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Arles, France

Maris V.,French Natural History Museum | Maris V.,CNRS Center of Evolutionary and Functional Ecology | Bechet A.,La Tour du Valat
Conservation Biology | Year: 2010

The conservation of biodiversity poses an exceptionally difficult problem in that it needs to be effective in a context of double uncertainty: scientific (i.e., how to conserve biodiversity) and normative (i.e., which biodiversity to conserve and why). Although adaptive management offers a promising approach to overcome scientific uncertainty, normative uncertainty is seldom tackled by conservation science. We expanded on the approach proposed by adaptive-management theorists by devising an integrative and iterative approach to conservation that encompasses both types of uncertainty. Inspired by environmental pragmatism, we suggest that moral values at stake in biodiversity conservation are plastic and that a plurality of individual normative positions can coexist and evolve. Moral values should thus be explored through an experimental process as additional parameters to be incorporated in the traditional adaptive-management approach. As such, moral values should also be monitored by environmental ethicists working side by side with scientists and managers on conservation projects. Acknowledging the diversity of moral values and integrating them in a process of collective deliberation will help overcome the normative uncertainty. We used Dewey's distinction between adaptation and adjustment to offer a new paradigm built around what we call adjustive management, which reflects both the uncertainty and the likely evolution of the moral values humans attribute to biodiversity. We illustrate how this paradigm relates to practical conservation decisions by exploring the case of the Sacred Ibis (Threskiornis aethiopicus. ), an alien species in France that is the target of an eradication plan undertaken with little regard for moral issues. We propose that a more satisfying result of efforts to control Sacred Ibis could have been reached by rerouting the traditional feedback loop of adaptive management to include a normative inquiry. This adjustive management approach now needs to be tested in real-case conservation programs. ©2010 Society for Conservation Biology. Source

Gayet G.,9 rue du 4 septembre | Eraud C.,Office National de la Chasse et de la Faune Sauvage | Benmergui M.,Office National de la Chasse et de la Faune Sauvage | Broyer J.,Office National de la Chasse et de la Faune Sauvage | And 4 more authors.
European Journal of Wildlife Research | Year: 2011

A number of native and exotic animal species show dramatic population increases in terms of both numbers and geographic range. Understanding the habitat selection processes behind such increases is crucial to implement adequate management measures. Mute swan (Cygnus olor) populations have experienced a tremendous demographic and geographic expansion in Western Europe during the twentieth century, colonizing a wide variety of aquatic habitats. We aimed at assessing how swans select nesting sites during the pre-laying and laying periods on medium to large fishponds (from 10 to 50 ha) in Eastern France, while accounting for detectability biases and testing for the effects of fishpond spatial configuration, vegetation resources, human disturbance and habitat management. Our results demonstrate that the mute swan is a non-selective species regarding its nesting habitat among such fishponds, using these independently from the parameters considered although fishpond characteristics varied. Although mute swan is one of the least cryptic Anatidae, owing to its white colour and large size, detection of breeding pairs remained imperfect for each over several sampling occasions. However, because we repeated the sampling sessions, detection of swan pairs by the end of the monitoring period was as high as 0. 94. These results are consistent with previous assertions that the mute swan is a species of high ecological plasticity, which may partly explain its recent colonization rates. Given that even swan breeding events were imperfectly detected on each occasion, we highlight the fact that most studies of breeding ducks (which are more cryptic) would be considerably improved by better considering detection biases. © 2011 Springer-Verlag. Source

In this paper we present data on breeding parameters of Little Tern Sterna albifrons, Common Tern Sterna hirundo and Gull-billed Tern Sterna nilotica nesting in Sfax salina in south-eastern Tunisia. The abundance peak was reached between the end of April and the beginning of May for the Little Tern and Common Tern and during May for Gull-billed Tern. Egg laying started from the third to the fourth week of April for Little and Common Terns and across May for Gull-billed Tern. In the three years of study, the number of nests per colony varied from 1 to 75 for Little Tern, from 1 to 101 for Common Tern, and from 1 to 114 for Gullbilled Tern. Clutch size varied between 1 and 4 for Little and Common Terns and from 1 to 3 for Gull-billed Tern, with significant differences among years. For the three species, the colony reproductive success, i.e. the number of fledged chicks per breeding pair, largely varied among colonies and years. Lowest and highest recorded values were 0 and 1.8 for Little Tern; 0 and 2 for Common Tern, and 0 and 0.8 for Gull-billed Tern. This low reproductive success is thought to be mainly caused by terrestrial predation and disturbance. Source

Gayet G.,9 rue du 4 septembre | Guillemain M.,Office National de la Chasse et de la Faune Sauvage | Mesleard F.,La Tour du Valat | Mesleard F.,University of Avignon | And 3 more authors.
Journal of Ornithology | Year: 2011

The Mute Swan (Cygnus olor) is a protected species whose population has shown a dramatic demographic expansion over the last decades in France. Today, Mute Swans are suspected of causing damages to wetlands, partly through their territorial behaviour towards other waterbirds. The behaviour of Mute Swan pairs and the distribution of other waterbirds was monitored over 84 fishponds in the Dombes, Eastern France, from April to July 2008. Interspecific aggressive behaviours by Mute Swan pairs were not detected during behavioural observations, and no negative impact of swan pair presence was demonstrated on waterbird distribution. Waterbirds were more abundant on fishponds where Mute Swan pairs were present, maybe due to the flocking of waterbirds where Mute Swans were established owing to shared habitat preferences. Indeed, the waterbirds whose presence was the most closely correlated to that of Mute Swan pairs were Coot (Fulica atra), Common Pochard (Aythya ferina) and Red-Crested Pochard (Netta rufina), all foraging on deep macrophyte beds as do the swans. All these species, including swans, may therefore be attracted to the same fishponds without massive interspecific competition occurring, due to abundant submerged aquatic vegetation resources. © 2010 Dt. Ornithologen-Gesellschaft e.V. Source

Guillaume G.,French Natural History Museum | Matthieu G.,Office National de la Chasse et de la Faune Sauvage | Pierre D.R.,Office National de la Chasse et de la Faune Sauvage | Patrick G.,La Tour du Valat
Hydrobiologia | Year: 2014

The increases in mute swan (Cygnus olor Gmelin) population size have caused concern among stakeholders, who sometimes consider it as a pest species. Here, we aim to review existing studies on the ecological effects that mute swans have on wetlands. Claim that mute swans threaten other waterbirds were partly supported: mute swans sometimes behave territorially towards conspecifics and other waterbird species, but this does not systematically occur. A second common claim, that mute swans damage aquatic plant beds, was upheld in that the species did indeed affect aquatic plant communities in several studies. However, grazing by mute swans does not systematically have negative effects on aquatic plants. Habitat patch size, distance between habitat patches, resource availability and water velocity affect habitat selection process by mute swans, with varying effects depending on season and mute swan breeding status. Scientific knowledge does not support the idea that mute swan population increase can be considered as a biological invasion in Europe. Conversely, there is a genuine risk of biological invasion in North America. In light of the literature review, we discuss the relevance of mute swan population management in Europe and in North America, and propose future research avenues. © 2013 Springer Science+Business Media Dordrecht. Source

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