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Differences of water chemistry, bird assemblages and nutrient loads introduced by waterbirds into morphologically similar waterbodies

Gwiazda Robert, Kosiba Joanna

Oceanological and Hydrobiological Studies

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2023

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Vol. 52, No. 4

430--436

EN

The number and structure of waterbirds is affected by the size of the waterbody, the presence of islands and macrophytes, but also by their trophy status. The aims of the study were to compare nutrients in water, numbers of waterbird assemblages, and the loading of nitrogen and phosphorus introduced by waterbirds in two similar waterbodies with different rates of water discharge. This study was conducted in two eutrophic shallow waterbodies, P1 and P2 in 2016 and 2017. The median concentrations of NO2-, NO3- and NH4+ were 4.0 times, 3.2 times, and 1.7 times greater in the P1 than in the P2 location, respectively. Similar proportions of organic matter in sediments were statistically greater in P1. The number of birds was also significantly greater in P1 than in P2. The waterbirds (Anas platyrhynchos, Aythya fuligula, Fulica atra, Phalacrocorax carbo and Chroicocephalus ridibundus) excreted 5.2 times more total phosphorous and 3.3 times more total nitrogen in P1 than in P2. Significant negative correlations were also found between the concentrations of NO3- and the number of waterbirds in P1.

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Impact of waterbirds on chemical and biological features of water and sediments of a large, shallow dam reservoir

Gwiazda R., Woźnica A., Łozowski B., Kostecki M., Flis A.

Oceanological and Hydrobiological Studies

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2014

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Vol. 43, No. 4

418--426

EN

Large numbers of Mallard Anas platyrhynchos (max. 10,490 ind.), Black-headed Gull Chroicocephalus ridibundus (max. 3,430 ind.) and Great Cormorant Phalacrocorax carbo (max. 1,449 ind.) were recorded on the Goczałkowice Reservoir, Poland (2,754 ha). Most of the waterbirds occurred in the backwater of this reservoir. The amount of phosphorus and nitrogen loaded by the most numerous waterbirds into Goczałkowice Reservoir was estimated at 958 kg and 2,621 kg, respectively in 2011 and 1,043 kg and 2,793 kg, respectively in 2012. In 2011 and 2012, the waterbirds introduced a considerable amount of phosphorus, nitrogen and a large number of coliforms into the backwater of the reservoir. The concentration of different forms of phosphorus and nitrogen, chlorophyll-a and bacteria coli in the water was not greater at the site of birds’ concentration (except dissolved organic nitrogen). The concentration of nitrates in the water at the site near the breeding colony of gulls in comparison with the reference site was not different. The amounts of P-tot and N-tot in the sediment were similar at the site affected by waterbirds and at the reference site. The dynamics of water masses was not the reason for the lack of differences between the studied sites.

3

The importance of winter catch crops compared with other farmland habitats to birds wintering in Poland

Goławski A., Kasprzykowski Z., Jobda M., Duer I.

Polish Journal of Ecology

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2013

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Vol. 61, nr 2

357--364

EN

The study examined the importance of winter catch crops (intercrops) to wintering birds in a low-intensity farming area of Poland. Birds were counted on two occasions between November 2009 and January 2010 in 514 research plots in two different parts of the country. During the two counts 28 species were recorded. Yellowhammer Emberiza citrinella, Corn Bunting Emberiza calandra, Tree Sparrow Passer montanus and Shorelark Eremophila alpestris were the most numerous species. The statistical analysis (GLZ) of the influence of survey, location and habitat types on the occurrence of birds in the farmland did not reflect the significant effect on any variables. Significant differences in densities of birds between the habitats analysed (GLM) were noted. The stubbles supported a relatively greater density of birds than the mustard winter catch crop and ploughed fields. Increasing the area of winter catch crops at the expense of ploughed fields may favour birds, but when winter crops are sown in fields that would otherwise be left as stubble, wintering conditions for birds deteriorate, especially for buntings.

4

Seasonal bird assemblages in a Mediterranean patchy wetland : corroborating the intermediate disturbance hypothesis

Malavasi R., Battisti C., Carpaneto G.

Polish Journal of Ecology

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2009

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Vol. 57, nr 1

171-179

EN

The structure of bird assemblages recorded in breeding and wintering period in a Mediterranean wetland of Central Italy was studied in order to evaluate their seasonal changes and the influence of land cover on their parameters. We identified three habitat macro-types, according to a man-disturbed gradient (from natural to man-made macro-types). Bird assemblages showed differences in relation to season and habitat type, either at quantitative (species richness, diversity index) or qualitative level (species composition and turnover, similarity). In winter, we obtained the higher values of mean species richness, Margalef richness, Shannon diversity, and [Beta]-diversity. The dendrogram of similarity showed a major clear-cut division between seasons, and a secondary division among habitat macro-types. In winter, assemblages were more rich and diverse, with a high turnover among point counts. The semi-natural habitat macro-types showed always the higher values of these indexes, with the exception of the [Beta]-diversity, which showed the highest value in winter but the lowest in the breeding period. The high mean values of richness ([alpha]-diversity) of the semi-natural habitat macro-types, especially in the breeding period could be mainly explained by the 'intermediate disturbance hypothesis'; on the contrary, differences in turn-over ([Beta]-diversity) between the seasons are mainly due to seasonal changes in habitat heterogeneity of this habitat macro-type (from an arid homogeneous pasture to a patchy flooded one). A pattern of intermediate disturbance was evident at mean species richness level (significant values) but not at diversity index level (not significant values). These results could imply specific strategies for the management of small wetlands, focused on maintaining a regime of natural (flooding) and man-made (grazing) disturbances.