Mapping microhabitat thermal patterns in artificial breakwaters: Alteration of intertidal biodiversity by higher rock temperature

• Published in: Ecology and evolution 2019-11, Vol.9 (22), p.12915-12927
• Main Authors: Aguilera, Moisés A., Arias, René M., Manzur, Tatiana
• Format: Article
• Language: English
• Subjects: Air sampling; Air temperature; artificial breakwaters; Biodiversity; Biodiversity loss; boulder fields; Breakwaters; Chemical analysis; Coastal ecosystems; coastal microclimate; Coastal structures; Community structure; Diurnal; Ecosystems; Habitats; Heat; Heterogeneity; Infrared imaging; Infrastructure; Mapping; Marine ecosystems; Microclimate; Microenvironments; Microhabitats; Original Research; Rocks; rocky intertidal; Seawater; Spatial heterogeneity; Species diversity; Stone; Substrates; Summer; thermal patterns; Thermography; Topography; Urbanization; Water analysis; Wind speed
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.5776

Urbanization is altering community structure and functioning in marine ecosystems, but knowledge about the mechanisms driving loss of species diversity is still limited. Here, we examine rock thermal patterns in artificial breakwaters and test whether they have higher and spatially less variable rock temperature than natural adjacent habitats, which corresponds with lower biodiversity patterns. We estimated rock temperatures at mid‐high intertidal using infrared thermography during mid‐day in summer, in both artificial (Rip‐raps) and natural (boulder fields) habitats. We also conducted diurnal thermal surveys (every 4 hr) in four seasons at one study site. Concurrent sampling of air and seawater temperature, wind velocity, and topographic structure of habitats were considered to explore their influence on rock temperature. Rock temperature was in average 3.7°C higher in the artificial breakwater in two of the three study sites, while air temperature was about 1.5–4°C higher at this habitat at summer. Thermal patterns were more homogeneous across the artificial habitat. Lower species abundance and richness in the artificial breakwaters were associated with higher rock temperature. Mechanism underlying enhanced substrate temperature in the artificial structures seems related to their lower small‐scale spatial heterogeneity. Our study thus highlighted that higher rock temperature in artificial breakwaters can contribute to loss of biodiversity and that integrated artificial structures may alter coastal urban microclimates, a matter that should be considered in the spatial planning of urban coastal ecosystems. We evaluated substrate thermal patterns in artificial breakwaters and natural adjacent boulder fields. We found higher rock and air temperature in the artificial habitat. Species abundance and richness were lower in the artificial habitat and related negatively with rock temperature.