Saulius Švažas

THE STATUS, NUMBERS AND DISTRIBUTION OF SWANS AND GEESE IN LITHUANIA

Abstract The status, numbers, distribution, populations trends and habitat use of swans and geese in Lithuania are analysed. 3 species of swans and 10 species of geese are recorded in Lithuania. Only the Mute Swan Cygnus olor, Whooper Swan Cygnus cygnus and Greylag Goose Anser anser breed, while all other species occur as passage migrants, winterers or vagrants. With few exceptions, the status of swan and goose populations in Lithuania is favourable. Most populations are stable or increasing. The only species which has markedly decreased in numbers during the last decades is the Bean Goose Anser fabalis. There is special concern about the status of the globally threatened population of the Lesser White-fronted Goose. In recent years several Lithuanian staging grounds has been holding up to 5% of the total Lesser White-fronted Goose NE Europe population, but so far this species in Lithuania is not protected and it is still in the list of huntable species. Conflict of migratory wildfowl with agriculture is ...

Global Climate Change and Its Impact on Wetlands and Waterbird Populations

The aim of this paper is to demonstrate the obtained data for the dependency of wetland carrying capacity upon the global climate change process. The article presents material confirming the impact of global climate change on different breeding bird species and populations, changes of their ranges and population state. A list of bird species, which are shifting their ranges north-eastward or eastward in the Baltic region under the influence of global warming, is presented. The impact of global warming on birds of water complexes was found to be more evident than the impact on terrestrial birds. We also attempted to explain changes in key bird staging and wintering areas due to climate change. Attention is focused on the aspects of the effect of climate change upon birds in environmental protection, aviation flight safety and other branches of economy.

Recent Changes in Distribution of Wintering Populations of Waterfowl Established on the Basis of Lithuanian Ringing Recoveries

Recent changes in the wintering grounds of the Lithuanian breeding population of Mute Swan, Mallard, Common Pochard, and Coot were established by means of the analysis of the long-term ringing data stored in the Data Bank of the Lithuanian Bird Ringing Centre. Significant changes in the wintering grounds of Mute Swan and Mallard of the Lithuanian breeding population have occurred since the late 1980s; the wintering grounds of Common Pochard and Coot, on the other hand, have changed just unremarkably. These changes were primarily caused by human impact and an increased number of mild winters during the present climatic amelioration.

Coexistence and population genetic structure of the whooper swan Cygnus cygnus and mute swan Cygnus olor in Lithuania and Latvia

Two closely related swan species, the mute swan Cygnus olor and the whooper swan Cygnus cygnus, were formerly allopatric throughout their breeding ranges, but during the last decades a sympatric distribution has become characteristic of these species in the Baltic Sea region. The whooper swan has gradually replaced the mute swan in many suitable habitats in Lithuania and Latvia. Marked differences in the genetic population structure of both species may partially explain the dominance of the whooper swan, as genetic population divergence can be a major factor affecting inter-specific competition. A homogenous genetic population structure was defined for mute swans breeding in Lithuania, Latvia, Poland and Belarus. Breeding mute swans in this region are mostly of naturalised origin. A diverse population genetic structure characterizes whooper swans breeding in Lithuania and Latvia.

Possible Impacts of Climatic Conditions on Changes in Numbers and in Distribution of Certain Breeding and Staging Wildfowl Spsecies in Lithuania

The long-term changes in numbers and distribution of 13 wildfowl species breeding and staging in Lithuania were analysed. Three species of wildfowl (Tufted Duck Aythya fuligula, Common Pochard Aythya farina and Goosander Mergus merganser) became established in Lithuania as new breeding birds in the late 19th century and 3 other species (Whooper Swan Cygnus Cygnus, Common Shelduck Tadorna tadorna and Gadwall Anas strepera) did so during several past decades in the 20th century. Marked changes in numbers and distribution of migratory wildfowl populations were recorded during the last decades. It is likely that the recent changes in numbers and distribution of certain wildfowl species have been resulted in partly by climatic factors.

PRODUCTIVITY OF STAGING GROUNDS FOR WATERFOWL IN LITHUANIA

Abstract The productivity of staging grounds for waterfowl and the reasons for the productivity were investigated using th. 1996–1997 country-wide survey data. 29 waterfowl staging grounds were grouped into 8 ecological types basing on trophical level, origin and distance from the Baltic Sea coast. The productivity of waterfowl staging grounds was proved to be due to a complex of different factors, ecological (water depth, submerged plants, bottom invertebrates, etc.) and geographical (distance from the Baltic sea coast) ones being the main. Ecological factors dominate over geographical ones, though the significance of the former depends upon species-specific diet and feeding habits, while the geographical factor is important to nearly all the species. Differently from other waterfowl species, for the geese feeding on the land it is the productivity of feeding habitats neighbouring wetlands and the size of seasonally flooded areas that are of the highest significance. Currently existing waterfowl staging ...

Identification of Flyways of Woodpigeon (Columba Palumbus) in Europe by using Genetic Methods

The attempt to identify the flyways of Woodpigeon (Columba palumbus) was made by means of genetic analysis. Samples for genetic study were collected in different breeding and wintering habitats (in Portugal, France, Spain, Germany, Sweden, Poland, Hungary, Latvia and Lithuania) of Woodpigeons. Five polymorphic loci controlling synthesis of five different liver proteins (Mc, Tf, PreTf, PostAl, PreAl) and fragments of randomly amplified polymorphic DNA obtained using ten random primers were explored during the study. Significant differences based on frequency of alleles of proteins between populations of Woodpigeons breeding in Portugal and the rest European migratory populations of Woodpigeons were detected. Woodpigeon populations breeding in the region of the Baltic Sea were represented by close clusters in a dendrogram on the contrary to absence of the close clustering among populations of Woodpigeons wintering in Spain and France. It is supposed that genetic variability of Woodpigeon populations is base...

Colonial and Associated with Coot (Fulica Atra) nesting in Great Crested Grebe (Podiceps Cristatus): Comparison of Three Lakes

Nesting of the Great Crested Grebe in loose colonies and in close association with the Coot was investigated in Lakes Meteliai and Obelija in 1983–1986 and 1999 and in Lake Žaltytis in 1984–1986. Particular lakes and years were considered as integrators of between-lake and between-year differences in breeding habitat characteristics and were used as nominal variables. The Chi-square analysis revealed significant relations between the rates of colonial and associated nesting on the one hand and the lake and the year of breeding on the other. The share and the total area of helophytes growing in 26–100-cm-deep and 11–50-stems/m2-density zones (indices of prime breeding habitat) were used to interpret the results of between-lake comparisons. Annual differences in emergent vegetation areas dependent on winter survival and lake water level were used to interpret the results of between-year comparisons.

Changes in Numbers and Distribution of Wintering Waterfowl Populations in Lithuania in the 20th Century

Changes in numbers and distribution of wintering waterfowl populations in Lithuania in the 20th century are assessed and their reasons analysed. A total number of wintering waterfowl species increased from 17 in the 1900s–1940s to 28 in the 1960s and to 42 in the 1990s. A total number of wintering wildfowl species doubled. In the 1930s, several thousand wintering waterbirds were recorded throughout the Lithuanian wetlands. In the late 1990s, about 150,000 wintering waterbirds were annually counted on coastal wetlands and about 50,000 of them – on inland water bodies. Major changes observed in species composition and in the abundance of wintering waterfowl in Lithuania were primarily caused by the human activities affecting waterbird habitats and by general climatic amelioration, an increased number of mild winters in the Eastern Baltic region in recent decades.

Long-Term Genetic Investigations – Background for Research on Wildfowl Populations in the Changing Environmental Conditions

Since the year 1980 genetic investigations of wildfowl have been performed in various breeding sites in the Northern Palearctic. The research was done on ca 800 individuals of 20 wildfowl species. To evaluate genetic diversity we used the following genetic markers: blood serum lipoprotein and common protein antigen systems, polymorphous common protein and isoenzyme systems, DNA random and microsatellite markers. It was found that the same species migrating from different wintering sites differed considerably not only by frequency of alleles of isoenzymes and common proteins, but also by frequency of random DNA fragments. We determined genetic diversity of seaducks wintering in the Baltic Sea, and the scope of inter-specific similarity and genetic distances between these species. Significant genetic differences were also identified among migratory and sedentary populations of Mallard (Anas platyrhynchos) in different sites of the eastern Baltic region. Genetic studies form the background for long-term ecol...