Contrasting water strategies of two Mediterranean shrubs of limited distribution: uncertain future under a drier climate

Abstract

Plants have evolved different strategies to cope with drought, involving alternative ecophysiologies and different levels of plasticity. These strategies are critical for species of limited distribution, which are especially vulnerable to the current rates of rapid environmental change. The aim of this study was to assess the water strategy of two species with limited distribution, Cneorum tricoccon L. and Rhamnus ludovici-salvatoris Chodat., and evaluate their interpopulation variability along an aridity gradient to estimate their vulnerability to a drier climate. We measured different ecophysiological traits influenced by drought--stomatal conductance, maximum photochemical efficiency of photosynthesis II, carbon isotope ratio and chlorophyll concentration--in two climatically contrasting years, before and during summer drought. Both species were vulnerable to drought at the aridity limit of the gradient, but showed contrasting water strategies: while C. tricoccon was consistent in its water conservation strategy across the aridity gradient, R. ludovici-salvatoris was not, displaying higher and more variable stomatal conductances and being able to increase water-use efficiency at the most xeric sites. Changes in length and intensity of drought events may favor one species' strategy to the detriment of the other: C. tricoccon is more vulnerable to chronic and prolonged droughts, whereas short but acute droughts might have a stronger effect on R. ludovici-salvatoris. In those communities where these two species coexist, such different strategies might lead to changes in community structure under climate change scenarios, with unknown cascade effects on ecosystem functioning.

Drivers influencing streamflow changes in the Upper Turia basin, Spain

“…forest disturbance and forest management, mortality and succession of vegetation, which are considered as a key challenge for ecohydrology and forest science disciplines (Newman et al, 2006). Finally, a finer scale of analysis and modeling would have allowed to distinguish water strategies under water stress between species (Lázaro-Nogal et al, 2013). Nevertheless, our findings are valuable for gaining understanding on the nexus between water planning and land management in the UTB and by enlargement for the Júcar river basin.…”

Differences in functional and xylem anatomical features allow Cistus species to co-occur and cope differently with drought in the Mediterranean region

“…In fact, it can be hypothesized that apparent differences in water-use strategies could explain the differences in the ecological niches they occupy. Contrasting water-use strategies have been already reported both among co-occurring species, including Mediterranean shrubs, from diverse taxonomic groups (Hernandez et al 2010, Quero et al 2011, MorenoGutierrez et al 2012, Lázaro-Nogal et al 2013 as well as within a single genus (David et al 2007, Tognetti et al 2007. The coexistence of different strategies within a certain area or ecosystem has been typically related to differences in plant functional traits (Filella and Peñuelas 2003).…”

Environmental and species-specific controls on δ13C and δ15N in dominant woody plants from central-western Argentinian drylands

“…Previous studies have shown species‐specific variations in plant δ 13 C associated with spatial and temporal (or seasonal) precipitation changes in drylands (Golluscio & Oesterheld ; Lázaro‐Nogal et al . ). These species‐specific responses are related to inter‐specific differences in water use strategies (Golluscio & Oesterheld ; Moreno‐Gutiérrez et al .…”

“…However, the importance of C and N isotope variations in the same plant species growing along rainfall gradients has been neglected (but see Lázaro‐Nogal et al . ), and studies of this variation could enhance our understanding of species‐specific plant responses to precipitation changes in water‐limited ecosystems.…”