Apex predator induces predator-rich ecosystem state innorthern lakes

• Large predators are disappearing from ecosystems around the world. If predator speciesfacilitate each other’s existence through niche construction, this development could causecascading predator collapses and reduce ecosystem resilience. However, the importance offacilitation for the assembly and function of predator communities remains poorly understood.Here, we show that a large piscivorous fish, the northern pike (Esox lucius), enables theformation of a numerous and diverse predator community by inducing a dwarf ecotype ofEuropean whitefish (Coregonus lavaretus). Pike increases the standing biomass of prey-sized(<200mm) whitefish with a factor of 12.6, allowing small-gaped fish species (Percafluviatilis, Lota lota, Salvelinus alpinus and Salmo trutta) to go from small-growinggeneralists, to large-growing piscivores. Similarly, a guild of piscivorous birds (Gavia arctica,G. stellata, Sterna paradisaea, S. hirundo, Mergus serrator and M. merganser) shift from amixed diet to relying mainly on whitefish prey in presence of pike. Through this regime shift,the functional piscivore biomass in the non-pike fish community increases with a factor of14.2, and the density- and species richness of piscivorous birds increase with factors of 2.08and 2.16, respectively. Our results demonstrate how feedbacks between presence/absence ofimportant predators and the phenotype of prey may keep complex ecosystems in predator-richor predator-depleted states.

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

Nyckelord

biokemisk farmakologi

biochemical pharmacology

biology

biologi

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