Vegetation dynamics and soil water balance in a water-limited Mediterranean ecosystem on Sardinia, Italy

Abstract

Mediterranean ecosystems are commonly heterogeneous savanna-like ecosystems, with contrasting plant functional types (PFTs, e.g. grass and woody vegetation) competing for water. Mediterranean ecosystems are also commonly characterized by strong inter-annual rainfall variability , which influences the distributions of PFTs that vary spatially and temporally. An extensive field campaign in a Mediterranean setting was performed with the objective to investigate interactions between vegetation dynamics, soil water budget and land-surface fluxes in a water-limited ecosystem. Also a vegetation dynamic model (VDM) is coupled to a 3-component (bare soil, grass and woody vegetation) Land surface model (LSM). The case study is in Orroli, situated in the mid-west of Sardegna within the Flumendosa river basin. The landscape is a mixture of Mediterranean patchy vegetation types: trees, including wild olives and cork oaks, different shrubs and herbaceous species. Land surface fluxes, soil moisture and vegetation growth were monitored during the May 2003-June 2006 period. Interestingly , hydrometeorological conditions of the monitored years strongly differ, with dry and wet years in turn, such that a wide range of hydrometeorological conditions can be analyzed. The coupled VDM-LSM model is successfully tested for the case study, demonstrating high model performance for the wide range of eco-hydrologic conditions. Results demonstrate also that vegetation dynamics are strongly influenced by the inter-annual variability of atmospheric forcing, with grass leaf area index changing significantly each spring season according to seasonal rainfall amount.

Forty-Four Years of Land Use Changes in a Sardinian Cork Oak Agro- Silvopastoral System: A Qualitative Analysis

“…It grows commonly in low-calcium soils, whose main constituent is silica [31]. Thus, on the basis of its ecological requirements cork oak may be defined as a thermophilous, hygrophilous, drought-tolerant, heliophilous species [32]. Winter cold is the most limiting factor for its spreading to the more continental interior zones [33].…”

Vegetation dynamics and responses to climate anomalies in East Africa

“…In a study by Ford and Quiring (2013), LAI was used to estimate the effects of dynamic inter-annual vegetation conditions on soil moisture, and they recommended that dynamic, rather than static, LAI parameters should be used to provide better estimates of intensity and duration of drought conditions. Global and regional studies on the causes of variations in vegetation have shown that climatic factors, particularly precipitation and temperature, significantly influence vegetation dynamics (Jiapaer et al, 2015;Liu et al, 2015;Montaldo et al, 2008;20 Tagesson et al, 2015). For instance, Tagesson et al (2015) reported a strong link between inter-annual variation in species composition and rainfall distribution in a semiarid savanna grassland study site in West Africa region.…”

Spatio-temporal vegetation dynamics and relationship with climate over East Africa

“…Studies on the causes of variations in vegetation have shown that climatic factors, particularly precipitation and temperature, significantly influence vegetation dynamics (Jiapaer et al, 2015;Liu et al, 2015;Montaldo et al, 2008;Tagesson et al, 2015). For instance, Tagesson et al (2015) reported a strong link between inter-annual variation in species composition and 25 rainfall distribution in a semiarid savanna grassland study site in West Africa region.…”