Habitat coupling mediated by the multi-interaction network linked to macrophyte meadows: ponds versus lakes

• Published in: Aquatic sciences 2021-07, Vol.83 (3), Article 55
• Main Authors: Puche, Eric, Rodrigo, María A., Segura, Matilde, Rojo, Carmen
• Format: Article
• Language: English
• Subjects: Aquatic plants; Benthos; Biomedical and Life Sciences; Composition; Connectors; Coupling; Ecology; Environmental Management; Food chains; Freshwater & Marine Ecology; Habitats; Herbivores; Lakes; Life Sciences; Macrophytes; Marine & Freshwater Sciences; Meadows; Microorganisms; Modules; Morphometry; Nodes; Oceanography; Phytoplankton; Plankton; Ponds; Redundancy; Research Article
• ISSN: 1015-1621; 1420-9055
• DOI: 10.1007/s00027-021-00809-4

Morphometric differences between ponds and lakes have implications in habitat-dimensioning and coupling. The prevalence of pelagic over benthic habitats in lakes differs from ponds, where macrophytes dominate, offering both within-meadow free water and support for benthic organisms. We assessed four Mediterranean waterbodies (two ponds and two lakes) situated along an environmental–morphometric gradient, combining a model based on taxonomic composition with a multi-interaction network perspective of habitat coupling. The communities’ composition (both regarding taxa and their corresponding nodes) fits to this gradient. The composition of benthic and within-meadow habitats was similar in the ponds, while in the lakes, the highest similarity occurred between planktonic habitats (pelagic and within-meadow), and the benthic habitat had unshared populations. The network approach suggests two contrasting patterns of habitat coupling between ponds and lakes. Three functional modules, coupled by macrophytes, herbivores, and mixotrophs, emerged in the ponds: a microbial loop, an autotrophic food chain, and macrophytes hosting benthic microalgae. In the lakes, two disconnected modules appeared: the pelagic plankton plus the within-meadow connector herbivores, and the benthos plus the within-meadow primary producers. Within-meadow herbivores and small phytoplankton nodes were central in the pond and lake networks. Furthermore, benthic nodes showed high functional redundancy and were highly influential in spreading the disturbances’ effects. These results demonstrate: (1) the diversity of functional structures in ponds emerging from a mixed composition; (2) the importance of within-meadow organisms as connectors, and (3) the relevance of benthos which has the greatest diversity and redundancy, as well as the most influential network’s elements.