The population of endemic babblers at the Mount Kanlaon Natural Park on Negros Island continues to drop owing to habitat loss and human-induced air pollution, a study published recently in the Sylvatrop Journal of the Ecosystems Research and Development Bureau (ERDB) of the Department of Environment and Natural Resources (DENR).
Besides timber poaching and cutting of trees for firewood and charcoal production, the bird hunting, human-induced air pollution and conversion of forest to agricultural commodities are seriously threatening the bird population in the area.
Mount Kanlaon Natural Park is a protected area covered by the National Integrated Protected Areas System Act. With a total area of 24,388 hectares—characterized by cool, dense forest—the park is home to a diverse wildlife, including wild boar, civet cat, leopard cat, spotted deer, and a variety of bird species.
Mountaineers frequently trek Mount Kanlaon, which is an active volcano, because of its aesthetic beauty and the perfect place to commune with nature when on Negros Island.
In Sylvatrop’s special issue with the Biodiversity Conservation Society of the Philippines, proponents of the study revealed both Negros babblers—the flame-templed babbler (Dasycrotapha speciosa), which is endemic to Negros and Panay, and striped babbler (Stachyris nigrorum), which exclusively found on Negros, have been classified as endangered by the International Union for Conservation of Nature (IUCN).
As of 2015, BirdLife International indicated that the population of flame-templed babbler on Mount Kanlaon ranged from 2,500 to 9,999 individuals. This was greater than the 600 to 1,700 mature individuals for striped babbler, according to the report.
The decrease in the population of the species, estimated from 50 percent to 90 percent, is believed to be continuing.
“[We should] intensify regular forest monitoring on Mount Kanlaon; establish and revisit biodiversity-monitoring system for the population of babbler species,” according to Sylvatrop authors Andrew T. Reintar, Shaira Grace B. Pios and Dennis A. Warguez.
They also pressed for conservation initiatives to start and create education materials to raise public awareness on the biodiversity threat.
ERDB Director Dr. Henry A. Adornado, in a statement accompanying the published study by Growth Publishing for the DENR’s research and development unit, said the study increases understanding of the status of Philippine biodiversity.
“These efforts are aligned with ERDB’s mission to provide science-based information for the improvement of our environment. May this scientific information inspire us to work hard for the conservation of our rich flora and fauna,” Adornado said.
Biodiversity protection promotes sustainable development of forests that are significant sources of food, timber and nontimber products and raw materials for manufacturing supplies, while generating livelihood for rural people, he added.
“We need biodiversity for its invaluable ecosystem services, providing oxygen, food, clean water, fertile soil, medicines, shelter, protection from storms and floods, a stable climate and recreation,” according to the Earth Institute.
Sought for reaction, Director Theresa Mundita S. Lim of the DENR’s Biodiversity Management Bureau said “the study highlights the need to protect the remaining habitats of our endangered birds. And not just for birds, but to benefit the communities, as well.”
“More than just simply reforesting, it is important to protect and restore the vegetation that these birds are associated with, such as the forest fruits and the invertebrates they feed on,” Lim said in a telephone interview with the BusinessMirror last week.
According to Lim, the presence of the birds ensures that the specialized ecosystems that support their survival continue to thrive and support the surrounding communities that are dependent on the same ecosystem for ecosystem services, such as food security, water, livelihoods and even climate-change adaptation.
“For a biodiversity-rich country, such as the Philippines, these results of scientific researches are important to further make this human-biodiversity link clearer to everyone,” she said.
The IUCN recommended more surveys in Panay and around Mount Silay and Mount Mandalagan in North Negros to locate other birds. It pushed for the establishment of the proposed Central Panay Mountains National Park and other key sites as the North Negros Forest Reserve.
“This lowland forest species has a very small, severely fragmented and declining range. It is estimated that just 10 percent of remaining forest on the two islands lies within the elevation range suitable for this species,”the IUCN said.
Reforestation is a solution to the birds’ threatened extinction.
According to the study, “Tree density was found to be significant in the abundance of striped babbler; a decrease in tree density would mean an increase in the abundance of striped babbler. This result strongly presses the fact that the species prefers mid-montane and mossy forest.”
It added thick undergrowth should be developed for flame-templed babbler, which is an omnivore. It feeds and breeds in understory bushes, trees, vines and ferns. The IUCN said while conservation sites have been identified, there has been no species management that successfully reintroduced the population, no awareness-education program and no action recovery plan or monitoring.
It added that needed protection includes site protection and management, and habitat and natural-process restoration.
Surveys in 1991 yielded tentative estimates of 22 flame-templed babbler per square kilometer on Mount Kanlaon, although only a few square kilometers of suitable forest remain.
In 1987 this species was discovered on Panay Island and is also now known to dwell in five localities in the Panay central mountains, although “it appears very uncommon and/or has a very patchy distribution,” the IUCN report said.
The babblers’ status was only threatened as of 1988. The IUCN has a six-stage Red List classification from least concern to extinct in the wild.
About 80 species of the babblers have already become extinct or critically endangered out of 678 recorded species and 206 endemics.
As birds are easier to monitor, it becomes an indicator of the status of other animals.
“The threatened extinction of bird species implies comparable losses in other groups and, hence, a major reduction in biodiversity,” the results published in the Sylvatrop journal said.
The study also found out that flame-templed babbler was most likely to be found at lower elevations from 400 meters above sea level (masl) to 900 masl.
On the other hand, the higher elevations were occupied by striped babbler or between 1,000 masl to1,800 masl.
Also found in secondary lowland forest, mixed forest plantation and plantation was the lowland-forest dwelling flame-templed babbler.
The study that covered an expanse of the 44-km path between 400 masl and 800 masl, 22 flame-templed babbler and no striped babbler were found.
In the middle elevation, between 850 masl and1450 masl, five flame-templed babbler and 10 striped babbler were found.
On the high elevation of between 1,450 masl and 1800 masl, four striped babbler and no flame-templed babbler were found.
Threats of tree cutting and charcoal production were numerous in Sitio Minoyan, Barangay Was, and Murcia, Negros Occidental.
“Other threats, such as butterfly collection and snare traps, for medium-sized mammals are evident throughout Sitio Minoyan, Barangay Wasay, Murcia and Guintubdan, Barangay Ara-al, La Carlota City in Negros Occidental.”
The Sylvatrop authors also pressed for the study to be published in peer-reviewed journals so that the research results can be shared in the scientific community.
Image credits: Sylvatrop/Growth Publishing