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Tapping another water source: below ground competition between lianas and trees

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HAL Id: hal-02796283

https://hal.inrae.fr/hal-02796283

Submitted on 5 Jun 2020

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L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de

Tapping another water source: below ground competition between lianas and trees

Hannes de Deurwaerder, Pedro Hervé-Fernández, Clement Stahl, Damien Bonal, Pascal Boeckx, Hans Verbeeck

To cite this version:

Hannes de Deurwaerder, Pedro Hervé-Fernández, Clement Stahl, Damien Bonal, Pascal Boeckx, et al.. Tapping another water source: below ground competition between lianas and trees. EGU General Assembly 2016, Apr 2016, Vienne, Austria. 20 p. �hal-02796283�

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Tapping another source: below ground 

water competition between lianas & trees

H. De Deurwaerder

P. Hervé‐Fernández

C. Stahl

D. Bonal

P. Boeckx

H. Verbeeck

(3)

Framework

Setup      Results       Conclusion

• Land‐cover change • Forest fragmentation

• Atmospheric CO2 increase

(4)

Framework

Setup      Results       Conclusion

HYPOTHESIS:

“There is strong below ground competition for the same water resources between  lianas and trees”

(5)

x

O

x

H

Framework

Setup      Results       Conclusion

(6)

Framework

Setup      Results       Conclusion

Dual isotope‐based studies: δ18O & δ2

δ 2 H   δ18O Precipitation Streams Ground water Ocean Evaporated water

(7)

Framework

Setup      Results       Conclusion δ 2 H   δ18O ‐15 ‐1 ‐1 ‐60 Ocean

(8)

Framework

Setup      Results       Conclusion δ 2 H   δ18O ‐15 ‐1 ‐1 ‐60 Enrichment of heavier water 

molecules

(1,1H

2180, 1,2H2180)

Soil evaporation line More strongly

bound water

(9)

Literature states: 

Framework

Setup      Results       Conclusion No  fr actiona tion δ 2 H   δ18O ‐15 ‐1 ‐1

Soil evaporation line

Soil evaporation Isotopic signature water taken up 

by roots = 

Isotopic signature xylem

Dual isotope‐based studies: δ18O & δ2

(10)

Diapositive 8

H7 3XWVRLOZDWHUILJXUHVPRUHDQG

(11)

Framework

Setup      Results       Conclusion δ 2 H   δ18O Water source

Our hypothesis

Soil evaporation line

‐15 ‐1

‐1

‐60

LIANAS

TREES

(12)

Framework      

Setup

Results       Conclusion 10 Period: ƒ Oct. 2015 Catchments:  ƒ White Sand (Sand)  ƒ Oxysol (Clay) Soil samples:

ƒ 6 soil cores per catchment

ƒ 0.1‐0.2‐0.3‐0.45‐0.6‐0.9‐1.2‐1.8m Tree samples:

ƒ cored xylem samples Liana samples:

(13)

δ 2 H  [in  ‰,  VS M O W ]

Framework      Setup      

Results

Conclusion

(14)

Framework      Setup      

Results

Conclusion δ 2 H  [in  ‰,  VS M O W ] δ18O [in ‰, VSMOW]

Lianas

Trees

Lianas

Trees

(15)

Framework      Setup      

Results

Conclusion

SLEL = 2.8

(16)

Diapositive 13

H5 5YDOXHVELMOLMQHQ

(17)

Framework      Setup      

Results

Conclusion δ 2 H  [in  ‰,  VS M O W ]

Lianas

Trees

Stream

Lianas

Trees

Stream

(18)

Framework      Setup      

Results

Conclusion δ 2 H  [in  ‰,  VS M O W ] Projected δ2H a a b a b a b b

(19)

Framework      Setup      

Results

Conclusion

Plausible explanation lies in seasonal replenishment of water compartments

Suzini data δ 2 H  [in  ‰,  VS M O W ] Rain fa ll [mm/mon th] Year: 1995

(20)

Framework      Setup      

Results

Conclusion a a a a All water  evaporated

Backtracking extractable range

(21)

Framework      Setup      

Results

Conclusion

(22)

19

Framework      Setup      Results       

Conclusion

ƒ Lianas and trees tap different precipitation water 

source, with lianas tapping heavier water

ƒ Different isotopic singature in lianas and trees might be linked to seasonaly replenishment of specific water compartments

ƒ Trees seem to have a broader extractable range  (mobile‐static water)

Æprobably linked to the interaction with mycorrhizae

ƒ Dual isotope study is a usefull and easy practice in  ecohydrology studies and understanding

(23)

Framework      Setup      Results       Conclusion

Thanks for your attention,

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