Coupling of ecosystem-scale plant water storage and leaf phenology observed by satellite

Feng Tian (1) , Jean-Pierre Wigneron (2) , Philippe Ciais (3) , Jérôme Chave (4) , Jérôme Ogée (2) , Josep Penuelas (5) , Anders Ræbild (6) , Jean-Christophe Domec (2) , Xiaoye Tong (6) , Martin Brandt (6) , Arnaud Mialon (7) , Nemesio Rodriguez‐fernandez (7) , Torbern Tagesson (8) , Amen Al-Yaari (2) , Yann H. Kerr (7) , Chi Chen (9) , Ranga Myneni (9) , Wenmin Zhang (8) , Jonas Ardo (10) , Rasmus Fensholt (8)

1 THU - Tsinghua University [Beijing]
2 UMR ISPA - Interactions Sol Plante Atmosphère
3 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
4 EDB - Evolution et Diversité Biologique
5 CREAF - Centre for Ecological Research and Applied Forestries
6 UCPH - University of Copenhagen = Københavns Universitet
7 CESBIO - Centre d'études spatiales de la biosphère
8 IGN - Department of Geosciences and Natural Resource Management [Copenhagen]
9 Department of Earth and Environment [Boston]
10 Department of Physical Geography and Ecosystem Science [Lund]

Plant water storage is fundamental to the functioning of terrestrial ecosystems by participating in plant metabolism, nutrient and sugar transport, and maintenance of the integrity of the hydraulic system of the plant. However, a global view of the size and dynamics of the water pools stored in plant tissues is still lacking. Here, we report global patterns of seasonal variations in ecosystem-scale plant water storage and their relationship with leaf phenology, based on space-borne measurements of L-band vegetation optical depth. We find that seasonal variations in plant water storage are highly synchronous with leaf phenology for the boreal and temperate forests, but asynchronous for the tropical woodlands, where the seasonal development of plant water storage lags behind leaf area by up to 180 days. Contrasting patterns of the time lag between plant water storage and terrestrial groundwater storage are also evident in these ecosystems. A comparison of the water cycle components in seasonally dry tropical woodlands highlights the buffering effect of plant water storage on the seasonal dynamics of water supply and demand. Our results offer insights into ecosystem-scale plant water relations globally and provide a basis for an improved parameterization of eco-hydrological and Earth system models.

Domaines: Biodiversité et Ecologie; Ecosystèmes

Feng Tian, Jean-Pierre Wigneron, Philippe Ciais, Jérôme Chave, Jérôme Ogée, et al.. Coupling of ecosystem-scale plant water storage and leaf phenology observed by satellite. Nature Ecology & Evolution, 2018, 2 (9), pp.1428-1435. ⟨10.1038/s41559-018-0630-3⟩. ⟨hal-02403104⟩