The vegetation and plant communities of Pulau Balambangan, Sabah, East Malaysia
Abstract
A survey of the vegetation and plant communities in Pulau Balambangan, a small island off the northern tip of Sabah, east of the larger island Pulau Banggi, was made during an expedition sponsored by the Sabah State Government and the World Wildlife Fund (Malaysia) in April 1977. The main vegetation types and plant communities were defined as (1) strand vegetation (with two indistinct facies); (2) mangrove; (3) brackish swamps; (4) freshwater marshes; (5) sandy heath; (6) forest over limestone, (7) forest over chert, (8) forest over ultrabasic rocks, and (9) marine vegetation (shores). Sample plots, transects, and intensive collecting methods revealed a flora of at least 309 species, 185 of which were first recorded from the island during this survey. The chief determinants of vegetation type are water (availability and relative salinity); exposure (to wind and insolation); fire; and the effects of human activity. Descriptions of the plant communities and mention of characteristic species are presented herein.
Summary
This article reports the botanical findings of a multi-disciplinary expedition to Pulau Balambangan in April 1977, organized by the Sabah State Government and the World Wildlife Fund (Malaysia) to evaluate the island’s potential as a national park. Working with Edward F. Anderson and Richard Albert, B.C. Stone defined nine major vegetation types—strand, mangrove, brackish swamp, freshwater marsh, sandy heath, limestone forest, chert forest, ultrabasic forest, and marine vegetation—and documented the flora through sample plots, transects, and intensive collecting. The central argument is that geological substrate (limestone, chert-spilite, ultrabasic ophiolite, and alluvium) is the primary determinant of vegetation type, with water availability and salinity, wind exposure, and fire acting as secondary but significant modifiers. Because the island’s maximum altitude is only about 500 ft, altitudinal zonation is absent; instead, vegetation mosaics arise from combinations of substrate, topography, and exposure (pp. 66–67).
The article also engages with the biogeographical position of the island. Stone argues against the simplistic framing of Balambangan and Banggi as possessing a “Philippine” element, proposing instead that the Palawan–Balabac–Banggi–Balambangan shelf constitutes a distinct insular floristic area with its own identity. The discovery of Pandanus occultus—previously known only from a single type specimen from Palawan—is interpreted as evidence of relict populations whose distributional continuity was severed by Pleistocene inundation, rather than as evidence of recent dispersal from the Philippines (pp. 86–87).
A postscript addresses the environmental conditions at the site of the first British settlement in Borneo, established by the Honourable East India Company at Tanjung Periok in 1773. Stone demonstrates that the settlement was sited in the sandy heath zone, which he identifies as the poorest local environment on the island for agriculture or sustained human habitation. He argues that even absent the 1775 Sulu attack, the settlement’s dependence on imported provisions—particularly water—would have made its long-term survival improbable (pp. 87–88).
Key Findings
- The survey recorded a flora of at least 309 species across all groups (Algae 22, Bryophyta 3, Pteridophyta 16, Gymnospermae 4, Angiospermae 264), of which 185 were first recorded from the island during the 1977 expedition (p. 69).
- Pandanus occultus Merr. was identified as a new record for Borneo, the species having been previously known only from a single type specimen collected in Palawan Island, Philippines (pp. 72, 83).
- A one-chain-square sample plot in the ultrabasic lowland forest recorded 71 trees, of which 23 (32%) were Dipterocarpus grandiflorus; the largest individual had a girth of 7 ft. 6 in., and the next largest a Dialium at 6 ft. (pp. 81–83).
- Sandy heath comprises approximately 40% of the island’s total land area, making it the most extensive single vegetation type (p. 79).
- Prior to the 1977 expedition, all botanical collections from the island totalled only 147 specimens (Agama 1, Kloss 1, Castro & Melegrito 62, Fox 83); the expedition added 454 specimens, distributed as six sets to Sandakan, KLU, Whitman College, Berkeley, Leiden, and Kew (p. 69).
- The old East India Company settlement at Tanjung Periok was situated within the sandy heath zone, which Stone characterizes as “the poorest local environment in an island which is characterized by comparatively poor environmental conditions” (pp. 79, 87).
Conclusion
Stone’s definitive historical takeaway is twofold. First, the flora of Pulau Balambangan constitutes a distinct insular entity best understood through its geological and biogeographical context on the Palawan–Balabac–Banggi–Balambangan shelf, rather than through political or broad regional boundaries. Second, the environmental conditions of the island—particularly the sterility of the sandy heath at the old settlement site and the chronic shortage of fresh water—render the East India Company’s choice of location fundamentally untenable, suggesting that the settlement would have been abandoned or relocated even in the absence of the 1775 Sulu attack.
Context
- Primary herbarium collections: Sabah SAN-series (Sandakan Forest Research Centre), with duplicates at Kew, Leiden (Rijksherbarium), Berkeley (UC), University of Malaya (KLU), and Whitman College; earlier collections by Castro & Melegrito and Agama were destroyed in WWII or the 1961 Sandakan fire, with surviving duplicates at Berkeley and Kew (p. 69).
- Historiographical contribution: This is the first comprehensive botanical survey of the island, building on fragmentary earlier work by Wood’s agents (1922–23), Kloss (1927), and Fox (1970). The postscript provides the first environmental assessment of the East India Company settlement site, complementing Warren’s (1977) historical account of the 1775 Sulu attack published in the same journal.