Tour du Valat

Azay-le-Rideau, France

Tour du Valat

Azay-le-Rideau, France
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Dixon M.J.R.,United Nations Environment Programme World Conservation Monitoring Center | Loh J.,University of Kent | Davidson N.C.,Charles Sturt University | Davidson N.C.,Ford Motor Company | And 3 more authors.
Biological Conservation | Year: 2016

We present a method for estimating broad trends in ecosystem area based on incomplete and heterogeneous data, developing a proof-of-concept for the first indicator of change in area of natural wetland, the Wetland Extent Trends (WET) index. We use a variation of the Living Planet Index method, which is used for measuring global trends in wild vertebrate species abundance. The analysis is based on a database containing 1100 wetland extent time-series records and the method identifies and addresses ecological and biogeographic biases in the dataset. Globally, the natural WET index, excluding human-made wetlands, declined by about 30% on average between 1970 and 2008. Declines varied between regions from about 50% in Europe to about 17% in Oceania over the same period. The WET index fills an important gap in the ecosystem coverage of global biodiversity indicators and can track changes related to a number of current international policy objectives. The same method could be applied to other datasets to create indicators for other ecosystems with incomplete global data. © 2015 Elsevier B.V.

Devineau O.,Center dEcologie Fonctionnelle et Evolutive | Guillemain M.,Office National de la Chasse et de la Faune Sauvage | Johnson A.R.,Tour du Valat | Lebreton J.-D.,Fundacion Charles Darwin
Wildlife Biology | Year: 2010

The impact of waterfowl harvest on the dynamics of duck populations remains incompletely understood. While wide-scale monitoring and management programs have been set up in North America, far less has been done in Europe where populations and harvest are essentially managed at country level with a sole focus on population size. Hence, comparing North American waterfowl populations with European waterfowl populations could be useful in suggesting flyway-scale management options in Europe. In our paper, we analyse historical capture-recapture-recoveries data for the European teal Anas crecca crecca and we compare the computed survival and harvest rates to those obtained from a North American recovery data set for the green-winged teal Anas crecca carolinensis, its sister taxon. During 1960-1976, the annual probability of survival was slightly lower in Europe (average over sexes: 0.485 ± 0.101) than in North America (0.545 ± 0.010 for both sexes). Assuming a 30 ring reporting rate, our estimate of the annual harvest rate was about three times higher in Europe (average over sexes: 0.178 ± 0.051) than in North America (average over sexes: 0.071 ± 0.014). Although the European population increased over the study period and continues to do so, such a hunting pressure may potentially reduce our flexibility in managing this population due to uncertainties such as environmental changes, and have deleterious effects in the long term. We use our results to discuss waterfowl research and management in Europe. Initiating studies to estimate ring reporting rate would be an essential first step to properly evaluate the impact of harvest on the dynamics of the teal population in Europe. © 2010 Wildlife Biology.

Devictor V.,Tour du Valat | Devictor V.,University of Oxford | Devictor V.,French National Center for Scientific Research | Whittaker R.J.,University of Oxford | Beltrame C.,Tour du Valat
Diversity and Distributions | Year: 2010

Aim: We assess whether and how datasets collected by the general public, so-called citizen science programmes, can improve biogeographical studies and contribute to large-scale conservation target-setting. Location: Worldwide. Methods: We first set a general framework highlighting the prerequisites of a relevant dataset for conservation biogeography. We then illustrate how many different citizen science programmes currently running in different countries can be placed within this framework. Results: We highlight that citizen science is particularly useful to address issues spanning large temporal and spatial extents. We then show how datasets based on citizen science can be used to investigate major aspects of global change impacts on biodiversity. We further highlight why these programmes are also particularly valuable in developing the preventative and educational component of conservation biogeography. Main conclusions: Conservation biogeography requires considerable amounts of data collected over large spatial and/or temporal extents. Beyond increasing technical advances to collect and analyse these data, citizen science seems to be a highly valuable tool in many aspects. However, while citizen science programmes are now popular and increasingly used in several countries, they are lacking in many others. We argue that the development of citizen science programmes should be encouraged as they can both be highly valuable for conservation biogeography and promote the reconnection between people and nature and more generally between people and science. © 2010 Blackwell Publishing Ltd.

Kazoglou Y.,Municipality of Prespa | Fotiadis G.,Technological Educational Institute of Kavala | Vrahnakis M.,Technological Educational Institute of Kalamata | Koutseri I.,Society for the Protection of Prespa SPP | Crivelli A.,Tour du Valat
Ecohydrology and Hydrobiology | Year: 2011

The QBR (Riparian Forest Quality) index and the RMP (Riparian Macrophyte Protocol) were used to assess habitat quality and inventory riparian forests in four rivers sustaining the endemic Prespa trout (Salmo peristericus). Total QBR index and total riparian cover (first component of the QBR index) values were found significantly higher in the upper parts of Brajcinska and Kranska rivers, while lower values were recorded in the upper parts of Agios Germanos river and Leva stream. Cover structure, cover quality and channel alteration (the other three components of the QBR index) did not differ significantly between the four watersheds. The greater presence of Fagus sylvatica in the former rivers principally contributes to their increased total riparian area and riverbed cover compared to those of the two latter rivers. In the altitudes below 900 m.a.s.l., where gradients are gentle and human activities intense, vegetation types in all four systems change considerably with the participation of non-native species, while riparian area and riverbed cover are reduced.

Millet B.,Aix - Marseille University | Robert C.,Aix - Marseille University | Grillas P.,Tour du Valat | Coughlan C.,Center for Environment | Banas D.,University of Lorraine
Hydrobiologia | Year: 2010

In shallow ecosystems, the short temporal variability of available underwater irradiance is considered a major process controlling submerged macrophytes development. Mechanistic models that estimate photosynthetically available radiation (PAR) in shallow ecosystems at very short time scales are needed for use in predicting submerged macrophyte growth and persistence. We coupled a 2D horizontal circulation model with, first, a 1D vertical numerical model of suspended solid (SS) re-suspension, diffusion and settling, and next, with a model of vertical extinction of irradiance, previously validated at the same site. The study site was the Vaccarès lagoon (France) where a large data set of high frequency bottom irradiance and SS concentration were available. SS and irradiance measurements were conducted at a vertical study station, monitored over a 6 month period (from December 1995 to May 1996) characterized by wide-ranging wind velocities (1.5-18 ms-1). In addition, grain-size analyses conducted over the whole lagoon, allowed adaptation of the 1D numerical model to the silt-sized (7 μm) and clay-sized (0.3 μm) fractions that prevail in the local sediment. First, model results showed that about 60% of the variance in bottom irradiance time series can be explained by our deterministic formulations, thus representing the same level of efficiency than those already obtained by a stochastic model previously developed with the same data set. Second, model results showed that the fit of the model to the field data (SS concentrations and bottom irradiance) depended mainly on storm occurrence and season (winter or spring). Finally, model results suggested that the underwater irradiance regime was controlled by seasonal succession of the horizontal circulation of turbid water in the lagoon, with increased solids concentrations in winter, followed by submerged canopy development and decreased solids concentrations in spring. © Springer Science+Business Media B.V. 2009.

Demnati F.,University Mohamed Khider of Biskra | Allache F.,University Mohamed Khider of Biskra | Ernoul L.,Tour du Valat | Samraoui B.,King Saud University
Ambio | Year: 2012

The objective of our study was to identify how actors from the main socio-economic sectors perceive their interactions and impacts on a sensitive wetland in an arid climate, specifically the salt pans of Chott Merouane in Algeria. The results revealed that there are three main economic stakes including agriculture, livestock production and salt mining, each activity providing a great benefit for local and national populations. The local population perceived that the current activities are conducted in such a way that they created conflict between socio-economic sectors and caused a threat for long term sustainability of the wetlands. The results highlighted the need to initiate an integrated management approach between the different sectors and to develop a shared vision for the territory. copyright; Royal Swedish Academy of Sciences 2012.

Ernoul L.,Tour du Valat | Ernoul L.,Aix - Marseille University | Sandoz A.,Tour du Valat | Sandoz A.,Aix - Marseille University | Fellague A.,Tour du Valat
Ocean and Coastal Management | Year: 2012

Land cover and land cover change, both in time and space, were analyzed in the Gediz Delta (Turkey) and the Rhone Delta (Camargue, France) to determine the evolution of two great deltas in the Mediterranean basin. Geographical Information Systems and remote sensing were used to estimate the impact of land use changes on habitats over a 35 year period from 1975 to 2010. The first images used MSS captures from 1975 with a spatial resolution of 80 m; precision was gained from 1980 with the use of LandSat satellite images (spatial resolution of 30 m in multi-band modes) and then with satellite images from Spot 4, Spot 5 and Google Earth Pro. The images were classified using GEO Image and then analyzed and laid out with the aid of ArcGis and Quantum GIS 1.7.0 software programs. The data was verified using a confusion matrix, which provided between 85 and 95% global precision rates. This qualitative data on the evolution reveals that despite important conservation measures (including Ramsar site, National Park, and Natural Park status) both deltas have been subject to substantial changes over this time period. Important declines in natural habitats such as sansouires, beaches, dunes and reed beds have been replaced by increased areas of urbanization and annual agricultural crops. This analysis demonstrates the important pressures that continue to impact the delicate natural Mediterranean habitats and puts in evidence the need to enforce current legislation in order to conserve the deltas in the future. © 2012 Elsevier Ltd.

Demnati F.,University Mohamed Khider of Biskra | Allache F.,University Mohamed Khider of Biskra | Ernoul L.,Tour du Valat
Environment, Development and Sustainability | Year: 2015

Faced with limited impact and growing pressures, conservation organizations are applying new approaches incorporating the local populations in the conservation processes. The lack of social, cultural and economic information concerning the population has limited the implication of the local population and the impact in many projects. Raising awareness begins with understanding the target population, such as identifying their current views on a particular issue and knowing how they receive their information. This case study defined the different existing population types using socio-economic criteria in four major wetlands in El Kala, Algeria. This typology provided useful targeting information to improve the impact of environmental education and awareness raising in El Kala and could serve as a reference for other protected areas in the Mediterranean basin. © 2015, Springer Science+Business Media Dordrecht.

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