TY - JOUR
T1 - Growth stress response to sea level rise in species with contrasting functional traits
T2 - A case study in tidal freshwater forested wetlands
AU - Zhai, Lu
AU - Krauss, Ken W.
AU - Liu, Xin
AU - Duberstein, Jamie A.
AU - Conner, William H.
AU - DeAngelis, Donald L.
AU - Sternberg, Leonel d.S.L.
N1 - Funding Information:
We thank the Department of Biology at the University of Miami for providing the equipment and funding to LZ for this study. LZ and DLD were supported in part by the Greater Everglades Priority Ecosystem Science Program administered by U.S. Geological Survey. WHC and JAD were supported in part by the National Institute of Food and Agriculture, U.S. Department of Agriculture , under project number SC-1700531 and Technical Contribution No. 6674 of the Clemson University Experimental Station. Additional research support and site accessibility, respectively, was provided by the U.S. Geological Survey, Land Change Science Research & Development Program and the U.S. Fish and Wildlife Service, Waccamaw National Wildlife Refuge. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/11
Y1 - 2018/11
N2 - With rising sea levels, mortality of glycophytes can be caused by water and nutrient stress under increasing salinity. However, the relative effects of these two stressors may vary by species-specific functional traits. For example, deciduous species, with leaves typically emerging during low salinity periods of the year, may suffer less from water stress than evergreen species. We sampled two woody species with contrasting functional traits: the evergreen and N2-fixing waxmyrtle (Morella cerifera), and the deciduous and non-N2 fixing baldcypress (Taxodium distichum) along a coastal river (South Carolina, USA) showing an increasing pattern of plant mortality along a salinity gradient. We first analyzed oxygen and hydrogen isotope ratios of plant stem water and river water to determine changes in plant source water at different sites. Then we analyzed foliar carbon and nitrogen isotope ratios (δ13C and δ15N) along with nitrogen and phosphorous content (%N and %P) as proxies for the water and nutrient stress. Results showed that: (1) the two species had different water sources at the higher salinity sites; (2) foliar δ15N values of baldcypress decreased with higher salinity while retaining a constant δ13C value, and both of these isotope values were positively related with foliar %P, suggesting greater nutrient stress but minor water stress under high salinity; and (3) foliar δ13C values of waxmyrtle increased with higher salinity while retaining a constant foliar δ15N value, and neither of the values was significantly related to foliar nutrients, suggesting greater water stress but minor nutrient stress under high salinity. The different responses of the two species to high salinity may be related to their differences in leaf phenology and N2-fixation. Our results suggest that nutrient stress, particularly of P, can contribute to stress and eventual high mortality of baldcypress exposed to salt water intrusion.
AB - With rising sea levels, mortality of glycophytes can be caused by water and nutrient stress under increasing salinity. However, the relative effects of these two stressors may vary by species-specific functional traits. For example, deciduous species, with leaves typically emerging during low salinity periods of the year, may suffer less from water stress than evergreen species. We sampled two woody species with contrasting functional traits: the evergreen and N2-fixing waxmyrtle (Morella cerifera), and the deciduous and non-N2 fixing baldcypress (Taxodium distichum) along a coastal river (South Carolina, USA) showing an increasing pattern of plant mortality along a salinity gradient. We first analyzed oxygen and hydrogen isotope ratios of plant stem water and river water to determine changes in plant source water at different sites. Then we analyzed foliar carbon and nitrogen isotope ratios (δ13C and δ15N) along with nitrogen and phosphorous content (%N and %P) as proxies for the water and nutrient stress. Results showed that: (1) the two species had different water sources at the higher salinity sites; (2) foliar δ15N values of baldcypress decreased with higher salinity while retaining a constant δ13C value, and both of these isotope values were positively related with foliar %P, suggesting greater nutrient stress but minor water stress under high salinity; and (3) foliar δ13C values of waxmyrtle increased with higher salinity while retaining a constant foliar δ15N value, and neither of the values was significantly related to foliar nutrients, suggesting greater water stress but minor nutrient stress under high salinity. The different responses of the two species to high salinity may be related to their differences in leaf phenology and N2-fixation. Our results suggest that nutrient stress, particularly of P, can contribute to stress and eventual high mortality of baldcypress exposed to salt water intrusion.
KW - N-fixation
KW - Nutrient stress
KW - Phenology
KW - Plant functional trait
KW - Salinity
KW - Sea level rise
KW - Stable isotope
KW - Taxodium distichum
KW - Water stress
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U2 - 10.1016/j.envexpbot.2018.07.023
DO - 10.1016/j.envexpbot.2018.07.023
M3 - Article
AN - SCOPUS:85050931915
VL - 155
SP - 378
EP - 386
JO - Environmental and Experimental Botany
JF - Environmental and Experimental Botany
SN - 0098-8472
ER -