Conservation implications of extraordinary Greater Scaup (Aythya marila) concentrations in the Odra Estuary, Poland

Human activities in marine coastal areas may coincide with protected areas for birds. Some of these anthropogenic activities may pose threats, such as gillnet fisheries, which can significantly affect populations of diving birds, especially gregarious species that gather in huge flocks in small areas such as Greater Scaup (Aythya marila). The Odra Estuary (Baltic Sea, Poland) is known for its importance as a wintering site for scaup; it is also used by fishermen using gillnets. Precise tools to determine the distribution and abundance of birds allow evaluation of risks faced by large aggregations. We used kernel density interpolation to estimate the spatial density of scaup in the Odra Estuary in spring 2011. At that time, an extraordinarily high number of scaup (95,400) was recorded, ~73% (63.0–94.5%) of the entire northwest European flyway population. Three variables are particularly important for conserving highly mobile long-distance migrating species: spatial distribution, abundance, and time (season of the year). This event concentrated most of the scaup flyway population in a small space, making the population vulnerable to mass mortality. We also show aggregated data of the spatial distribution of scaup during the 2015–2016 and 2016–2017 seasons to highlight differences in the spatial use of the area between seasons. Vast areas occupied by scaup in 2011 were not used during 2 other studied seasons; this spatial variation may be crucial in conservation planning of this species. Our results are a first step in documenting the spatial distribution of scaup in the Odra Estuary and identifying the potential area of overlap with fishing activity.

Aspects of the environment and nature protection in the German-Polish border region of the Oder lagoon

The environmental problems of today have more and more border-crossing character. In the present paper the ecological problems of the german-polish border region of the Odra estuary, which form a border crossing ecological sensible unit, were studied for special parts of environmental protection, nature protection and water management regarding the quality of internal and external coastel waters, international conventions for protection of the Baltic Sea, cooperation in the field of protection and management of groundwater and waste water. A critical summarized evaluation based on the analysis was established which helps identifing the defizits and possibilities for progess of the bilateral cooperation and which indicate precise focal points for border-crossing fields of actions in the region of Odraestuary, to ensure a sustainable and continuing developpement of this region.

Macromycetes of the proposed nature reserve Wilcze Uroczysko-Olszanka in the Odra estuary

The paper presents a characterisation of the mycoflora on the cupola-type rised bog in the Odra river valley. The characteristic of each species includes: type of substrate and plant community, date of fruitbody occurence, and the forest unit, where the species was observed. Systematic, ecological and sociological analyses of the mycoflora have been performed and the protected and endangered species singled out.

Heavy Metals in the Waters of Dąbie Lake (West-Pomeranian Voievodship, North-West Poland)

Heavy metal pollution is an ever increasing problem of our lakes. These toxic heavy metals entering in aquatic environment are adsorbed onto particulate matter, although they can form free metal ions and soluble complexes that are available for uptake by biological organisms. The increase in residue levels of heavy metal content in water, sediments and biota has resulted in decreased productivity and increase in exposure of humans to harmful substances. Many of these metals tend to remain in the ecosystem and eventually move from one compartment to the other within the food chain. Food chain contamination by heavy metals has become a burning issue in recent years because of their potential accumulation in biosystems through contaminated water, soil, sediment and air. Dąbie Lake is an integral part of the River Odra estuary. It is a shallow (2.5 m mean depth) water body with two distinct basins: the large (Dąbie Wielkie) and the small (Dąbie Małe). The aim of the studies, carried out in the years 2008 - 2009, was to determine the content of Cadmium (Cd), Chromium (Cr), Copper (Cu), Mercury (Hg), Nickel (Ni), Lead (Pb) and Zinc (Zn) in the waters of Dąbie Lake, being the internal part of the tertiary Odra estuary.

The relative growth of walking legs of adult Chinese mitten crabs, Eriocheir sinensis in the Odra estuary (Poland). The major axis statistical modeling

We have quantified the relative growth of the merus and the propodus & carpus of walking legs of an adult of Eriocheir sinensis against the carapace width by fitting the major axis lines. Different lines have been fitted to data relative to male and female individuals. Slope and elevation tests have been performed to investigate sexual dimorphism. Isometry tests have been used to classify the relative growth of each part of the legs against the carapace width as isometric or allometric.All the slope tests have not rejected the null hypothesis of a common slope for the major axes fitted to male data and to female data. However, all the elevation tests have rejected the null hypothesis of a common elevation; so sexual dimorphism was detected for all measured leg parts. The isometry tests have rejected the null hypothesis of isometry only for the merus of the first (left and right) legs of male individuals. All the other isometry tests have not rejected the null hypothesis of isometry. So the relative growth of all the measured leg parts, but the merus of the first (left and right) legs of males, against the carapace width was isometric both for males and for females.

Major axis approach to the statistical analysis of the relative growth of Chinese mitten crab (Eriocheir sinensis) in the Odra estuary (Poland)

A total of 379 individuals of Eriocheir sinensis (198 males and 181 females) were captured in the Odra estuary (Poland). The crabs were thawed and their carapace length (CL), the maximum carapace width (CW) and the maximum height (CH) were measured. Measurements were also taken on each claw, the claw length (CHL1, the right claw; CHL2, the left claw), the width (CHW1 and CHW2 for the right and the left claw, respectively), and the height (CHH1 and CHH2 for the right and the left claw). For each crab, the wet weight was measured for each of the following body components: the whole crab (CrWe), the carapace (CaWe), the right claw (WRC) and the left claw (WLC). For females, the relationship between CL and CW, CH and CW were isometric, and for all linear measures, the relationship with CW was positively allometric. For males only this first relationship was isometric, but others were positively allometric. The differences between relative growth parameters for males and females were statistically significant.