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Table 1 Covariates of total nitrogen (TN) included in the study and their correlation with log (TN) within all streams

From: The effects of nutrients on stream invertebrates: a regional estimation by generalized propensity score

Variable Description Units r
ELEV Elevation m − 0.18
Longitude Longitude Degree 0.57
Log(PRECIP) Annual precipitation in log scale mm − 0.58
Log(AREA) Catchment area in log scale km2 0.47
Log(CL) Cl concentration in log scale μg/L 0.62
Log(HCO3) HCO3 concentration in log scale μg/L 0.55
Log(SO4) SO4−2 concentration in log scale μg/L 0.61
SED Sand and fine substrate in the stream (< 2 mm in diameter) μg/L 0.63
STRMTEMP Stream temperature Degree 0.49
Percent.AGT Percentage of catchment in agricultural land use μg/L 0.57
Percent.URB Percentage of catchment in urban land Percentage 0.30
Percent.Canopy Percentage of open canopy Percentage 0.47
Riparian.Disturb Riparian agricultural disturbance index Index 0.49
  1. All correlation coefficients are statistically significant (p < 0.05)