Complex competitive networks of corals at Buctot and Pinagkiyawan, Calauit Island, Busuanga, Palawan

Date

3-1999

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Lemmuel V. Aragones

Abstract

One-time observation of the interspecific competitions between corals for space revealed that most families (with sofa corals considered as one group) form competitive networks where most of the corals were competitively equivalent. Size and disturbances most likely influence this competition. Three types of competition were considered: overgrowth, overtopping, and digestion. Overgrowth competition occurs when the edge of a coral grows over (winner) another coral (loser). In instances when a coral shades out (winner) an adjacent coral (loser) without any physical contact, the competitive interaction is called overtopping. Digestion or direct aggression by corals was recognized as a white patch of dead tissue (loser) due to the sweeper tentacles or mesenterial filaments of an adjacent coral (winner). Instances of win-lose situations considering these three types of competition and the sizes of the colonies involved were recorded using the line intercept method and with the aid of SCUBA. These observations were carried out at four and ten meter depths at Buctot and Pinagkiyawan, Calauit Island, Palawan, Philippines. The data from the two areas were pooled to increase the sample size for statistical analysis and to conform to the appropriate statistical assumptions. Only the seven most abundant coral groups (sofi corals and hard corals of the families Acroporidae, Dendrophylliidae, Faviidae, Merulinidae, Pocilloporidae, and Poritidae) were used in the data analyses. Majority of the groups had similar win-lose ratios for the three types of competition (Chi-Square Homogeneity test, p>0.05), suggesting that they have the same competitive abilities. One out of five interactions between coral groups tested for relative size effects was significant: big acroporids win most of the time over small faviids at the four meters depth (Chi-Square one-sample test, 20.013). Among the remaining four interactions, three showed trends that bigger corals win over smaller corals (i.e., bigger corals had wins ranging from four to six compared to just one for the smaller species). Using a matrix and the binomial test to examine for significant winners of coral interactions, the overall competitive abilities of the coral

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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