Creation of microhabitats (tidepools) in ripraps with climax communities as a way to mitigate negative effects of artificial substrate on marine biodiversity

• Published in: Ecological engineering 2018-09, Vol.120, p.522-531
• Main Authors: Ostalé-Valriberas, E., Sempere-Valverde, J., Coppa, S., García-Gómez, J.C., Espinosa, F.
• Format: Article
• Language: English
• Subjects: Aquatic habitats; Artificial structures; Artificial substrata; Artificial wetlands; Biodiversity; Biology; Biota; Breeding; Coastal structures; Coasts; Colonization; Composition effects; Control; Ecological engineering; Ecosystems; Environmental monitoring; Fragmentation; Habitats; Intertidal assemblages; Introduced species; Invasive species; Littoral environments; Marine biology; Marine ecology; Marine engineering; Microhabitat; Microhabitats; Offshore structures; Ova; Pools; Regrowth of biodiversity; Riprap; Shores; Species composition; Species diversity; Species richness; Strait of Gibraltar; Substrates; Tide pools; Tidepools; Tides; Underwater habitats; Urbanization; Vagile species
• ISSN: 0925-8574; 1872-6992
• DOI: 10.1016/j.ecoleng.2018.06.023

•The creation of intertidal tidepools on coastal defence structures with climax communities increases the local biodiversity.•In a year, artificial tidepools exceeded control species richness by 39.21% and diversity by 30.70%.•Adjacent halo around the pool (5 cm) showed that the newly created habitat extends its influence beyond the limits of the tidepools.•Tidepools increased the number of species on ripraps and contributed to reduced fragmentation of some vagile species populations. Urbanisation and the construction of commercial structures on coasts cause a significant impact on natural marine habitats. The concept of ¨Ecological Engineering¨, recently applied to marine biology, integrates ecology, economy and society’s needs into the design of artificial marine structures. Recently, some ecological designs, such as the addition of pools, pits, and crevices, have been proposed in order to reduce habitat modification, diminish colonization by invasive species, and spread and maintain ecosystem functioning and biodiversity indexes that are more similar to those of the natural environment. Within the features that may increase artificial habitats’ diversity, tidepools are unique habitats that reduce stress in the intertidal, favouring breeding and feeding, as well as providing shelter and a greater degree of moisture to a certain group of species, which may present an advantage for them. Nevertheless, the ecological benefits that arise from the inclusion of these features on fully mature artificial structures are still poorly known. In the present study, tidepools were created on artificial substrate with an affordable method (jackhammer) in the locality of Ceuta (Strait of Gibraltar). The pools were carved on dolomitic riprap at two different intertidal levels, high and low shore (+0.75 m and +0.25 m higher than the lowest tide, respectively) with an average area of 195.2 cm2 and 353.01 cm3 of volume. These coastal defence structures were built more than eight years ago, thus the biota has substantially completed its colonization period and is set in terms of species composition. To test humidity effects on benthic assemblages around tidepools, the adjacent halo around the pool, with a width of 5 cm, was equally traced. Pool assemblages were compared to adjacent artificial and natural substrate and also to nearby natural pools. One year later, the results in species richness and diversity were significantly higher in the tidepools than the other two studi