interpreting random effects

I have have measured the trait frequency for a "mountain" associated allele across a number of sites and years. In my (glmer) model I have summarized the allele frequency by site and year as the dependent (binomial) variable and specified site and year as random effects. The fixed effects are latitude, longitude, altitude, and latitude|longitude. When I run the model and then drop and update each random effect separately to see if they are important to the model, site appears to be significant and year does not. Two questions:

  1. Can I re-summarize my dependent variable for by site rather than site and year?
  2. Given that we did not sample each site the same number of times (years) and have different numbers of samples at each site (and year), should I standardize my dependent variable?