Data on morphological and biochemical traits of the bladderwrack Fucus vesiculosus were obtained from individuals simultaneously collected in September 2011 in 20 stations along the Baltic Sea and 4 stations in the North Sea. The individuals included in the analysis were collected at 0.5-1.0 m depth. Frond length, frond width, stipe width and number of fronds were directly determined in the field. All collected individuals were transported to the laboratory in cooler boxes at temperatures below 5 °C, then frozen at -20 °C within 12 h, and shipped to the GEOMAR-Helmholtz Centre for Ocean Research Kiel (Germany) on dry ice. Measurements of chlorophyll a and fucoxanthin in surface and tissue extracts, mannitol, phlorotannins and carbon:nitrogen ratio were performed in the laboratory (see further methodological details in the related article). The relative palatability of the algal material collected in all 24 stations was determined in palatability assays, using reconstituted algal pellets and the pan-Baltic grazer Idotea balthica. In addition to the trait information, environmental data on sea surface salinity, sea surface summer temperature, photosynthetically active radiation (PAR), wave exposure and total nitrogen have been obtained from the Swedish Meteorological and Hydrological Institute (SMHI) or local monitoring services.
The dataset is composed of a) hyperspectral imagery acquired during airplane overflights on August 7th, 2008 and August 20th, 2009 consisting of 126 and 125 spectral bands, respectively, ranging from VIS to SWIR (456 - 2490 nm and 453 - 2480 nm) wavelength regions; b) spectral reference measurements acquired with an portable ASD field spectroradiometer in 2150 spectral bands (350 - 2500nm) in the same phenological periods of July/August/September 2008/09 c) plant species assemblages on 81 moist and 72 dry habitats consisting of the fractional cover of all vascular plants, mosses and lichens.
The overall goal of the study was to map plant species shift along environmental gradients relating spectral information to the floristic composition. Reference plots of 1 or 2 m² size were thereby located in typical plant communities as well as in transition zones affected by species shift due to management measures such as grazing or shrub removal. In addition 17 field plots were analyzed with regard to soil horizon parameter (e.g. pH, grain size, carbonate content) in the year 2011. Soil types are further available on 51 auger probes.