環境擾動與生物多樣性影響翡翠水庫浮游植物生質量之穩定性

一方面，生物多樣性被認為能維持生態穩定性，儘管有些爭議圍繞在物種豐度和物種均勻度的影響。另一方面，由極端氣候事件造成的擾動會降低生態穩定性。我使用翡翠水庫從1999年12月到2013年11月的每月浮游植物時間序列資料，檢測生物多樣性和擾動對生態穩定性的影響。我假設越強的擾動會降低生態穩定性，而越高的生物多樣性則會提升生態穩定性。我使用不重疊的每三個月的視窗(即每個季節)進行調查。為了測試假說，我以每一季節的浮游植物總生質量的變異係數(Coefficient of variation)當作是不穩定指標(proxy of instability)；使用三個月平均的生物多樣性指數包含物種豐度、香儂多樣性指數(Shannon-Wiener index of diversity)和皮洛均勻度指數(Pielou’s evenness index)檢測生物多樣性的效應；使用每一季節的降雨量、表層水溫、表層營養鹽和表層濁度的平均與變異係數評估擾動的效應。我使用廣義混合線性模型(Generalized linear mixed-effect model)，檢測浮游植物總生質量的變異係數與擾動及生物多樣性之間的關係，並把季節當作隨機因子(random effect)，避免得到的統計結果單純是因為季節變異所造成的。我發現浮游植物總生質量在高物種豐度和低溫度變化時較穩定，但生物多樣性和擾動之間的交互作用是不顯著的。此外，在翡翠水庫系統中，溫度變化的效應在影響浮游植物穩定性上比物種豐度更重要。本篇的貢獻是使用野外長期的時間資料，發現擾動和生物多樣性的交互作用影響浮游植物總生質量的穩定性是不存在的。

關鍵字

生物多樣性；擾動；穩定性；浮游植物生質量；翡翠水庫

並列摘要

On the one hand, biodiversity has been suggested to maintain ecological stability, although some debates surround on species richness versus evenness effects. On the other hand, disturbances as a result of extreme weather events were found to destabilize ecosystems. Here, using monthly data of phytoplankton community and environmental variables in Feitsui Reservoir from December 1999 to November 2013, I examined the effects of biodiversity and disturbance on ecological stability. I hypothesized that a higher level of disturbance results in lower ecological stability, whereas a higher level of biodiversity promotes stability. Specifically, I used a non-overlapping window of three-month data (i.e. one season) for investigation. To test the hypotheses, I used coefficient of variation (CV) of phytoplankton total biomass at community level in each season as a proxy for instability, examined biodiversity effects using the average of three months diversity indices including species richness, Shannon-Wiener index of diversity, and Pielou’s evenness index, and evaluated disturbance effects using mean and CV of precipitation, water temperature, nutrients and turbidity at the surface layer in each season. I then used generalized linear mixed-effect model (GLMM) to examine the relationship between phytoplankton stability versus biodiversity and disturbance, with season as random effect to avoid spurious results that simply arise due to seasonality. I found that the phytoplankton biomass was more stable with a higher level of species richness as well as a lower level of CV of temperature, whereas the interaction was not significant. Moreover, effect of CV of temperature was stronger than species richness on affecting phytoplankton biomass stability in Feitsui Reservoir. The contribution of this study was to suggest that the interactive effect of disturbance and biodiversity on phytoplankton stability may not exist by using long-term data in natural system.

並列關鍵字

biodiversity ； disturbance ； stability ； phytoplankton biomass ； Feitsui Reservoir

參考文獻

Akaike, H. (1974). A new look at the statistical model identification. IEEE Transactions on Automatic Control, 19(6), 716-723.

American Public Health Association (APHA), American Water Works Association, Water Environmental Federation. (1998). Standard Methods for Examination of Water and Wastewater, 20th ed. Washington, DC.

Breslow, N. E., & Clayton, D. G. (1993). Approximate inference in generalized linear mixed models. Journal of the American statistical Association, 88(421), 9-25.

Chen, C. S., Chen, Y. L., Liu, C. L., Lin, P. L., & Chen, W. C. (2007). Statistics of heavy rainfall occurrences in Taiwan. Weather and Forecasting, 22(5), 981-1002.

Cottingham, K. L., Brown, B. L., & Lennon, J. T. (2001). Biodiversity may regulate the temporal variability of ecological systems. Ecology letters, 4(1), 72-85.

國際替代計量

環境擾動與生物多樣性影響翡翠水庫浮游植物生質量之穩定性

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