I don't (I'd imagine it's of a similar quality to people in the US northeast whose ancestors came over on the Mayflower). However, I wouldn't be surprised at the finding that their presence has had a network effect (and a cultural effect) that encouraged people coming from Mexico more recently to settle in that area rather than (for example) spread into the Louisiana Purchase territory, for the same reasons that immigration from other countries also tends to settle and self-perpetuate in enclaves.