California perennial grasses are physiologically distinct from both Mediterranean annual and perennial grasses

Abstract

In the Central Valley of California, native perennial grass species have been largely replaced by Eurasian annual species, while in many parts of the Mediterranean Basin native perennial grasses continue to dominate, even on disturbed or degraded sites. We assessed whether differences in summer rainfall patterns have lead to the development of different plant-water strategies between grasses from these two regions. We compared six measures of plant-water physiology for three guilds of grasses: California perennial grasses, Mediterranean perennial grasses, and Mediterranean annual grasses. Discriminant analysis distinguished between the three guilds; Mediterranean perennial grasses were characterized by a more conservative water-relations physiology than Mediterranean annual grasses, whereas California perennial grasses were in some ways intermediate between the two Mediterranean grass guilds. For individual traits, California perennial grasses were either intermediate or more like Mediterranean annuals than Mediterranean perennials. Our results suggest California perennials are more drought tolerant than Mediterranean annuals but less drought tolerant than Mediterranean perennials, despite the fact that California's Central Valley has a more intense summer drought than the Mediterranean Basin. These patterns may help explain why Mediterranean annuals, but not Mediterranean perennials, have been more successful invaders of interior California grasslands.

The partitioning of water uptake between growth forms in a Neotropical savanna: do herbs exploit a third water source niche?

“…Annual and perennial grasses were included in this study, and as a group, they showed strongly anisohydric behaviour. This was also found in a comparative study between Mediterranean perennial and annual grasses (Vaughn et al. 2011).…”

Plant drought survival under climate change and strategies to improve perennial grasses. A review

“…Annual species dominate these plant communities and complete their growth cycles before the onset of summer drought, thus minimising competition for limiting resources with the summer-dormant grasses (Fernández-Alés et al 1993). Preliminary research suggests that summerdormant grasses originating from the Mediterranean Basin and introduced to Mediterranean environments of California have very limited potential for invasiveness when compared with introduced Mediterranean annuals and native summerdormant grasses (Vaughn et al 2011). Thus, initial attempts to establish and grow lucerne and summer-dormant tall fescue mixtures in north Texas and southern Oklahoma have proven unsuccessful (Stein et al 2009).…”

Evaluación y comparación de las respuestas fenológicas, morfológicas y ecofisiológicas de 4 especies de Quercus típicas de los bosques del trópico seco (Paisaje Terrestre Protegido Miraflor-Moropotente – Nicaragua)

“…Foliar area and perimeter were determined from computer imaging of harvested leaves (Image Tool 3.0), and used to calculate Specific Leaf Weight (SLW) (gDW / m-2leaf) and Leaf Fractal Index (Foliar Perimeter / Foliar area-1) (Serrano et al 2005, Vaughn et al 2011.…”

“…Then they were placed in containers filled with distilled water and kept in darkness at 2-4°C during 24-48 hours to reach maximum turgor (TW). Leaves were then left out of water during 60 minutes to allow stomata to open, and cuticular transpiration rate was measured gravimetrically along a four hour period (one measurement every 30 minutes) (Vaughn et al 2011).…”