Suchergebnisse

Wetlands are key habitats connected physically and socially with processes occurring over a much wider territory. The biotic connection through dispersal mechanisms among wetlands is of primary importance to wetland management and policies. However, traditional wetland conservation approaches are based on the preservation of isolated sites considered to be of special importance (typically owing to their importance for concentrations of migratory waterbirds). Research linking local species richness and bird migration suggests that the effect of wetland loss on regional diversity might be much larger than what would be expected from direct habitat loss. Since the biotic connection among wetlands serviced by waterbirds appears to be more efficient within a limited range, the distribution of wetlands in space is a key aspect determining wetland connectedness even in the absence of direct hydrologic links. Protected areas should thus be defined with regard to waterfowl movements and waterbird migration as functional processes contributing to aquatic species migration and local species richness. This calls for a regional approach to wetland management within a continental context. This paper aims at defining an operational view of the dispersion function of wetlands and its implication for conservation policies. For this purpose, we examined the conservation policies of the Ramsar Convention (the international treaty that protects wetlands) and the European Union (as an example of relevant continental level policy-making) from the viewpoint of bird-mediated dispersal of aquatic organisms. We propose nine specific avenues for the inclusion of bird-mediated dispersal in the policy documents examined. Non-governmental organisations and other organisations working in waterbird conservation should also recognise the importance of their policies for aquatic biodiversity at broader levels and avoid compartmentalising their conservation activities. ; Peer reviewed

W. Solarz, K. Najberek, A. Pociecha & E. Wilk-Woźniak (2017, Diversity and Distributions, 23, 113–117) published a letter in Diversity and Distributions debating our view that waterbirds are important vectors of alien species (C. Reynolds, N. A. F. Miranda & G. S. Cumming, 2015 Diversity and Distributions, 21, 744–754; A. J. Green, 2016 Diversity and Distributions, 22, 239–247) and question whether future research into the mechanisms under-pinning this phenomenon can be advantageous for the practical management of alien species. Additionally, Solarz et al. suggest that human activities are the primary source of all alien species introductions and that waterbirds may only act as vectors of secondary dispersal. In this letter, we respond to several arguments raised by the authors surrounding the relevance of waterbird-mediated dispersal in the introduction and spread of alien species. We emphasize the partly deterministic nature of waterbird dispersal and the significance of long-distance dispersal events (and hence the potential for primary introductions of new alien species across political boundaries). Finally, we reaffirm the importance of further research into dispersal by birds to improve our capacity to foresee and manage invasions of those alien species with strong capacity to spread via avian vectors. ; Peer reviewed

The White-headed Duck Oxyura leucocephala is listed as Endangered on the IUCN Red List of Threatened Animals. It is also listed on Annex I of the European Union Directive on the Conservation of Wild Birds (79/409/EEC) (Birds Directive), on Appendix II of the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention), on Appendix I of the Convention on the Conservation of Migratory Species of Wild Animals (Bonn Convention), and Appendix II of the Convention on International Trade in Endangered Species (CITES Convention). The White-headed Duck is a highly aquatic diving duck of the stifftail tribe Oxyurini. Globally, there are four populations; two of which are declining, one stable and one increasing. The decreasing populations include the main Central Asian population of 5,000-10,000 birds and the Pakistan wintering population, which is on the verge of extinction. The resident North African population (400- 600 birds) is stable and the Spanish population (ca. 2,500 birds) increasing. The White-headed Duck occurs regularly in 26 countries, and in another 22 as a vagrant. Nine countries hold significant breeding numbers (Algeria, Islamic Republic of Iran, Kazakhstan, Mongolia, Russian Federation, Spain, Tunisia, Turkey, and Uzbekistan), but most are concentrated in Mongolia, Kazakhstan, Russian Federation, and Spain. Birds occur commonly on migration in 10 countries, and in winter (December to February) in 13. The most important wintering countries differ from year-to-year, presumably depending on weather conditions. In recent years, 10 countries have held over 1,000 birds (Azerbaijan, Bulgaria, Greece, Islamic Republic of Iran, Israel, Kazakhstan, Russian Federation, Spain, Turkey, and Uzbekistan – see Table 2). Seven countries hold significant numbers of birds throughout the year (Algeria, Islamic Republic of Iran, Russian Federation, Spain, Tunisia, Turkey, and Uzbekistan). ; Peer Reviewed

© 2015 Elsevier B.V. The lack of space and opportunity for development has been identified as key reasons behind the stagnation of the European aquaculture industry. With the historical loss and degradation of current European wetlands there is an opportunity for harnessing the commercial investment of the aquaculture industry in construction of dual purpose wetlands that incorporate both conservation and extensive aquaculture activities. These wetlands can be used to expand the area available to suitable aquaculture into ecologically sensitive areas, such as Natura 2000 sites. Veta la Palma (VLP) situated in the Doñana Natural Park (and a Natura 2000 site) is an example of such an aquaculture development and a possible model for future opportunities. In the current study some of the important ecosystem services that are provided by VLP are assessed. The provisioning services of VLP were the economic rationale for the investment and more than 820tonnesyr -1 of fish and shrimp is produced, through a mixture of semi-extensive and extensive aquaculture. The regulating services include nutrient absorption, and the flow of river water through VLP and high primary production results in the absorption of 377tonnes of dissolved inorganic nitrogen yr -1 , and 516tonnes of Cyr -1 . Supporting services include the provision of habitat for more than 94 bird and 21 fish species. The primary production that supports the birds, extensive and semi-extensive aquaculture production was also estimated to be 167,000tonnes, 50,000tonnes and 133,000tonnesyr -1 , respectively. The losses to birds are substantial and these estimates indicate that almost half of the primary production supports the wetland birds which directly consume 249tonnes of fish and 2578tonnes of invertebrates per annum. However it is the ecological credentials of the farm that enable premium prices and hence ensure the economic viability of the farm. The study demonstrates the possibility of using aquaculture to mitigate the historical loss of wetlands, provide significant ecosystem services and contribute to achievement of the European environmental legislative goals, and furthers the opportunity for the expansion of aquaculture into sensitive but impacted habitats. ; Peer Reviewed

Many of the world's wetlands may be profoundly affected by climate change over the coming decades. Although wetland managers may have little control over the causes of climate change, they can help to counteract its effects through local measures. This is because direct anthropogenic impacts, such as water extraction and nutrient loading, work in concert with climate change to damage wetlands. Control of these local stressors may therefore ameliorate undesired effects of climate change, such as a shift towards dominance by invasive floating plants, increasingly frequent cyanobacteria blooms, or extinction of key species. Using the iconic Doñana wetlands in Spain as a case study, we illustrate how the concept of creating a "safe operating space" may be implemented to better ensure that ecosystems do not surpass thresholds for collapse during an era of global change. ; WIMEK grant for a research stay at WUR. JAE DOCTORES. European Union. European Social Fund. Grant Number: ESF2007‐2013. Spanish Ministry for Economy and Competitiveness. EU FP7 project FAST. Grant Number: 607131. European Union's Horizon 2020 research and innovation program. Grant Number: 641762 ; Peer reviewed

Many of the world's wetlands may be profoundly affected by climate change over the coming decades. Although wetland managers may have little control over the causes of climate change, they can help to counteract its effects through local measures. This is because direct anthropogenic impacts, such as water extraction and nutrient loading, work in concert with climate change to damage wetlands. Control of these local stressors may therefore ameliorate undesired effects of climate change, such as a shift towards dominance by invasive floating plants, increasingly frequent cyanobacteria blooms, or extinction of key species. Using the iconic Doñana wetlands in Spain as a case study, we illustrate how the concept of creating a "safe operating space" may be implemented to better ensure that ecosystems do not surpass thresholds for collapse during an era of global change. ; AJG was supported by a WIMEK grant for a research stay at WUR. EPM was supported by a JAE DOCTORES 2010 contract funded by the European Union (European Social Fund, ESF2007-­2013) and the Spanish Ministry for Economy and Competitiveness, as well as the EU FP7 project FAST (grant 607131). Funding was also provided by the European Union's Horizon 2020 research and innovation program under grant agreement number 641762 to the ECOPOTENTIAL project. C Perennou provided helpful comments on earlier versions of the manuscript. Maps were made using data from CHG­ uadalquivir (www.chguadalquivir.es/ide) with QGIS (www.qgis.org) and the Google Maps API. ; PDF 9 pages