Complex sentence: On 8/4/04, the United States Fish and Wildlife Service listed the California tiger salamander as "threatened" within the Central Valley Distinct Population Segment, the Santa Barbara and Sonoma County populations were returned to Endangered status on 8/19/05.
Split into simpler sentences: On 8/4/04, the United States Fish and Wildlife Service listed the California tiger salamander as "threatened" within the Central Valley Distinct Population Segment. However, the Santa Barbara and Sonoma County populations were returned to Endangered status on 8/19/05.