Trophic cascades across ecosystems

• Published in: Nature 2005-10, Vol.437 (7060), p.880-883
• Main Authors: Knight, T.M, McCoy, M.W, Chase, J.M, McCoy, K.A, Holt, R.D
• Format: Article
• Language: English
• Subjects: adult insects; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Anisoptera (Odonata); Aquatic ecosystems; Aquatic insects; Biological and medical sciences; Boundaries; community ecology; Ecosystem; Ecosystems; Eutrophication; Fishes - physiology; Florida; Food Chain; Food chains; Foraging behavior; Fresh Water; Freshwater; freshwater fish; Fundamental and applied biological sciences. Psychology; General aspects; Habitats; Humanities and Social Sciences; insect ecology; insect pollination; Insecta - physiology; lakes; Larva - physiology; larvae; letter; limnology; multidisciplinary; Plant Physiological Phenomena; Plant reproduction; plants; Pollen; Pollen - physiology; pollinating insects; Pollinators; Ponds; Population Dynamics; Predation; predator-prey relationships; Predatory Behavior - physiology; Reproduction - physiology; Science; Science (multidisciplinary); Synecology; Terrestrial ecosystems; Trophic relationships
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature03962

Predation can be intense, creating strong direct and indirect effects throughout food webs. In addition, ecologists increasingly recognize that fluxes of organisms across ecosystem boundaries can have major consequences for community dynamics. Species with complex life histories often shift habitats during their life cycles and provide potent conduits coupling ecosystems. Thus, local interactions that affect predator abundance in one ecosystem (for example a larval habitat) may have reverberating effects in another (for example an adult habitat). Here we show that fish indirectly facilitate terrestrial plant reproduction through cascading trophic interactions across ecosystem boundaries. Fish reduce larval dragonfly abundances in ponds, leading to fewer adult dragonflies nearby. Adult dragonflies consume insect pollinators and alter their foraging behaviour. As a result, plants near ponds with fish receive more pollinator visits and are less pollen limited than plants near fish-free ponds. Our results confirm that strong species interactions can reverberate across ecosystems, and emphasize the importance of landscape-level processes in driving local species interactions.