Table 1.

Predictor variables used in the boosted regression trees analysis. MHI, main Hawaiian Islands; NWHI, Northwestern Hawaiian Islands.

	variable	description	range
MHI	GrazerBiom	grazer biomass in g m−2	0–28.3
	ScraperBiom	scraper biomass in g m−2	0–13.9
	BrowserBiom	browser biomass in g m−2	0–22
	latitude	latitude in decimal degrees (WGS 1984)	18.97–22.24
	depth	depth in metres	2–29
	DistCoast	distance in metres from nearest shoreline to survey location	14–2509
	DistStream	distance in metres from nearest stream to survey location	96–20 130
	effluent	the total effluent in million gallons per day (mgd) discharged within parcels that intersected with a 10 km buffer from survey location	600–7 177 840
	population	human population density in a 10 km buffer from survey location based on 2010 census data	232–523 576
	UrbanIndex	representation of urban disturbance standardized from 0 to 1	0–0.98
	PointIndex	representation of the density of sources of point pollution standardized from 0 to 1	0–0.50
	FragIndex	representation of stream fragmentation standardized from 0 to 1	0–0.31
	FormplIndex	representation of lands that were formerly pineapple or sugarcane plantations standardized from 0 to 1	0–0.54
	DitchIndex	representation of the relative density of ditch infrastructure standardized from 0 to 1	0–0.73
	AgrIndex	representation of agricultural disturbance standardized from 0 to 1	0–0.65
NWHI	GrazerBiom	grazer biomass in g m−2	0–29.6
	ScraperBiom	scraper biomass in g m−2	0–30.8
	BrowserBiom	browser biomass in g m−2	0–146.4
	LPredBiom	large predator biomass in g m−2	0–2961.8
	latitude	latitude in decimal degrees (WGS 1984)	23.63–28.45
	depth	depth in metres	1–28
	ReefZone	zones of the reef: fore reef—back reef—lagoon	n.a.