Volume 19 Nos. 1 & 2

Assessment of community vulnerability to environmental changes in Caliraya Watershed, Laguna, Philippines


Vulnerability assessment of Caliraya Watershed was conducted to assess the degree of impacts of environmental changes in relation to social, economic, and biophysical attributes together with the coping mechanisms of the community to reduce such impacts.

A total of 367 randomly selected respondents from five direct-impact study sites were interviewed. The survey revealed that the communities living in the watershed are highly vulnerable to social, economic, and biophysical stressors due to environmental changes such as conversion of land use to agricultural farming and kaingin cultivation, increasing charcoal production, in-migration of landless families, and economic activities of resorts and rest houses, among others.

High level of social vulnerability was due to lack of knowledge on tenure system, unmet basic needs of the family, and susceptibility to hazards that greatly affect their wellbeing. Economy in terms of income, livelihood, employment, and agricultural productivity for home consumption was highly vulnerable due to environmental changes. The very high biophysical vulnerability is perceivably brought about poor management and overexploitation of the natural resources in the watershed.

Overall assessment of the respondents showed that the community was highly vulnerable to environmental changes. Results of the study opened up significant issues and concerns that need immediate action, particularly on the coping mechanisms to mitigate and reduce the vulnerability of the community.



Tree species composition and physiognomy of Kinabuhayan River riparian zones, Mt. Banahaw-San Cristobal Protected Landscape


The study was conducted to determine the tree species composition and physiognomy of Kinabuhayan River riparian zones, Mt. Banahaw-San Cristobal Protected Landscape in Quezon Province. Specifically, it aimed to determine the dominant species association, species richness, and forest structure of the area as influenced by trees. Quadrat sampling technique of vegetation analysis showed that there were 37 families represented by 59 genera, 75 species, and 783 individuals. The dominant species associations at different elevations were composed of families represented by species thriving typically in primary forest along streams and moist areas at low and medium altitudes.

The area is diverse but there was no complete similarity on species composition between and among elevations. In terms of physiognomic characteristics, smaller diameter classes dominated the trees in the area emphasizing that it is on its late succession stage and still in dynamic phase of development.



Survey of marine turtle nesting sites in the Philippines


Three of the five species of endangered marine turtles nest in coastal areas around the Philippines. The green turtles (Chelonia mydas) nest in white sandy beaches of Turtle Islands, Tawi-Tawi; the hawksbills (Eretmochelys imbricata) nest in coral rubbles along the coast of Misamis Oriental, Davao del Sur, Oavao del Norte, and Surigao del Sur while the olive ridleys (Lepidochelys olivacea) nest in metallic gray sandy beaches of Bataan, Zambales, and Batangas. Joint DENR and Local Government Units (LGUs) conservation and protection activities were carried out in the said nesting beaches. The LGU of Davao City has initiated the establishment of the nesting beach at Punta Dumalag, Matina Aplaya, Davao City as a critical habitat of the critically endangered hawksbill turtles. The Provincial Government of Zambales declared the whole coasts of Zambales as critical habitat for the olive ridley turtles.

In the 1980s, the identified marine turtle nesting sites declared as marine turtle sanctuaries were solely managed by the DENR. In 2001, the DENR tapped the assistance of LGUs in managing the confirmed nesting beaches.



Seed health testing of bungalon (Avicennia marina) and api-api (A. officinalis) from Southern Luzon mangrove areas


Seed health testing using blotter test was conducted to detect and identify insects and fungi associated with seeds of bungalon (Avicennia marina) and api-api (A. officinalis) collected in four sites/ namely: San Juan and Lian, Batangas; Pagbilao, Quezon; and Las Piñas City, Metro Manila.

The most commonly observed seed-feeding insects were the fruit fly (Bactrocera umbrosa Fabricius), snout beetle (Coleoptera: Curculionidae), plume moth (Stenoptilodes sp.), noctuid moth (Lepidoptera: Noctuidae), and tineid moth (Lepidoptera: Tineidae). Important morphological characters of these five insect species were described and their host ranges/ economic importance, and nature of damage were listed.

On seed pathogens/ three fungi were observed infecting the seeds of bungalon collected in Las Piñas City. These were Curvularia sp., Fusarium solani, and Aspergillus sp. For api-api seeds collected in Pagbilao, Quezon, Phomopsis sp. was isolated while Aspergillus niger andPenicillium sp. Were found associated with seeds collected from the grounds of San Juan, Batangas.

Correlation analyses of seed germination versus infestation revealed a significant linear relationship for the two species of Avicennia.



Comparison of water quality indices based on benthic macroinvertebrates in the Zwalm River Basin, Belgium*: its potential applicability in Laguna de Bay Watershed, Philippines


Europe has formulated a Europe-wide system for assessing the ecological quality of rivers using benthic macroinvertebrates. To fully strengthen the European Union Water Framework Directive (EU WFD), the AQEM project entitled "Development and Testing of an Integrated Assessment System for the Ecological Quality of Streams and Rivers throughout Europe using Benthic Macroinvertebrates" was studied.

This study aimed to: 1) assess the water quality of the Zwalm River Basin in Belgium based on benthic macroinvertebrates, 2) apply the AQEM assessment system on the Zwalm River Basin for calculating the newly developed AQEM Ecological Quality Class (EQC) and compare their results with the Belgian Biotic Index (BBI), Indice Biologique Globale Normalise France (IBGN), Average Score Per Taxon (ASPT), Biological Monitoring Working Party System (BMWP), diversity and evenness indices, and 3) assess trends between the indices and physico-chemical parameters and hydro-morphological characteristics.

Water quality assessment was done in the 60 sampling sites of the Zwalm River Basin. Based on the newly developed EQC and BBI, the water quality could be assigned as "moderately polluted" in most of the sites, although ASPT and IBGN classified the river basin as "bad" quality. The study further assessed the relationships of the biological parameters through indices measurements via the AQEM assessment system with the physico-chemical and hydro-morphological parameters. Although the results revealed mostly low correlations, it further presented a common pattern showing relations between the indices and the physico-chemical parameters, specifically Ammonium (NH 4 +), dissolved oxygen (DO), chemical oxygen demand (COD), Total Phosporus (Total P), Phosphate (PO4 3-) Total Nitrogen (TotaI N), and conductivity.

To apply the idea of the stressor-specific assessment which will further identify the causes or impacts of different stressors on the community, further studies that would focus on a more refined typology is recommended.