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Pernollet C.A.,Office National de la Chasse et de la Faune Sauvage | Green A.J.,CSIC - Donana Biological Station | Curco Masip A.,Parc Natural del Delta de lEbre | Dies B.,Oficina de Gestion Tecnica del Parc Natural de lAlbufera | And 5 more authors.
Biological Conservation

Agricultural lands can provide suitable habitat for birds under some conditions. In particular, waterfowl sometimes rely on ricefields as nocturnal foraging habitat during winter if post-harvest practices make food accessible. To assess whether the winter flooding of ricefields could be a major driver of duck regional abundance in Europe, we relied on a combination of spatial and temporal analyses. In the former, five of the most important western European rice growing regions in Spain, Italy and France were compared in terms of habitat composition over the 2002-2012 period. The relative importance of natural wetlands and ricefields (either dry or flooded) in determining the abundance of wintering ducks was then established. In the second approach, the trends in duck numbers before and after implementation of winter-flooding Agri-Environment Schemes (AES) were compared in two of the study regions. Both approaches highlighted the role of winter ricefield flooding in explaining wintering duck numbers and complementing the natural wetlands; flooding harvested ricefields improves habitat attractiveness by enhancing food resource accessibility. In Europe, the proportion of ricefields flooded during winter varies considerably between countries (0.17-62%), owing to differences in policy initiatives such as Agri-Environment Schemes. Promoting such schemes more widely across the European rice production area could make a big difference in terms of waterfowl habitat quality at the scale of their wintering range. © 2015 Elsevier Ltd. Source

Oro D.,CSIC - Mediterranean Institute for Advanced Studies | Jimenez J.,Conselleria de Medio Ambiente | Curco A.,Parc Natural del Delta de lEbre

In recent centuries and above all over the last few decades, human activities have generated perturbations (from mild to very severe or catastrophes) that, when added to those of natural origin, constitute a global threat to biodiversity. Predicting the effects of anthropogenic perturbations on species and communities is a great scientific challenge given the complexity of ecosystems and the need for detailed population data from both before and after the perturbations. Here we present three cases of well-documented anthropogenic severe perturbations (different forms of habitat loss and deterioration influencing fertility and survival) that have affected three species of birds (a raptor, a scavenger and a waterbird) for which we possess long-term population time series. We tested whether the perturbations caused serious population decline or whether the study species were resilient, that is, its population dynamics were relatively unaffected. Two of the species did decline, although to a relatively small extent with no shift to a state of lower population numbers. Subsequently, these populations recovered rapidly and numbers reached similar levels to before the perturbations. Strikingly, in the third species a strong breakpoint took place towards greater population sizes, probably due to the colonization of new areas by recruits that were queuing at the destroyed habitat. Even though it is difficult to draw patterns of resilience from only three cases, the study species were all long-lived, social species with excellent dispersal and colonization abilities, capable of skipping reproduction and undergoing a phase of significant long-term population increase. The search for such patterns is crucial for optimizing the limited resources allocated to conservation and for predicting the future impact of planned anthropogenic activities on ecosystems. © 2012 Oro et al. Source

Ibez C.,IRTA - Institute of Agricultural-Alimentary Research and Technology | Curc A.,Parc Natural del Delta de lEbre | Riera X.,SEO BirdLife | Ripoll I.,SEO BirdLife | Snchez C.,SEO BirdLife

Most literature on birds and rice (Oryza sativa) focuses on the non-growing period and little is known about the influence of management practices during cultivation. A review found that the main factors affecting species composition and abundance in rice fields during the growing season were water level, flooding period, rice plant structure and size, and pesticide use. Highest bird density and diversity occurred at intermediate water levels (1020 cm). Early flooding and late drying favored waterbird density and diversity, and the stopover of migrating species. Taller plants, at higher densities, reduced prey availability to most waterbirds but favored smaller species. Pesticides and herbicides have been shown to be toxic to birds and reduce food resources. A case study is presented for the Ebro delta, Spain. Three management schemes were compared: organic, agri-environmental and conventional. Bird density, biomass and diversity throughout the growing and non-growing seasons were determined in three consecutive years. Bird biomass, density and diversity averaged higher in the organic rice fields, but only biomass was significantly different. The higher biomass reflects the presence of a higher biomass of prey items (fish, invertebrates and macrophytes) in the organic rice fields, likely due to the lack of pesticides. Further research should focus on a quantitative assessment of the effects of specific management practices. Source

Clavero M.,CSIC - Donana Biological Station | Lopez V.,Parc Natural del Delta de lEbre | Franch N.,Parc Natural del Delta de lEbre | Pou-Rovira Q.,Sorello | Queral J.M.,Parc Natural del Delta de lEbre
Agriculture, Ecosystems and Environment

Rice fields constitute a significant proportion of the existing wetlands in the Mediterranean basin and are important areas for the conservation of different vertebrate species, especially birds. However, little is known on how fish and crayfish use rice fields in Mediterranean areas. In this work we analyze fish communities and crayfish populations occupying rice fields and their associated irrigation network (inflow and outflow channels) in the Ebro Delta (NE Spain). We set fyke nets in 104 sites and captured almost 23,000 fish belonging to 19 species, 9 of which were found to occupy rice fields, as well as over 3000 red swamp crayfish (. Procambarus clarkii). Stone moroko (Pseudorasbora parva), common carp (Cyprinus carpio), dojo loach (Misgurnus anguillicaudatus) and Eastern mosquitofish (Gambusia holbrooki) were the most common fish found in rice fields. More than 95% of the fish individuals captured belonged to non-native species. Dojo loach, a recently introduced species well adapted to rice cultivation cycles in its native range, used rice fields as reproduction ground. Outflow channels seemed to be a more important source of fish colonizing rice fields than inflow channels. Colonization was the main limitation for the establishment of fish populations in rice fields and fish tended to be more abundant in rice fields than in channels for any given frequency of occurrence. The importance of fish as trophic resource for natural predators and the possible interactions between fish occupying rice fields and rice yield, largely unexplored in the Mediterranean areas, could be managed by modulating connectivity between rice fields and irrigation channels. Rice fields, however, are not important areas for the conservation of native fish biodiversity, being largely occupied by non-native fishes. Moreover, the influence of low-conductivity water diverted for rice cultivation on natural wetlands favors the establishment and expansion of different non-native fish species. © 2015 Elsevier B.V.. Source

Alba A.,Autonomous University of Barcelona | Bicout D.J.,VetAgro Sup | Vidal F.,Parc Natural del Delta de lEbre | Curco A.,Parc Natural del Delta de lEbre | And 6 more authors.

Design, sampling and data interpretation constitute an important challenge for wildlife surveillance of avian influenza viruses (AIV). The aim of this study was to construct a model to improve and enhance identification in both different periods and locations of avian species likely at high risk of contact with AIV in a specific wetland. This study presents an individual-based stochastic model for the Ebre Delta as an example of this appliance. Based on the Monte-Carlo method, the model simulates the dynamics of the spread of AIV among wild birds in a natural park following introduction of an infected bird. Data on wild bird species population, apparent AIV prevalence recorded in wild birds during the period of study, and ecological information on factors such as behaviour, contact rates or patterns of movements of waterfowl were incorporated as inputs of the model. From these inputs, the model predicted those species that would introduce most of AIV in different periods and those species and areas that would be at high risk as a consequence of the spread of these AIV incursions. This method can serve as a complementary tool to previous studies to optimize the allocation of the limited AI surveillance resources in a local complex ecosystem. However, this study indicates that in order to predict the evolution of the spread of AIV at the local scale, there is a need for further research on the identification of host factors involved in the interspecies transmission of AIV. © 2012 Alba et al. Source

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