Complex sentence: The Sardinian brook salamander is classified by the IUCN Red List of Threatened Species as endangered, because the area it occupies is less than in total and fragmented into a number of separate populations.
Split into simpler sentences: The Sardinian brook salamander is classified by the IUCN Red List of Threatened Species as endangered. This is because the area it occupies is less than in total and fragmented into a number of separate populations.