JAKARTA, July 10 (Xinhua) -- Environmentalist organization Greenpeace demanded the Indonesian government take legal measures against firms owning concession land that failed to preserve habitat of endangered animals.

The demand came following the arrest of an illegal logger in concession land ran by Mohairson Pawan Khatulistiwa (MPK), which hosted six nests of endangered animal of orangutan.

In a further combing around the area in West Kalimantan province's peatland area of Sungai Putri, rangers found orangutans around their nests.

The illegal logger used the canal in the concession land to transport the stolen logs out of the area.

The finding of illegal activities strengthened Greenpeace allegation, which had previously been publicized, over the disturbed orangutan habitat in MPK land concession.

Based on those facts, Greenpeace demanded related institutions take legal measures against MPK for its failure to preserve their concession areas that consequently endangers the sustainability of endangered animal.

"The government already has enough evidences to proceed with legal measures against MPK," Greenpeace Indonesia Forest Campaigner Ratri Kusumohartono said in a statement released on Tuesday.

She added that the firm has yet to abide by the existing regulation to close down its canal in preventing illegal activities in the firm concession land.

Citing national forestry law, she said the concession land owner, MPK, has the responsibility to preserve the sustainability of nature from harmful activities that may wreck the areas.

"Government must protect all peatland area in Sungai Putri by preventing MPK in expanding its concession land. The ministry must have action plans to protect the whole landscape in the area," she said.

Orangutan endemically lives in Indonesia's Sumatra and Kalimantan forests. Its existence is endangered due to expansion of plantations ran by palm oil and pulp firms.