scholarly journals Small-Scale and Long-Term Variability in Population Dynamics of the Cockle Cerastoderma edule in a Southern North Sea Tidal Flat System

2021 ◽  
Vol 8 ◽  
Author(s):  
Julia Meyer ◽  
Ingrid Kröncke ◽  
Alexander Bartholomä ◽  
Mathias Heckroth ◽  
Gregor Scheiffarth
Keyword(s):  
Population Dynamics ◽  
Food Web ◽  
North Sea ◽  
Wadden Sea ◽  
Environmental Changes ◽  
Blue Mussel ◽  
Bird Species ◽  
Small Scale ◽  
Cerastoderma Edule

The cockle Cerastoderma edule is one of the most common macrofauna species in the Wadden Sea areas of the North Sea. Cockle population dynamics are influenced by various abiotic and biotic factors such as temperature, food availability, and inter- and intraspecific competition. Cockles play an important role in the food web of the Wadden Sea, for instance, large shellfish-eating birds, such as oystercatchers and common eiders, use the cockle C. edule and the blue mussel Mytilus edulis as a main diet component. However, the populations of shellfish-eating bird species have been declining dramatically across the Wadden Sea since the beginning of the 21st century. While there are detailed monitoring programs in blue mussels due to commercial interests, little information is known about the stocks and long-term dynamics of cockles in the German Wadden Sea. To fill this gap, in 2005 a local conservation society (“Der Mellumrat e.V.”) initiated a study to sample cockles at one transect per year south of the island of Mellum, which was extended by 5 more transects in 2011. In addition to the spatial analysis, we analyzed the long-term variability in cockle population dynamics. Min/max autocorrelation factor analysis (MAFA) revealed a decline in cockle abundance, while no clear length trends were found. Canonical and spearman correlation analyses exposed significant correlations between cockle abundance and length and chlorophyll a, mussel bank area as well as oystercatcher and common eider populations. This study clearly shows that there is an urgent need for comprehensive time series of cockle data to analyze and explain ecological long-term changes in cockle population dynamics in relation to environmental changes and to point out how parts of the Wadden Sea food web, such as shellfish-eating birds are affected by these changes.

scholarly journals Long-term population dynamics of breeding bird species in the German Wadden Sea area

1989 ◽  
Vol 43 (3-4) ◽  
pp. 357-365 ◽  
Author(s):  
Gottfried Vauk ◽  
Johannes Prüter ◽  
Eike Hartwig
Keyword(s):  
Population Dynamics ◽  
Wadden Sea ◽  
Bird Species ◽  
Breeding Bird ◽  
Sea Area

Long-term changes in species composition of demersal fish and epibenthic species in the Jade area (German Wadden Sea/Southern North Sea) since 1972

2016 ◽  
Vol 181 ◽  
pp. 284-293 ◽  
Author(s):  
Julia Meyer ◽  
Ingrid Kröncke ◽  
Alexander Bartholomä ◽  
Joachim W. Dippner ◽  
Ulrike Schückel
Keyword(s):  
Species Composition ◽  
North Sea ◽  
Wadden Sea ◽  
Demersal Fish ◽  
Southern North Sea ◽  
Long Term Changes

Small-scale benthos distribution modelling in a North Sea tidal basin in response to climatic and environmental changes (1970s-2009)

2016 ◽  
Vol 551 ◽  
pp. 13-30 ◽  
Author(s):  
A Singer ◽  
U Schückel ◽  
M Beck ◽  
O Bleich ◽  
HJ Brumsack ◽  
...  
Keyword(s):  
North Sea ◽  
Environmental Changes ◽  
Small Scale ◽  
Tidal Basin ◽  
Distribution Modelling

КОМПЛЕКСНА ОЦІНКА ДИНАМІКИ ЧИСЕЛЬНОСТІ УГРУПОВАНЬ КОЛОНІАЛЬНИХ НАВКОЛОВОДНИХ ПТАХІВ (НА ПРИКЛАДІ ДЕЯКИХ ОСТРОВІВ СИВАШУ)

2011 ◽  
Vol 1 (3) ◽  
pp. 85
Author(s):  
О. V. Matsyura
Keyword(s):  
Population Dynamics ◽  
Bird Species ◽  
Breeding Birds ◽  
Extinction Rate ◽  
Breeding Bird ◽  
Key Species ◽  
Number Dynamics ◽  
Long Term Monitoring ◽  
Term Monitoring

<p>The problem of the mathematical analysis of the number dynamics of the nesting waterbirds for the islands of the south of Ukraine is examined. The algorithm of the evaluation of changes in the number of island birds is proposed. Data of the long-term monitoring of the number of birds were analyzed according to this algorithm. The necessity of the implementation of the statistical indices together with the graphic representation of island birds’ turnover is proved. The trends of population dynamics are determined for the key species. The discussed procedure of the complex evaluation is proposed for the management planning of the island bird species and their habitats.</p> <p>The performed analysis of the number dynamics of the key-stone breeding island birds showed that, with the exception of little tern, the population status and the prognosis of number are sufficiently favorable.  From the data of long-term monitoring we came up with the conclusion about the existence of island habitats with carrying capacity to maintain the additional number of breeding birds. In the case of unfavorable conditions like strengthening of anthropogenic press, concurrent interrelations, deficiency of feed resources or drastic reduction of breeding biotopes, the birds due to turnover are capable to successfully react even without reducing their number and breeding success. The extinction rate of the breeding bird species from the island sites directly correlates with the number of breeding species. For the species with equal abundance, the extinction probability is higher for birds, whose numbers are unstable and characterized by significant fluctuations. This testifies the urgency of the constant monitoring and analysis of the number dynamics of breeding bird species in region.</p> <p>The suggested procedure of analysis is recommended for drawing up of management plans and performing of prognoses of number of breeding island bird species. More detail analysis with use of quantitative data on breeding birds will be the next step of the study of the island birds’ turnover. The results of the analysis of population dynamics assist to count the minimal population size for the colonization of new islands and stable existence of bird communities.  Detailed analysis will allow to estimate the effect of competition on population and to determine the competitive variability inside and between the species breeding on islands.</p> <p><em>Key words: Ukraine, colonial waterbirds, islands, dynamics of number, analysis</em></p> <p> </p>

scholarly journals Spatio-temporal variation in stable isotope and elemental composition of key-species reflect environmental changes in the Baltic Sea

2021 ◽  
Author(s):  
Camilla Liénart ◽  
Andrius Garbaras ◽  
Susanne Qvarfordt ◽  
Jakob Walve ◽  
Agnes M. L. Karlson
Keyword(s):  
Stable Isotope ◽  
Baltic Sea ◽  
Temporal Variation ◽  
Food Web ◽  
Elemental Composition ◽  
Environmental Changes ◽  
The Baltic Sea ◽  
Open Sea ◽  
The Baltic

AbstractCarbon and nitrogen stable isotope ratios are increasingly used to study long-term change in food web structure and nutrient cycling. We retrospectively analyse elemental composition (C, N and P) and stable isotopes (δ13C, δ15N) in archived monitoring samples of two important taxa from the bottom of the food web; the filamentous ephemeral macroalgae Cladophora spp. and the blue mussel Mytilus edulis trossulus from three contrasting regions in the Baltic Sea (coastal Bothnian Sea and Baltic Proper, open sea central Baltic). The aim is to statistically link the observed spatial and interannual (8–24 years’ time-series) variability in elemental and isotope baselines with their biomass trends and to the oceanographic monitoring data reflecting the ongoing environmental changes (i.e., eutrophication and climate) in this system. We find clear differences in isotope baselines between the two major Baltic Sea basins. However, the temporal variation in Mytilus δ13C was similar among regions and, at the open sea station, mussels and algae δ13C also correlated over time, likely reflecting a global (Suess) effect, whereas δ15N of both taxa varied with local and regional dissolved nitrogen concentrations in water. δ15N in source amino acids allowed detection of diazotrophic N in Mytilus, which was masked in bulk δ15N. Finally, Cladophora N:P reflected regional nutrient levels in the water while P%, which differed for both taxa, was linked to food quality for Mytilus. This study highlights the potential of a multi-taxa and multi-stable isotope approach to understand nutrient dynamics and monitor long-term environmental changes.

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