Find research datasets worth reusing

opencc-zeroDec 2017View details →

Data from: Seasonal dynamics and changing sea level as determinants of the community and trophic structure of oribatid mites in a salt marsh of the Wadden Sea

Global change processes affect seasonal dynamics of salt marshes and thereby their plant and animal communities. However, these changes have been little investigated for microarthropod communities. We studied the effect of seasonality and changes in sea level on oribatid mites in the natural salt marsh and on artificial islands in the back-barrier environment of the island Spiekeroog (Wadden Sea, Germany). Three zones of the artificial islands were filled with transplanted sods from the lower salt marsh zone and thereby exposed to three different inundation frequencies. We hypothesized that oribatid mite communities will differ along the natural salt marsh vegetation zones [upper salt marsh (USM), lower salt marsh (LSM), pioneer zone (PZ)], which are influenced by different tidal regimes. Accordingly, total oribatid mite densities declined from the USM and LSM to the PZ. Similarly, oribatid mite species compositions changed along the salt marsh transect and also responded to variations in inundation frequency in LSM on artificial islands with typical species of the USM, LSM and PZ being Multioppia neglecta (USM), Hermannia pulchella (LSM), Zachvatkinibates quadrivertex (LSM, PZ) and Ameronothrus schneideri (LSM, PZ). Oribatid mite density in the salt marsh and on the artificial islands was at a maximum in winter and spring; this was due in part to high density of juveniles, pointing to two reproductive periods. We hypothesized that oribatid mite trophic structure changes due to variations in abiotic (e.g., tidal dynamics, temperature) and biotic conditions (e.g., resource availability). Stable isotope (15N, 13C) and neutral lipid fatty acid analyses indicated that oribatid mite species have different diets with e.g., Z. quadrivertex feeding on macroalgae and fungi, A. schneideri feeding on microalgae and bacteria, and Scheloribates laevigatus and M. neglecta feeding on dead organic matter, bacteria and fungi. Overall, the results indicate that oribatid mite species in salt marshes are affected by changes in environmental factors such as inundation intensity, with the effects being most pronounced in species with narrow trophic niches and limited niche plasticity. The results also indicate that oribatid communities of the LSM respond little to short-term (one year) changes in inundation frequency.

opencc-zeroDec 2015View details →

Data from: Consensus forecasting of intertidal seagrass habitat in the Wadden Sea

After the dramatic eutrophication-induced decline of intertidal seagrasses in the 1970s, the Wadden Sea has shown diverging developments. In the northern Wadden Sea, seagrass beds have expanded and become denser, while in the southern Wadden Sea, only small beds with low shoot densities are found. A lack of documentation of historical distributions hampers conservation management. Yet, the recovery in the northern Wadden Sea provides opportunity to construct robust habitat suitability models to support management. We tuned habitat distribution models based on 17 years of seagrass surveys in the northern Wadden Sea and high-resolution hydrodynamics and geomorphology for the entire Wadden Sea using five machine learning approaches. To obtain geographically transferable models, hyperparameters were tuned on the basis of prediction accuracy assessed by non-random, spatial cross-validation. The spatial cross-validation methodology was combined with a consensus modelling approach. The predicted suitability scores correlated amongst each other and with the hold-out observations in the training area indicating that the models converged and were transferable across space. Prediction accuracy was improved by averaging the predictions of the best models. We graphically examined the relationship between the consensus suitability score and independent presence-only data from outside the training area using the area-adjusted seagrass frequency per suitability class (continuous Boyce index). The Boyce index was positively correlated with the suitability score indicating the adequacy of the prediction methodology. We used the plot of the continuous Boyce index against habitat suitability score to demarcate three habitat classes – unsuitable, marginal and suitable – for the entire international Wadden Sea. This information is valuable for habitat conservation and restoration management. Divergence between predicted suitability and actual distributions from the recent past indicates that unaccounted factors limit seagrass development in the southern Wadden Sea. Synthesis and applications. Our methodology and data enabled us to produce a robust and validated consensus habitat suitability model. We identified highly suitable areas where intertidal seagrass meadows may establish and persist. Our work provides scientific underpinning for effective conservation planning in a dynamic landscape and sets monitoring priorities.

Fig. 5 in Species status and population structure of mussels (Mollusca: Bivalvia: Mytilus spp.) in the Wadden Sea of Lower Saxony (Germany)

Fig. 5 Phylogenetic tree of the concatenated COI and VD1 * haplotypes (n 084) based on maximum likelihood estimates as constructed using RAxML. Asterisks indicate bootstrap values ≥95%

Fig. 3 Haplotype-networks for a in Species status and population structure of mussels (Mollusca: Bivalvia: Mytilus spp.) in the Wadden Sea of Lower Saxony (Germany)

Fig. 3 Haplotype-networks for a COI (n haplotypes 0 15; n sequences 0 111), b VD1 (n haplotypes 0 17; n sequences 0 81), and c the combined data set (n haplotypes 0 16; n sequences 0 64). The sizes of the symbols are proportional to the number of individuals sharing that haplotypes (unique haplotypes are not included), with the rectangular haplotype having had the largest outgroup weight. Each node corresponds to one mutation step. The patterns used for the symbols match those used in the geographical distribution maps (Fig. 2)

Fig. 2 in Species status and population structure of mussels (Mollusca: Bivalvia: Mytilus spp.) in the Wadden Sea of Lower Saxony (Germany)

Fig. 2 Geographical distribution and abundance of the haplotypes for a COI (n haplotypes 0 43; n sequences 0 139), b VD1 (n haplotypes 0 70; n sequences 0 134), and c the combined data set (n 084 haplotypes; n sequences 0 132). Unique haplotypes are pooled and indicated in gray; all other patterns represent haplotypes found in two or more individuals. The patterns for the latter match with those used for the corresponding minimum-spanning-networks (Fig. 3)

Fig. 1 in Species status and population structure of mussels (Mollusca: Bivalvia: Mytilus spp.) in the Wadden Sea of Lower Saxony (Germany)

Fig. 1 Sampling locations within the Wadden Sea of Lower Saxony (Germany). For the population genetic analyses, the sampling area was subjectively separated into three areas: west, central and east. The arrows represent the average current direction and strength (Loewe et al. 2004)

opencc-zeroDec 2022View details →

Data from: A re-evaluation of the effects of mechanical cockle dredging in the Dutch Wadden Sea

<p>The three datasets are obtained directly from the papers we discuss or from their authors. The first two datasets concern recruitment of cockles and Balthic tellins at seven sites in the Wadden Sea. The third dataset contains data on dredging and suitability for knots at 272 1 km<sup>2</sup> grid cells in the western Wadden Sea.</p>

publicMar 2023View details →

Data from: A re-evaluation of the effects of mechanical cockle dredging in the Dutch Wadden Sea

Open the record for dataset details and reuse information.

publicNov 2018View details →

Data from: Seasonal dynamics and changing sea level as determinants of the community and trophic structure of oribatid mites in a salt marsh of the Wadden Sea

Open the record for dataset details and reuse information.

publicAug 2016View details →

Data from: Consensus forecasting of intertidal seagrass habitat in the Wadden Sea

Open the record for dataset details and reuse information.

zenodo28/100

Figure 5 in Onset and duration of gray seal (Halichoerus grypus) molt in the Wadden Sea, and the role of environmental conditions

Figure 5. The proportion of visible molting seals in late-molt over time for the years between 2004 and 2010. The onset of molt varied per year: the earliest onset in 2009 and the latest onset in 2008. The bubble size indicates the number of animals with an observation quality score of 1 for each survey. The dashed horizontal line shows the 50% level and the vertical bold red and black dashed lines show at what day of the year 50% of the visible molting animals were in late-molt, respectively.

opencc-by-4.0Apr 2017View details →

zenodo20/100

Fig. 4 in Species status and population structure of mussels (Mollusca: Bivalvia: Mytilus spp.) in the Wadden Sea of Lower Saxony (Germany)

Fig. 4 Phylogenetic trees of a the COI and b VD1 haplotypes based on maximum likelihood estimates as constructed using RAxML. Symbols indicate either bootstrap values ≥95% (asterisks) or species affinity of the outgroup sequences obtained from GenBank: triangle M. trossulus, filled hexagon M. galloprovincialis, empty hexagon M. galloprovincialis sharing a haplotype with a Wadden Sea M. edulis, filled square M. californianus, empty square M. coruscus