Columbia subject headings:
Endangered plants--Protection--California--Humboldt Bay.
Humboldt Bay National Wildlife Refuge (Calif.)--Environmental conditions.
Sand dune conservation--California--Humboldt Bay.
Wetland animals--California--Humboldt Bay.
Harvard subject headings:
Endangered plants--Protection--California--Humboldt Bay.
Humboldt Bay National Wildlife Refuge (Calif.)--Environmental conditions.
Sand dune conservation--California--Humboldt Bay.
Wetland animals--California--Humboldt Bay.
Princeton subject headings:
Endangered plants--Protection--California--Humboldt Bay.
Humboldt Bay National Wildlife Refuge (Calif.)--Environmental conditions.
Sand dune conservation--California--Humboldt Bay.
Wetland animals--California--Humboldt Bay.