Invasive alien shredders clear up invasive alien leaf litter. Issue 20 (3rd October 2018)

• Record Type: Journal Article
• Authors: Doherty‐Bone, Thomas M.; Dunn, Alison M.; Brittain, Joel; Brown, Lee Eric
• Is Part Of: Ecology and evolution. Volume 8:Issue 20(2018)
• Page Start: 10049
• Page End: 10056
• Publication Date: 2018-10-03
• Subjects: ecosystem functioning -- Eriocheir sinensis -- Pacifastacus leniusculus -- Rhododendron ponticum; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.4430
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Biological invasions have the potential to alter ecosystem processes profoundly, but invaders are rarely found alone. Interactions between different invasive alien species, and their cumulative impact on ecosystem functioning, have led to hypotheses of invasion meltdown whereby effects become additive leading to further ecosystem stress. Invasive riparian plants (e.g., Rhododendron ponticum ) deposit leaf litter in freshwaters, which may be unconsumed by indigenous species, potentially affecting habitat heterogeneity and flow of energy to the food web. However, invasive alien decapod crustaceans are effective consumers of leaf litter, and it was hypothesized that they would also consume inputs of invasive riparian leaf litter. This study shows that invasive alien signal crayfish ( Pacifastacus leniusculus ) and Chinese mitten crab ( Eriocheir sinensis ) effectively break down different types of leaf litter, including invasive alien R. ponticum, at higher rates than indigenous white‐clawed crayfish. Secondary products were more varied, with more fine particulate organic matter generated for the less palatable alien leaf litter species. Leaf species caused different changes in body mass of decapods but effects were heterogeneous by leaf and decapod: P. leniusculus showed lower mass loss when consuming R. ponticum while E. sinensis lost mass when consuming A. pseudoplatanus . Impacts of riparian invasions on detritus accumulation in freshwaters are thus potentially buffered by invasive alien decapods, illustrating a need for a more detailed consideration of both positive and negative interspecific feedbacks during biological invasions. Abstract : Ecosystems often hold more than one invasive alien species, which may exert either antagonistic, neutral, or complementary effects on ecosystem processes. We show that leaf litter from invasive alien riparian plants (that are not normally processed by native shredding invertebrates) is processed by invasive alien shredding invertebrates (crayfish and crabs). This suggests that one invasive alien species can mitigate the impacts of another for ecosystem processes.