Diversity and vegetation analysis in Delta Island, Lumbocan, Butuan city, Agusan Del Norte, Philippines
By: Chennie L. Solania, Laurence B. Calagui
Key Words: Vegetation Analysis, Delta, Importance value.
J. Bio. Env. Sci. 9(1), 400-409, July 2016.
Vegetation analysis is a way to study species composition and structure of a plant community. At the mouth of the Agusan River, two deltas was formed through the accumulation of silt, sand and mud over years. The main island “Isla Noah” is a densely vegetated delta. Four 50 meter transect lines with a width of 5 meters each were established in the Delta Island. A total of 17 species of plants belonging from 11 families were observed. The most encountered plant species in all transect lines includes: Saccharum spontaneum, Paspalum conjugatum, Phragmites vulgaris, Ipomoea pescaprae and an unidentified Fabaceae plant. In terms of plant habit, trees (4.5 ± 1.19) dominated the area while the least observed species was the graminoids (3.25 ± 0.5). The only threatened species observed in the area was the Avicennia lanata. Species dominance is low (0.20) and species evenness (0.58) is moderate. Overall species diversity is also low (2.03) because floral community were most likely to be similar in all transects. Overall grass cover ranges from rare to frequent. Using braycurtis similarity matrix, transect 2 and 3 had a 0.80 similarity. The most important species as calculated in the importance value was Ipomoea pescaprae (28%) followed by Cocos nucifera (9%) and Terminalia catappa (8%). These species were accordingly most important since they were abundant and frequently encountered. Since the area harbors a vulnerable species and provides habitat to many arthropods, insects, mammals, reptiles and birds, the area needs to be protected. Long-term sustainable plan for the stabilization of the banks is necessary to prevent the soil in cascading.