Examinando por Autor "Morente-Lopez, Javier"

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Addition of nocturnal pollinators modifies the structure of pollination networks
(Scientific Reports, 2024-01-12) García, Yedra; Giménez-Benavides, Luis; Iriondo, Jose M; Lara-Romero, Carlos; Marcos, Méndez; Morente-Lopez, Javier; Santamaría, Silvia
Although the ecological network approach has substantially contributed to the study of plant-pollinator interactions, current understanding of their functional structure is biased towards diurnal pollinators. Nocturnal pollinators have been systematically ignored despite the publication of several studies that have tried to alleviate this diurnal bias. Here, we explored whether adding this neglected group of pollinators had a relevant effect on the overall architecture of three high mountain plant-pollinator networks. Including nocturnal moth pollinators modified network properties by decreasing total connectivity, connectance, nestedness and robustness to plant extinction; and increasing web asymmetry and modularity. Nocturnal moths were not preferentially connected to the most linked plants of the networks, and they were grouped into a specific “night” module in only one of the three networks. Our results indicate that ignoring the nocturnal component of plant-pollinator networks may cause changes in network properties different from those expected from random undersampling of diurnal pollinators. Consequently, the neglect of nocturnal interactions may provide a distorted view of the structure of plant-pollinator networks with relevant implications for conservation assessments.
Direct and indirect effects of shrub encroachment on alpine grasslands mediated by plant-pollinator interactions
(2016-01-21) Lara-Romero, Carlos; Cristina, Gar; Morente-Lopez, Javier; Iriondo, Jose M
1. Mutualistic interactions structure ecological communities and they are strongly influenced by the combined effect of different drivers of global change. Land-use changes and global warming have elicited rapid shrub encroachment in alpine grasslands in recent decades, which may have detrimental outcomes for native alpine forbs. In spite of the importance of this process, we lack knowledge about how shrub encroachment modifies community-wide patterns of plant–pollinator mutualistic interactions. 2. Based on the functional biodiversity hypothesis (FBH), which predicts higher pollinator biodiversity in species-rich plant communities, we asked whether the increase in nutritional resources available for pollinators due to shrub expansion modifies pollinator niche breadth and species richness, and whether these changes affect plant–plant interactions. 3. For this purpose, we compared quantitative plant–flower visitor interaction network assemblages at replicated plots in two habitat types in dry cryophilic grasslands of Sierra de Guadarrama (Spain): (i) encroached pastures (EP) and (ii) pastures dominated by forb species where shrub species are absent (PA). 4. As predicted by FBH, flower visitor richness increased in EP, but their niche breadth did not vary. Furthermore, shrubs had more interactions with flower visitors and received more visits per plant than forbs in EP in agreement with their significantly higher linkage and strength. 5. Overall, results revealed that moderate levels of shrub encroachment affected the flower visitation patterns of forb species in alpine grasslands as flower visitor diversity increased and plant–plant competition for shared flower visitors became greater. These findings highlight the need to use an integrative approach to study the cascading effects of global change drivers on species interactions and their impact on the structure and functioning of threatened ecological communities.
Individual spatial aggregation correlates with between-population variation in fine-scale genetic structure of Silene ciliata
(2016-05) Lara-Romero, Carlos; Garcia-Fernández, Alfredo; Robledo-Arnuncio, Juan J.; Roumet, Marie; Morente-Lopez, Javier; Lopez-Gil, Angela; Iriondo, Jose M
Fine-scale genetic structure (FSGS) can vary among populations within species depending on multiple demographic and environmental factors. Theoretical models predict that FSGS should decrease in high-density populations and increase in populations where individuals are spatially aggregated. However, few empirical studies have compared FSGS between populations with different degrees of individual spatial aggregation and microhabitat heterogeneity. In this work, we studied the relationship between spatial and genetic structure in five populations of alpine specialist Silene ciliata Poiret (Caryophyllaceae). We mapped all individuals in each population and genotyped 96 of them using 10 microsatellite markers. We found significant FSGS consistent with an isolation-by-distance process in three of the five populations. The intensity of FSGS was positively associated with individual spatial aggregation. However, no association was found between FSGS and global population density or microhabitat heterogeneity. Overall, our results support theoretical studies indicating that stronger spatial aggregation tends to increase the magnitude of FSGS. They also highlight the relevance of characterizing local plant distribution and microhabitat to better understand the mechanisms that generate intraspecific variation in FSGS across landscapes.