A comparison of growth in two juvenile flatfish species in the Dutch Wadden Sea: Searching for a mechanism for summer growth reduction in flatfish nurseries

In a series of trials at Grasslands Gore, over 10 years, the late-flowering tetraploid red clover 'Grassland Pawera' was more productive and persistent than other red clover cultivars. The strong summer growth of Pawera meets the need for heavy-weight lamb feed and high quality forage for conservation in intensive sheep farming systems in Southland. Lenient. infrequent defoliation is necessary to maximise DM production and persistence of Pawera. The most compatible of the grasses evaluated was 'Grasslands Roa' tall fescue. However, 'Grasslands Nui' ryegrass will still be the major grass sown with Pawera owing to its widespread acceptance. In ryegrass mixtures, sowing rates of 5-7 kg/ha of red clover were needed to optimise establishment and subsequent yield. Evidence of oestrogenic activity of Pewera to sheep prompted Grasslands Division to select within Pawera for a low formononetin cultivar. Keywords: red clover, Pawera. Hamua, Turoa. G21. G22, G27. oestrogenic activity, Nui ryegrass, Roa tall fescue, Maru phalaris. Southland, sheep grazing, frequency, intensity, quality. seasonal growth

Download Full-text

La perception sociale des derniers endiguements de la Mer des Wadden : résultats d'un sondage d'opinion réalisé en Frise du Nord (Social perception of the latest dyking up on the Wadden Sea coast : results of an opinion poll in Northern Friesland)

Bulletin de l Association de géographes français ◽

10.3406/bagf.1995.1862 ◽

1995 ◽

Vol 72 (5) ◽

pp. 466-481 ◽

Cited By ~ 2

Author(s):

Lydie Goeldner

Keyword(s):

Social Perception ◽

Wadden Sea ◽

Opinion Poll ◽

Sea Coast

Download Full-text

The Wadden Sea: Denmark, The Netherlands, and Germany

Coastal World Heritage Sites - Coastal Research Library ◽

10.1007/978-94-024-1528-5_76 ◽

2018 ◽

pp. 521-526

Author(s):

Vanda Claudino-Sales

Keyword(s):

The Netherlands ◽

Wadden Sea

Download Full-text

4 Protecting the natural and cultural values of the Wadden Sea coast in the Anthropocene

Waddenland Outstanding ◽

10.1515/9789048537884-005 ◽

2018 ◽

pp. 67-80

Keyword(s):

Cultural Values ◽

Wadden Sea ◽

Sea Coast

Download Full-text

Phylogeography in an “oyster” shell provides first insights into the genetic structure of an extinct Ostrea edulis population

Scientific Reports ◽

10.1038/s41598-021-82020-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sarah Hayer ◽

Dirk Brandis ◽

Alexander Immel ◽

Julian Susat ◽

Montserrat Torres-Oliva ◽

...

Keyword(s):

Large Scale ◽

Wadden Sea ◽

Atlantic Coast ◽

Phylogenetic Reconstruction ◽

Oyster Shell ◽

Glacial Refugia ◽

Late Nineteenth Century ◽

Ostrea Edulis ◽

Geographic Ranges ◽

The North

AbstractThe historical phylogeography of Ostrea edulis was successfully depicted in its native range for the first time using ancient DNA methods on dry shells from museum collections. This research reconstructed the historical population structure of the European flat oyster across Europe in the 1870s—including the now extinct population in the Wadden Sea. In total, four haplogroups were identified with one haplogroup having a patchy distribution from the North Sea to the Atlantic coast of France. This irregular distribution could be the result of translocations. The other three haplogroups are restricted to narrow geographic ranges, which may indicate adaptation to local environmental conditions or geographical barriers to gene flow. The phylogenetic reconstruction of the four haplogroups suggests the signatures of glacial refugia and postglacial expansion. The comparison with present-day O. edulis populations revealed a temporally stable population genetic pattern over the past 150 years despite large-scale translocations. This historical phylogeographic reconstruction was able to discover an autochthonous population in the German and Danish Wadden Sea in the late nineteenth century, where O. edulis is extinct today. The genetic distinctiveness of a now-extinct population hints at a connection between the genetic background of O. edulis in the Wadden Sea and for its absence until today.

Download Full-text

The Wadden Sea as a National Park and UNESCO World Heritage Site: Students’ Word Associations with These Two Conservation Designations

Sustainability ◽

10.3390/su13148006 ◽

2021 ◽

Vol 13 (14) ◽

pp. 8006

Author(s):

Till Schmäing ◽

Norbert Grotjohann

Keyword(s):

National Parks ◽

National Park ◽

Wadden Sea ◽

World Heritage ◽

World Heritage Site ◽

Unesco World Heritage ◽

Word Associations ◽

Heritage Site ◽

Unesco World Heritage Site ◽

Significant Difference

The Wadden Sea ecosystem is unique in many respects from a biological perspective. This is one reason why it is protected by national parks in Germany and by its designation as a UNESCO World Heritage Site. In biology didactics, there are only a few studies that focus on the Wadden Sea. This work investigates students’ word associations with the two stimulus words “national park” and “UNESCO World Heritage Site”. The survey was conducted among students living directly at the Wadden Sea and among students from the inland. The analysis of the identified associations (n = 8345) was carried out within the framework of a quantitative content analysis to be able to present and discuss the results on a group level. A statistically significant difference was found between the two groups. Overall, results showed that the students made subject-related associations as well as a large number of associations to both stimulus words that could be judged as non-subject-related. In some cases, a connection with the region of residence could be found, but this was not generally the case. Even students’ immediate residential proximity to the Wadden Sea is no guarantee that they have knowledge of the two considered protection terms.

Download Full-text

Large-scale sequencing of flatfish genomes provides insights into the polyphyletic origin of their specialized body plan

Nature Genetics ◽

10.1038/s41588-021-00836-9 ◽

2021 ◽

Author(s):

Zhenming Lü ◽

Li Gong ◽

Yandong Ren ◽

Yongjiu Chen ◽

Zhongkai Wang ◽

...

Keyword(s):

Retinoic Acid ◽

Large Scale ◽

Body Plan ◽

Monophyletic Group ◽

Transcriptomic Data ◽

Flatfish Species ◽

Genetic Origins

AbstractThe evolutionary and genetic origins of the specialized body plan of flatfish are largely unclear. We analyzed the genomes of 11 flatfish species representing 9 of the 14 Pleuronectiforme families and conclude that Pleuronectoidei and Psettodoidei do not form a monophyletic group, suggesting independent origins from different percoid ancestors. Genomic and transcriptomic data indicate that genes related to WNT and retinoic acid pathways, hampered musculature and reduced lipids might have functioned in the evolution of the specialized body plan of Pleuronectoidei. Evolution of Psettodoidei involved similar but not identical genes. Our work provides valuable resources and insights for understanding the genetic origins of the unusual body plan of flatfishes.

Download Full-text

A Classification Scheme for Sediments and Habitats on Exposed Intertidal Flats with Multi-Frequency Polarimetric SAR

Remote Sensing ◽

10.3390/rs13030360 ◽

2021 ◽

Vol 13 (3) ◽

pp. 360

Author(s):

Wensheng Wang ◽

Martin Gade ◽

Kerstin Stelzer ◽

Jörn Kohlus ◽

Xinyu Zhao ◽

...

Keyword(s):

Classification Scheme ◽

Wadden Sea ◽

Relative Difference ◽

Polarimetric Synthetic Aperture Radar ◽

Intertidal Flats ◽

Sediment Types ◽

X Band ◽

Good Potential ◽

L Band ◽

Sar Data

We developed an extension of a previously proposed classification scheme that is based upon Freeman–Durden and Cloude–Pottier decompositions of polarimetric Synthetic Aperture Radar (SAR) data, along with a Double-Bounce Eigenvalue Relative Difference (DERD) parameter, and a Random Forest (RF) classifier. The extension was done, firstly, by using dual-copolarization SAR data acquired at shorter wavelengths (C- and X-band, in addition to the previously used L-band) and, secondly, by adding indicators derived from the (polarimetric) Kennaugh elements. The performance of the newly developed classification scheme, herein abbreviated as FCDK-RF, was tested using SAR data of exposed intertidal flats. We demonstrate that the FCDK-RF scheme is capable of distinguishing between different sediment types, namely mud and sand, at high spatial accuracies. Moreover, the classification scheme shows good potential in the detection of bivalve beds on the exposed flats. Our results show that the developed FCDK-RF scheme can be applied for the mapping of sediments and habitats in the Wadden Sea on the German North Sea coast using multi-frequency and multi-polarization SAR from ALOS-2 (L-band), Radarsat-2 (C-band) and TerraSAR-X (X-band).

Download Full-text