Research team:
Coordinator
Researcher´s:
Mgr. Matyáš Adam
Mgr. Jan Zouhar
The influence of station conditions of fragmented wetland localities on the occurrence and quantity of non-migrating water birds (ACTIVITY 4)
Influence of station conditions of different wetland territories, its quantity and its changes with 17 water birds spending winter in the Czech Republic in a quantity of at least 100 individuals is analyzed in ACTIVITY 4. Gained data will be used to evaluate preferences of environment of different kinds and at the same time to evaluate the significance of different types of fragmented wetlands for water birds.
State of the research:
Wetland biotopes are naturally fragmented areas ensuring high species diversity. This diversity can manifest itself in various stages of the lifecycle of individual species of animals (Finlayson and Moser 1991). The loss of natural wetlands in the territory of the European continent occurred with great intensity, especially in the course of the past centuries, and the natural wetlands have been partly replaced by artificial wetlands (Pullin 2002). In our country these wetlands made or affected by human activities predominate over natural wetlands, functioning as important waterbird wintering grounds. Effective protection of the wintering populations requires knowledge of their biotope preferences, evaluated primarily on the basis of long-term data series. Having sufficient information on the demands made by the individual species is crucial for the application of effective protective measures. The traditionally studied groups of animals include waterbirds, which are also regarded as indicators of the state of the environment (Palmgren, 1936, Bibby et al., 1992, Boere et al. 2006). Determination of their population, distribution and their changes is traditionally done by means of long-term monitoring programmes, which involve a large number of volunteers (Boere et al. 2006). Detailed analyses evaluating the preferences of the wetland habitat conditions in fragmented localities of different species of wintering waterbirds are carried out as an activity with the title: Impact of wetland habitat conditions in fragmented localities on the incidence and population of wintering waterbirds.
The aim of the activity was to analyse the influence of wetland habitat conditions in the individual localities on the population, population changes, the first year of the occurrence and frequency of occurrence of 17 monitored species of wintering waterbirds in the territory of the Czech Republic. The data analysed during the activity come from the database International Waterbird Census (IWC) in the Czech Republic. This monitoring is coordinated worldwide by Wetlands International. The census is taken every year in mid-January when waterbirds concentrate on unfrozen localities and it is possible to quite accurately determine their exact numbers. The census has been taken every year with the assistance of a great many volunteers in standing and flowing waters across the country since 1966. The set of the conditions for the individual localities contains the following data: latitude and longitude, elevation above sea level, degree of settlement, representation of wetlands and open landscape in the vicinity (using CORINE Land Cover), degree of protection and climatic characteristics (average day temperature in winter from middle of November to end of January, total precipitation and snow cover in January). The influence of the site characteristics of the individual localities on a population, its changes, and relative frequency of Individual species was analysed using the linear regression method.
The type of wetland biotope (dams, ponds, industrial waters and running waters) and altitude and locality are the most important factors explaining the preference of habitat conditions in 15 of the 17 species monitored in terms of the type of wetland, and 14 of the 17 species in terms of altitude above sea level. Generally speaking, the monitored species prefer localities at a lower altitude. The proportion of wetlands in the vicinity is an important factor affecting the population and occupation of presence of diving ducks (common pochard, tufted duck and common goldeneye), gulls (common gull and black=headed gull) and short-winged (Eurasian coot and common moorhen).
One quite alarming finding is that the conservation status of the locality (specifically belonging to Natura 2000, or Special Protection Area) emerged as the least significant in terms of preference of habitat conditions in the observed localities. More frequent occurrence in the Special Protection Areas was statistically significant only for the greylag goose and the greater white-fronted goose. By contrast, the mute swan, wild duck, tufted duck, common moorhen, Eurasian coot and the black-headed gull, the frequency of occurrence in the Special Protection Areas was significantly lower in statistical terms.
Wintering waterbird populations in the western Palearctic realm in recent decades have changed their distribution, probably in consequence of climatic and environmental changes (e.g. Lehikoinen et al. 2013 Pavón-Jordan et al., 2015 Podhrázský et al. 2016). Changes in the distribution of the individual species were assessed by long-term changes in population size in the individual localities. The changes in distribution suggest an increasing abundance of the wild duck and Merganser in the eastern localities, and increases in the numbers of the great cormorant in the northeast. These three species and the black-headed gull significantly increase their populations at higher altitudes. The numbers significantly change within individual types of wetlands, with increasing numbers of mute swans, and, conversely, dwindling populations of wild ducks at dams. The populations of piscivorous species, such as great cormorant, grey heron and common merganser, increase in ponds and industrial waters. At the same time, the population of the common merganser increases in localities with a greater proportion of open landscape and built-up areas.
The results of the activity show that wintering populations of waterbirds have some common features within the framework of the preference of habitat conditions in fragmented wetland localities. At the same time, some species change their distribution and probably also boundaries of their distribution and change the preference for habitat conditions. When evaluating population trends of the individual species in individual localities it was found that only in a very small number of localities the population is stable, which means that for most of the species there are significant differences in the local population trends, which may lead to changes in the distribution and shifts of wintering places.
To ensure effective management of the protection of wintering waterbird populations it is essential to have in place annual long-term monitoring of an extensive area providing detailed information on the individual wetlands. On the basis of long-term monitoring we can assess the population and distribution of the individual species and to determine important waterbird wintering places at the national and international level; it is also possible to evaluate the stability of wintering through changes in the population and distribution of the individual species. Regular long-term monitoring of the entire territory is the precondition for the success of the testing of protective measures in the future.
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