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Appendix G. A table of significant site-level covariates that were significant (or whose inclusion made a fixed factor significant) in exploratory analyses when added individually to the baseline mixed model (predator exposure and density) examining mortality and dry tissue growth responses of each species.

Protothaca mortality	Venerupis mortality	Protothaca growth	Venerupis growth
Predation × Organics	Predation × Crab biomass	Predation × Crab biomass	Predation × Crab numbers
Predation × Stdev Organics	Predation × Crab numbers	Predation × Crab numbers	Predation × Density × Crab numbers
Predation × Ln Venerupis Biomass	Predation × Organics	Predation × Stdev Chlorophyll	Predation × Ln Protothaca Biomass
Predation × Ln Protothaca Biomass	Predation × Stdev Organics	Predation × Ln Venerupis Biomass	Ln Protothaca Biomass
Ln Protothaca Biomass	Predation × Bird number	Predation × Density × Ln Venerupis Biomass	Predation × Ln Venerupis Biomass
Density × Ln Protothaca Biomass	Predation × Ln Venerupis Biomass	Predation × Total Clam Biomass	Density × Ln Protothaca Biomass
	Crab biomass	Predation × Density × Total Clam Biomass	Predation × Density × Ln Venerupis Biomass
	Bird number	Predation × Organics
	Organics	Density × Ln Protothaca Biomass
		Predation × Density × Ln Protothaca Biomass
		Predation × Density × Exotic Biomass
		Predation × Exotic Biomass

   Notes: Covariate terms are listed in order of significance. Factors significant to gonad growth were the same as those for growth for each species. Stdev is the standard deviation. The effect of crabs on both clam growth and mortality explains why the interaction of predator exposure and ambient Venerupis biomass significantly affected experimental clams. Notably, crab biomass is inversely related to Venerupis biomass (R² = 0.46). Thus, when ambient Venerupis biomass was low, crabs were abundant, and both clams exhibited lower growth and survivorship in open topped enclosures that exposed them to predators.