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Bonthoux S.,French National Institute for Agricultural Research | Bonthoux S.,CNRS Cities, Territories, Environment and Societies | Baselga A.,University of Santiago de Compostela | Balent G.,French National Institute for Agricultural Research
PLoS ONE | Year: 2013

To predict the impact of environmental change on species distributions, it has been hypothesized that community-level models could give some benefits compared to species-level models. In this study we have assessed the performance of these two approaches. We surveyed 256 bird communities in an agricultural landscape in southwest France at the same locations in 1982 and 2007. We compared the ability of CQO (canonical quadratic ordination; a method of community-level GLM) and GLMs (generalized linear models) to i) explain species distributions in 1982 and ii) predict species distributions, community composition and species richness in 2007, after land cover change. Our results show that models accounting for shared patterns between species (CQO) slightly better explain the distribution of rare species than models that ignore them (GLMs). Conversely, the predictive performances were better for GLMs than for CQO. At the assemblage level, both CQO and GLMs overestimated species richness, compared with that actually observed in 2007, and projected community composition was only moderately similar to that observed in 2007. Species richness projections tended to be more accurate in sites where land cover change was more marked. In contrast, the composition projections tended to be less accurate in those sites. Both modelling approaches showed a similar but limited ability to predict species distribution and assemblage composition under conditions of land cover change. Our study supports the idea that our community-level model can improve understanding of rare species patterns but that species-level models can provide slightly more accurate predictions of species distributions. At the community level, the similar performance of both approaches for predicting patterns of assemblage variation suggests that species tend to respond individualistically or, alternatively, that our community model was unable to effectively account for the emergent community patterns. © 2013 Bonthoux et al.

Bonthoux S.,CNRS Cities, Territories, Environment and Societies | Balent G.,French National Institute for Agricultural Research
Ecological Complexity | Year: 2015

Metacommunity theory provides a framework to understand how ecological communities vary in space and time. However, few studies have investigated metacommunity processes in a context of long term changes. Environmental changes can impact species distribution and therefore the structure of metacommunities. Using two complementary methods, this study evaluated the temporal variability of bird metacommunity processes in an agricultural landscape after 25 years of changes in land-cover. Bird and landscape data were recorded in the same locations using a series of 256 point counts in 1982 and 2007. First, variance partitioning was applied to quantify the roles of environmental filtering (i.e. landscape composition variables) and spatial variables to organize bird metacommunities each year. Second, changes in the structure of the bird metacommunity were examined by quantifying three of its components: coherence, species turnover and species range boundary clumping. Our results demonstrate that landscape variables explained slightly more bird metacommunity patterns than spatial variation of unknown origin each year. The bird metacommunity had a Clementsian structure (i.e. grouped distribution of species along environmental gradients) which was correlated with a landscape gradient ranging from open farmland to wooded sites. This structure was similar each year. To conclude, the study shows that environmental filtering with specializations to different habitats is a major process in determining bird metacommunities in landscapes. Moreover, our results suggest that metacommunity structure can remain constant over time despite demographic and environmental changes. © 2015 Elsevier B.V.

Minassian H.T.,CNRS Cities, Territories, Environment and Societies
Annales de Geographie | Year: 2016

Video games are today a major cultural practice, present in many parts of society. Nevertheless, we still lack precise studies on the place they occupy in everyday life. A study of the various publics and practices of video games, based upon a questionnaire by phone and semi-structured interviews, shows that the place of video games in the spaces of everyday life varies, according to the commitment of videogame players. Taking here the example of domestic places, this study gives an indication on the importance of this leisure in everyday life of the players and, at the same time, shows the capacity of individuals to produce and appropriate their home. Thus, domestic space appears as a topological, appropriated and negotiated space. © Armand Colin.

In the cities of the Maghreb, informal settlements are proving to be a privileged observatory of the relations between institutional policies and social dynamics. The focus here is put on the subtle links between the processes of marginalization and informalization and forms of domination of the populations concerned. The segregation and injustice that characterize the legalization policy undertaken by the State in the late 1980s had disgruntled the aspirations of empowerment and affirmation of the urbanity of the inhabitants of Cherarba. The government lost its legitimacy among residents and the neighborhood then passed into the hands of radical Islamist opposition who had to turn to informal channels to finance its activities. People’s expectations and hopes of change this time encountered aggressive Islamist authoritarianism and the situation passed from a symbolic kind of violence to deadly violence that was probably the cause of the change in position of a large part of the population : a change in position and disaffection which she paid for by amassacre. The suppression of terrorismand the “pacification” that followed were accompanied by a desire of the government to reconquer the territory, through the revival of housing programs and development of several amenities. Residents of the area want only one thing : turn the page of the Civil War and delete the terrorist image of Cherarba. The government’s relations with the populations of informal settlements are forged with a form of government whose purpose is primarily political, which even more strongly raises the democratic question, especially in the current context of Arab countries. © Armand Colin.

Sellami H.,Catholic University of Louvain | La Jeunesse I.,CNRS Cities, Territories, Environment and Societies | La Jeunesse I.,French National Center for Scientific Research | Baghdadi N.,IRSTEA | Vanclooster M.,Catholic University of Louvain
Hydrology and Earth System Sciences | Year: 2014

In this study a method for propagating the hydrological model uncertainty in discharge predictions of ungauged Mediterranean catchments using a model parameter regionalization approach is presented. The method is developed and tested for the Thau catchment located in Southern France using the SWAT hydrological model. Regionalization of model parameters, based on physical similarity measured between gauged and ungauged catchment attributes, is a popular methodology for discharge prediction in ungauged basins, but it is often confronted with an arbitrary criterion for selecting the "behavioral" model parameter sets (Mps) at the gauged catchment. A more objective method is provided in this paper where the transferrable Mps are selected based on the similarity between the donor and the receptor catchments. In addition, the method allows propagating the modeling uncertainty while transferring the Mps to the ungauged catchments. Results indicate that physically similar catchments located within the same geographic and climatic region may exhibit similar hydrological behavior and can also be affected by similar model prediction uncertainty. Furthermore, the results suggest that model prediction uncertainty at the ungauged catchment increases as the dissimilarity between the donor and the receptor catchments increases. The methodology presented in this paper can be replicated and used in regionalization of any hydrological model parameters for estimating streamflow at ungauged catchment. © Author(s) 2014. CC Attribution 3.0 License.

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