•Extensive experimental and observational evidence of climate change impacts on Mediterranean plants and ecosystems is provided.•Genetics, epigenetics, morphology, physiology and phenology of living ...organisms are changing.•As a result, interactions between species and the species composition of communities are also altered.•The capacity of C uptake is reduced and the risk of nutrient losses is increased.•The experimental and observational data provides useful information for the management of Mediterranean forests.
Climate change is increasing temperatures globally and drought in many regions. If climate change continues at its current rate, the resilience of many ecosystems will likely be exceeded, altering their structure and function. A consistent understanding of the impacts, however, remains elusive due to the difficulty of obtaining data of field studies at different scales from local to regional. We review the impacts of climate change on terrestrial ecosystems of the Mediterranean region based mostly on long-term field experiments of climatic manipulation and monitored field sites in Catalonia (NE Spain). These studies provide diverse experimental and observational field evidences that rising temperatures, new patterns of precipitation and other climatic changes are already affecting ecosystems in this Mediterranean region. Rapid genetic, epigenetic and metabolomics changes in plants have been described. They have resulted in changes in morphology, physiology, growth, reproduction, and mortality. Some species are more vulnerable to these changes than others are, which has altered their competitive ability and thereby changed microbial, plant and animal community composition. Many other impacts have been observed in response to climate change, for example an increase in the emission of biogenic volatile organic compounds or an increased risk of fire and a decrease in the absorption of CO2 in periods of drought. A reduction of the capacity to retain nutrients and C in vegetation is accompanied, in the short term, by an increase in soil C and nutrient contents due to a decrease in the enzymatic capacity and mineralization of soil. The projected increase of torrential rainfalls introduces a scenario of uncertain changes in nutrient cycles, soil fertility and nutrient fluxes at medium and long terms. All these changes in water and nutrient availability suggest, though, net losses in the capacity of Mediterranean forests and shrublands to act as C sinks. Future research should quantify C in above- and belowground biomasses and soils under drought and warming, because this necessary information is lacking. Future studies should also investigate the losses of soil nutrients by leaching and erosion, and the possible feedbacks of land cover changes on water availability and regional climate. Policies of environmental and forestry management should take into account these impacts of the environmental and climatic conditions projected for the coming years and decades.
Half of all mental health disorders appear during adolescence, although it is still far from clear how they relate to gender (not sex) criteria. This study aims both to analyse the relationship ...between gender and adolescent mental health and to propose an index: the Gender Adherence Index (GAI). We used cross-sectional, secondary data from 3888 adolescents (aged 13–19) from the FRESC Health Survey on Adolescence in Barcelona. We analysed the interaction among sex, age and socio-economic status with several mental health indices. Additionally, we computed a Gender Adherence Index (GAI) to transcend the information-poor binary sex label, and thus assess to what extent mental health can be predicted by the gender expression of adolescents irrespective of their biological sex. We found that older age and lower economic status have a greater impact on the emotional distress of girls, who reported lower self-perceived mental health than boys. Nevertheless, girls obtained higher scores regarding their prosocial behaviour, which is protective against mental health problems. The GAI was retained in all statistical models stressing it as a relevant metric to explain the variability of adolescent emotional distress. Young people who showed adherence to normative femininity in their lifestyles showed higher prosocial behaviour but did not tend to present more emotional distress. Despite its limitations, this is a novel attempt to explore the relationship between gender expression and mental health. Better defined indices of gender adherence could help us to improve our predictive capacity of mental health disorders during adolescence.
The possibility of using the elemental compositions of species as a tool to identify species/genotype niche remains to be tested at a global scale. We investigated relationships between the foliar ...elemental compositions (elementomes) of trees at a global scale with phylogeny, climate, N deposition and soil traits. We analysed foliar N, P, K, Ca, Mg and S concentrations in 23,962 trees of 227 species. Shared ancestry explained 60-94% of the total variance in foliar nutrient concentrations and ratios whereas current climate, atmospheric N deposition and soil type together explained 1-7%, consistent with the biogeochemical niche hypothesis which predicts that each species will have a specific need for and use of each bio-element. The remaining variance was explained by the avoidance of nutritional competition with other species and natural variability within species. The biogeochemical niche hypothesis is thus able to quantify species-specific tree niches and their shifts in response to environmental changes.
Fine roots mediate plant nutrient acquisition and growth. Depending on soil nutrient availability, plants can regulate fine root biomass and morphological traits to optimise nutrient acquisition. ...Little is known, however, about the importance of these parameters influencing forest functioning. In this study, we measured root responses to nutrient additions to gain a mechanistic understanding of plant adaptations to nutrient limitation in two tropical forests in French Guiana, differing twofold in their soil nutrient statuses. We analysed the responses of root biomass, mean root diameter (RD), specific root length (SRL), specific root area (SRA), root tissue density (RTD) and carbon (C), nitrogen (N) and phosphorus (P) concentrations in roots down to 15 cm soil depth after three years of N and P additions. At the lower‐fertility site Paracou, no changes in root biomass or morphological traits were detected with either N or P addition, although P concentrations in roots increased with P addition. In the higher fertility site, Nouragues, root biomass and P concentrations in roots increased with P addition, with no changes in morphological traits. In contrast, N addition shifted root traits from acquisitive to more conservative by increasing RTD. A significant interaction between N and P in Nouragues pointed to stronger responses to P addition in the absence of N. Our results suggest that the magnitude and direction of root biomass and trait expression were regulated by soil fertility, corroborated by the response to N or P additions. At low fertility sites, we found lower plasticity in root trait expression compared to more fertile conditions, where N and P additions caused stronger and antagonistic responses. Identifying the exact role of mechanisms affecting root nutrient uptake in Amazon forests growing in different soils will be crucial to foresee if and how rapid global changes can affect their carbon allocation.
The increase in aridity, mainly by decreases in precipitation but also by higher temperatures, is likely the main threat to the diversity and survival of Mediterranean forests. Changes in land use, ...including the abandonment of extensive crop activities, mainly in mountains and remote areas, and the increases in human settlements and demand for more resources with the resulting fragmentation of the landscape, hinder the establishment of appropriate management tools to protect Mediterranean forests and their provision of services and biodiversity. Experiments and observations indicate that if changes in climate, land use and other components of global change, such as pollution and overexploitation of resources, continue, the resilience of many forests will likely be exceeded, altering their structure and function and changing, mostly decreasing, their capacity to continue to provide their current services. A consistent assessment of the impacts of the changes, however, remains elusive due to the difficulty of obtaining simultaneous and complete data for all scales of the impacts in the same forests, areas and regions. We review the impacts of climate change and other components of global change and their interactions on the terrestrial forests of Mediterranean regions, with special attention to their impacts on ecosystem services. Management tools for counteracting the negative effects of global change on Mediterranean ecosystem- services are finally discussed.
The availability of soil phosphorus (P) often limits the productivities of wet tropical lowland forests. Little is known, however, about the metabolomic profile of different chemical P compounds with ...potentially different uses and about the cycling of P and their variability across space under different tree species in highly diverse tropical rainforests.
We hypothesised that the different strategies of the competing tree species to retranslocate, mineralise, mobilise, and take up P from the soil would promote distinct soil
P profiles. We tested this hypothesis by performing a metabolomic analysis of the soils in two rainforests in French Guiana using
P nuclear magnetic resonance (NMR). We analysed
P NMR chemical shifts in soil solutions of model P compounds, including inorganic phosphates, orthophosphate mono- and diesters, phosphonates, and organic polyphosphates. The identity of the tree species (growing above the soil samples) explained > 53% of the total variance of the
P NMR metabolomic profiles of the soils, suggesting species-specific ecological niches and/or species-specific interactions with the soil microbiome and soil trophic web structure and functionality determining the use and production of P compounds. Differences at regional and topographic levels also explained some part of the the total variance of the
P NMR profiles, although less than the influence of the tree species. Multivariate analyses of soil
P NMR metabolomics data indicated higher soil concentrations of P biomolecules involved in the active use of P (nucleic acids and molecules involved with energy and anabolism) in soils with lower concentrations of total soil P and higher concentrations of P-storing biomolecules in soils with higher concentrations of total P.
The results strongly suggest "niches" of soil P profiles associated with physical gradients, mostly topographic position, and with the specific distribution of species along this gradient, which is associated with species-specific strategies of soil P mineralisation, mobilisation, use, and uptake.
Tropical rainforests harbor a particularly high plant diversity. We hypothesize that potential causes underlying this high diversity should be linked to distinct overall functionality (defense and ...growth allocation, anti-stress mechanisms, reproduction) among the different sympatric taxa. In this study we tested the hypothesis of the existence of a metabolomic niche related to a species-specific differential use and allocation of metabolites. We tested this hypothesis by comparing leaf metabolomic profiles of 54 species in two rainforests of French Guiana. Species identity explained most of the variation in the metabolome, with a species-specific metabolomic profile across dry and wet seasons. In addition to this "homeostatic" species-specific metabolomic profile significantly linked to phylogenetic distances, also part of the variance (flexibility) of the metabolomic profile was explained by season within a single species. Our results support the hypothesis of the high diversity in tropical forest being related to a species-specific metabolomic niche and highlight ecometabolomics as a tool to identify this species functional diversity related and consistent with the ecological niche theory.
Productivity of tropical lowland moist forests is often limited by availability and functional allocation of phosphorus (P) that drives competition among tree species and becomes a key factor in ...determining forestall community diversity. We used non-target 31P-NMR metabolic profiling to study the foliar P-metabolism of trees of a French Guiana rainforest. The objective was to test the hypotheses that P-use is species-specific, and that species diversity relates to species P-use and concentrations of P-containing compounds, including inorganic phosphates, orthophosphate monoesters and diesters, phosphonates and organic polyphosphates. We found that tree species explained the 59% of variance in 31P-NMR metabolite profiling of leaves. A principal component analysis showed that tree species were separated along PC 1 and PC 2 of detected P-containing compounds, which represented a continuum going from high concentrations of metabolites related to non-active P and P-storage, low total P concentrations and high N:P ratios, to high concentrations of P-containing metabolites related to energy and anabolic metabolism, high total P concentrations and low N:P ratios. These results highlight the species-specific use of P and the existence of species-specific P-use niches that are driven by the distinct species-specific position in a continuum in the P-allocation from P-storage compounds to P-containing molecules related to energy and anabolic metabolism.
Forest restoration is an effective tool to mitigate climate change, but its implementation in highly diverse and threatened tropical dry forests (TDFs) is particularly challenging due to the hostile ...environment. Intraspecific trait variability (ITV) in response to these constraints may be very informative for predicting the potential for species acclimation and therefore for improving trait‐based species screenings that best match each particular scenario of forest restoration. We analyzed ITV during seedling establishment of three widely distributed and ecologically contrasting TDF species in a greenhouse multifactorial experiment crossing levels of resource availability (nutrients and water) and herbivory to assess the capacity of ITV to discern strategies of seedling establishment and to predict species’ growth rates and acclimation potential. The three species studied had contrasting responses to the experimental treatments, suggesting different strategies of seedling establishment. The species with the most plastic pattern of growth performed the best, especially due to its ability to modulate the trade‐off of root‐to‐shoot allocation of biomass depending on nutrient availability. Almost 50% of the variation in the root mass ratio was within species, half of which was a direct response of the treatments, indicating a strong acclimation potential. Individual‐level trait measurements, however, were poor predictors of seedling growth rates. ITV, particularly the ability to adapt the pattern of biomass allocation, can be critical during seedling establishment. We propose incorporating information about ITV and the ability of species to modulate their phenotypic expression to cope with environmental variability into programs of forest restoration. Easily implemented and standardized greenhouse experiments are an inexpensive way to obtain high‐quality data on the plasticity of forest species, which can be very valuable for predicting the potential of species acclimation and thus improving the selection of species that better match each particular scenario of restoration.
Tropical plants are expected to have a higher variety of defensive traits, such as a more diverse array of secondary metabolic compounds in response to greater pressures of antagonistic interactions, ...than their temperate counterparts. We test this hypothesis using advanced metabolomics linked to a novel stoichiometric compound classification to analyze the complete foliar metabolomes of four tropical and four temperate tree species, which were selected so that each subset contained the same amount of phylogenetic diversity and evenness. We then built Bayesian phylogenetic multilevel models to test for tropical-temperate differences in metabolite diversity for the entire metabolome and for four major families of secondary compounds. We found strong evidence supporting that the leaves of tropical tree species have a higher phenolic diversity. The functionally closer group of polyphenolics also showed moderate evidence of higher diversity in tropical species, but there were no differences either for the entire metabolome or for the other major families of compounds analyzed. This supports the interpretation that this tropical-temperate contrast must be related to the functional role of phenolics and polyphenolics.
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