From physiology to salt marsh management challenges with sea level rise: the case of native Spartina foliosa, invasive S. densiflora and their hybrid

12 páginas.- 2 figuras.- 2 tablas.- referencias.-Sea level rise (SLR) imposes increasing salinity and inundation stresses in salt marshes which simultaneously face invasions by exotic plant species. We aimed to improve and apply knowledge on the ecophysiological responses of halophytes to SLR to conservation management of salt marshes. In a mesocosm experiment, we measured and compared phosphoenolpyruvate carboxylase (PEPC) activity and related functional traits of the California-native Spartina foliosa, invasive S. densiflora and their hybrid S. densiflora × foliosa in response to increasing levels of salinity and inundation. S. foliosa was moderately sensitive to salinity, showing a 57% reduction in PEPC specific activity from freshwater to hypersalinity. This native species compensated for the reduction of PEPC activity with increased salinity through 80% higher enzyme activation by phosphorylation. PEPC functional trait responses of S. foliosa were mostly independent of inundation depth. In view of these results, managers should conserve undeveloped lands for accommodation space above current high tide lines to facilitate colonization of stress-tolerant S. foliosa. Our results on functional responses of PEPC traits recorded high sensitivity to salinity for S. densiflora. This was reflected by 65% lower PEPC specific activity together with increasing accumulation of free proline (+96%) and total proteins (+23%) with elevated salinity. These results suggest prioritized eradication of S. densiflora populations in brackish habitats. Measured PEPC responses support the high stress tolerance of the S. densiflora × foliosa hybrid. PEPC traits for the hybrid were mostly independent of salinity and inundation. The hybrid showed higher PEPC-specific activity than S. foliosa (+70%) and S. densiflora (+15%) in freshwater under intermediate inundation. Results suggest that eradication of the hybrid should be the highest management priority. Our study shows that the responses of key functional physiological traits to environmental stresses serve as biological indicators that can guide ecosystem management practices in a scenario of climate change.This work was supported by Plan Propio de Investigación of Universidad de Sevilla by awarding a research contract to Blanca Gallego-Tévar and by a cooperative agreement between the United State Department of Agriculture, Agricultural Research Service (USDA-ARS) Invasive Species and Pollinator Health Research Unit, Davis, California, and the University of Seville [58-2030-6-043-F]

Transgenerational responses to climate change in Mediterranean annual species with contrasting functional strategies

11 páginas.- 4 figuras.- 3 tablas.- 89 referencias.- Supplementary data associated with this article can be found in the online version at doi:10.1016/j.envexpbot.2022.104817Increasing temperature and aridity predicted by climate change models in the Mediterranean region will pose a significant challenge for the survival of some plant species. The mechanisms by which species modify their phenotype across generations in response to the environment have been identified as essential to cope with the new climatic conditions. However, this transgenerational transfer remains unexplored for species with contrasted resource-use strategies (fast-growing or acquisitive versus stress-tolerant or conservative species). For this purpose, transgenerational responses to warming and drought of annual plant species with different resource-use strategies were assessed by conducting three experiments. In a field experiment, climatic treatments of increased temperature and rainfall exclusion were imposed on five herbaceous species typical of Mediterranean grasslands. The descendants of the individuals sampled in the field were employed in two greenhouse experiments to: (1) analyze the transgenerational response by re-imposing warming and drought conditions, and (2) identify possible maternal effects by maintaining them at optimal conditions of air temperature and water availability and comparing with maternal performance. We measured reproductive output, plant growth and survival variables as plant performance indicators. We found contrasting transgenerational responses to warming and drought depending on the functional strategy of the species. Direct effects of the abiotic stressors on parental plants were retained or new ones appeared in their offspring, with special negative impact on one of the most acquisitive species (Crepis capillaris). In contrast, the most conservative species (Bromus madritensis) highly tolerated increased climatic stress but deleterious maternal effects were registered, given the high negative impact on the performance of the descendants of maternal plants that were subjected to climatic treatments. Our study highlights the importance of evaluating plant responses to stress across generations to better understand their potential ability to face new environmental conditions in species with different functional strategies. © 2022 The AuthorsFunding support to conduct the experiments was entirely funded by the MICINN project DECAFUN ( CGL2015-70123-R ). IMP-R and BG-T were funded by a “ Ramón & Cajal ” contract ( RYC-2013-13937 ) and a “ Juan de la Cierva-Formación ” contract ( FJC2019-039115-I ), respectively.Peer reviewe

Warming and drought stress in plants with contrasting functional strategies induce different phenotypic variability in their offspring

Comunicación oral presentada en el XV Congreso Nacional de la AEET. "El valor de la naturaleza par una sociedad global"18-21 de octubre, Plasencia, CáceresPhenotypic plasticity, both within and across generations, is a mechanism by which plant species respond to changing environmental conditions. This is particularly relevant in a context of global change since organisms face rapid variations of climatic conditions to which should adjust and adapt. Specifically, plasticity across generations is receiving special attention, but the understanding of key aspects, such as the environmental conditions in which it occurs or the role that different functional groups might play in this process, remains understudied. Here, we investigated the magnitude and variability in the responses of herbaceous plant species with contrasting functional strategies to two main climatic stressors (warming and drought), analyzing the heritability of these responses from maternal plants to their offspring. With this aim, we conducted field surveys and greenhouse experiments with five co-occurring dominant herbaceous species of Mediterranean rangelands and measured their performance in terms of growth, reproduction and survival in response to increased temperature and decreased water availability. We found that resource-acquisitive species tended to show greater sensitivity and phenotypic variability in response to climatic treatments. However, the opposite trend was observed in the next generation, presenting the offspring of conservative species a high phenotypic variability when comparing seeds coming from mother plants exposed to different climatic scenarios. Our results suggest that the effect that maternal environment have on offspring performance vary in different functional groups of plants and its role in a context of adaptation to climate change is discussed.N

Climate change alters pasture productivity and quality: Impact on fatty acids and amino acids in Mediterranean silvopastoral ecosystems

12 páginas.- 7 figuras.- 2 tablas.- referencias.- Supplementary data associated with this article can be found in the online version at doi:10.1016/j.agee.2023.108703Climate change is threatening ecosystem functioning and sustainability worldwide. In silvopastoral systems, ongoing warmer and drier conditions could impact productivity and quality of pastures (in terms of protein content and digestibility), with important economic consequences. However, the extent to which climate change could alter other nutritional traits with a potential role in livestock nutrition and production, such as essential fatty acids and amino acids, is a question that remains poorly known. We designed a field manipulative experiment of increased temperature (+2–3 °C) and rainfall exclusion (−30%) aimed to evaluate the influence of forecasted climate variations on the yield and nutritional composition of pastures (i.e. proteins, lipids, fibers, amino acids, fatty acids and digestibility) in a Mediterranean silvopastoral system. To test whether scattered trees typical of these ecosystems could buffer the effects of higher aridity, experimental plots were installed under trees and in open grasslands. First, we found that plant communities under tree canopies were less productive but exhibited higher quality than those located in open grasslands, likely due to the shade and higher soil fertility provided by trees. Both climatic stressors had a significant influence on pasture productivity and nutritional composition. Thus, pastures subjected to rainfall reduction produced less biomass with higher content in nitrogen, proteins, essential amino acids and lipids, likely as a mechanism of plant tolerance to water stress. In contrast, warming increased plant productivity and enhanced the proportion of unsaturated fatty acids, likely mediated by alterations in plant community composition. Finally, our results suggest that trees might slow the impact of climate change on productivity and specific amino acids in pasture. These results could be also applied for the design of management strategies to ensure the ecologic and economic value of silvopastoral ecosystems under future climate scenarios.R. Martins-Noguerol was financially supported by the Spanish Universities Ministry and European Union - Next Generation EU. This work was financially supported by the MICINN projects DECAFUN (CGL2015-70123-R) and INTERTROPHIC (PID2021-128907OB-I00).Peer reviewe