DOI: 10.5061/dryad.g6s5j
title: Data from: Native species dispersal reduces community invasibility by increasing species richness and biotic resistance

description: 1. Recent studies indicate that diversity-invasibility relationships can
 depend upon spatial scale, but the contributing role of native species
 dispersal among local communities in mediating these relationships remains
 unaddressed. Metacommunity ecology highlights the effects of species
 dispersal rates on local diversity, thereby suggesting native species
 dispersal may influence local biotic resistance to invasion by non-native
 species. However, effects of native species dispersal rates on local
 native diversity and invasibility could depend upon any intraspecific
 differences of the invader that may alter establishment success. 2. Here,
 I experimentally tested for the influence of native dispersal-diversity
 relationships on the invasibility of native communities by a non-native
 species represented by core, midrange, and peripheral regions of the
 introduced geographic range. 3. In mesocosms, native plankton communities
 were connected by low or moderate rates of dispersal to yield
 dispersal-rate driven differences in native species richness prior to
 invasion by a non-native zooplankter, Daphnia lumholtzi. After invasion,
 establishment success and effects of the non-native species on native
 community structure and ecosystem properties were evaluated as a function
 of dispersal rate and invader source region relative to a control without
 native species. 4. Native species richness was greater at the moderate
 dispersal rate than the low dispersal rate, and yielded a dispersal rate
 dependent diversity-invasibility relationship that was robust to invader
 source region. There was almost no establishment success of the non-native
 species at moderate dispersal and reduced success at low dispersal
 relative to the control. Invader population growth rates were negative
 only at the moderate dispersal rate. Effects of species dispersal on
 native community and ecosystem response were more influential than effects
 of invasion and impacts associated with invader source region. 5. The
 results demonstrate that dispersal-diversity relationships can influence
 diversity-invasibility relationships at the local spatial scale. These
 dispersal-driven responses of invasion were unaffected by any ecological
 differences associated with invasion history related intraspecific
 variation of the non-native species. This study emphasizes that dispersal
 rates of native species in metacommunities can differentially alter local
 biotic resistance to invasion. Thus, native species dispersal rates have
 largely been an underappreciated local diversity maintenance mechanism
 that can confer insurance against biological invasions.
description: Howeth_JAE2017_Treatment_AssignmentsDispersal rate and invader (Daphnia lumholtzi) source region 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.Howeth_JAE2017_Zooplankton_DensityZooplankton species density (number per liter) by mesocosm and sample date.Howeth_JAE2017_Native_Zooplankton_BiomassNative zooplankton biomass (µg per liter) by mesocosm and sample date.Howeth_JAE2017_Immigrant_Zooplankton_DensityNative zooplankton immigrant density by species (number per liter), date of immigration (dispersal), and dispersal rate treatment (L, low; M, moderate).Howeth_JAE2017_In_Vivo_FluorescenceTotal and edible (&lt;35µm) in vivo fluorescence by mesocosm and sample date.Howeth_JAE2017_Dissolved_OxygenDissolved oxygen (mg per L) concentrations in the morning (AM) and evening (PM) by mesocosm and sample date.Howeth_JAE2017_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.Howeth_JAE2017_TemperatureMesocosm water temperature (degrees Celsius) recorded every four hours by each of the two data loggers in the experiment.Howeth_JAE2017_Chlorophyll_ConversionIn vivo fluorescence and extracted chlorophyll a data used to generate a regression equation representing the statistical relationship between the two variables. The regression equation was subsequently used to convert in vivo fluorescence to extracted chlorophyll a values in the experiment. Data were sourced from 11 ponds located in the Oakmulgee District, Talladega National Forest, Alabama. Pond name, geographic coordinates, sample date, replicate in vivo fluorescence values (total fluorescence), and extracted chlorophyll a (µg per L) values are reported.Howeth_JAE2017_Source_Region_Lake_DataAbiotic conditions of lakes representing the core, midrange, and peripheral source regions of the introduced North American geographic range of Daphnia lumholtzi. Lake name, geographic coordinates, sample date, specific conductivity (mS), total nitrogen (TN, mg per L), total phosphorus (TP, mg per L), and water temperature (depth-integrated average of the epilimnion, in degrees Celsius) are reported.