Data from: Regional diversity reverses the negative impacts of an alien predator on local species-poor communities

• Main Authors: Loewen, Charlie J. G., Vinebrooke, Rolf D.
• Format: Dataset
• Language: unknown
• Published: 2017
• Subjects: spatial insurance effects; Eucyclops agilis; functional structure; Diaphanosoma birgei; biodiversity–ecosystem functioning; trait analysis; Macrocyclops albidus; Diacyclops thomasi; Leptodiaptomus tyrrelli; mountain lakes; Predator–prey interactions; Acanthodiaptomus denticornis; Acanthocyclops vernalis; Leptodiaptomus sicilis; multiple stressors; Chydorus sphaericus; Leptodiaptomus nudus; Arctodiaptomus arapahoensis; Aglaodiaptomus leptopus; Diacyclops navus; Chaoborus; Scapholeberis kingi; Ceriodaphnia quadrangula; Hesperodiaptomus arcticus; Bosmina longirostris; sportfish; Zooplankton
• Online Access: https://zenodo.org/record/4969156; https://doi.org/10.5061/dryad.pj763

Species diversity is often an implicit source of biological insurance for communities against the impacts of novel perturbations, such as the introduction of an invasive species. High environmental heterogeneity (e.g., a mountainous gradient) is expected to beget greater regional species diversity and variation in functional traits related to environmental tolerances. Thus, heterogeneous metacommunities are expected to provide more tolerant colonists that buffer stressed local communities in the absence of dispersal limitation. We tested the hypothesis that importation of a regional zooplankton pool assembled from a diverse array of lakes and ponds lessens the impacts of a novel predator on local species-poor alpine communities by increasing response diversity (i.e., diversity of tolerances to environmental change) as mediated by variation in functional traits related to predator evasion. We also tested if impacts varied with temperature, as warming may modify (e.g., dampen or amplify) invasion effects. An eight-week factorial experiment ([fishless vs. introduced Oncorhynchus mykiss (rainbow trout)] x [ambient temperature vs. heated] x [local vs. local + regional species pool]) was conducted using thirty-two 1000 L mesocosms. Associations between experimental treatments and species functional traits were tested by RLQ and fourth-corner analyses. Although the introduced predator suppressed local species richness and community biomass, colonization by several montane zooplankters reversed these negative effects, resulting in increased species diversity and production. Invasion resistance was unaffected by higher temperatures, which failed to elicit any significance impacts on the community. We discovered that the smaller body sizes of imported species drove functional overcompensation (i.e., increased production) in invaded communities. The observed ecological surprise showed how regionally sourced biodiversity from a highly heterogeneous landscape can offset, and even reverse, the local negative impacts of an ...