Variability of the photosynthetic and fluorescence response of high mountain plants to climate change.

<p>Alpine ecosystems have a high ecological value, high biodiversity, and provide important ecosystem services. However, alpine communities are highly vulnerable to climate changes. Changes in biodiversity and its distribution will affect the goods and services that these ecosystems provide. Also, it can affect climate regulation by altering the exchanges of greenhouse gases (GHG) and the cycles of carbon (C) and nitrogen (N), in feedback processes. Due to their ecological importance and vulnerability, alpine meadows deserve special attention. In this regard, the main objective of the IBERALP project is the analysis of the interactions between components of biodiversity, mainly plant and soil microbial diversity, and their relationship with GHG fluxes; and how these interactions are affected by climate change.</p> <p>&#160;</p> <p>IBERALP is focused on the alpine communities of five Iberian mountain National Parks: Picos de Europa, Ordesa and Monte Perdido, Aig&#252;estortes i Estany de Sant Maurici, Sierra Nevada, and Sierra de Guadarrama. In each National Park, we selected two different altitudes and two different alpine community types based on soil conditions (mesic and xeric). Here we study leaf physiological and fluorescence parameters assimilation, respiration, the quantum yield of photosystem II (<em>PhiPSII</em>), maximum quantum efficiency (Fv`/Fm`) and photochemical quenching (qP) in two representative plant species (a legume (<em>Trifolium repens</em>) and a grass (<em>Nardus strita</em>)) present in each National Park. In addition, we recorded altitude and humidity soil condition using a portable photosyntheic system (Li-cor 6800; Li-Cor Inc.) with an integrated fluorescence chamber head.</p> <p>&#160;</p> <p>Multiple factors affect the ability of plants to assimilate CO₂ and photoprotect themselves from solar radiation excess, so there was no common pattern for all Parks. However, in general, plants at higher altitudes showed a greater photosynthetic and photoprotection capacity against high irradiances compare to those at lower altitudes. Similar behaviour was found in mesic versus xeric communities. Exceptions were found, such as, for example, in Picos de Europa National Park, where the intense fog and grazing (with continuous contribution of N to the soil) modified these patterns of photosynthesis and photoprotection.&#160;</p> <p>This work was supported by the OAPN through the project PN2021-2820s (IBERALP).</p>