Les villages préhistoriques des bords des lacs circum-alpins entre le Ve et IVe millénaire av. J.-C.

Connus sous le nom populaire de palafittes, les habitats préhistoriques construits sur les rives des lacs subalpins du Néolithique à l’aube de l’âge du Fer (entre 5300 et 700 av. J.-C.) offrent des informations exceptionnelles sur l’évolution culturelle d’une importante région européenne, grâce à la préservation remarquable des matériaux organiques, en particulier du bois. À partir de la deuxième moitié du XXe siècle, le perfectionnement des techniques de fouille subaquatiques et de la dendrochronologie permettront la construction d’un schéma chronologique précis pour l’Europe nord-alpine. Les recherches contribueront à des observations d’ordre écologique à l’échelle locale et régionale et à l’identification des rythmes de développement des villages. Sous l’égide de l'UNESCO, les années 2010 verront la constitution d’un inventaire vaste et uniforme des sites préhistoriques des lacs circumalpins, classés Patrimoine culturel mondial en juin 2011.

Eco-evolutionary Dynamics of Individual-Based Food Webs

The past decade has seen the rise of high resolution datasets. One of the main surprises of analysing such data has been the discovery of a large genetic, phenotypic and behavioural variation and heterogeneous metabolic rates among individuals within natural populations. A parallel discovery from theory and experiments has shown a strong temporal convergence between evolutionary and ecological dynamics, but a general framework to analyse from individual-level processes the convergence between ecological and evolutionary dynamics and its implications for patterns of biodiversity in food webs has been particularly lacking. Here, as a first approximation to take into account intraspecific variability and the convergence between the ecological and evolutionary dynamics in large food webs, we develop a model from population genomics and microevolutionary processes that uses sexual reproduction, genetic-distance-based speciation and trophic interactions. We confront the model with the prey consumption per individual predator, species-level connectance and prey–predator diversity in several environmental situations using a large food web with approximately 25,000 sampled prey and predator individuals. We show higher than expected diversity of abundant species in heterogeneous environmental conditions and strong deviations from the observed distribution of individual prey consumption (i.e. individual connectivity per predator) in all the environmental conditions. The observed large variance in individual prey consumption regardless of the environmental variability collapsed species-level connectance after small increases in sampling effort. These results suggest (1) intraspecific variance in prey–predator interactions has a strong effect on the macroscopic properties of food webs and (2) intraspecific variance is a potential driver regulating the speed of the convergence between ecological and evolutionary dynamics in species-rich food webs. These results also suggest that genetic–ecological drift driven by sexual reproduction, equal feeding rate among predator individuals, mutations and genetic-distance-based speciation can be used as a neutral food web dynamics test to detect the ecological and microevolutionary processes underlying the observed patterns of individual and species-based food webs at local and macroecological scales.

Adaptation to Changes in the Coffee Value Chain and the Price of Coiffee among Coffee Producers in Two Villages in Kilimanjaro, Tanzania

Market liberalization in Tanzania has eroded the monopoly of the cooperative unions by allowing private coffee buyers (PCBs) to compete with them on equal footing. Similarly, farmers groups and primary societies are now allowed to sell coffee at auction. Thus, farmers have various options for selling their coffee. Similarly, the coffee industry has experienced large fluctuations in prices and stagnation in production. How do farmers react to these changes? Can and do farmers profit from different market conditions and sell to different traders at the lower end of the value chain, or do they remain with cooperatives or farmers groups? This study was conducted in Mruwia and Mshiri villages in Moshi Rural district. Whereas Mshiri village remains attached to the Kilimanjaro Native Cooperative Union (KNCU), Mruwia has detached from this organization and sells coffee independently. The sample (103) was randomly selected from the coffee farmers in the two villages. Data were collected through surveys, focus group discussions (FGDs), and socio-anthropological methods (participant-observation, biographies, and thematic interviews). Results indicate that the selection of whom to sell coffee depends largely on farmers’ dependence on coffee and prices, other benefits accrued, and whether the initial costs are covered by buyers. Additionally, most respondents did not sell coffee to PCBs. Thus, prices, the institutional infrastructure, and the structure of local communities were important when making decisions about how and with whom to trade.

Del castagno e della castanicoltura nelle contrade insubriche: tentativo di una sintesi eco-storica

Il contributo ripercorre la relazione uomo-castagno partendo dalle ultime glaciazioni per arrivare ai giorni nostri, con una crescente attenzione per le contrade insubriche, dove la castanicoltura raggiunse livelli straordinari di sviluppo. Dopo una sintesi critica sui primi indizi di coltivazione, si esamina la castanicoltura nel mondo greco e romano fino all’introduzione della coltivazione del castagno nell’area insubrica. Particolare attenzione è riservata al periodo aureo tardomedievale della castanicoltura nella Svizzera italiana, comprovato con dati linguistici, con l’analisi dei sistemi produttivi (composizione varietale, tecniche di essiccazione) e delle consuetudini locali. Si indagano in seguito le ragioni e le tappe storiche del declino della castanicoltura tradizionale. Si conclude discutendo la situazione attuale e le prospettive future dei castagneti a Sud delle Alpi, confrontati con alcuni problemi incalzanti come l’invecchiamento delle ceppaie nei cedui abbandonati e la comparsa di un insidioso parassita, il cinipide galligeno.

Eco-Evolutionary Spatial Dynamics. Rapid Evolution and Isolation Explain Food Web Persistence

One of the current challenges in evolutionary ecology is understanding the long-term persistence of contemporary-evolving predator–prey interactions across space and time. To address this, we developed an extension of a multi-locus, multi-trait eco-evolutionary individual-based model that incorporates several interacting species in explicit landscapes. We simulated eco-evolutionary dynamics of multiple species food webs with different degrees of connectance across soil-moisture islands. A broad set of parameter combinations led to the local extinction of species, but some species persisted, and this was associated with (1) high connectance and omnivory and (2) ongoing evolution, due to multi-trait genetic variability of the embedded species. Furthermore, persistence was highest at intermediate island distances, likely because of a balance between predation-induced extinction (strongest at short island distances) and the coupling of island diversity by top predators, which by travelling among islands exert global top-down control of biodiversity. In the simulations with high genetic variation, we also found widespread trait evolutionary changes indicative of eco-evolutionary dynamics. We discuss how the ever-increasing computing power and high-resolution data availability will soon allow researchers to start bridging the in vivo–in silico gap.

Mit Eco-Drive gegen Strassenlärm. Evaluation eines Interventionsprogramms zur Förderung eines leisen Fahrstils.

Strassenlärm ist diejenige Verkehrslärmquelle, die am meisten Menschen belastet. Veränderungen im Handeln der Lärmverursachenden stellen eine vielversprechende Möglichkeit dar, bisherige Lärmbekämpfungsmassnahmen zu ergänzen. Die vorliegende Studie, welche vom Schweizerischen Bundesamt für Umwelt und dem Ministerium für Umwelt, Landwirtschaft, Ernährung, Weinbau und Forsten Rheinland-Pfalz gefördert wurde, widmete sich der Frage, wie die Förderung eines leisen Fahrstils zur Bekämpfung von Strassenlärm nutzbar gemacht werden kann. Hierzu erarbeiteten wir ein Interventionsprogramm zur Förderung eines leisen Fahrstils, welches in Zusammenarbeit mit Mitarbeitenden einer Stadtverwaltung umgesetzt und evaluiert wurde. Die Ergebnisse dieser Studie deuten darauf hin, dass es sich lohnt, einen leisen Fahrstil im Rahmen der Lärmbekämpfung zu fördern; während der mehrwöchigen Durchführung des Programms konnte eine Reduktion der durchschnittlichen Drehzahl, des durchschnittlichen Treibstoffverbrauchs, des gemittelten Summenpegels des Motorengeräuschs wie auch der prozentualen Fahrzeit mit Motorengeräuschen über 60dB(A) beobachtet werden. Befragungen der TeilnehmerInnen gaben zudem Auskunft über die diesen Veränderungen zu Grunde liegende Motivstruktur. Wir präsentieren in diesem Bericht sowohl eine detaillierte Darstellung des verwendeten Interventionsprogramms, des Vorgehens bei dessen Evaluation, sowie die entsprechenden Auswertungen. Wir hoffen, dass durch diese Studie zukünftige Programme zur Förderung eines leisen Fahrstils angeregt werden und von unseren Ergebnissen profitieren können.

Do relocated villages experience more forest cover change? Resettlements, shifting cultivation and forests in the Lao PDR

This study explores the relationships between forest cover change and the village resettlement and land planning policies implemented in Laos, which have led to the relocation of remote and dispersed populations into clustered villages with easier access to state services and market facilities. We used the Global Forest Cover Change (2000–2012) and the most recent Lao Agricultural Census (2011) datasets to assess forest cover change in resettled and non-resettled villages throughout the country. We also reviewed a set of six case studies and performed an original case study in two villages of Luang Prabang province with 55 households, inquiring about relocation, land losses and intensification options. Our results show that resettled villages have greater baseline forest cover and total forest loss than most villages in Laos but not significant forest loss relative to that baseline. Resettled villages are consistently associated with forested areas, minority groups, and intermediate accessibility. The case studies highlight that resettlement coupled with land use planning does not necessarily lead to the abandonment of shifting cultivation or affect forest loss but lead to a re-spatialization of land use. This includes clustering of forest clearings, which might lead to fallow shortening and land degradation while limited intensification options exist in the resettled villages. This study provides a contribution to studying relationships between migration, forest cover change, livelihood strategies, land governance and agricultural practices in tropical forest environments.