Temporal variations of macroalgal cover and biomass (wet weight and dry weight) abundance and assemblage structure, and also the relationships between abiotic factors and assemblage structure, were studied in northeastern Taiwan (GPS: 25o06¡¦80¡¨N; 121o54¡¦60¡¨E¡^during 2001-2003. This study also investigated the causes affecting Gelidium natural resource and its management. Twenty-seven families with 67 species (5 families with 13 species for Chlorophyta, 3 families with 8 species for Phaeophyta, 19 families with 46 species for Rhodophyta) were recorded. The dominant species such as Pterocladiella capillacea and Polyopes polyideoides belong to temperate species. Macroalgal coverage, areal biomass, diversity, eveness and assemblage structure during 2001-2003 showed significant temporal changes with year and seasonal variations; however, the seasonal rhythm is changing between years. The seasonal pattern is different between 2001 and 2002/2003, biomass peaked in spring of 2002 and 2003. Pterocladiella capillacea, Polyopes polyideoides, Marginisporum crassissimum, Jania ungulate and Chondrus ocellatus contribute to temporal variations in assemblage structure. The results of multi-variate and uni-variate analysis suggest significant temporal variations in macroalgal assemblage structure in northeastern Taiwan, and the data from ANOSIM and SIMPER analysis demonstrated that the seasonal pattern was variable between years, in which it is coincident with seasonal variations in macroalgal abundance. Water temperature, summer high temperature, winter low temperature, nutrient and typhoon are attributable to temporal variations in macroalgal assemblage structure.
Low temperature in winter, nutrient availability, and also typhoon restrict the natural resource of Gelidium in northeastern Taiwan; it is hypothesized that low P condition together with enhanced collection deep the decline of Gelidium resource, finally limiting the recovery of Gelidium population in next year. We found that the agar contents of Pterocladiella capillacea showed year and season variations with a negative relationship to biomass. Temporal fluctuations in agar contents was enhanced by low temperatures and high P but decreased by high N. Based on the observations, we conclude that over-collection in winter results in a decline of Gelidium resource in the coming years, thus it could be suggested that winter collection has to be controlled to maintain the sustainable utilization of Gelidium in northeastern Taiwan.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0624105-132206 |
| Date | 24 June 2005 |
| Creators | Hwang, Jui-lien |
| Contributors | Tse-min Lee, Kwang-Tsao Shao, Kuo-tien Lee |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0624105-132206 |
| Rights | not_available, Copyright information available at source archive |
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