The Baetic System, together with the Rif Mountains of Morocco, which face the Baetic Ranges across the Alboran Sea, is one of the Mediterranean basin's ten biodiversity hotspots, known to ecologists as the Baetic-Rifan complex. The Baetic mountains are home to a rich assemblage of Mediterranean plants, including a number of relict species from the ancient laurel forests, which covered much of the Mediterranean basin millions of years ago when it was more humid.