable methods and limited evidence base, additional rigorous research across a greater variety of contexts is urgently needed to better understand if and when FSPs can be successful in achieving synergies between conservation and livelihoods.
- LSSThe role of culture in land system scienceYann Waroux, Rachael D. Garrett, Mollie Chapman, and 5 more authorsJournal of Land Use Science, Nov 2021
Land system science (LSS) has substantially advanced understanding of land dynamics throughout the world. However, studies that explicitly address the causative role of culture in land systems have been fairly limited relative to those examining other structural dimensions (e.g. markets, policies, climate). In this paper, we aim to start a discussion on how to better include culture in LSS. Through four examples, we show how aspects of culture influence land systems in myriad ways. Building on existing causal land system models, we propose a conceptual framework for the role of culture in land use and summarize promising methodological innovations for exploring it further. We conclude with some thoughts on how the study of culture and its integration through reflexive, locally grounded approaches, while challenging, provides new opportunities for the development of LSS.
- ELife3D cell neighbour dynamics in growing pseudostratified epitheliaHarold Fernando Gomez, Mathilde Sabine Dumond, Leonie Hodel, and 2 more authorsNov 2021
During morphogenesis, epithelial sheets remodel into complex geometries. How cells dynamically organise their contact with neighbouring cells in these tightly packed tissues is poorly understood. We have used light-sheet microscopy of growing mouse embryonic lung explants, three-dimensional cell segmentation, and physical theory to unravel the principles behind 3D cell organisation in growing pseudostratified epithelia. We find that cells have highly irregular 3D shapes and exhibit numerous neighbour intercalations along the apical-basal axis as well as over time. Despite the fluidic nature, the cell packing configurations follow fundamental relationships previously described for apical epithelial layers, that is, Euler’s polyhedron formula, Lewis’ law, and Aboav-Weaire’s law, at all times and across the entire tissue thickness. This arrangement minimises the lateral cell-cell surface energy for a given cross-sectional area variability, generated primarily by the distribution and movement of nuclei. We conclude that the complex 3D cell organisation in growing epithelia emerges from simple physical principles.
- BMCMorphological study of embryonic Chd8+/− mouse brains using light-sheet microscopyHarold F. Gómez, Leonie Hodel, Odyssé Michos, and 1 more authorNov 2021
Objective:Autism spectrum disorder (ASD) encompasses a group of neurodevelopmental conditions that remain poorly understood due to their genetic complexity. CHD8 is a risk allele strongly associated with ASD, and heterozygous Chd8 loss-of-function mice have been reported to exhibit macrocephaly in early postnatal stages. In this work, we sought to identify measurable brain alterations in early embryonic development. Results:We performed light-sheet fluorescence microscopy imaging of N-cadherin stained and optically cleared Chd8+/− and wild-type mouse brains at embryonic day 12.5 (E12.5). We report a detailed morphometric characterization of embryonic brain shapes and cortical neuroepithelial apical architecture. While Chd8+/− characteristic expansion of the forebrain and midbrain was not observed this early in embryogenesis, a tendency for a decreased lateral ventricular sphericity and an increased intraocular distance in Chd8+/− brains was found compared to controls. This study advocates the use of high-resolution microscopy technologies and multi-scale morphometric analyses of target brain regions to explore the etiology and cellular basis of Chd8 haploinsufficiency.
2019
- bioRxivAboave-Weaire’s law in epithelia results from an angle constraint in contiguous polygonal latticesRoman Vetter, Marco Kokic, Harold Gómez, and 6 more authorsNov 2019
It has long been noted that the cell arrangements in epithelia, regardless of their origin, exhibit some striking regularities: first, the average number of cell neighbours at the apical side is (close to) six. Second, the average apical cell area is linearly related to the number of neighbours, such that cells with larger apical area have on average more neighbours, a relation termed Lewis’ law. Third, Aboav-Weaire’s (AW) law relates the number of neighbours that a cell has to that of its direct neighbours. While the first rule can be explained with topological constraints in contiguous polygonal lattices, and the second rule (Lewis’ law) with the minimisation of the lateral contact surface energy, the driving forces behind the AW law have remained elusive. We now show that also the AW law emerges to minimise the lateral contact surface energy in polygonal lattices by driving cells to the most regular polygonal shape, but while Lewis’ law regulates the side lengths, the AW law controls the angles. We conclude that global apical epithelial organization is the result of energy minimisation under topological constraints.