Soil CO2 Efflux from a Mountainous forest-grassland Ecosystem in Central Taiwan

台灣中部高山森林－草原生態系土壤二氧化碳釋放率

高文媛(Wen-Yuan Kao) ； 章國威(Kuo-Wei Chang)

《Botanical Studies》 50卷3期 (2009/07) Pp. 337-342

摘要

本文比較台灣中部一高山生態系內芒草(Miscanthus transmorrisonensis)覆蓋的草原區，以及主要為鐵杉(Tsuga chinensis var. formosana)覆蓋的森林區白天之土壤呼吸率。從2003年10月起到2004年10月每個月在原地測量其土壤二氧化碳釋放率和土壤溫度。結果發現土壤二氧化碳釋放率和土壤溫度有季節性變化：草原區土壤溫度變化從4 to 16℃，而森林區則從2 to 15℃；白天草原區土壤二氧化碳釋放率從0.6到2.2μmol m^(-2)s^(-1)，森林區則從0.3到1.6μmol m^(-2)s^(-1)；在同一測量時段森林區土壤二氧化碳釋放率皆低於草原區土壤。兩區的土壤二氧化碳釋放率都跟土壤溫度成指數正相關。從土壤二氧化碳釋放率跟土壤溫度迴歸相關推算森林區平均Q10值（當溫度改變10℃時，土壤呼吸率的變化倍數）為3.5高於草原區的2.8；此結果顯示：森林區土壤二氧化碳釋放率對土壤溫度變化的敏感度高於草原區的土壤。

關鍵字

鐵杉 ； 草原 ； Miscanthus transmorrisonensis ； Q10值 ； 土壤二氧化碳釋放率 ； 土壤溫度 ； Tsuga chinensis var. formosana ； 台灣

並列摘要

Daytime soil CO2 efflux from a mountainous forest-grassland ecosystem in central Taiwan was measured approximately monthly from Oct. 2003 to Oct. 2004. The system featured two zones, each dominated by a different vegetation type, one a C4 grass (Miscanthus transmorrisonensis) and the other a hemlock (Tsuga chinensis var. formosana). The relationship between the soil temperature and soil CO2 efflux of these two zones was also investigated, and seasonal patterns in these two variables emerged. Soil temperature in the grassland zone ranged from 4 to 16℃, and in the hemlock zone from 2 to 15℃. The magnitude of the daytime soil CO2 efflux varied from 0.6 to 2.2 μmol m^(-2) s^(-1) and from 0.3 to 1.6 μmol m^(-2) s^(-1) for the grassland and forest zones, respectively. Within the same measuring period, the forest zone had significantly lower soil respiration than the grassland zone. Seasonal changes in the soil CO2 efflux of both zones correlated strongly with soil temperature. The average Q10 values, the factor by which the respiration rate differs for a temperature interval of 10℃, calculated from the exponential relation between soil CO2 efflux and soil temperature, were 3.5 and 2.8 for the forest and grassland zones, respectively. The result indicates that the soil CO2 efflux from the forest zone is more sensitive to changes in soil temperature than that from the grassland zone.

並列關鍵字

Hemlock ； Grassland ； Miscanthus transmorrisonensis ； Q10 value ； Soil CO2 efflux ； Soil temperature ； Tsuga chinensis var. formosana ； Taiwan