Indigenous knowledge on biodiversity gained formal recognition when researchers documented Clerodendrum kelli, a shrub the Bugkalot people have used for generations to treat sick dogs, as a distinct species found only in an 8-square-kilometer area of Nueva Ecija province, now assessed as critically endangered.
Indigenous knowledge on biodiversity demonstrates how traditional ecological understanding can guide scientific documentation. The Bugkalot people of the Caraballo Mountain Range call it kelli. They mash the oval-shaped leaves and mix them with food to restore health to ailing dogs. Despite this generations-long familiarity, science only formally identified the plant as a distinct species in December 2025.
Clerodendrum kelli grows as a small shrub reaching about one meter in height. It inhabits humid montane rainforests between 1,170 and 1,362 meters above sea level in two specific localities: Mt. Meddengen and Sitio Binbin. Both sites sit within the Pantabangan-Carrangalan Watershed Forest Reserve in Nueva Ecija province.
The plant stands out with green leaves accented by pale purple undersides. Its white, tube-shaped flowers bloom from reddish-pink bases. These flowers arrange themselves in loose, open clusters, unlike the dense groupings characteristic of other Clerodendrum species. The Bugkalot recognize kelli as growing in the colder mountain areas.
David Justin Ples, John Patykowski, Leonardo Udasco, John Charles Altomonte, Adriane Tobias, and Rene Alfred Anton Bustamante of the Ateneo de Manila University published their findings in Gardens’ Bulletin Singapore in December 2025. The scientific name honors the Bugkalot term.
The documented medicinal use reflects the Bugkalot’s deep understanding of the species and its habitat. Importantly, researchers found no indication that traditional use led to the plant’s scarcity. Rather, habitat loss from land conversion and natural landslides poses the greatest threat to survival.
Despite formal protection through the watershed forest reserve designation, ongoing habitat degradation continues to reduce Clerodendrum kelli’s range. This shrinkage proves especially severe along steep ridges where the species grows. Forest clearing and slope failures compound the problem. The species now exists in a total area of just 8 square kilometers.
Indigenous knowledge on biodiversity highlighted conservation urgency. Researchers assessed the species as critically endangered the moment they formally described it. The International Union for Conservation of Nature (IUCN) classification uses the designation CR B1ab(iii)+2ab(iii), indicating extremely restricted range and continuing habitat decline.
The species never appears abundant or common even within its limited range. It maintains a subtle presence in the landscape. Researchers recorded it growing under partial to full shade on loam or clay soils topped with thick leaf litter. Associated vegetation includes dominant species like Syzygium bataanense and genera including Agathis, Nageia, and Lithocarpus in Sitio Binbin. At Meddengen, Clethra canescens dominates alongside Saurauia, Calophyllum, and Syzygium species.
The discovery occurred through field surveys conducted in March, August, and October between 2022 and 2023. Teams documented flowering in March and August. The plant produces flowers with shorter corolla tubes compared to related species. This morphological distinction, along with the reddish-pink calyces with ovate lobes, differentiates Clerodendrum kelli from similar species.
Indigenous knowledge on biodiversity bridges traditional and formal understanding. The Ateneo de Manila University research office emphasized this overlap. Indigenous communities possess detailed knowledge of species distinctions, habitat preferences, and practical applications. Formal science provides systematic documentation, comparative analysis, and conservation assessment.
This collaboration benefits both knowledge systems. Indigenous communities gain formal recognition of their expertise. Scientific databases expand to include species previously known only to local populations. Conservation efforts can mobilize resources and legal protections once species receive official documentation.
The Philippines hosts exceptional biodiversity. The archipelago’s isolation and varied topography created numerous endemic species. However, habitat loss threatens many before science documents them. Deforestation rates remain high despite legal protections. Mining, logging, and agricultural expansion continue to degrade forests.
The Pantabangan-Carrangalan Watershed Forest Reserve provides critical water resources for surrounding communities. The reservoir supplies irrigation and hydroelectric power. Forest cover maintains water quality and regulates flow. Species like the Clerodendrum kelli indicate ecosystem health.
Indigenous knowledge on biodiversity could accelerate conservation action. Researchers can prioritize surveys in areas where indigenous communities report the presence of unique or threatened species. This targeted approach uses limited resources efficiently. It also respects indigenous expertise by treating traditional knowledge as valid information rather than folklore requiring verification.
The Bugkalot community’s sustainable use of kelli over generations demonstrates conservation compatibility. Indigenous resource management often maintains populations better than unregulated exploitation. Traditional ecological knowledge includes an understanding of seasonal patterns, sustainable harvest levels, and habitat requirements.
Modern conservation increasingly recognizes indigenous peoples as partners rather than obstacles. Protected area management improves when it incorporates local knowledge and ensures community benefits. The Pantabangan-Carrangalan Watershed Forest Reserve could strengthen conservation by formalizing Bugkalot participation in monitoring and management.
Climate change adds urgency to documenting species before they become extinct. Temperature shifts and altered rainfall patterns affect montane species adapted to specific conditions. Clerodendrum kelli’s restriction to higher elevations makes it particularly vulnerable. As conditions warm, suitable habitat shrinks toward mountain peaks with nowhere else to go.
The species’ medicinal properties deserve further research. Traditional veterinary practices often contain compounds with therapeutic value. Scientific analysis could identify active ingredients and mechanisms. This knowledge could benefit both traditional users and broader applications.
Indigenous knowledge on biodiversity also raises intellectual property questions. The scientific name acknowledges Bugkalot’s contribution, but formal mechanisms for benefit sharing remain underdeveloped. If commercial applications emerge from traditional knowledge, indigenous communities should receive recognition and compensation.
The Clerodendrum genus contains approximately 400 species distributed across tropical and subtropical regions. Many produce compounds with medicinal properties. Various species are used in traditional medicine systems throughout Asia, Africa, and the Pacific. Formal documentation of indigenous uses could guide pharmaceutical research while protecting traditional knowledge.
Future surveys should prioritize areas with high potential for indigenous knowledge on biodiversity. The Philippines is home to numerous indigenous communities with deep ecological expertise. Systematic collaboration could document species before habitat loss eliminates them. This knowledge would strengthen conservation planning and resource allocation.
