BIBLIOS

Document type
Journal articles

Document subtype
Full paper

Title
Water use partitioning of native and non‐native tree species in riparian ecosystems under contrasting climatic conditions

Participants in the publication
Elena Granda (Author)
Cristina Antunes (Author)
cE3c/FCUL
Cristina Máguas (Author)
Dep. Biologia Vegetal
cE3c
Pilar Castro‐Díez (Author)

Summary
One of the suggested mechanisms behind the success of non-native plants in recipient ecosystems is competition avoidance with natives by means of different resource-use strategies, such as deeper water uptake under dry conditions.\nWe aimed at evaluating water source partitioning between native and non-native tree species coexisting in central Spain floodplains; determining the dependency on drought stress of such water sources use; and assessing if the reliance on deeper water sources relates with physiological and growth performance.\nWe assessed water uptake depth, leaf functional traits related to physiological performance and growth of native (Populus alba) and non-native trees (Ailanthus altissima, Robinia pseudoacacia) coexisting in riparian forests under different drought conditions (drier, intermediate and wetter). We analysed δ2H and δ18O isotopes in xylem water and in soil water from top, mid and deep soil depths and determined the contribution of each water source to overall plant xylem water. Leaf traits related with resource use and secondary growth were assessed for each species.\nWe found stronger differences between sites than between species, with all species taking more deep water in the driest site (~45% of the xylem water) than in the wettest (~15%). However, under drier conditions, species differences were significant for top-soil water use, with R. pseudocacia withdrawing more superficial water (~22%) than A. altissima (~8%). These results indicate stronger water partitioning under drier conditions. Non-native species showed a physiological strategy characterized by greater leaf N, water content, and enriched δ13C and δ15N values independently of the deep-water uptake. However, a positive relationship between deep soil water use and such strategy was found for P. alba.\nWe highlight that those native and non-native species differences were more evident regarding physiological performance at leaf level than for deep-water uptake or growth. Furthermore, our results suggest that differences in water sources used by coexisting species may increase under drier conditions.


Where published
Functional Ecology

Publication Identifiers
ISSN - 0269-8463

Publisher
Wiley



Document Identifiers
DOI - https://doi.org/10.1111/1365-2435.14149
URL - http://dx.doi.org/10.1111/1365-2435.14149

Keywords
drought growth nice segregation non-native trees physiological performance riparian ecosystems water isotopes