Gunung Mulu National Park, also called Mulu National Park, is a protected area in Miri Division, Sarawak, Malaysia. It is a UNESCO World Heritage Site that includes caves and rock formations in a mountainous rainforest located near the equator. The park is well-known for its caves and the scientific studies that have taken place to explore them and their surrounding rainforest. A major example is the Royal Geographical Society Expedition of 1977–1978, during which more than 100 scientists worked in the area for 15 months. This effort began a series of over 20 explorations now known as the Mulu Caves Project.

The national park is named after Mount Mulu, which is the second-highest mountain in Sarawak.

History

In 1858, Spenser St. John, a British Consul in Brunei, wrote about the Mulu caves in his book Life in the Forests of the Far East. He described "detached masses of limestone, much water-worn, with caverns and natural tunnels." Later, Spenser tried to climb Mount Mulu but failed because of limestone cliffs, dense forests, and sharp rock formations.

In the 19th century, Charles Hose, an administrator in the Raj of Sarawak, also tried to climb Mount Mulu but failed. In the 1920s, a Berawan rhino hunter named Tama Nilong discovered a path on the south-west ridge of Mount Mulu, which led to the summit. In 1932, Tama Nilong guided Edward Shackleton during an Oxford University Expedition to the summit of Mount Mulu. This was the first successful climb to the top of Mount Mulu.

In 1961, G.E. Wilford, a geologist from the British Borneo Geological Survey, visited the Mulu caves. He studied the Deer Cave and Cave of the Winds and predicted more caves would be found in the future.

In 1974, the Sarawak government declared Mount Mulu and its surrounding areas a national park. In 1978, the Royal Geographical Society organized a scientific expedition to Mulu National Park, the largest such expedition ever sent from the United Kingdom. The expedition lasted 15 months, and a small group explored and mapped 50 km (31 mi) of caves, including Clearwater Cave, Green Cave, Wonder Cave, and Prediction Cave. At that time, there was no airport or logging roads near Mulu. A base camp was set up at Long Pala, which was a three-day journey from Miri upriver. This allowed explorers to study caves on the western side of Mount Api.

In December 1980, another British team visited Mulu Caves for four months. During this trip, they discovered the Sarawak Chamber in Gua Nasib Bagus. In 1984, Gunung Mulu was named an ASEAN Heritage Park. In 1985, the park officially opened to the public. In 1988, a British expedition connected Clearwater Cave and Cave of the Winds, making Clearwater Cave 58 km (36 mi) long, the longest cave passage in Southeast Asia. Blackrock Cave was also discovered during this trip.

In 1991, a passage was found linking Blackrock Cave and Clearwater Cave, extending Clearwater Cave to 102 km (63 mi), making it the 7th longest cave passage in the world. Between 1993 and 2000, British teams explored the eastern side of Mount Api, discovering new areas in the Hidden Valley.

Between 1995 and 2000, an American team from the National Speleological Society studied Gunung Buda (Mount Buda). They discovered Deliverance Cave during these expeditions. In 2000, Gunung Mulu National Park was declared a UNESCO World Heritage Site. It covers 52,864 hectares (528.64 km²; 130,630 acres) and is the largest national park in Sarawak open to tourists. In 2001, Gunung Buda National Park was declared by the Sarawak government.

Since 2000, British teams have focused on exploring caves near Mount Benarat. In 2003, Whiterock Cave at Mount Api was discovered. In 2005, Whiterock Cave was linked to the Clearwater Cave system, extending it to 129.4 km (80.4 mi). Api Chamber was also found during this expedition. Later explorations focused on finding hidden passages in Whiterock Cave. In 2017, Whiterock Cave was measured at 100 km (62 mi), and Clearwater Cave was measured at 226.3 km (140.6 mi).

Geography

Gunung Mulu National Park is the most studied tropical karst area in the world. It has 295 kilometers of explored caves that are home to millions of bats and swiftlets. The national park is located on the border between Sarawak and Brunei, 100 kilometers (330,000 feet) south of Bandar Seri Begawan. It lies between the headwaters of the Tutoh River and the Mendalam River, which is a tributary of the Limbang River. The western side of the park includes lowland areas (38% of the park), while the eastern side has mountain ranges made of limestone and sandstone. The landforms in the park include rugged summits, steep ridges, escarpments, sheer cliffs, gorges, karst towers, caves, terraces, hot springs, floodplains, and waterfalls.

The park is dominated by three mountains: Mount Mulu (2,376 meters or 7,795 feet), Mount Api (1,750 meters or 5,740 feet), and Mount Benarat (1,858 meters or 6,096 feet). Mount Mulu is a sandstone mountain, while Mount Api and Mount Benarat are limestone mountains. The top of Mount Mulu is covered by moss forests, and limestone pinnacles are found on the upper part of Mount Api. The Melinau Gorge separates Mount Benarat from Mount Api. Mount Buda is separated from Mount Benarat by the Medalem Gorge. Mount Buda is part of another national park called Gunung Buda.

The national park has three notable caves: Sarawak Chamber, one of the largest underground chambers in the world; Deer Cave, the largest cave passage in the world; and Clearwater Cave, the longest cave system in Southeast Asia. The Sarawak Chamber is 600 meters (2,000 feet) long, 415 meters (1,362 feet) wide, and at least 80 meters (260 feet) high, with a volume of 12,000,000 cubic meters (420,000,000 cubic feet) and an unsupported roof span of 300 meters (980 feet). Deer Cave has a diameter of 120 meters (390 feet) to 150 meters (490 feet). As of October 2018, Clearwater Cave has 227.2 kilometers (745,000 feet) of explored passages. Other caves in the area include Gua Nasib Bagus, Benarat Cavern, and Cave of the Winds.

The geology of the park includes rock layers formed during the Palaeocene to Miocene periods. Mount Mulu is located in the southwest of the park and was formed during the Palaeocene to Upper Eocene periods with layers of sandstone and shale. The other mountains (Mount Api, Mount Benarat, and Mount Buda) are on the western side of Mount Mulu. These younger mountains were formed from a 40-kilometer band of limestone during the Upper Eocene to Lower Miocene periods. The extensive cave system developed in this area due to tectonic uplift of the karst about 2 to 5 million years ago. The caves are typical of tropical river caves, with features such as elliptical tubes connecting different levels and speleothems like aragonite and calcite needles. The limestone is either very white or grey. The pinnacles on Mount Api are the result of extreme weathering of limestone rocks. The soil in the national park ranges from peaty-podzolic to red-yellow podzolic and black organic soil.

The climate of Gunung Mulu National Park is influenced by the northeast monsoon (December to March) and the southwest monsoon (May to October). Rainfall is very high, ranging from 4,000 millimeters (160 inches) to 5,000 millimeters (200 inches). In the lowlands, temperatures range from 23°C (73°F) to 26°C (79°F). At the summit of Mount Mulu, temperatures range from 14°C (57°F) to 18°C (64°F). Climate data is based on measurements from Mulu village near the airport and the park entrance. Interior and higher areas of the park are cooler and wetter.

Biodiversity

Gunung Mulu National Park is home to 20,000 species of invertebrates, 81 species of mammals, 270 species of birds, 55 species of reptiles, 76 species of amphibians, and 48 species of fish.

Eight species of hornbill have been seen in Mulu, including the rhinoceros hornbill (Buceros rhinoceros), the wrinkled hornbill (Aceros corrugatus), and the helmeted hornbill (Rhinoplax vigil), which has a large solid casque (a part of the bill that is enlarged).

Twenty-eight species of bats live in the park. Deer Cave contains twelve bat species and is home to about three million wrinkle-lipped free-tailed bats (Chaerephon plicatus). Every evening, millions of bats leave the cave to find food, while swallows and swiftlets fly into the cave. This pattern reverses in the morning.

Other mammals found in the park include the Sunda pangolin (Manis javanica), tufted ground squirrel (Rheithrosciurus macrotis), silvery gibbon (Hylobates moloch), Malayan sun bear (Helarctis malayanus euryspilos), maroon leaf monkey (Presbytis rubicunda), and yellow-throated marten (Martes flavigula).

There are 25 species of snakes in the park, including the reticulated python (Malayopython reticulatus), Calamaria snakes, and the banded Malayan coral snake (Calliophis intestinalis).

Some amphibians are only found in Gunung Mulu National Park, such as the Borneo squat frog (Calluella flava) and the Gunung Mulu stream toad (Ansonia torrentis).

The park has a large number of plant species. It contains 17 vegetation zones, 3,500 species of vascular plants, and 1,500 species of flowering plants. There are 109 species of palms in 20 genera, over 1,700 mosses and liverworts, 8,000 species of fungi, and 442 species of spore-producing pteridophytes. Examples of vegetation zones include peat swamp forest, heath, mixed dipterocarp forest, moss forest, and montane ecosystems. Lowland forests cover 40% of the park, while montane forests cover 20%.

Strangler fig trees are common in peat swamp areas. Mixed dipterocarp forests are found up to 800 meters in altitude. Trees in this region include Shorea, Durian, Garcinia, Calophyllum, and Eugenia. Between 800 and 1,200 meters, lower montane forests grow. Quercus subsericea is the dominant tree in this area. Upper montane forests are found between 1,200 and 2,170 meters. Epiphytes are common here, and the canopy height ranges from 10 to 20 meters. Upper montane forests can be divided into short facies, tall facies, and stunted summit facies. Small trees and shrubs like Rhododendron and Vaccinium, and pitcher plants such as Nepenthes tentaculata and Nepenthes muluensis, are found only on Mount Mulu.

Limestone forests in the park are mostly made up of calcareous plant species. These forests include scree forests, cliff vegetation, cave vegetation, and montane forests. Examples of species found here are Monophyllae beccarii, Calamus neilsonii, and the endemic palm Salacca rupicola.

Demographics and culture

The local population near the park includes the Orang Ulu, Kiput, Kenyah, Kayan, Mulut, and Penan tribes. The Penan people originally lived by moving from place to place, but now they live in partially settled communities in the southwest part of the park near Batu Bungan and Long Iman. A small group of Penan people also live on the eastern side of the park, and 300 of them have the right to hunt pigs and deer in specific areas. The Berawan people also retain their hunting rights in the region. Members of these tribes often wear traditional clothing, such as feathered hats and loincloths decorated with tattoos on their arms, chest, and necks. Some women have small tattoos on their bodies, and others have their earlobes stretched to reach their shoulders.

Excavations at the Cave of Winds uncovered artefacts and human remains that are estimated to be between 500 and 3,000 years old.

Trekking routes

The national park has three climbing treks: The Pinnacles Summit Trek, The Headhunter's Trail, and Gunung Mulu Summit Trek. The Pinnacles Summit Trek lasts three days and two nights, ending at the view of the Gunung Mulu Pinnacles. The trek usually begins with a one- or two-hour boat ride from the Melinau River to Kuala Berar (Berar delta). Base Camp 5 is a 7.8 km walk from Kuala Berar. Camp 5 is near the Melinau Gorge, which separates Mount Benarat from Mount Api. After Camp 5, hikers walk 1.2 km uphill, rising 1,200 meters, through a dipterocarp forest to a moss forest. The final section requires ropes and ladders to assist with the climb.

The Headhunter's Trail is the route used to enter or leave Gunung Mulu National Park. It follows the path once taken by the Kayan people from the Melinau River to the Melinau Gorge. The trail begins with a boat ride to Kuala Berar, then a two- to three-hour trek to reach Camp 5. From Camp 5, hikers walk 11.2 km to Kuala Terikan, a journey that takes four to five hours. Climbers may stay at a ranger station called Nanga Metawai (15 minutes from Kuala Terikan) or a longhouse named Rumah Bala Lesong (three to four hours by longboat from Kuala Terikan). A boat ride further downriver reaches Nanga Medamit, where a road connects to Limbang.

The Gunung Mulu Summit Trek is the only route to reach the top of Mount Mulu. The summit is 24 km from the park headquarters. The trek starts at the park headquarters and reaches Camp 3 after a 12 km hike through primary forests at an elevation of 1,200 meters. The mossy forest begins at Camp 3. It takes several hours to climb to Camp 4. After Camp 4, hikers face steep climbs requiring knotted ropes, which lead to the summit. Camp 1 is located along the path descending from the summit of Mount Mulu. From Camp 1, hikers walk 3 hours to reach the park headquarters.

Management and facilities

The Protected Areas and Biodiversity Conservation (PABC) Unit of the Sarawak Forestry Corporation manages the Totally Protected Areas (TPA) in Gunung Mulu National Park. This area covers 90% of the park and is not open to the public. The remaining 10% of the park is open to visitors and is managed by Borsarmulu Park Management Sdn Bhd.

Since 1974, the Sarawak government has not built any roads inside the park to limit access. This helps protect the park’s environment and its natural resources. Laws such as the National Parks and Nature Reserves Ordinance of 1998 and the National Parks and Nature Reserves Regulations of 1999 were created to manage the park properly. Ninety percent of the park and 95% of the caves are closed to visitors except for scientific research. Only four caves are open to the public: Clearwater Cave, Wind Cave, Deer Cave, and Lang’s Cave. All visitors must have a permit and a guide. Visitors must travel in groups of ten and wait 20 minutes between groups at the four show caves. Seven other caves are available for caving in groups of six if visitors have proper equipment. A 480-meter skywalk through the tree canopy is also available. Other activities include rock climbing, kayaking, and mountain biking.

The park headquarters is located near the Melinau River, southwest of the park. It includes a visitor registration building, an interpretation center, an audio-visual room, and washrooms. The Royal Mulu Resort, which has 188 rooms, includes an air-conditioned longhouse, guest house, four cabins, and a hostel. These facilities are near the park entrance.

The park can be reached by air from Miri, Limbang, and Bandar Seri Begawan through Mulu Airport. Visitors can also travel by boat from Marudi through the Tutoh and Baram Rivers. There are no roads leading to the park.

A proposed expansion of the park to include Gunung Buda National Park and Labi Forest Reserve in Brunei may help create a larger area to protect the environment around Gunung Mulu National Park.

Controversies

In 2019, the Penan and Berawan people living near Mulu National Park blocked a logging company that was invading their land to cut down trees and grow oil palm plants. The Sarawak government claimed that the logging work would not harm the environment of Mulu National Park. On March 15, 2019, the native groups filed an official report with UNESCO to draw attention to the situation.

In the media

In 1991, a documentary film titled Secrets of the Natural Wonder focused on Mulu National Park. Another film, World's Wonder Mulu (1996), also highlighted the park. Both documentaries were produced by Filem Negara Malaysia.