Stony reefs are ecologically important, providing irreplaceable ecosystem services. These fragile environments are recognised as conservation priorities by all relevant global and European policies. Bottom-contacting fi sheries are an important source of anthropogenic disturbance to the sea fl oor ’ s physical and ecological integrity having immediate and destructive consequences on stony reefs and compromising ecological functions. This study, aimed to assess the ecological status (community composition and functions) of two stony reef areas -Northwest and Hinder Banks study sites -in Belgian waters using multiple remote sensing tools. Insights on the study sites ’ geomorphological context and fi shing patterns were gained using echo-sounding and publicly available satellite data. Video-based benthic community data were assessed against the exposure to fi shing pressure using a trait-based approach linked to the biotas ’ resistance and recovery potential. In the Northwest study site, between 2019 and 2022 there was a signi fi cant decline in the abundance of benthic species classi fi ed with low resistance and recovery potential to trawling. Conversely, there was a notable increase in species with moderate scores. During the same period, this site experienced an eight-fold increase in fi shing effort and the hydroacoustic data revealed the presence of several trawl-marks in 2022. Similar changes in benthic communities were observed in the Hinder Banks too. Here, the abundance of species with low resistance and recovery potential was signi fi cantly lower in locations that were geomorphologically exposed to trawling compared to sheltered ones. Exposed locations had a higher abundance of opportunistic species, with moderate to high scores. The presence of several trawl marks on the sea fl oor was observed in the exposed locations, corresponding to fi shing hotspots identi fi ed in the satellite data. Trawling activities marginally impacted richness and total abundance, but negatively altered benthic functional composition. The fi ndings of this study provide scienti fi c evidence of the detrimental impact of bottom-contacting fi sheries on conservation priority biotopes and argues against the coexistence of such activities with Marine Protected Areas. The results of our investigation are of interest to environmental managers for the adequate implementation of environmental legislation in the face of rapid and widespread anthropogenic changes.
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RBINS Staff Publications 2023
The North Sea will soon see the installation of a higher number of wind turbine foundations, greatly expanding the habitat options for reef species. These offshore structures constitute a new, artificial, hard substratum habitat on the Belgian continental shelf, where the seafloor is primarily made up of muddy and sandy sediment. The possibility of co-designing offshore wind farms with more microhabitats through increasing habitat complexity is one method for the multiple uses of wind farms. This method is known as nature-inclusive building. The structure and dynamics of ecological communities are significantly influenced by habitat complexity. Hence, an increased complexity frequently results in greater species variety and abundance. The objective of this study was to investigate whether adding complexity to the scour protection layer (SPL) increased the diversity and functionality of the ecosystem already present at the bottom of wind turbines (macrobenthos community). To study this, three different variables of 76 species were analysed: richness, biomass, and abundance. Despite being the first time to manipulate the SPL of wind farms, it has been possible to observe and demonstrate that the complexity of these structures affects the ecosystem’s richness. Of the four different treatments, a greater number of species were observed in the most complex ones (3 and 4) compared to the others. In addition, although there were no significant differences, trends of higher biomass of certain species (belonging to decapods and sea anemones) were observed in the presence of higher complexity. Conversely, the constant presence of amphipods was observed across all the treatments. With this study, we wanted to emphasise the importance of the artificial reef effect of the SPL and, together with the microhabitats that it can provide, if at the time of its construction, an attempt is made from an “eco-friendlier” perspective, combining the knowledge of ingested together with the biological. In addition, it provides more knowledge and understanding of this methodology by improving it and obtaining results more similar to those expected in the future.
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RBINS Staff Publications 2022
Ce résumé n'est disponible qu'en anglais. Deze samenvatting is alleen beschikbaar in het Engels. Abstract This work is largely based on the author's doctoral thesis in which new graphic representations, with the accent on mapping systems, were developed in the field of fundamental and applied geology and this particular for continental deposits. Useful mapping systems for Quatemary continental deposits were indeed for the greatest part absent or still in a primary stage of development. Among certain geologists exists still the idea that the construction of a geological map is the initial step in making the survey of an area and that the understanding of the geological constitution and evolution comes only in a later stage. This specific study is than mainly based on the already surveyed map of that particular area. This idea is only tenable to a certain level when it concerns rather homogeneous deposits extended over long distances and at a particular level, for example in a superficial or outcropping position. But once the geologist is dealing with widely differing deposits, like for instance the Quatemary deposits in Belgium, the above described method is out of question. Besides, during the study it became clear that although the general Quatemary evolution is rather well known, essential elements necessary in both the fundamental and applied geology are still missing. Consequently the necessity forced itself to follow the next procedure in order to get a detailed overview of the geological build-up of the survey area. Detailed information is gathered by studying primary sedimentary structures in correlation with texture and palaeontological data obtained from palaeozoölogy and palaeobotany. The basic and largest part of information is got from undisturbed cored borings, provided by the Belgian Geological Survey, and outcrop observations, both completed by hand drillings as weIl as borehole descriptions. The latter ones are derived from the archives of the Belgian Geological Survey. This kind of information made the reconstruction of the sedimentary paleao-environments and paleao-subenvironments possible which for their part form the building blocs of the fundamental geological map called profile type map. The construction of the profile type map however is explained in this work step by step since in the present literature such a "manual" is still missing. Derived from the basic data the construction of other thematic maps is possible. An engineering geological map is introduced as an example. Usefulness and applicability of these maps are discussed in previous articles written by the author.
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