Examinando por Autor "Benavides, Raquel"

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Drivers of phenotypic variation and plasticity to drought in populations of a Mediterranean shrub along an environmental gradient
(Elsevier, 2024-10-18) Ramos-Muñoz, Marina; Castellanos, María Clara; Blanco-Sánchez, Mario; Pías, Beatriz; Ramírez-Valiente, José Alberto; Benavides, Raquel; Escudero, Adrián; Matesanz, Silvia
Assessing the factors driving intraspecific phenotypic variation is crucial to understand the evolutionary trajectories of plant populations and predict their vulnerability to climate change. Environmental gradients often lead to phenotypic divergence in functional traits and their plasticity across populations. We studied the entire environmental range of the Mediterranean gypsum endemic shrub Helianthemum squamatum to evaluate the factors underlying quantitative population differentiation and phenotypic plasticity to drought, using a common garden with 16 populations that covered the main geographic and the entire climatic range of the species. Sampling followed a hierarchical approach to assess trait genetic variation within and among four distinct geographical regions. We found high but similar plastic responses across populations, which were consistent with adaptive plasticity to drought, including advanced phenology, more sclerophyllous leaves, higher water use efficiency and larger seeds in dry conditions. Despite these generally similar plastic responses, we found significant population differentiation in quantitative traits, part of which was structured at the regional scale. Such differentiation was not associated with environmental variation, including differences in climate and soil conditions. This suggests that non-adaptive processes might have had a role on genetic differentiation in H. squamatum, likely due to the island-like configuration of gypsum habitats and the lack of effective seed dispersal of the study species. Our results emphasize the role of phenotypic plasticity in adaptive drought response and the importance of considering both adaptive and non-adaptive processes shaping intraspecific phenotypic variation, which is crucial for predicting plant population vulnerability to climate change
Phenotypic integration does not constrain phenotypic plasticity:differential plasticity of traits is associated to their integrationacross environments
(Wiley, 2021) Matesanz, Silvia; Ramos-Muñoz, Marina; Blanco-Sánchez, Mario; Cruz, Marcelino de la; Benavides, Raquel; Escudero, Adrián
Understanding constraints to phenotypic plasticity is key given its role on the response oforganisms to environmental change. It has been suggested that phenotypic integration, thestructure of trait covariation, could limit trait plasticity. However, the relationship betweenplasticity and integration is far from resolved. Using a database of functional plasticity to drought of a Mediterranean shrub that included20 ecophysiological traits, we assessed environmentally-induced changes in phenotypic inte-gration and whether integration constrained the expression of plasticity, accounting for thewithin-environment phenotypic variation of traits. Furthermore, we provide the first test ofthe association between differential trait plasticity and trait integration across an optimumand a stressful environment. Phenotypic plasticity was positively associated with phenotypic integration in both environ-ments, but this relationship was lost when phenotypic variation was considered. The similarityin the plastic response of two traits predicted their integration across environments, with inte-grated traits having more similar plasticity. Such variation in the plasticity of traits partlyexplained the lower phenotypic integration found in the stressful environment. We found no evidence that integration may constitute an internal constraint to plasticity.Rather, we present the first empirical demonstration that differences in plastic responses mayinvolve a major reorganization of the relationships among traits, and challenge the notion thatstress generally induces a tighter phenotype.
Species richness influences the spatial distribution of trees in European forests
(Wiley, 2020-03) Bastias, Cristina C.; Truchado, Daniel A.; Valladares, Fernando; Benavides, Raquel; Bouriaud, Olivier; Bruelheide, Helge; Coppi, Andrea; Finér, Leena; Gimeno, Teresa E.; Jaroszewicz, Bogdan; Scherer-Lorenzen, Michael; Selvi, Federico; De la Cruz, Marcelino
The functioning of plant communities is strongly influenced by the number of species in the community and their spatial arrangement. This is because plants interact with their nearest neighbors and this interaction is expected to be stronger when the interacting individuals are ecologically similar in terms of resource use. Recent evidence shows that species richness alters the balance of intra- versus interspecific competition, but the effect of species richness, and phylogenetic and functional diversity on the spatial pattern of the plant communities remain less studied. Even far, how forest stand structure derived from past management practices can influence the relationship between species richness and spatial pattern is still unknown. Here, we evaluate the spatial distribution of woody individuals (DBH >7.5 cm) in 209 forest stands (i.e. plots) with an increasing level of species richness (from 1 up to 10 species) in six forest types along a latitudinal gradient in Europe. We used completely mapped plots to investigate the spatial pattern in each forest stand with point pattern techniques. We fitted linear models to analyze the effect of species richness (positively correlated with phylogenetic diversity) and functional diversity on tree spatial arrangements. We also controled this relationship by forest type and stand structure as a proxy of the management legacy. Our results showed a generalized positive effect of species richness and functional diversity on the degree of spatial clustering of trees, and on the spatial independence of tree sizes regardless of the forest type. Moreover, current tree spatial arrangements were still conditioned by its history of management; however its effect was independent of the number of species in the community. Our study showed that species richness and functional diversity are relevant attributes of forests influencing the spatial pattern of plant communities, and consequently forest functioning.
The effect of plant–plant interactions as a key biotic process mediating the spatial variation of phenotypes in a Pinus sylvestris forest
(Springer, 2022-05-09) Carvalho, Barbara; De la Cruz, Marcelino; Escudero, Adrián; Bastias, Cristina C.; Valladares, Fernando; Benavides, Raquel
Plant interactions are among the fundamental processes shaping the structure and functioning of ecosystems as they modulate competitive dynamics. However, the connection between the response of individual growth to neighbours and to environmental conditions and the mechanisms determining interactions in monospecific stands remain poorly understood. Here, we followed a phenotypic-based approach to disentangle the effect of plant size, neighbourhood interactions and microhabitat effects on Pinus sylvestris growth and traits, as well as their spatial variation of growth. We mapped all adult trees (1002 pines) in a 2 ha stand and measured their height, DBH and crown projection. For each individual, we assessed its growth and a competition index in relation to the closest neighbours. Soil chemical and physical properties and ground cover were also measured in a grid within the stand. We analysed the effects of tree size, neighbour competition and microhabitat variation on tree growth with a linear model. We also used spatial mark-correlation functions to explore the spatial dependence of tree age, secondary growth and phenotypic traits. Our results showed that trees with close neighbours displayed lower growth rates, whilst individuals with larger growths appeared scattered throughout the stand. Moreover, we found that growth depended on competition, tree height and crown area while tree growth poorly correlated with age or microhabitat conditions. Our findings highlight the importance of forest structure, in regulating inter-tree competition and growth in a Mediterranean pure stand and they provide insight into the causes and consequences of intraspecific variation in this system.