DOI: 10.5061/dryad.j6h2852
title: Data from: Propagule pressure and native community connectivity interact to influence invasion success in metacommunities

description: Mechanistic insights from invasion biology indicate that propagule
 pressure of exotic species and native community structure can
 independently influence establishment success. The role of native
 community connectivity via species dispersal and its potential interaction
 with propagule pressure on invasion success in metacommunities, however,
 remains unknown. Native community connectivity may increase biotic
 resistance to invasion by enhancing species richness and evenness, but the
 effects could depend upon the level of propagule pressure. In this study,
 a mesocosm experiment was used to evaluate the independent and combined
 effects of exotic propagule pressure and native community connectivity on
 invasion success. The effects of three levels of exotic Daphnia lumholtzi
 propagule pressure on establishment success, community structure, and
 ecosystem attributes were evaluated in native zooplankton communities
 connected by species dispersal versus unconnected communities, and
 relative to a control without native species. Establishment of the exotic
 species exhibited a propagule dose-dependent relationship with high levels
 of propagule pressure resulting in the greatest establishment success.
 Native community connectivity, however, effectively reduced establishment
 at the low level of propagule pressure and further augmented native
 species richness across propagule pressure treatments. Propagule pressure
 largely determined the negative impacts of the exotic species on native
 species richness, native biomass, and edible producer biomass. The results
 highlight that native community connectivity can reduce invasion success
 at a low propagule dose and decrease extinction risk of native
 competitors, but high propagule pressure can overcome
 connectivity-mediated biotic resistance to influence establishment and
 impact of the exotic species. Together, the results emphasize the
 importance of the interaction of propagule pressure and community
 connectivity as a regulator of invasion success, and argue for the
 maintenance of metacommunity connectivity to confer invasion resistance.
description: King and Howeth Oikos
 2019 Treatment AssignmentsDispersal and exotic
 Daphnia lumholtzi propagule pressure treatment assignments for each of the
 48 mesocosms in the experiment. In the Dryad raw data files associated
 with this publication, these treatment combinations are conserved by
 mesocosm number.King&Howeth_Oikos2019_Treatment_Assignments.csvKing and Howeth Oikos 2019 Zooplankton DensitiesZooplankton species density (number per liter) by mesocosm and sample date.King&Howeth_Oikos2019_Zooplankton_Densities.csvKing and Howeth Oikos 2019 Native Zooplankton BiomassNative zooplankton biomass (µg per liter) by mesocosm and sample date.King&Howeth_Oikos2019_Native_Zooplankton_Biomass.csvKing and Howeth Oikos 2019 Daphnia lumholtzi BiomassExotic Daphnia lumholtzi biomass (µg per liter) by mesocosm and sample date.King&Howeth_Oikos2019_Daphnia_lumholtzi_Biomass.csvKing and Howeth Oikos 2019 In Vivo FluorescenceTotal and edible (&lt;35µm) in vivo fluorescence by mesocosm and sample date.King&Howeth_Oikos2019_In_Vivo_Fluorescence.csvKing and Howeth Oikos 2019 Dissolved OxygenDissolved oxygen (mg per L) concentrations in the morning (AM) and evening (PM) by mesocosm and sample date.King&Howeth_Oikos2019_Dissolved_Oxygen.csvKing and Howeth Oikos 2019 NutrientsNutrients measured at the end of the experiment by mesocosm. Total nitrogen (TN), total dissolved nitrogen (TDN), total phosphorus (TP), and total dissolved phosphorus (TDP) concentrations reported in mg per L.King&Howeth_Oikos2019_Nutrients.csvKing and Howeth Oikos 2019 TemperatureMesocosm water temperature (degrees Celsius) recorded every four hours by each of the two data loggers in the experiment.King&Howeth_Oikos2019_Temperature.csv