TY - JOUR
T1 - Hydraulic traits of co-existing conifers do not correlate with local hydroclimate condition
T2 - a case study in the northern Rocky Mountains, U.S.A
AU - Clute, Tim
AU - Martin, Justin
AU - Looker, Nate
AU - Hu, Jia
N1 - Funding Information:
TC and all related research was supported by National Science Foundation grant number, DEB‐1457720, the Montana National Science Foundation Established Program to Stimulate Competitive Research and the Montana Institute on Ecosystems. Acknowledgment
Funding Information:
TC and all related research was supported by National Science Foundation grant number, DEB?1457720, the Montana National Science Foundation Established Program to Stimulate Competitive Research and the Montana Institute on Ecosystems. The manuscript is to be part of a Special Issue honoring Russ Monson. His true talent is his ability to bridge ecophysiology with many different disparate fields, from plant biochemistry to ecosystem ecology. Russ has always excelled at identifying the pressing and novel scientific questions and creating a comprehensive and creative research plan to address those issues. We would also like to thank Dave Roberts, Yuriko Yano, Chase Dart, Jim Junker, Corinne Moss, and Claire Qubain with help on data collection and helpful discussions.
Publisher Copyright:
© 2021, Springer-Verlag GmbH Germany, part of Springer Nature.
PY - 2021/12
Y1 - 2021/12
N2 - In this study, we examined the inter- and intra-specific variation of hydraulic traits of three conifers of the Northern Rockies: Pinus ponderosa, Picea engelmannii, and Pseudotsuga menziesii to understand the mechanisms that allow different plant species to co-exist across a watershed. We quantified differences in plant xylem water potential (ψx), xylem tissue vulnerability to cavitation (P50, or ψ causing 50% loss of hydraulic conductivity), and safety margins for co-occurring trees from low and high elevations. We then investigated xylem vulnerability to cavitation with rooting depth. We found that xylem vulnerability to cavitation did not correspond to where tree species were found in the landscape. For example, P. ponderosa grew in more xeric locations, while P. engelmannii were largely confined to more mesic locations, yet P. engelmannii had more negative P50 values. P. menziesii had the lowest P50 value, but displayed little variation in vulnerability to cavitation across the hydroclimatic gradient. These patterns were also reflected in the safety margins; P. menziesii had the widest safety margin, P. engelmannii was intermediate, and P. ponderosa displayed the narrowest safety margin. All three species were also using water sources deeper than 30 cm in depth, allowing them to persist throughout the mid-summer drought. Overall, species-specific hydraulic traits did not necessarily follow a predictable response to the environment; instead, a combination of physiological and morphological traits likely allow trees to persist across a broader hydroclimatic gradient than would be otherwise expected from hydraulic trait measurements alone.
AB - In this study, we examined the inter- and intra-specific variation of hydraulic traits of three conifers of the Northern Rockies: Pinus ponderosa, Picea engelmannii, and Pseudotsuga menziesii to understand the mechanisms that allow different plant species to co-exist across a watershed. We quantified differences in plant xylem water potential (ψx), xylem tissue vulnerability to cavitation (P50, or ψ causing 50% loss of hydraulic conductivity), and safety margins for co-occurring trees from low and high elevations. We then investigated xylem vulnerability to cavitation with rooting depth. We found that xylem vulnerability to cavitation did not correspond to where tree species were found in the landscape. For example, P. ponderosa grew in more xeric locations, while P. engelmannii were largely confined to more mesic locations, yet P. engelmannii had more negative P50 values. P. menziesii had the lowest P50 value, but displayed little variation in vulnerability to cavitation across the hydroclimatic gradient. These patterns were also reflected in the safety margins; P. menziesii had the widest safety margin, P. engelmannii was intermediate, and P. ponderosa displayed the narrowest safety margin. All three species were also using water sources deeper than 30 cm in depth, allowing them to persist throughout the mid-summer drought. Overall, species-specific hydraulic traits did not necessarily follow a predictable response to the environment; instead, a combination of physiological and morphological traits likely allow trees to persist across a broader hydroclimatic gradient than would be otherwise expected from hydraulic trait measurements alone.
KW - Conifers
KW - Hydraulic vulnerability
KW - Safety margin
KW - Source water
KW - Water potential
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U2 - 10.1007/s00442-020-04772-z
DO - 10.1007/s00442-020-04772-z
M3 - Article
C2 - 33025266
AN - SCOPUS:85092093909
VL - 197
SP - 1049
EP - 1062
JO - Oecologia
JF - Oecologia
SN - 0029-8549
IS - 4
ER -