# Calculate Weighted Average Inferences  
#Only select taxa for which tolerance values
#   have been computed.

df1 <- merge(site.species.or, env.data.or, by = "SITE.ID")
mat1 <- as.matrix(df1[, names.match])                      

# First get total abundance

tot.abn <- apply(mat1, 1, sum)                           

# Use matrix multiplication to compute the sum of all
# observed tolerance values, and then divide by total
# abundance to get the mean tolerance value.

mean.tv <- (mat1 %*% WA[names.match])/tot.abn       
plot(df1$temp, mean.tv, xlab = "Temperature",
     ylab = "Mean weighted average")