Substrate Heterogeneity as a Trigger for Species Diversity in Marine Benthic Assemblages

Abstract

Many studies show that habitat complexity or habitat diversity plays a major role in biodiversity throughout different spatial scales: as structural heterogeneity increases, so does the number of available (micro-) habitats for the potential species inventory. The capability of housing species (even rare species) increases rapidly with increasing habitat heterogeneity. However, habitat complexity is not easy to measure in marine sublittoral sediments. In our study, we came up with a proposal to estimate sublittoral benthic habitat complexity using standard underwater video techniques. This tool was subsequently used to investigate the effect of habitat complexity on species richness in comparison to other environmental parameters in a marine protected area situated in the Fehmarn Belt, a narrow strait in the southwestern Baltic Sea. Our results show that species richness is significantly higher in heterogeneous substrates throughout all considered sediment types. Congruently, the presence of rare species increases with structural complexity. Our findings highlight the importance of the availability of microhabitats for benthic biodiversity as well as of the study area for regional ecosystem functioning.

Baseline Inventory of Benthic Macrofauna in German Marine Protected Areas (2020–2022) before Closure for Bottom-Contact Fishing

“…Where bottom-contact fishing occurs, it is often found to be among the most significant disturbances of macrofauna taxonomic [ 39 ] and functional composition [ 91 ], resulting in clear declines in benthic abundance and species richness [ 18 , 92 ]. Remarkably, despite including the most heavily trawled spots for our Baltic Sea study area, the Fehmarnbelt MPA provided home for the highest number of recorded species (264 taxa) and showed the largest variation in assemblage composition between its stations, not least due to its transition position, variety of habitat types, and highest salinity among Baltic Sea focus areas (see [ 93 ]). Generally, in the North and the Baltic Seas, the mobile bottom-contact fishing intensity has more or less decreased since the early 2000s (see Supplementary Material S2 refs.…”

Untangling Coastal Diversity: How Habitat Complexity Shapes Demersal and Benthopelagic Assemblages in NW Iberia

“…TRI values were extracted from digital elevation models in Quantum Gis (QGIS) [42] using the algorithm available within the open-source GDAL (Geospatial Data Abstraction Library) tools [43]. This topographic heterogeneity is considered an essential factor in species distribution since when heterogeneity increases, the number of microhabitats and the ability to shelter species also increase [44]. Low TRI values represent relatively flat and homogeneous areas, such as sand and mud, in contrast to high values, which represent rugged and more heterogeneous areas (Table 1).…”

Protected yet unmanaged: insights into the ecological status of conservation priority stony reefs in Belgian waters based on the integrative use of remote sensing technologies

“…Over the past decade, advancements in underwater photography, particularly still imagery, has revolutionised the study of SNHS biotopes (Michaelis et al, 2019a, b;van der Reijden et al, 2019;Becker et al, 2020;Montereale Gavazzi et al, 2021;Romoth et al, 2023). This technology allows for the observation of micro-scale (1 mm 2 -1 cm 2 ) features and processes at ecologically relevant spatial scales, while also ground truthing hydroacoustic remote sensing data.…”