Cardamom Mountains rainforests

• Category: Forest Biomes
• Geographic Location: Asia
• Summary: The Cardamom Mountains Rainforests contain very rich habitats, largely untouched but now in need of protective intervention by governmental and environmental organizations.

The Cardamom Mountains rainforests in western Cambodia are among the most species-rich and intact natural habitats in southeast Asia, and among the least explored. The rainforests form a biome covering the entire Gulf of Thailand coastal region of Cambodia and extend inland as much as 200 miles (320 kilometers) across rugged terrain. The northwestern edge of the Cardamom region abuts the Thai border and the easternmost part stretches to within 60 miles (100 kilometers) of the Cambodian capital of Phnom Penh. The region's area is 2.5 million acres (1.0 million hectares), and the highest point in the range is Mount Aural, at 5,948 feet (1,813 meters). Five main rivers run through the Cardamom, creating dozens of waterfalls.

About 25,000 people live in this remote region, some of whom are ethnic tribal minorities. Two wildlife sanctuaries in the Cardamom Mountains were decreed by King Norodom Sihanouk in 1993, based soley on aerial imagery. Khmer Rouge guerrillas retreated to the Cardamom Mountains after losing power in 1979, and for the next twenty years, few would enter the area for fear of the Khmer Rouge and the land mines they left behind. As a result, the region remained largely untouched and undeveloped. Ironically, surveys revealed this isolation preserved one of Southeast Asia's last intact rainforest ecosystems. However, modern road construction and development projects threaten this accidental conservation success

Plant Life

Despite the political upheaval and the years of war ravaging the countryside and the rainforests, Cambodia is home to many plant life. The area's fauna and flora are not uniformly distributed, providing unique plant and wildlife species throughout the Cardamom Mountains. Plant life is largely divided by elevational zones, though it has been poorly studied overall.

The lowland evergreen forest of the Cardamom range is abundantly furnished with vegetation, including tall trees such as ficus (Moraceae spp.) and various species of bamboo, rattan, and liana. At altitudes of 2,300 to 2,600 feet (700 to 800 meters), shorter trees such as Lithocarpus (Fagaceae spp.) and syzygium (Myrtaceae spp.) are common. The forest floor is covered with leaf litter from numerous plant species, including small orchids and terrestrial mistletoe.

One of the most abundant canopy species in the wet evergreen forests is the Hopea pierrei, a small tree of limited distribution outside this area. Another is the Anisoptera costata, an emergent tree of up to 213 feet (65 meters).

A carnivorous pitcher plant, Nepenthes holdeniinamed after the British photographer Jeremy Holden of Fauna and Flora International (FFI), who discovered the species in 2010grows on steep ridges in peat-type soil, fully exposed to sunlight. It has large leaves with a wide opening at the top. The leaves, formed into a deep pitcher-like structure, catch and digest insects that enable the plant to nourish itself rather than rely on nutrient-poor soil. They also hold water, making the plant drought-resistant; its roots are relatively fire-resistant.

Endangered Animal Species

The forests support endangered species such as the pileated gibbon, tiger, Siamese crocodile, and Asian elephant. Distinctive mammals include the sun bear, clouded leopard, gaur, banteng, and kouprey. Some species here are otherwise found only on Thailand's southern peninsula, such as the flying lemur, mustached hawk cuckoo, buffy fish-owl, silver oriole, and greater mouse deer. More than 450 species of birds are here, including several that are endemic to this biome.

The Cambodian forest ox, the kouprey (Bos sauveli), is one of the most elusive mammals. It was not known to Western science until 1937 and has been seen only a few times since then. The animal resembles a gray forest ox with frayed horns and a long dewlap hanging around its neck. The kouprey inhabits low, rolling hills with patches of dry forests, grazing in the open areas during the day and entering the forests for shelter from predators and sunlight.

The kouprey's range is primarily in northern and eastern Thailand, southern Laos, and western Vietnam. Sihanouk designated it the national animal of Cambodia in the 1960s, partly due to its mystique. The kouprey has always been elusive, and the destruction of its habitat due to slash-and-burn agriculture, logging, warfare, hunting, and disease has caused many experts to believe that it has become extinct—it has not reliably been seen since 1988.

Pileated gibbons are found in the tropical forests here. The gibbon uses its long arms to throw itself from tree to tree, covering gaps of 33 feet (10 meters) or more. An estimated two million to three million pileated gibbons lived in Thailand before aggressive deforestation in recent decades. While the International Union for Conservation of Nature classified the pileated gibbon as Endangered in 1994, preservation programs have improved the creature's status to Vulnerable. In the medium term, pileated gibbons in the wild are still at risk for extinction due to habitat degradation and reduced hunting grounds for food.

A 2023 camera trap study in the region captured the first confirmed tiger footage in Cambodia since 2007, sparking both excitement and concern among conservationists. While the study proved tigers still exist in these forests, the single sighting underscores their critically low numbers. Meanwhile, other surveys conducted around the same time frame indicated only about 400 pileated gibbons remain in the wild, a dramatic decline from previous estimates.

Ecological Threats

Today, the Cardamom Mountains region is the largest wilderness in mainland southeast Asia, preserving many endangered species not found elsewhere. Overall, the rainforests of Cambodia are relatively intact, but the areas in southeast Thailand are under pressure from illegal logging, animal poaching, and widespread hunting. About one-third of the ecoregion has been designated as protected areas, the largest of which is Phnom Sankos Wildlife Sanctuary. Other sizeable parks include Phnom Aural, Preah Monivongm, and Botum-Sakor, although the level of active protection in all mountain parks is uneven. However, in the 2020s, poaching was problematic even in protected regions. In one month in 2021, park rangers discovered and confiscated six hundred snares in the Central Cardamom Mountains National Park. According to Rangers, the problem extends beyond a local issue, as an extensive network is in place to trade endangered animals and forest timber.

The Cardamom Mountains are sparsely populated by humans, most of whom are very poor. In 1992, FFI initiated a study with the Cambodian government to identify the needs of the local population and to instruct the people in basic agricultural skills. The goal was to help the communities become self-sufficient and to prevent escalating social problems and environmental destruction related to hunger. Since 2000, FFI has led a program integrating community-based ecological conservation and sustainable development in the greater Cardamom ecosystem. The program is now linked with national and nongovernmental organizations to conserve natural resources and Indigenous peoples.

Global climate change is projected to increase temperature, rainfall, and extreme weather events in the Cardamom Mountains rainforests. The biome provides carbon storage of an estimated 230 million tons and protection against floods while serving as a vital natural water reservoir for drier areas to the east. With Cambodia's growing economic and political stability, pressure has increased from logging, mining, and agribusiness interests to develop parts of the rainforest. Such activity would degrade this ecosystem's capacity to support species diversity and deliver its recognized ecological services.

Bibliography

Boulos, Nick. “Cambodia's Cardamom Mountains, Full of Secrets.” Washington Post, 10 Aug. 2012, https://www.washingtonpost.com/lifestyle/travel/cambodias-cardamom-mountains-full-of-secrets/2012/08/09/0b63cf10-d837-11e1-b360-33e7ac84e003‗story.html. Accessed 15 Nov. 2024.

Daltry, Jenny, and Frank Momberg, eds. Cardamom Mountains: Biodiversity Survey 2000. Fauna & Flora International, 2000.

McPherson, Stewart, et al. Pitcher Plants of the Old World. Volume One. Redfern Natural History Productions, 2009.

Patchett, Joe. "Grassroots Work to Save Remaining Cardamom Mountain Rainforests." Climate Tracker, 26 Mar. 2021, climatetracker.org/new-crowdfunding-campaign-to-install-solar-panels-on-schools-across-thailand/. Accessed 25 July 2022.

Wildlife Conservation Society. "Cardamom Mountains Biodiversity Survey Report." WCS Cambodia, 2023, cambodia.wcs.org/reports/cardamom-mountains-biodiversity-survey-2023.pdf. Accessed 11 Nov. 2024.