Space and water, key factors of urban growth in the South-Western United States: Case study of Tucson and Pima County (Arizona)

François-Michel Le Tourneau, Fabrice Dubertret, L'espace géographique, Tome 48 n° 1-2019, Pages 39-56

Urban sprawl is one of the most important factors of landscape transformation in the United States. The Southwestern region, especially the state of Arizona, is often viewed as a example of this phenomenon in which significant quantities of space and water are consumed. The city of Tucson and the Pima County, where it is located, seem to be a counter-model in this respect since they have been trying to dissociate themselves from the ‘‘growth at all costs’’ model since the 1980s. Based on the statistics and spatial data available on this area, this paper compares Tucson’s declared aims and the reality of its spatial development. Crossing data from different sources, we are able to highlight not only some successes pertaining to water resource management, but also the difficulties that the authorities face in monitoring the transformation of the landscape and the urbanization, as well as resulting imbalances which will prove difficult to rectify in the medium or long term.

Optimality Versus Viability in Groundwater Management with Environmental Flows

Jean-Christophe Pereau, Alexandre Pryet, Tina Rambonilaza, Ecological Economics, Volume 161, July 2019, Pages 109-120

The protection of environmental flows is a main challenge pursued by water regulating agencies in their groundwater management policies. A stylised hydro-economic model with natural drainage is used to compare the outcome of the optimal control approach in which environmental flows are introduced as an externality with the viable approach in which environmental flows are modelled as a constraint to satisfy. The optimal and viable paths for the water table, water extraction for irrigation and environmental flows are analytically derived together with their long-term values. We show how results are sensitive to some key parameters like the discount factor and the monetary value of the externality in the optimal control approach. We show how the value of the environmental flows target in the viable approach can be derived from the optimal control approach. Numerical simulations based on the Western La Mancha aquifer illustrate the main results of the study. Read article.


François-Michel Le Tourneau, CNRS Editions, April 4, 2019

« L’Amazonie n’existe pas » : c’est sur ce constat paradoxal que s’ouvre cet ouvrage, pour souligner que la dimension mythique et mythologique de cette région l’emporte souvent sur la réalité géographique. Tout commence par son nom, qui fait référence à une légende tirée de l’Antiquité grecque, à mille lieues du contexte de la forêt équatoriale que les voyageurs du XVIe siècle venaient d’aborder…

Dès leur arrivée, les Européens ont eu du mal à comprendre l’Amazonie, mais plutôt que d’apprendre des sociétés locales à le décoder, ils ont cherché à l’analyser sur la base de leurs références culturelles. L’ouverture de la grande forêt aux scientifiques, à partir du XIXe siècle, n’a pas dissipé cette méprise. Deux visions oscillent alors, toutes deux encore très ancrées dans nos imaginaires : celle de « l’enfer vert », hostile à l’homme, qui demande à être dompté, et celle de la « forêt vierge », pure et intouchée, qu’il faut préserver en l’état. Mal informées sur l’Amazonie, les sociétés occidentales s’obstinent à y implanter des modèles de gestion en totale inadéquation avec son environnement, entraînant des conséquences dramatiques pour les équilibres écologiques non seulement sur le plan local mais aussi sur le plan régional, voire global.

Consacré à l’Amazonie brésilienne qui représente près de 60 % de la forêt « amazonienne », cet ouvrage s’attache à étudier l’histoire longue des populations et de l’environnement en montrant que la vision occidentale relève d’un « malentendu » qu’il est urgent de lever. 

Land tenure in Arizona: public land domination and the paradoxal complexity of land management

François-Michel Le Tourneau, Cybergeo, article 888, March 13, 2019

Land tenure in the Western US, in particular in the most recent states, reflects the processes of appropriation which took place after the annexing of Northern Mexico by the US in 1848. It is characterized by a high proportion of public (federal and state) lands, as well as by a spatial configuration where influences of the homesteading and of land grants to railroad companies are still highly visible. Another aspect of land tenure in those states is its complexity, the number of public agencies involved and the multiple scales of intervention implied in its management. The state of Arizona is a good example of such dynamics. The paper therefore describes the private appropriation of lands in this state and the current extent of private lands. We then review the categories of public lands and their history. Finally, we pinpoint a number of difficulties that derive from the contemporary configuration of land tenure in Arizona, especially when local policies are to be developed. Link to site.

An Instrumented Methodology to Analyze and Categorize Information Flows on Twitter Using NLP and Deep Learning : A Use Case on Air Quality

Brigitte Juanals, Jean-Luc Minel, Lecture Notes in Artificial Intelligence, Springer, 2018, Foundations of Intelligent Systems, pp.315-322.

This article focuses on the development of an instrumented methodology for modeling and analyzing the circulation message flows concerning air quality on the social network Twitter. This methodology aims at describing and representing, on the one hand, the modes of circulation and distribution of message flows on this social media and, on the other hand, the content exchanged between stakeholders. To achieve this, we developed Natural Language Processing (NLP) tools and a classifier based on Deep Learning approaches in order to categorize messages from scratch. The conceptual and instrumented methodology presented is part of a broader interdisciplinary methodology, based on quantitative and qualitative methods, for the study of communication in environmental health. A use case of air quality is presented. Read the article...

Public participation, trust and data sharing: gardens as hubs for citizen science and environmental health literacy efforts

Shana Sandhaus, Dorsey Kaufmann and Monica Ramirez-Andreotta, International Journal of Science Education Nov 7, 2018

Gardenroots: A Citizen Science Project (2015) is the product of a needs assessment, revealing environmental quality concerns of gardeners living near hazardous waste or resource extraction activities. Participants were trained, collected garden samples for analysis, and later received their data visualized (individual and aggregated) via community events or mail. This article describes participant motivations, changes in knowledge and efficacy, and whether these depend on the mode of data sharing and visualization. Motivations were internal, and self-efficacy increased, while knowledge and satisfaction were higher in event attendees due to increased researcher contact. This reveals importance of data-sharing events, data visualizations, and participatory research processes. Link to article...

LE blog des SEPT bornes : La série « Guyane », entre fiction et réalité

François-Michel Le Tourneau, CNRS Le Journal 2018/09

À l’occasion de la diffusion du premier épisode de la Saison 2 de « Guyane » sur Canal+, François-Michel Le Tourneau  revient sur la Saison 1 et débroussaille le vrai du faux. De quoi casser quelques idées reçues sur l’orpaillage clandestin. Voir l'article...

Clade diversification dynamics and the biotic andabiotic controls of speciation and extinction rates

Robin Aguilée, Fanny Gascuel, Amaury Lambert, Régis Ferrière, Nature Communications August 2018

How ecological interactions, genetic processes, and environmental variability jointly shape the evolution of species diversity remains a challenging problem in biology. We developed an individual-based model of clade diversification to predict macroevolutionary dynamics when resource competition, genetic differentiation, and landscape fluctuations interact. Diversification begins with a phase of geographic adaptive radiation. Extinction rates rise sharply at the onset of the next phase. In this phase of niche self-structuring, speciation and extinctionprocesses, albeit driven by biotic mechanisms (competition and hybridization), have essentially constant rates, determined primarily by the abiotic pace of landscape dynamics. The final phase of diversification begins when intense competition prevents dispersing individuals from  establishing  new  populations.  Species’ ranges  shrink,  causing  negative  diversity-dependence of speciation rates. These results show how ecological and microevolutionary processes shape macroevolutionary dynamics and rates; they caution against the notion of ecological limits to diversity, and suggest new directions for the phylogenetic analysis of diversification.

Open access to article licensed under a Creative Commons Attribution 4.0 Internatinal License

Using Small Spatial Units to Refine Our Perception of Rural America

François-Michel Le Tourneau, GeoJournal August 2018 Vol. 82 n° 4 p. 803–817

More than half of the US rural population lives inside metro or micropolitan areas and even at more disaggregated scales, such as the census tracts, most spatial units mix rural and urban population. At a national scale, only 30% of the country are inhabited by 100% urban or 100% rural population, implying that more than two third of the US territory are somewhere in between both situations. As the rural/urban dichotomy appears today to be blurred by the emergence of new phenomena like rurbanization or exurbanization, our perception of rural America may be somewhat twisted and the reality of rural areas underplayed. This paper focuses on using finer-grade spatial units such as the census blocks and block groups, in order to provide new elements about the extension, localization and characteristics of rural America as well as about its inner dynamics. To that end, we analyze and process geographical and social data at these two levels of information, and use population density as a main factor of analysis. This allows us not only to propose new measurement of the extent of rural space in the USA but also to propose a new vision of its spatial dynamics by studying how several social indicators such as income, median age or sex ratio reveal regional and micro-regional variations and situations in the rural part of the US.

Drôle de guerre en forêt

François-Michel Le Tourneau, CNRS Le Journal 2017/11

Le géographe François-Michel Le Tourneau a mené trois missions dans la forêt guyanaise, au côté des militaires et gendarmes qui combattent l'orpaillage illégal. Mais rien ne semble dissuader les chercheurs d'or brésiliens, ou garimpeiros, d'abandonner leur lucrative activité...

The “Common-Pool Resources” Put to the Test of Mining Activity: The Case of the Constancia Project in Peru

Claude Le Gouill, Critique Internationale 2017/4 N° 77

The article draws upon the natural resources management model developed by economist Elinor Ostrom to examine the Constancia (Peru) mining project. It's a study of local communities’ capacity for decentralized and adaptive management within the new rhetoric of sustainable mining advanced by the companies. In what ways does this new mode of regulation allow local communities to provide for their self-organization? Do they have any influence in the very hierarchical power relations characteristic of the mining context? At issue is their ability to maintain sovereignty over their territories and manage the “Common-Pool Resources”. By taking into account the mediating role played by new professionals in the participatory process institutionalized by the state, the Peruvian legal framework offers a relevant example for analyzing the relationships of these communities with the mining companies.

Environmental Conflict and Public Participation in the Semi-arid Southwestern United States: The Rosemont Mining Proposal, Pima County, Arizona

Anne-Lise Boyer, Claude Le Gouill, Franck Poupeau, Lala Razafimahefa, Participations 2017/3 N° 19 p. 189-217

The study focuses on the public participation process that was implemented in the United States by the National Environmental Protection Act. It analyzes the stakeholders’ discourses, which were produced within institutional forums of participation in the case of the Rosemont mine proposal. Our results show that this kind of public participation reaches a socio-economically large and diverse public. However, the public is strongly controlled by interest groups, therefore the participation process can be defined in terms of “quantity” rather than “quality.” This article reveals that analyzing public participation helps to assess environmental controversies.

les etudes sur les amériques en france

 François-Michel Le Tourneau, Hélène Harter, Jean-Michel Lacroix et Paul-Henri Giraud (coord.), Institut des Amériques 2016

Présenter l’américanisme universitaire en France est une gageure tant cette tradition intellectuelle s’est diffusée dans le paysage des universités et centres de recherches. Marginale à son origine, ayant eu du mal à se frayer un chemin, elle est aujourd’hui une composante reconnue dans de nombreux centres de recherche, insérée dans les disciplines les plus diverses. Mais qu’est-ce que l’américanisme et peut-on y voir la moindre trace d’une unité qui justifierait l’emploi d’un seul substantif alors que le continent américain est éminemment pluriel ?

A la découverte des grands espaces américains

Le blog de François-Michel Le Tourneau, géographe et Directeur adjoint CNRS de l'UMI iGlobes