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| Tamarix water-use along the Cimarron River in south-western, KS | |
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Tamarix species are highly invasive in riparian ecosystems throughout North America and have displaced large areas of native vegetation. Little is known about the primary physiological and growth mechanisms that allow this species to be so highly invasive. We are investigating ways that Tamarix ramosissima may adjust belowground root responses to track the water table over a very short period of time. Increased vertical root growth or activation to catch the water table may be possible from very high and constant photosynthetic rates despite high leaf-level water stress. Growth responses in Tamarix occur rapidly (within weeks), even after prolonged drought and high daily air temperatures. Our work shows that Tamarix rapidly tracks changes in the water table through in root growth, a paradigm which has rarely been shown for any species. Our initial data suggests the plasticity and robustness of Tamarix ramosissima allows this species to respond dynamically to changes in water availability, and maintain high levels of productivity even if droughts become more prominent with future climate changes. |
| Tamarix outside Ashland, KS (approx. 8' tall), groundwater well (blue post) and a leaf gas exchange system (LI-6400 on tripod). | |
Future work will assess the feedbacks of Tamarix water use with climate variability and water availability. Specific objectives of proposed research are to: (1) Isolate the role of Tamarix evapotranspiration on groundwater fluctuations and relate these variations to driving climate variables; (2) Conduct multi-scale evapotranspiration measurements to derive scaling relationships from leaf to community; and (3) Synthesize groundwater fluctuations and scaling relationships with remotely sensed observations to examine impacts of land cover and climate changes on Tamarix expansion. This proposed research will provide detailed assessments of water consumption and changes in distribution by Tamarix based on future climate predictions. This research is timely considering predictions of reduced water availability for human, agricultural, and environmental consumption in a drier future climate. |
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| The Cimarron River, varies from extreme drought (left photo: 2006) to flood (right photo: 2007). The ability of riparian vegetation (namely Tamarix) to respond to these extremes and subsequently drive the hydrological cycle provides the context for our work | |