On the transpiration of wild olives under water-limited conditions in a heterogeneous ecosystem with shallow soil over fractured rock

Abstract

Mediterranean ecosystems are typically heterogeneous and savanna-like, with trees and grass competing for water use. By measuring sap flow, we estimated high transpiration of wild olive, a common Mediterranean tree, in Sardinia despite dry conditions. This estimate agrees with independent estimates of tree transpiration based on energy balance, highlighting the wild olive’s strong tolerance of dry conditions. The wild olive can develop an adaptation strategy to tolerate dry conditions. In this Sardinian case study, the wild olive grew in shallow soil, and the tree roots expanded into the underlying fractured basalt. The trees survived in dry periods using water infiltrated during wet seasons into fractured rocks and held in soil pockets. We estimated a high upward vertical flux through the bottom soil layer from the underlying substrate, which reached 97% evapotranspiration in August 2011. The water taken up by tree roots from bedrock hollows is usually neglected in ecohydrological modeling.

Climate Change Impacts on the Water Resources and Vegetation Dynamics of a Forested Sardinian Basin through a Distributed Ecohydrological Model

“…Future scenarios predict a decrease in the mean annual precipitation (MAP) from ~810 mm in the recent 2001−2020 period to ~690−790 mm in the future (varying according to the representative concentration pathways scenarios of HadGEM2-AO), which could still be sufficient MAP values for sustaining the actual tree cover density in the basin. Sankaran et al (2005) [34], Yang et al (2016) [128], Axelsson and Hanan (2017) [35] and Corona and Montaldo (2020) [129] identified a MAP threshold of ~650−700 mm under which woody cover development becomes directly limited by rain in semi-arid ecosystems. In this Sardinian basin, future hydrological scenarios seem to still satisfy tree water needs to the limit: in the future scenarios, the rock moisture is predicted to further decrease on average by up to 10%, highlighting the achievement of a dangerous borderline condition, below which the underlying root-zone reservoir could no longer sustain tree water needs.…”

Modeling water balance components of conifer species using the Noah-MP model in an eastern Mediterranean ecosystem

“…Evapotranspiration, which is a combination of evaporation from soil and vegetation and transpiration from vegetation, plays a crucial role in the terrestrial water cycle (Zhan et al, 2019) and is recognized as the most determinative component of the water balance in Mediterranean ecosystems (Corona and Montaldo, 2020). Evapotranspiration is controlled by atmospheric demand and water availability, which are in turn influenced by climate, vegetation, and soil conditions (Wang et al, 2015).…”

Tree morphology dependent transpiration reduction function of Schefflera arboricola for landfill cover restoration

“…In recent times, plants are subjected to excessive drought stress due to climate change (Corona and Montaldo, 2020;Findlay et al, 2020;Leštianska et al, 2020). Past studies (Balashov et al, 2021;Moore, et al, 2010;Pochodyła et al, 2022;Šimanský and Šrank, 2021) have employed drought mitigation approaches utilizing nutrients, biochar, and chemical surfactants Root embolization or root death due to excessive drought stress can have drastic effects on the functioning of geoenvironmental infrastructure such as landfill covers, and mining sites post closure of operations.…”