Evidence of surplus carrying capacity for benthic invertebrates with the poleward range extension of the tropical seagrass Halophila decipiens in SE Brazil. (December 2020)

• Record Type: Journal Article
• Authors: Pavone, Carla B.; Gorman, Daniel; Flores, Augusto A.V.
• Is Part Of: Marine environmental research. Volume 162(2020)
• Publication Date: 2020-12
• Subjects: Community structure -- Ecosystem engineer -- Exotic species -- Marine invertebrates -- Organic matter -- Physical complexity -- Poleward range extension -- Seagrass -- Tropicalization; Marine pollution -- Environmental aspects -- Periodicals; Marine ecology -- Periodicals; Mer -- Pollution -- Aspect de l'environnement -- Périodiques; Écologie marine -- Périodiques; Electronic journals; 577.705
• DOI: 10.1016/j.marenvres.2020.105108
• Languages: English
• ISSNs: 0141-1136

Abstract

Abstract: Seagrasses may enhance the abundance and diversity of benthic invertebrates through trophic facilitation. We investigated this potential ecological function for two seagrasses in SE Brazil: Halodule emarginata, a native species, and Halophila decipiens, a tropical seagrass recently established in the region. At Halophila sites, the organic matter (or carbon) in sediments decreased steadily from seagrass patches to isolated bare grounds, indicating surplus primary production. This was not observed at Halodule sites. At one of the two Halophila sites, localized trophic enrichment was also consistently linked to increased invertebrate abundance within patches, chiefly through increased carrying capacity of small mesoherbivores. Rather than spillover, edge effects were observed at bordering bare habitats, where polychaete predators were abundant. The transition from seagrass edges to isolated bare habitats was marked by an increase of the density of sipunculid worms. The current spread of Halophila may thus change the spatial distribution of benthic ecological functions. Highlights: The tropical seagrass Halophila decipiens has recently established in SE Brazil. H. decipiens, not Halodule emarginata, locally add organic matter to sediments. H. decipiens may increase benthic carrying capacity by facilitating mesoherbivores. When present, effects cascade to seagrass edges where roving predators are favored. The spread of H. decipiens may reshape the distribution of ecological functions.