I am not sure exactly what information you would like regarding this quote, but I assume you would like an explanation of its meaning.
"Beauty is to be preserved" means, simply put, that what is beautiful must be saved. True beauty is a rare and wonderful thing, whether it is evident in a person, an element of nature, an inanimate object, or anything else. Because something that is inherently beautiful is not common, it should be revered and treated with wonder and respect. Anything as special as something that reflects sincere beauty must be saved because of its rareness. True beauty is indicative of a degree of purity and goodness, so it is remarkable in its own right.