Complex sentence: It has recently been designated as the Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR), and is the 25th National Estuarine Research Reserve in the United States.
Split into simpler sentences: It has recently been redesignated as the Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR). It is the 25th National Estuarine Research Reserve in the United States.