Macroalgae and aquatic plant biodiversity and productivity between aquaculture and non-aquaculture sites within Taal Lake (Philippines).

Abstract

The integrity of Taal Lake ecosystem has been adversely affected by anthropogenic activities, especially in areas with aquaculture. This study aims to determine and compare the biodiversity and productivity of macroalgae and aquatic plants between aquaculture and nonaquaculture sites. Mean total phosphorus level in water was higher in Bañaga (0.71mg/L) than in Gonzales (0.17mg/L). Chara vulgaris, with an importance value of 0.48, was the most important species in Gonzales. In Bañaga, the most important species was Ceratophyllum c.f. demersum with an importance value of 0.58. Simpson’s index of diversity was also determined, with Gonzales (0.79) being more diverse than Bañaga (0.49). Average chlorophylls a and b contents for all plants were also greater in Bañaga (4.53mg/L and 3.38mg/L) than in Gonzales (3.74mg/L and 2.94mg/L). While physico-chemical parameters of water and sediment have affected the growth and distribution of macroalgae and aquatic plants, the plants themselves have also affected their environment due to their unique characteristics. The most important species for both sites had effects on the other plants that were found in the area, thereby affecting biodiversity. With the high productivity but low biodiversity in Bañaga, the phenomenon called paradox of enrichment was observed. These show that there is a difference in macroalgae and aquatic plant biodiversity and productivity between aquaculture and non-aquaculture sites in Taal Lake.