Floristic diversity of major river systems in Zamboanga del Norte
Paper Details
Floristic diversity of major river systems in Zamboanga del Norte
Abstract
Riparian ecosystems are biologically diverse and ecologically important, yet floristic inventories remain limited in many Philippine river systems. This study assessed the diversity, composition, conservation status, and economic uses of riparian flora in the seven major river systems of Zamboanga del Norte, Philippines. A field survey was conducted from May to December 2021 using a descriptive quantitative biodiversity assessment with a quadrat-based sampling design. Fifty-four sampling stations were established across upstream, midstream, and downstream sections of the rivers. Trees were inventoried using 10 × 10 m quadrats, while shrubs, herbs, and weeds were assessed within 1 × 1 m nested subplots. Species diversity was evaluated using the Shannon–Wiener Diversity Index (H′), while relative abundance, dominance, and Importance Value Index (IVI) were calculated to determine species ecological significance. A total of 152 plant species representing 63 families and 3,388 individuals were documented, including 133 angiosperm species and 19 pteridophyte species. Cocos nucifera exhibited the highest Importance Value Index in most river systems, indicating its ecological dominance. The study identified one endangered species (Shorea astylosa) and four vulnerable species (Dracontomelon dao, Shorea contorta, Diospyros discolor, and Pterocarpus indicus). Approximately 46% of the recorded species possess economic value as sources of timber, food, medicine, fuelwood, raw materials, and feed supplements. These findings provide essential baseline data for biodiversity monitoring and highlight the need to strengthen riparian conservation, ecological restoration, and sustainable land-use management to protect threatened plant species and maintain the ecological integrity of Zamboanga del Norte’s major river systems.
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Copyright © 2026 by the Authors. This article is an open access article and distributed under the terms and conditions of the Creative Commons Attribution 4.0 (CC BY 4.0) license.