Aquatic birds as bioindicators of trophic changes and ecosystem deterioration in the Mar Menor lagoon (SE Spain (original) (raw)
Related papers
Ecological Indicators, 2011
a b s t r a c t Southern Mediterranean lagoons are among the more vulnerable systems regarding human activities (e.g. agriculture, tourism, urbanization) leading to eutrophication. We analyse the relationship of waterbirds with locally measured or modelled environmental variables (nutrient load, fish production, jellyfish blooms) related with this process, in the Mar Menor lagoon (Murcia, SE Spain), and discuss the potential value of birds as indicators of the trophic status of the wetland. We use GLMs to relate the biomass of the five most abundant and representative waterbird species to these variables, accounting for the potential influence of external factors affecting their population at higher biogeographical scales. A significant effect of such factors was only found for Great Cormorant, which biased the positive response of the piscivore guild to nutrient load (NLD). Red-breasted Merganser appeared relatively insensitive to nutrient enrichment, although declined in the long term. The remaining species responded positively, NLD being a significant predictor of their biomass when a 2-year lag was allowed, although this variable alone had a low explanatory power except for the Coot. When homogeneous temporal phases were defined, grebes could be identified as early warners of eutrophication, and Coot as late-stage ones. The increase of piscivores along a period of declining fish catches could reflect a shift in fish community composition or structure that favours their feeding preferences. The interactive role of jellyfish, buffering temporally the loading of nutrients, may also be related to these changes.
Lakes and Reservoirs: Research and Management, 2008
The Mar Menor, a 135-km2 saline lake, is the largest water surface on the western Mediterranean coast, and an internationally important bird area. It is surrounded by a large irrigated agricultural plain, with dense tourism developments. Although the impacts of these activities on water quality are locally evident, their effects on waterbird populations are poorly known. In the winter 2004–2005, we studied the distribution of four waterbird species (Podiceps cristatus, Podiceps nigricollis, Phalacrocorax carbo and Fulica atra) around the main drainage channel that discharges into the lake, where it was feasible to infer spatial patterns of eutrophication (alongshore and shore centre) from previous environmental surveys. Waterbirds were counted along a stretch of undeveloped shoreline extending southwards from the channel outlet, in contiguous sections, and in bands parallel to the shoreline. Linear mixed models (LMM) indicated the population density increased only markedly for grebes (Podiceps cristatus, Podiceps nigricollis) and coot (Fulica atra) in littoral bands qualifying as eutrophic, but not an alongshore response, with their finescale alongshore distribution being apparently unrelated to nutrient sources. Considering the whole lake, however, the temporal trends and distribution of the wintering populations indicated that waterbirds respond numerically, in a guild-specific way, to nutrient inputs. Grebes and coot could be a useful ‘two-stage’ warning signal for potential problem areas affected by similar influences.
Waterbirds and nutrient enrichment in Mar Menor Lagoon, a shallow coastal lake in southeast Spain
2008
The Mar Menor, a 135-km 2 saline lake, is the largest water surface on the western Mediterranean coast, and an internationally important bird area. It is surrounded by a large irrigated agricultural plain, with dense tourism developments. Although the impacts of these activities on water quality are locally evident, their effects on waterbird populations are poorly known. In the winter 2004-2005, we studied the distribution of four waterbird species (Podiceps cristatus, Podiceps nigricollis, Phalacrocorax carbo and Fulica atra) around the main drainage channel that discharges into the lake, where it was feasible to infer spatial patterns of eutrophication (alongshore and shore centre) from previous environmental surveys. Waterbirds were counted along a stretch of undeveloped shoreline extending southwards from the channel outlet, in contiguous sections, and in bands parallel to the shoreline. Linear mixed models (LMM) indicated the population density increased only markedly for grebes (Podiceps cristatus, Podiceps nigricollis) and coot (Fulica atra) in littoral bands qualifying as eutrophic, but not an alongshore response, with their finescale alongshore distribution being apparently unrelated to nutrient sources. Considering the whole lake, however, the temporal trends and distribution of the wintering populations indicated that waterbirds respond numerically, in a guild-specific way, to nutrient inputs. Grebes and coot could be a useful 'two-stage' warning signal for potential problem areas affected by similar influences.
Effect of habitat loss and change on waterbirds
1997
The development of a correlative approach relating bird distribution and remotely sensed sediment distribution to predict the consequences to shorebirds of habitat change and loss 138 M G Yates & J D Goss-Custard .-n. Acknowledgements This Symposium was jointly organised by the Universidade de Aveiro (UA) and the Instituto da Conserva0o da Natureza (ICN) for the Waterfowl Ecology Specialist Group of the International Waterfowl and Wetlands Research Bureau (now Wetlands International). We would like to thank all those at ICN/Habitats and Ecosystems Division and at the U.A./ Department of Biology who helped setting up this organisation, as well as Dr John Goss-Custard and Dr Janine van Vessem who provided the organising team with extremely valuable advice. The Funda0o Joao Jacinto Magalbiles took care of the accounting as well as many other financial and organisational matters in a very smooth and efficient way, and we wish to thank all the staff members of the Foundation who were actually involved with this Symposium, and especially Dra Maria de Jesus Galaricha. We wish to thank the Junta Nacional de Investiga0o Cientifica e Tecnologica (JNICT), which funded the organisation of this Symposium as well as the Camara Municipal de Aveiro, the Comissao Vitivinicola da Bairrada and Mr Luis Pato for the wonderful wine reception at the Council Museum. We also thank the Institute of Terrestrial Ecology, Wetlands International and the Universidade de Aveiro for their financial contributions to these Proceedings. Finally, we are extremely grateful for the tremendous amount of help and effort which Penny Ward and Karen Goodsir of the Institute of Terrestrial Ecology at Merlewood have put into producing this volume. v explolir :whYhtli&, maip:!pcies7 Mallard tuefted duck pochard :and ga# shifted thoir,:relative.ii:titing,pif6i-encefro7::iiif iltralicin mOto easily prey upon nienbanrig:fernales 4ndrtheir :nes.ts...: in infiltration
Aquatic ecology of the Mondego River basin global importance of local experience, 2002
The effects of eutrophication on birds are difficult to assess, as the predicted decline in numbers with the spread of algae mats is a long-term processo However, indirect evidences of this phenomenon can be obtained through the study of the predator-prey relationships. ln this paper, a multi-scale approach to this problem in the Mondego estuary was adopted, integrating observational and experimental analysis of the relationships between the birds and their invertebrate prey populations in relation to the spreading and abundance of the algae mats. The results suggest that the presence of algae does not influence the distribution of wader species, particularly when algae are abundant, nor their feeding behaviour. This is confirmed by the results of the exclosure experiments, which show that predation by waders on the densities of most prey species is independent of the amount of algae presento The advantages and problems of using the multi-scale approach are discussed.
Estimating the contribution of carnivorous waterbirds to nutrient loading in freshwater habitats
Freshwater Biology, 2007
1. We estimated nitrogen (N) and phosphorus (P) loading into wetlands by carnivorous waterbirds with alternative physiological models using a food-intake and an excretaproduction approach. The models were applied for non-breeding and breeding Dutch inland carnivorous waterbird populations to quantify their contribution to nutrient loading on a landscape scale. 2. Model predictions based on food intake exceeded those based on excretion by 59-62% for N and by 2-36% for P, depending on dietary assumptions. Uncertainty analysis indicated that the intake model was most affected by errors in energy requirement, while the excretion model was dependent on faecal nutrient composition. 3. Per capita loading rate of non-breeders increased with body mass from 0.3-0.8 g N day )1 and 0.15 g P day )1 in little gulls Larus minutus to 4.5-11.5 g N day )1 and 2.1-3.2 g P day )1 in great cormorants Phalacrocorax carbo. For breeding birds, the estimated nutrient loading by a family unit over the entire breeding period ranged between 17.6-443.0 g N and 8.6 g P for little tern Sterna albifrons to 619.6-1755.6 g N and 316.2-498.1 g P for great cormorants. 4. We distinguished between external (i.e. importing) and internal (i.e. recycling) nutrient loading by carnivorous waterbirds. For the Netherlands, average external-loading estimates ranged between 38.1-91.5 tonnes N and 16.7-18.2 tonnes P per year, whilst internal-loading estimates ranged between 53.1-140.5 tonnes N and 25.2-39.2 tonnes P and per year. The average contribution of breeding birds was estimated to be 17% and 32% for external and internal loading respectively. Most important species were black-headed gull Larus ridibundus and mew gull Larus canus for external loading, and great cormorant and grey heron Ardea cinerea for internal loading. 5. On a landscape scale, loading by carnivorous waterbirds was of minor importance for freshwater habitats in the Netherlands with 0.26-0.65 kg N ha )1 a )1 and 0.12-0.16 kg P ha )1 a )1 . However, on a local scale, breeding colonies may be responsible for significant P loading.
Science of The Total Environment, 2016
Floodplains are among the most threatened ecosystems worldwide because of multiple stressors, i.e., invasive species, pollution and aquifer overexploitation; the Tablas de Daimiel National Park (Spain) is a clear example of these kinds of impact. This work aims to test whether invasive fish and/or the water and sediment quality are significant drivers of the decline of stonewort (Chara spp.) meadows in the Tablas de Daimiel, investigating how this could explain changes observed in the waterbird community. Bird surveys performed monthly between June 2010 and April 2014 have shown that herbivorous species like the red-crested pochard (Netta rufina) reached historical records between September 2010 and June 2011, but have decreased since then. Piscivorous waterbirds like the great cormorant (Phalacrocorax carbo) and herons increased in population after 2011, however. These changes may be due to the decline of Chara spp. meadows, connected to overexploitation by herbivores, or to changes in water and sediment quality. To test this hypothesis, we studied the growth of Chara spp. biomass in ten sites of the Tablas de Daimiel, where experimental exclosures were set up to exclude herbivory by birds, and bioturbation and herbivory by fish. Our results have shown that the absence of Chara spp. in the Tablas de Daimiel is mostly explained by presence of invasive fish (i.e. common carp). Moreover, the
Regional Environmental Change, 2004
Parc Natural s'Albufera de Mallorca is an internationally recognised resting area for a wide array of migratory birds, and like most wetlands it has many other ecological functions and socioeconomic values. In the catchment, in which the wetland is situated, expanding tourism and intensification of agriculture place much pressure on a limited amount of freshwater. The freshwater supply to the wetland decreased due to waterextraction mainly driven by intensification of agriculture in the catchment. As a result saltwater intrusion increased since 1983-1985. This had considerable impacts on the ecological integrity of the wetland as reflected by changes in the state of the aquatic ecosystem. The distribution of submerged plants, less tolerant of salinity, declined or disappeared, while the distribution of species, known to prefer high salinity increased. As a contribution to the development of monitoring programs and management strategies that address both socio-economic and natural water demand, this article will formulate ecological criteria to assess the natural water demand by selection of (bio)indicators within the aquatic ecosystem.
Extensive aquaculture in coastal and estuarine wetlands can support both increased food production and wider ecosystem services when underpinned by effective management to promote productivity and hence food webs that support both commercial species and biodiversity. Changing hydrology, specifically water movement, within wetlands significantly impacts the physico-chemical properties of the water body and hence can be employed to manipulate productivity and alter patterns of recruitment of commercial species and may also transfer nonnative species from the supplying water bodies. The reconstructed wetlands of Veta la Palma in the Doñana Natural Park are subjected to either a 1% or 5% d −1 water exchange with water drawn from the adjacent Guadalquivir estuary. This site provides an excellent opportunity for examining the effect of water management on the food webs that support both the birdlife and aquaculture activities for which this habitat is managed. Stable isotopes were used to examine food webs in three replicate lagoons under each water management scheme. In lagoons receiving higher water exchange, phytoplankton productivity appeared to be more important than benthic production in supporting food webs. Increased water exchange also changed the shape of the food webs, facilitated the colonisation of at least one non-native species and increased the importance of non-native species in the diets of large commercially harvested fish (N 60% of seabass diet). Lagoons with high water flows also had between three and four times greater shrimp biomass than those of low flow lagoons. Non-native fauna were opportunistic omnivores, eating marginally more non-natives in lagoons with greater water exchange. Overall non-native cordgrass Spartina densiflora contributed only slightly more to food webs compared with the native reed Phragmites australis, despite the lagoon edge occupancy ratio of 9:1, respectively. Non-natives also appear to enhance food provision for large predators and wetland birds, by increasing biomass, without competing for resources with native species, supporting the dual management objectives of aquaculture and waterbird conservation. Statement of relevance: Extensive aquaculture productivity appears to be positively correlated with water exchange rates.