Threat of Potential Bioinvasion in a Natural Forest in Poitan, Banaue, Ifugao, Cordillera Administrative Region
Nestor T. Baguinon1,3 and Jacqueline Miel2
1Professor, Department of Forest Biological Sciences,
College of Forestry and Natural Resources,
University of the Philippines Los Baños, College, Laguna
2Licensed Forester Research Assistant, University of the Philippines Los Baños
3Regular Member, National Research Council of the Philippines,
DOST Complex, Bicutan, Taguig City
Enumeration of a natural forest (muyong) coupled to rice terraces (payoh) in Poitan, Banaue, Ifugao resulted in the recognition of three types of vegetation after raw data from 22 plots composed of importance values of tree species were analyzed and subjected to Polar Ordination Analysis and Principal Component Analysis. The three clusters were named according to their most dominant species, namely Pinus kesiya cluster, Vaccinium whitfordii cluster, and Clethra tomentella-Swietenia macrophylla cluster. Shannon-Wiener Diversity Indices (H) of 22 plots were determined and results show that Pinus plots had lower H values compared with both Vaccinium and Clethra-Swietenia H values. This is attributed to the greater shade in Pinus plots as the pine trees there are large with bigger crowns. In the two other clusters, more light reaches the forest floor allowing a diverse recruitment of light demanding tree taxa. Two of the three alien tree taxa, Large Leaf Mahogany Swietenia macrophylla and Yemane Gmelina arborea. are definitely introduced. However, the presence of a third alien tree species, Japanese Alder Alnus japonica, in the muyong is uncertain if it was also purposely introduced in the forest study area. Visually, this light-demanding wind-dispersed temperate Asian taxon is randomly numerous in open areas, thickets and secondary forests of the Cordillera highlands. The present study and survey will also be replicated in Barangays Amganad and Kinakin, Banaue, Ifugao.
Any or a combination of the following enumerated factors, namely, ecological substitution (refers to man-made ecosystem taking over natural ecosystem leading to the fragmentation of natural forests), overharvesting (e.g. runaway logging and mining etc.), climate change (e.g. global warming induced by anthropogenic greenhouse gases), and bioinvasion (e.g., proliferation plus exclusive competition of exotic species versus native species) could inflict irreversible losses of biodiversity. . . . . . . . . . . . . . . .
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