Seasonal variation in water sources of the riparian tree species Acer negundo and Betula nigra, southern Appalachian foothills, USA
| Autor: | William K. Smith, Joseph C. White |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Botany. 93:519-528 |
| ISSN: | 1916-2804 1916-2790 |
| DOI: | 10.1139/cjb-2015-0003 |
| Popis: | Determining which water sources a plant accesses throughout a year is an important step in understanding how changes in source characteristics affect utilization by plants. Water sources of Acer negundo L. and Betula nigra L. of the foothills of the southern Appalachians Mountains were examined during one full year, including the phenological stages of leaf bolt, flowering, and leaf senescence and abscission. Source utilization was monitored, comparing the isotopic composition of water samples from woody tissue with those of possible water sources at the site. Species used deep ground and shallow soil water, with a greater reliance on deeper sources during the late growing season. Betula nigra was typically more depleted in δ2H than all water sources measured, while values from A. negundo were more variable throughout the study. Intraspecifically, isotopic values did not vary monthly or seasonally for either species (P > 0.56), while interspecific values were different for December, January, and July samplings (P < 0.02). Positive relationships occurred between air temperature and isotopic values of both species (P < 0.04), and may reflect increased evaporation from the upper soil layers at warmer temperatures, which both species appeared to use. An inability to sample all sources prevented the application of mixing models and may weaken conclusions. |
| Databáze: | OpenAIRE |
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