Ecophysiological responses ofBetula pendula,Pinus uncinataandRhododendron ferrugineumin the Catalan Pyrenees to low summer rainfall

Abstract

Climate change is producing modifications in the intensity and frequency of rainfall in some regions of the planet. According to predictions, annual rainfall distribution in Western Europe will result in an increase in episodes of drought, thereby negatively affecting nutrient availability. Since high mountain systems will be particularly vulnerable, the physiological and nutritional responses to changes in summer rainfall were monitored over the course of two consecutive summers on three species, which are representative of subalpine forests: birch (Betula pendula Roth.), rhododendron (Rhododendron ferrugineum L.) and mountain pine (Pinus uncinata Mill.). Birch was especially susceptible to scarce precipitation showing alterations in leaf morphology and a decline in net photosynthesis (A) due to stomatal closure, which led to photoinhibition and to early leaf senescence as shown by the photosynthetic nitrogen-use efficiency (PNUE), carbon/nitrogen (C/N) ratio, foliar N and C isotope discrimination (ΔC) results. The ΔC of the soluble fraction is a good estimator of intrinsic water-use efficiency in this species. Rhododendron and mountain pine had sclerophyllous leaves, as indicated by leaf mass per area, ΔC, PNUE and C/N results. Rhododendron was particularly affected by short periods of scarce rainfall, which negatively affected gas exchange and photochemistry, and reduced the remobilization of leaf N and P. Mountain pine was the most tolerant species since alterations of gas exchange, photochemistry and ΔC were not observed. Its highest investment of N in RuBisCo and highest potassium, iron and magnesium leaf concentration contributed to the highest A rates observed.

Last-century vegetation dynamics in a highland Pyrenean national park and implications for conservation

“…A recent ecophysiological study in the PNAESM indicated that Pinus uncinata exhibits high tolerance to variations in precipitation, while Betula pendula is particularly vulnerable to low precipitation levels, and Rhododendron ferrugineum is adversely affected by brief drought events (Fernàndez-Martínez et al, 2016). Consequently, continued drying and a potential increase in drought frequency could further solidify the dominance of black pine.…”

Species Richness of the Family Ericaceae along an Elevational Gradient in Yunnan, China

“…Here, we found that species richness for Ericaceae was significantly correlated with MAP, PDM, and PWM, although the relative importance of water availability in explaining the elevational pattern of richness was smaller than temperature. Rhododendron ferrugineum L. is thought to be particularly affected by short periods of scarce rainfall, which negatively affects leaf gas exchange [61]. Snow cover during winter provides protection for the plants at high elevation.…”

Leaf density and chemical composition explain variation in leaf mass area with spectral composition among 11 widespread forbs in a common garden

“…A large number of studies focusing on the plasticity of LMA to abiotic factors have found that it responds to numerous changes in environmental conditions in nature; the factors driving variation in LMA include light (Coble & Cavaleri, 2015;Fajardo & Siefert, 2016), temperature (Fajardo & Piper, 2011;Zhang et al, 2020), water (Fernandez-Martinez et al, 2016;Sanchez-Gomez et al, 2013), nutrients (Onoda et al, 2008;Wang et al, 2019), and CO 2 (Hikosaka et al, 2005;Ishizaki et al, 2003). However, a meta-analysis from Poorter et al (2009) Sunlight does not only supply the essential energy input for photosynthesis (Hikosaka et al, 1994;Moss, 1967;Oguchi et al, 2017), but importantly provides cues that regulate leaf traits and dictate plant functional strategy (Ballaré, 2014;Jenkins et al, 2001;Wang et al, 2020).…”

“…A large number of studies focusing on the plasticity of LMA to abiotic factors have found that it responds to numerous changes in environmental conditions in nature; the factors driving variation in LMA include light (Coble & Cavaleri, 2015; Fajardo & Siefert, 2016), temperature (Fajardo & Piper, 2011; Zhang et al, 2020), water (Fernandez‐Martinez et al, 2016; Sanchez‐Gomez et al, 2013), nutrients (Onoda et al, 2008; Wang et al, 2019), and CO 2 (Hikosaka et al, 2005; Ishizaki et al, 2003). However, a meta‐analysis from Poorter et al (2009) has identified that light is the dominant factor driving LMA variation, exceeding temperature in importance, based on LMA data from a total of 3800 species across functional groups and ecosystems types.…”