A novel use of Stereo Baited Remote Underwater Video and Drop-Down Video for biodiversity and marine landscape mapping and prediction

PLOS ONE | https://doi.org/10.1371/journal.pone.0319355 April 3, 2025 16 / 23 PLOS ONE Marine landscape and biodiversity mapping using SBRUVs and DDV if a high degree of fragmentation leads to patches which are too small, predation can have a negative impact on some demersal species [82,83]. Our results show that the highest predicted biodiversity was associated with a high mix of substratum types, with lower diversity found in areas of extended mud, as found in some other studies [33]. The complex structures formed by maerl provide refuge for many spe- cies including juvenile fish [84–86]. Valuable interstitial structures, such as those provided by maerl, are sensitive due to their vulnerability to degradation and fragmentation through practices such as trawling and dredging [40,87,88]. Other substrata that were found in close association with areas of maerl gravel were algal dominated areas (Fig 13). There may be a combination of algal/maerl gravel/sand association that provides the best opportunities for the highest number of taxa in foraging opportunities, shelter, area, and composition [89–91]. When examining differences in biodiversity between substrata, algae and sand displayed sta- tistically significant differences to mud. This aligns with previous work illustrating how seabed composition may drive demersal and epibenthic species present [18]. Kriged predictions of biodiversity, as diversity was measured from SBRUV deployments alone, resulted in all data being gathered solely from sites closer inshore and as such predic-

tions into deeper water further from shore are made with increasing standard error (Fig S1). Fig 12. Results from 500 x 500 m gridded breakdown of predicted substrata and diversity within the MPA study area. Mean proportional coverage of each substratum type and mean Inverse Simpson’s Diversity Index for each gridded 500 m x 500 m square (Fig S2) in the South Arran MPA broken down by fishing management limitations (Fig 2, Table 1). Blue crosses denote the median and bars indicted the mean. https://doi.org/10.1371/journal.pone.0319355.g012