Browsing by Author "Wang, Chiao-Ping"

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    Distinct epiphyte responses to drought in tropical mountain cloud forests
    (Wiley, 2023-10) Tsai, Yi-Chen; Wang, Lixin; Wang, Chiao-Ping; Lin, Teng-Chiu; Earth and Environmental Sciences, School of Science
    Epiphytes are often considered to be significantly impacted by precipitation changes because their lack of direct access to soil water. However, few in situ studies have examined how reduction in water availability may affect epiphyte growth. Using a unique stemflow collection and diversion device, we examined the effects of stemflow reduction of 25% and 50% on the growth and leaf traits of two common but distinct epiphyte species in a subtropical forest. One species (Asplenium nidus) has a large substrate, and another (Haplopteris zosterifolia) without known water storage structure. The 25% stemflow reduction had limited effects on the growth and leaf traits of the two epiphytes, indicating that 25% stemflow reduction did not reach the water stress threshold for the two epiphytes. It is also possible that the actual reduction in water availability was less than 25% since epiphytes do not use all available stemflow and there could be other sources of water such as fog and throughfall. The 50% stemflow reduction reduced leaf number and leaf area of H. zosterifolia, but not A. nidus, likely because water stored in the large substrate of A. nidus mitigated the impact of stemflow reduction. The thinner leaves, smaller leaf dry matter content, and lower δ13C of A. nidus than H. zosterifolia support the role of water storage of the substrate of A. nidus on mitigating water stress. The 50% stemflow reduction increased leaf thickness, leaf dry matter content of H. zosterifolia, and thickness of abaxial cuticle layer of both epiphytes but had no effect on δ13C. Stemflow reduction had no effects on nutrient concentration and nutrient ratios of both epiphytes suggesting that the epiphytes were able to maintain stoichiometry. Our results indicate that the epiphytes minimized nonstomatal water loss when environmental dryness increased but maintained stomata conductance, which could be important in minimizing the impacts of drought on plant growth and quickly resuming growth once drought ends. Our study highlights that not all epiphytes are similarly vulnerable to drought and precipitation reduction may change the relative abundance of epiphytes with and without water storage structure.
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    On the seasonality of long-range transport of acidic pollutants in East Asia
    (IOP, 2022-08-07) Chang, Chung-Te; Wang, Lixin; Wang, Lih-Jih; Liu, Chiung-Pin; Yang, Ci-Jian; Huang, Jr-Chuan; Wang, Chiao-Ping; Lin, Neng-Huei; Lin, Teng-Chiu; Earth and Environmental Sciences, School of Science
    East Asia currently has the largest SO2 and NOx emissions in the world. The long-range transport (LRT) of acidic pollutants in this region is of great concern but the extent is not well understood. Here results from combined long-term (⩾20 years) atmospheric deposition monitoring and air trajectory analysis in East Asia were reported. The results showed that despite the large decrease of SO2 and NOx emissions in Taiwan, annual deposition of non-sea-salt sulfate (nss-SO2−4 ) in northern Taiwan showed no decreasing trend during 1994–2020. However, when divided seasonally, both nss-SO2−4 and nitrate (NO−3 ) deposition had a significant decreasing trend in the summer but not in the winter. Similar patterns were found for Japan and Korea. Air trajectory models in combination with a regional emission map indicate that LRT from eastern China contributed up to 70% of the winter deposition of nss-SO2−4 and NO−3 in Taiwan and up to 50% in Japan and Korea. The results indicate that LRT obscured the efficacy of local pollution control measures in East Asia and suggest that transboundary air pollution regulations are required to combat acid deposition.
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    Precipitation controls on nutrient budgets in subtropical and tropical forests and the implications under changing climate
    (Elsevier, 2017-05) Chang, Chung-Te; Wang, Lih-Jih; Huang, Jr-Chuan; Liu, Chiung-Pin; Wang, Chiao-Ping; Lin, Neng-Huei; Wang, Lixin; Lin, Teng-Chiu; Department of Earth Sciences, School of Science
    Biological, geological and hydrological drivers collectively control forest biogeochemical cycling. However, based on a close examination of recent literature, we argue that the role of hydrological control particularly precipitation on nutrient budgets is significantly underestimated in subtropical and tropical forests, hindering our predictions of future forest nutrient status under a changing climate in these systems. To test this hypothesis, we analyzed two decades of monthly nutrient input and output data in precipitation and streamwater from a subtropical forested watershed in Taiwan, one of the few sites that has long-term nutrient input-output data in the tropics and subtropics. The results showed that monthly input and output of all ions and budgets (output – input) of most ions were positively correlated with precipitation quantity and there was a surprisingly greater net ion export during the wet growing season, indicating strong precipitation control on the nutrient budget. The strong precipitation control is also supported by the divergence of acidic precipitation and near neutral acidity of streamwater, with the former being independent from precipitation quantity but the latter being positively related to precipitation quantity. An additional synthesis of annual precipitation quantity and nutrient budgets of 32 forests across the globe showed a strong correlation between precipitation quantity and nutrient output-input budget, indicating that strong precipitation control is ubiquitous at the global scale and is particularly important in the humid tropical and subtropical forests. Our results imply that climate change could directly affect ecosystem nutrient cycling in the tropics through changes in precipitation pattern and amount.