An invasive species may be better than none: invasive signal and native noble crayfish have similar community effects.

摘要: Human activities have resulted in the decline of native crayfish and promoted spread invasive species European fresh waters, threatening ecosystem structure functioning. We compared effects noble (Astacus astacus), signal (Pacifastacus leniusculus) absence on leaf litter breakdown invertebrate prey density biomass stream ecosystems. In microcosm experiments, shredder was significantly reduced by presence but similarly affected two species. While did not directly influence breakdown, their decay rates through predation shredders (i.e. trophic cascade). These were again similar between differed among Field experiments confirmed that crayfish. Although total predation, species-specific observed (e.g. Limnephilidae [Trichoptera] densities crayfish) differ Our results show can strong, species-specific, indirect breakdown. Contrary to previous findings popular belief, also indicate communities. Hence, from a management perspective, it may be preferable than no when impairment unsuitable habitats for