It is known that 30% of the land on Kamchatka Peninsula is nationally reserved land.
Kurile Lake is known as the place with the most bears in Russia.
この場合、次のような言い方ができます。
ーIt is known that 30% of the land on Kamchatka Peninsula is nationally reserved land.
「カムチャツカ半島の30%の土地が国立保護区として知られている」
ーKurile Lake is known as the place with the most bears in Russia.
「クリル湖はロシアで最もクマがいる場所として知られている」
ご参考まで!