A male Siberian tiger named Amur is now free in the wild. Kazakhstan released the animal into a nature reserve, an area of land protected for wildlife.
in the wild= 自然の中で、野生で(動物園や飼育下ではなく自然環境で生きていること)。
Amur is the second tiger to enter the reserve. Tigers have been extinct in Kazakhstan for more than 70 years, meaning no wild tigers have lived in the country for all that time.
meaning= 「つまり〜ということ」という意味で、直前の文の内容(絶滅していること)を分かりやすく説明しています。
The release is part of an ambitious plan to bring wild tigers back to the country.