This is the 14463rd most frequent Russian word.
охранный
"Protective" or "guarding".
In this sentence, 'охранную' describes the function the dog has, meaning 'guard' or 'protective' in relation to security.
Собака выполняет охранную функцию в доме.
The dog performs a guard function in the house.
Here, 'охранной' relates to the conservation or protection of natural elements within the park.
Парк является охранной зоной для редких растений.
The park is a protected area for rare plants.
In this usage, 'охранные' qualifies cameras, emphasizing their function in monitoring and securing the area.