The use of exotic species in reforestations is one of the highly criticized forest policies in the Philippines, mainly due to their perceived negative impacts on biodiversity conservation. To ascertain the influence of exotic plantations on native flora establishments, we inventoried the structure, composition, and diversity of understory woody regeneration in three exotic stands in Southern Philippines and compared them to adjacent second growth forest. The mean total density of regeneration did not differ significantly among the stands, except for the separate density of saplings and seedlings where natural forest had significantly the lowest and highest density, respectively, over the exotic stands. Teak (Tectona grandis L.) and mangium (Acacia mangium Willd.) stands generally had the bigger basal area, indicating the dominance of saplings in these areas. A low diversity characterized the four stands with the lowest and highest diversity indices observed, respectively, in the mahogany (Swietenia macrophylla King) and natural forest. Despite their proximity, each stand exhibited uniqueness in species composition, with some of the endangered species observed only in the exotic stands. Therefore, it would be interesting to know how continued protection of these stands would affect the trajectory of succession of native species over time.
This study aimed to generate a GIS-based flashflood hazard susceptibility map using the geographical information system (GIS) and frequency ratio (FR) techniques in one of the geographically isolated and disadvantaged areas (GIDAs) of the country, which is the barangay Bukang Liwayway of Kibawe, Bukidnon. There are 160 sample points conducted for flashflood inventory to calculate FR and the flashflood prediction weights values needed to generate the flashflood susceptibility map. The elevation, slope, aspect, curvature, topographic wetness index, drainage density, LULC, normalized difference vegetation index, and rainfall are the nine controlling factors that are selected. Results show that the areas exposed to flashflood with low, medium, and high-risk levels of susceptibility consist of 89.8, 4.4, and 5.7% of the total land, respectively, with 25 households exposed to high risk. The study determined the possible site for the evacuation center based on the spatial analysis resulting in the overlaying of different thematic map layers based on flashflood susceptibility factors. The study emphasizes the integration of the findings in the localized comprehensive land-use plan to realize the challenge of building a sustainable and hazard-resilient human community in Bukang Liwayway.
Abstract. The present study was aimed to investigate the occurrence of mycorrhiza in an inland ultramafic mountain ecosystem to determine if the extreme soil conditions associated with high concentrations of toxic heavy metals could deter their presence across various elevation gradients. Twelve (12) sampling plots distributed across the major elevation gradient were used in this study. Soil samples were collected at a depth of 30cm and were analyzed to determine the heavy metal content. The standard protocol in the separation of spores was followed. Spore identification was based on existing literatures. Results revealed four genera of arbuscular mycorrhiza fungi (AMF) which includes Glomus, Acaulospora, Scutellospora and Entrophospora. Among the four genera, Glomus was the most abundant and widespread comprising of 40 species while Acaulospora sp. and Entrophospora sp. were the least observed. Further, no significant correlation was observed between mycorrhizal spore count to nickel and chromium implying that these heavy metals did not significantly affect the occurrence and distribution of mycorrhiza. However, a similar pattern of decreasing spore count with increasing elevation was also observed in comparison to tropical mountain forest ecosystems with normal soil conditions.
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