Palawan Research Articles

Status of coral reefs in Southeast Asia: threats and responses : C. R. Wilkinson, L. M. Chou, E. Gomez, A. R. Ridzwan, S. Soekarno & S. Sudara, in: Proceedings of the colloquium on global aspects of coral reefs, Miami, 1993, ed R.N. Ginsburg & F.G.W. Smith, (University of Miami, RSMAS), 1994, pp 311–317

Mangroves, seagrasses, and salt marshes or collectively known as blue carbon ecosystems are gaining salience because of their essential roles in reducing the risks and impacts of climate change through carbon sequestration and other beneficial services. Despite this, they are globally declining because of their vulnerability to natural and anthropogenic disturbances. Similar trends are also observed in Busuanga Island, Palawan province in the Philippines, where blue carbon ecosystems along with other coastal environments are perceived to be threatened by a number of factors. To better understand the state changes of blue carbon ecosystems, we collected the drivers and pressures and their impact on the whole coastal ecosystem as well as existing management responses by interviewing 26 stakeholders representing community organizations, non-government organizations, and municipal level government units from two municipalities (Busuanga and Coron) in the island. We used the Drivers-Pressures-State-Impact-Response (DPSIR) framework to analyze the information gathered from the interviews. The results of this study show that lack of institutional capacities (indirect driver) is the leading factor that hinders the progress or efficacy of the management. Most pronounced pressures caused by direct drivers to blue carbon ecosystems include overexploitation and coastal developments. The responses collected in the interviews can be grouped into policies and implementation, capacity building development, welfare and livelihood development, ecosystems management, and tourism measures. The information gathered in this study can be used to improve or change existing responses into more precise and contextualized measures in addressing specific impacts observed in the local areas.

Biogeography of palawan mosses

The moss flora of Palawan was updated and consists of 192 species in 88 genera. Because of the dry, semi-deciduous forest, Palawan has a relatively depauperate moss flora compared with the flora of moist forest on other islands of similar area. The number of species is higher in riverine forest than in inland forest, and highest at mid-mountain elevation. Its flora is mainly an extension of the Philippine moss flora, showing little influence from Borneo. Likewise, its floristic affinity is with the moss floras of the Philippine archipelago, Java, and Lesser Sundas, but not with the Bornean moss flora. Additionally, the role of Palawan Island as a refugium for the survival of a past, xeric moss flora in South-East Asia is discussed on the basis of evidence from moss distribution. Clastobryum asperrimum (Dix.) Tan was proposed as a new combination and Leucoloma mittenii Heisch. was considered to be a new synonym of L. walkeri Broth.

<p><strong>Three new and remarkable species of mosses from China and the Philippines</strong></p>

Distichophyllum meizhii Tan & Lin and D. wanianum Tan & Lin (Hookeriaceae) collected from southwestern region of China are described as new to science. Also, Horikawaea redfearnii Tan & Lin is described as a new species based on collections from Hainan Island of China and Palawan Island of the Philippines. The sporophytic specimen of Horikawaea Nog. was collected for the first time and support a family placement in Pterobryaceae.

The application of Rapid Rural Appraisal techniques in coastal resources planning: experience in Malampaya Sound, Philippines

The Rapid Rural Appraisal (RRA) techniques often employed to fast-track the assessments of agricultural and forest resource systems were applied to the coastal resource planning of Malampaya Sound in Palawan Island, western Philippines. The RRA was classified as exploratory: the aim was to describe the problems and opportunities in the area through the active participation of the local communities. The exercise was jointly undertaken by six researchers and representative household members from seven villages. Qualitative diagrams were constructed depicting the human interactions with the coastal resources in terms of four patterns: space, time, product flow and decision making. The four key coastal issues that emerged in the problem analysis chart were: low fishery production, the low prices of fisheries produce, low agricultural production and poor health conditions. The final outputs were proposed projects or action strategies to be used as mitigating measures for the coastal problems identified. The RRA techniques were found to be useful as participatory tools for problem identification and initial project development. The documentary outputs have served as guides for the rapid survey of other coastal sites in Palawan.

New stygobiont amphipods (Crustacea Amphipoda) from the Philippine Islands

The author has studied the amphipods collected in the Philippines during a research campaign concerning groundwater fauna. The new mesopsammic genus Cottarellia, found on Sabang beach (eastern Mindoro), is described. This genus, represented by one exceptionally small (1.2 mm) blind species (Cottarellia minima), is most closely related to Hornellia Walker 1904 and Metaceradocus Chevreux 1925. Two other species were also found during this campaign: Bollegidia sootai (Coineau & Rao 1972), hitherto known only in the Andaman Islands and Malaysia, and a species of Bogidiella Hertzog 1933 which is probably new but could not be described because of the poor state of preservation of the two specimens examined. In the phreatic fresh water of Palawan Island a new species of Bogidiella, B. daccordii, was found; it has been provisionally placed in the subgenus Medigidiella Stock 1981. This species is most closely related to Bogidiella sarawacensis Stock 1988.

Application of seroepidemiology in identification of local foci in a malarious community in Palawan, The Philippines.

The value of seroepidemiology in malaria control programs has long been recognized, but its use in such situations has been limited. We therefore conducted a seroepidemiologic study in a frontier community on Palawan Island, The Philippines, an area where malaria is highly endemic. The first serologic survey was done at the end of the rainy season and the second was done during the dry season. The sera were examined using an indirect fluorescent antibody test. There was a significant difference in the geometric mean reciprocal titer (GMRT) during the rainy season as compared with the GMRT during the dry season. There were seasonal changes in the distribution of high- and low-titer responses, which is suggestive of the occurrence of recent past malaria epidemics. The differences in the geographic distribution of high and low titers were indicative of permanent foci of malaria transmission in this community. Results of a parallel parasitologic study were consistent with those of the serologic study. These findings may be of practical value not only in the proper reorientation of the local malaria control program, but of those of other endemic countries as well.

Helium isotopic and chemical composition of gases from volcanic-hydrothermal systems in the Philippines

Relative 3He, 4He, Ne, Ar, N 2 and CO 2 contents of gases collected from high temperature geothermal systems associated with active subduction zones in the Philippines, (Cagua, Alto Peak, Mahagnao, Mambucal and Mount Apo) correspond to 3He/ 4He ratios of 6.9 to 7.6 R A, CO 2/ 3He ratios of 10 to 50 × 10 9 and N 2/Ar ratios of 200 to 500. The data suggest that He is essentially of upper mantle origin and that CO 2 and N 2 are predominantly derived from subducted sediments. Highest CO 2/He ratios are observed for systems along the centerline between major zones of active subduction to the E and W of the Philippine islands. The high values may tentatively be explained in terms of derivation from an especially CO 2-rich magmatic environment created by the supply of volatiles from two subduction systems. The low 3He/ 4He ratios of 0.4 and 0.6 R A for two springs on the island of Palawan indicate that the thermal waters there are the result of only residual geothermal activity associated with an, at present, inactive subduction zone.

The marrango or philippine neem tree,Azadirachta excelsa (=A. Integrifoliola): A new source of insecticides with growth-regulating properties

The best-known species of the genusAzadirachta (family Meliaceae) isA. indica (Indian neem tree). There are at least two other congeneric species in Southeast Asia, namely,A. siamensis (Thai neem tree) andA. excelsa (Jack) Jacobs (marrango or Philippine neem tree). To extend our limited knowledge of the marrango tree, investigations were carried out in the Philippines on the island of Palawan, and in Germany. Comparisons of the properties ofA. indica withA. excelsa showed many similarities but also clear differences. WhereasA. indica thrives in hot dry regions,A. excelsa is a plant of lowland monsoon forests in Southeast Asia and tolerates greater rainfall thanA. indica. Bioassays of leaf, bark and seed extracts of both species against insects revealed greater bioactivity forA. excelsa, which contains azadirachtin as well as marrangin, a new compound closely related to azadirachtin, in its seed kernels. Marrangin was more toxic than azadirachtin to the Mexican bean beetle,Epilachna varivestis.A. excelsa could be a valuable source of growth-regulating pesticides in greater rainfall areas of the tropics. It also produces a high-value timber and its leaves can be used as a vegetable or for medicinal purposes. However,A. excelsa is an endangered plant owing to the deforestation in Southeast Asia.

A New Species and an Annotated World List of the Sucking Louse Genus Neohaematopinus (Anoplura: Polyplacidae)

A new species of sucking louse, Neohaematopinus sundasciuri, collected from the tree squirrel, Sundasciurus juvencus, is described from Palawan Island, Philippines. An updated world list of the genus Neohaematopinus is presented; this documents descriptive citations, known hosts, and geographical distributions with interpretive annotations for each of the 32 species now included in the genus. The geographical distributions of Neohaematopinus sciuri and N. sciurinus are discussed.

Evidence of internal swash associated with Sulu Sea solitary waves?

Vertical temperature profiles were measured near the shelf edge off the coast of Palawan Island (Philippines) during the passage of several “rip bands” of choppy surface waves. Such rip bands are commonly associated with internal waves. Coincident with the passage of one of the rip bands, the temperature near the bottom decreased by 2.5°C within 1.4 min, becoming colder than any water on the shelf. Furthermore, the apparent depth of our CTD decreased by about 8 m despite the fact that the “line-out” was held fixed. We interpret these limited data, along with a sea-level record, as evidence of internal swash created by breaking internal solitary waves which are generated by tidal flow over a shallow bank in the southeastern Sulu Sea (described by Apel et al., 1985 , Journal of Physical Oceanography, 15, 1625–1651).

Deforestation and detribalization in the Philippines: The Palawan case

Palawan Island contains the largest remaining expanse of unbroken forest cover in the Philippines. The forest is currently threatened by agricultural colonization, as numerous migrants from throughout the Philippines settle annually in the island's forested uplands. Further, Palawan is being heavily logged and is, in consequence, the focus of an acrimonious national environmental debate. This paper examines how land alienation and other forms of socioeconomic marginalization attending these pressures have undermined the well-being of Palawan's indigenous tribal peoples. It also explains how lack of secure tenure and failure to achieve popular participation so distort the gap between the ideal and the practice of agroforestry programs aimed at these peoples that such programs not only fail to ameliorate the ecological situation but further undermine tribal well-being.

Pre‐Eocene Synmetamorphic Structure in the Mindoro‐Romblon‐Palawan Area, West Philippines, and implications for the history of southeast Asia

The structure of the pre‐Eocene rocks, considered as the “basement” of the Philippines, has been investigated in the Mindoro‐Lubang, Romblon‐Tablas‐Sibuyan, and North Palawan areas. In the former two areas the same pre‐Eocene succession of units is recognized from top to bottom: (1) a pre‐Eocene olistostrome; (2) an ophiolitic nappe; (3) a schistose sequence (pelites, sandstones, basic schists and marbles); and (4) a gneissic unit. The nature of the contact between the olistostrome and the underlying units is unclear, but the ophiolite and the schistose sequence form two thrust sheets of oceanic origin thrust upon the gneissic unit that is considered a part of a continental basement called the West Philippines Block. Small‐scale structures show that the early deformation stage is characterized by a submeridian (0°–N40°E) lineation formed in greenschist to amphibolite facies conditions during the thrusting. Kinematic analysis show that the thrusting was from north to south. In North Palawan, metamorphic rocks with similar microtectonic and kinematic characteristics are found. They are overlain by a Late Jurassic olistostrome which is correlated with the olistostromes found in Calamian, North Mindoro, Carabao, and Buruanga peninsula (North Panay). The microstructural features and the presence of the olistostrome suggest that the North Palawan, Mindoro, Tablas, Romblon, Sibuyan, and Carabao islands belong to the same North Palawan block of Hamilton (1979) which is a continental fragment rifted from Asia in Cenozoic times. It is assumed that the Western Panay and Zamboanga areas, which are characterized by Mesozoic ophiolites and metamorphic rocks, also belong to the North Palawan Block. All these islands experienced, to some extent, the same Mesozoic geohistory: the south verging thrusting is interpreted as the result of an oblique collision of the West Philippines Block with Asia. The contemporaneous left‐lateral strike‐slip faulting and the calc‐alkaline magmatism widespread along the Chinese margin are also included in the geodynamic model.

EXCAVATION AT CHAMBER 1, GURI CAVE ON PALAWAN ISLAND, THE PHILIPPINES: SOME PRELIMINARY OBSERVATIONS

The articles presents the lithic findings of the Philippine National Museum from the Guri Cave on the south-west cost of the Palawan Island. These archeological findings are said to provide a wealth of information and an opening for archeologists to understand the economic systems of prehistoric communities.

Three new species of chiggers (Acari: Trombiculidae) from the Philippine Islands

Abstract Schoengastia baguoiensis n. sp. and Gahrliepia (Ripiaspichia) serrata n. sp. are described from specimens collected off Rattus species on Luzon Islands, Philippine Islands, and Cheladonta (Susa) palawanensis n. sp. from an unidentified small mammal taken on Palawan Island, Philippine Islands.

Biostratigraphie, Mikrofazies und Diagenese tertiärer Karbonate aus dem Südchinesischen Meer (Dangerous Grounds—Palawan, Philippinen)

This study is based on dredged carbonate samples from the Dangerous Grounds (South China Sea). They cover an area of approximately 130 000 km2. Carbonate samples from wells at the NW-shelf of Palawan and from the St. Paul's complex exposed on the island of Palawan are compared. Most samples contain abundant larger foraminifera. They are Upper Oligocene—Lower Miocene (often more precise Lower Miocene; Te, mostly Te5 referring to the Southeast Asian Tertiary letter classification) for all three sample groups. Because of their abundance in the investigated material, larger foraminifera are studied in more detail. Compilation of existing literature on the (paleo-) ecology shows that foraminifera associations can be used for sophisticated facies interpretation. This is especially helpful for evaluation of the isolated dredge samples. Facies interpretations are checked using four known Oligocene-Miocene facies distribution models, resulting from detailed investigations in the Philippines, N-Borneo (2 studies) and Australia. These models describe the distribution patterns for larger foraminifera. Samples can be assigned to various shallow-water facies zones. Facies and faunal characteristics of each sample are given in Chapter 4.3. To establish a consistent ‘model’ showing the facies distribution pattern for the S. China Sea would need more intensive sampling. It can be shown that the samples originally had been deposited in the euphotic depth zone (0–120 m water-depth). Based on their comparable age, the geographical distribution of sampling sites and an extensive MCS survey these carbonates represent a drowned Oligocene-Miocene carbonate platform. This platform is now encountered at waterdepths up the 2400 m. These results are in agreement with the recently confirmed interpretation of the Reed Bank—Dangerous Grounds area as foundered continental fragment (HINZ & SCHLUTER 1985; KUDRASS, WIEDICKE et al. 1986). The platform age gives a maximum age for the onset of rapid (?) subsidence. The metastable mineralogy of shallow-water carbonates can be used to compare diagenetic changes in the three sample groups (offshore-wells-onshore): The offshore samples (dredged and piston-cored) show only moderate loss of primary textures—the St. Paul's samples suffered most. This can be demonstrated with fossil shells and foram tests. Comparison of samples established a stability ranking of the different taxonomic groups: (Lowest stability) aragonitic skeletons (corals, bivalves) —soritids—lepidocyclinids/miogypsinids—Cycloclypeus —coralline algae-echinoderms—amphisteginids (stable). Typical diagenetic changes of shell-structures mainly of foraminifera groups are described in Chapter 6.1. From detailed examination of textural elements such as biogenic components, primary sedimentary structures, solution phenomena and different cement generations, relative age-relations could be established (Chapter 6.5). The analysis of trace elements revealed very low Sr yields in the samples (680–180 ppm) regardless of sampling group. In contrary to some older interpretations in Sr-literature, this low Sr content can be achieved assuming solely ‘marine’ diagenesis (marine porewater). Oxygen and carbon stable isotope analysis confirm this interpretation. Late diagenetic dog-tooth cement, often interpreted as resulting from frehwater diagenesis, and larger foraminiferal tests revealed unusually heavy oxygen isotope values (∂18O = O to 2.5%) in the offshore samples. These heavy values are interpreted as secondary values of diagenetically stabilized metastable components. Comparable heavy values are seen in some bathyal cemented sediment samples (fp-limestone; Chapter 6.7). This diagenetic shift of isotope values is attributed to (late diagenetic) lower water temperatures resulting from the drowning and subsidence of the shallow-water carbonates. The combined textural and geochemical indications were used to propose several diagenetic stages defining the diagenetic history of the investigated sample material (Chapter 6.8).

The relationship between coastal seiches at Palawan Island and tide‐generated internal waves in the Sulu Sea

A rigorous analysis of tide records from Puerto Princesa on Palawan Island in the Philippines demonstrates that the harbor's fortnightly varying seiche activity is coherent with the cycle of spring‐neap tides in the Sulu Sea and lags it by 2.9 days. This delay closely matches the time required for the formation and travel of tide‐generated internal solitary waves northwestward across the Sulu Sea and strongly supports the hypothesis that coastal seiches can derive their energy from the tide‐producing forces by way of tidal currents and internal waves. However, the analysis also indicates that the quantity of energy transferred from the tide to the seiches has a pronounced seasonal variability which may be related to seasonal variations in wind stress. It is unlikely that accurate predictions of tide‐produced seiches will be possible without a sound theoretical understanding of the mechanisms by which energy is transferred to them by deep‐sea internal waves.

Sampling Malayan Black Bugs (Heteroptera: Pentatomidae) in Rice

Sampling Malayan black bugs, Scotinophara coarctata (F.), in rice was conducted on the island of Palawan, the Philippines, using fluorescent-street-light traps, Petromax gas-lantern traps, and visual counts in the field. Peak catches in light traps occurred around the time of the full moon, especially during mid-August 1984, mid-April to mid-May, and June 1985. However, we found no relationship between densities of S. coarctata in light traps and in the field. Population sampling revealed that data from S. coarctata fit a negative binomial distribution, with a clumping coefficient of k = 0.50. A sequential sampling plan was developed and compared with intensive sampling using visual counts of bugs on individual hills of rice. Using sequential sampling, 44–56% fewer samples were needed to arrive at the same decision obtained by intensive sampling. Over 90% agreement between intensive sampling and sequential sampling was found.

87:6072 The relationship between coastal seiches at Palawan Island and tide-generated internal waves in the Sulu Sea: Giese, G.S. and R.B. Hollander, 1987. J. geophys. Res., 92(C5):5151–5156

87:6072 The relationship between coastal seiches at Palawan Island and tide-generated internal waves in the Sulu Sea: Giese, G.S. and R.B. Hollander, 1987. J. geophys. Res., 92(C5):5151–5156

Stratigraphy of Palawan Island, Philippines

Stratigraphy of Palawan Island, Philippines

An economic analysis of environmental protection and management: An example from the Philippines

The island of Palawan covers some 12000 km2 and is located in the southwest of the Philippines archipelago. It is a beautiful and as yet relatively unspoilt island but in recent years the social and economic pressures on its natural resources and environment have begun to mount. If present trends continue, severe environmental damage will result. In recognition of this danger, the Philippines government and the European Economic Community have commissioned the preparation of an Integrated Environmental Program (IEP) for the island, as part of an overall economic development program. Phase one of the IEP study comprised an assessment of the island's resources and present situation and the formulation of a plan for the future protection of its environment, taking due account of the need for continuing economic development. An analysis was made of the likely economic returns from the proposed environmental protection program, using conventional benefit-cost analysis methodology. Due to the inadequate data base and the wide-ranging assumptions which had to be made, this was inevitably very approximate in nature. It was carried out in terms of the three main types of conservation activity proposed, namely land-based conservation, mangrove conservation and inshore marine conservation, and the program as a whole. The main benefits and costs were identified and, where appropriate, quantified for inclusion in the analysis. Choice of discount rate and length of analysis period are critical factors affecting the economics of environmental protection, which essentially involves the pursuit of long-term rather than short-term gains, output in the immediate future being restricted to the level of long-term sustained yield for the benefit of future generations. Use of the high discount rates customarily applied for project analysis in countries such as the Philippines (typically, 10–15 percent) places a heavy premium on short-term gains and attributes little or no value to benefits and costs further in the future. To take account of this problem the present values of costs and benefits were calculated using low discount rates of zero and 5 percent. Though this was a necessarily crude and arbitrary method of adjustment it was considered to be a better alternative than that of following normal convention and applying the high rates of discount customarily used in the Philippines. The analysis indicated that the various conservation activities could be expected to produce acceptable, though not spectacular, levels of economic return. Mangrove conservation would be particularly beneficial and the irrigation benefits from preserving river base flows and preventing an increase in peak floods, by means of catchment protection, would be high. The unquantifiable ecological and social benefits would also be substantial.