A description of Florida estuarine gradient complexes and the implications of habitat factor covariation for community habitat analysis. (5th January 2022)

• Record Type: Journal Article
• Authors: Michaud, Brianna C.; Kilborn, Joshua P.; MacDonald, Timothy C.; Peebles, Ernst B.
• Is Part Of: Estuarine, coastal and shelf science. Volume 264(2022)
• Publication Date: 2022-01-05
• Subjects: Community analysis -- Multivariate statistics -- Spatial analysis -- Estuarine management; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2021.107669
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: A multi-parameter dataset from 13 Florida estuaries demonstrated complications that multiple gradients (the estuarine gradient complex, EGC) 1 impose when trying to characterize species distributions using regression-based analyses. Variation in the beta diversity of assemblages consisting of 974 taxa in four groups (ichthyoplankton, invertebrate zooplankton, seine nekton, trawl nekton) were assessed using 29 habitat factors. Habitat data were obtained from measurements made during biotic collections, associated characterizations of local habitats, data obtained from the United States Environmental Protection Agency Storage and Retrieval database, and from data that characterized the timing and magnitude of freshwater inflow and turnover. When all habitat factors were used in multivariate regression models (distance-based redundancy analysis, dbRDA) with the objective of explaining variation in beta diversity, the models accounted for as much as 52% of the variation and included factors such as salinity, color, water temperature, distance to the Gulf of Mexico, water depth, presence of mud bottom, and the amount of freshwater input. Habitat factors that contributed to the EGC were identified by performing correlation analyses between each habitat factor and distance to the Gulf of Mexico. This step indicated that, in surface-fed estuaries, submerged aquatic vegetation, mangroves, and warmer temperatures were more common downstream, and lower pH, deeper depths, lower bottom dissolved oxygen, lawn-and-tree shorelines, and manmade bottom substrates were more common upstream. In spring-fed estuaries, oysters and mangroves were more common downstream, and lawn-and-tree shorelines were more common upstream. These correlated factors were used to represent the EGC and were explicitly included in dbRDAs where they explained as much as 78% of the variability in beta diversity. A subsequent partial-dbRDA was performed on the variation that was not explained by EGC habitat factors, and non-EGC factors (freshwater inputs, artificial shorelines, shoreline slope, and the presence of sand bottom) explained as much as an additional 7% of the variability. These results demonstrate the complications inherent in assigning influence to any one habitat factor in estuaries where many habitat factors covary spatially. The substantial amount of beta diversity variation explained by the EGC indicates a goal of estuarine management should be to promote heterogeneity in habitat factors contained in the EGC to maintain overall community diversity. Graphical abstract: Image 1 Highlights: Multiple covariate habitat factors comprise estuarine gradient complexes (EGCs). The presence of an EGC complicates beta-diversity analysis. The EGC differs between Florida spring-fed and surface-fed estuaries. Using the EGC as a covariate suite reveals the importance of habitat heterogeneity.