Appendix B. Test statistics, P values, and inferences for hypothesis tests involving the three alternative predator-dependent models.

Test statistics, P values, and inferences for hypothesis tests involving the three alternative predator-dependent models

Appendix A. Maximum likelihood parameter estimates (with bootstrap 95% confidence intervals) for the best-fit models for the nineteen data sets.

Maximum likelihood parameter estimates (with bootstrap 95% confidence intervals) for the best-fit models for the nineteen data sets

Quantity and quality of snail food resources by canopy cover state.

<p>Mean (±1 SE) chlorophyll <i>a</i> (A), ash-free dry mass (AFDM) (B), and molar C:N ratios of epilithon (C). RAM  =  Ramdeen Stream, ARI  =  Aripo River, YAR  =  Yarra River. Gray and white bars represent data collected in closed and open canopy sites, respectively (“closed” is ≥75% and “open” is ≤25% canopy cover). Asterisks above bars represent significant differences (<i>p</i><0.05) among canopy types within streams.</p

Appendix B. Data collection summary statistics, LA-ICP-MS quality control data, and univariate statistics for element:calcium ratios from otolith samples.

Data collection summary statistics, LA-ICP-MS quality control data, and univariate statistics for element:calcium ratios from otolith samples

Influence of canopy state on nitrogen excretion by <i>T. granifera</i> in three streams.

<p>Panels from top represent Ramdeen Stream (RAM), Aripo River (ARI), and Yarra River (YAR). Open and closed circles represent individual snails collected in open and closed canopy habitats, respectively. Solid lines represent trends in closed canopy habitats, and broken lines represent trends in closed canopy habitats. All data were log-transformed.</p

<i>Tarebia granifera.</i>

<p>The quilted melania snail has invaded freshwater habitats throughout much of the Neotropics. Photo credit: S. B. Snider.</p

Appendix C. Detailed methodology: otolith preparation, microchemical analysis, and Bayesian analysis.

Detailed methodology: otolith preparation, microchemical analysis, and Bayesian analysis

Canopy state and snail growth rates.

<p>Effect sizes of canopy state on snail growth rates as measured in a reciprocal transplant experiment. Error bars represent 95% confidence intervals and effect sizes were measured as response ratios (Hedges et al. 1997). “Open to closed canopy” represents snails collected from open canopy habitat and moved to closed canopy habitat where growth rates were measured after 10 days, and “closed to open canopy” is vice versa.</p

Influence of canopy state on areal snail excretion rates in three streams.

<p>Mean (±1 SE) areal N excretion by <i>T. granifera</i> in 2008. RAM  =  Ramdeen Stream, ARI  =  Aripo River, YAR  =  Yarra River. Closed and open bars represent data collected in closed and open canopy sites, respectively. Canopy effect was significant across all streams (<i>p</i><0.0001).</p

Mean <i>T. granifera</i> biomass by size class.

<p>Top row of panels are 2007 data and bottom row are 2008 data. Size classes were based on 5 mg AFDM increments. RAM  =  Ramdeen Stream, ARI  =  Aripo River, YAR  =  Yarra River. Gray and white bars represent data collected in closed and open canopy sites, respectively. Canopy type had a significant impact on <i>T. granifera</i> areal biomass (<i>F</i> = 22.06, <i>p</i><0.0001). Note log scale. No data were collected in YAR in 2007.</p