Examinando por Autor "Espinosa, Carlos I."

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Climate seasonality and tree growth strategies in a tropical dry forest
(Wiley Online Library, 2019-11-16) García-Cervigón, Ana I.; Camarero, J. Julio; Cueva, Eduardo; Espinosa, Carlos I.; Escudero, Adrián
Questions: Do tree species in seasonally dry tropical forests differ in the timing oftheir secondary growth? And in their growth rates between consecutive years? If so,how are these contrasting patterns linked to seasonality in climatic variables (tem-perature, precipitation)? Which is the role of leaf phenology and functional traits asdrivers of stem radial increment responses to climate?Location: A Tumbesian tropical dry forest in southern Ecuador.Methods: We used a 12-year database of stem radial increments to characterizeintra- and inter-annual patterns of secondary growth in 13 co-existing dominant treespecies. For each species, we adjusted an additive model to describe intra-annualincrement patterns and created a mean series of annual increments to describe inter-annual changes. Adjusted increments were then correlated with monthly tempera-ture and rainfall data over the study period, and also with the crown percentagecovered by leaves. The role of functional traits (leaf area, wood density, maximumtree height, seed dry mass) was explored using average trait values per species.Results: We observed continuous variation in the seasonality of radial increments,ranging from species that started incrementing their diameter as early as first rainsoccurred in the season to species that showed delayed responses. Variability in intra-and inter-annual increment patterns was explained by functional traits (leaf area andseed dry mass, and maximum height and wood density, respectively) and leaf phenol-ogy, but this variation was not clearly matched with any functional trait configura-tion. This, combined with the absence of homogeneous responses of annual growthrates to climate, suggests the existence of contrasting strategies that virtually vary ina species-specific fashion.Conclusions: Co-existing tree species in seasonally dry tropical forests show differ-ent growth strategies to face intra- and inter-annual climate variations, which mayincrease the resilience of these forests against projected climatic variations.
Dispersal syndrome influences the match between seed rain and soil seed bank of woody species in a Neotropical dry forest
(Wiley, 2020-11) Jara-Guerrero, Andrea; Espinosa, Carlos I.; Méndez, Marcos; De la Cruz, Marcelino; Escudero, Adrián
Aims Plant recruitment may occur immediately after seed dispersal from the mother plant, or be delayed through the formation of soil seed banks. These strategies are known to be mediated by adaptations of seed dispersal and reproductive phenology, which if analyzed together can provide valuable information about the regeneration strategies of species. We explored whether dispersal syndrome and/or seed dispersal phenology control the similarity between standing vegetation, seed rain and soil seed bank in a seasonally dry tropical forest (SDTF) in Southern Ecuador. Location Arenillas Ecological Reserve, Southwestern Ecuador, the biogeographic region of Pacific Coastal Ecuador. Methods We recorded standing vegetation of woody species in a 9-ha permanent plot and sampled soil seed bank from 265 cores of 0.06 m2. Additionally, we sampled seed rain from 265 seed traps of 0.64 m2 for one year. We evaluated similarity in species composition, species richness, and abundance between the three components for all species and for each dispersal syndrome. Results The community we studied showed a high similarity in species composition between components. The similarity was influenced by dispersal syndrome and the seed dispersal phenology. Similarity between seed rain and standing vegetation was high in species that dispersed in the rainy season, such as zoochorous species, while for autochorous species, compared with the other dispersal syndromes it was higher between seed bank and standing vegetation. Conclusions In our SDTF, dispersal phenology seemed to influence whether seeds had direct germination or entered the soil seed bank and influenced the match between seed rain and soil seed bank, suggesting different regeneration strategies related to dispersal ability.
Focusing on individual species reveals the specific nature of assembly mechanisms in a tropical dry-forest
(Elsevier, 2018-10) Gusmán-M., Elizabeth; De la Cruz, Marcelino; Espinosa, Carlos I.; Escudero, Adrián
We employed an individual-species approach based on the plant’s eye perspective to disentangle the effects of individual species on community assembly in a dry tropical forest of southern Ecuador. We completely mapped a forest plot of 9 ha, and measured several functional traits (leaf area, specific leaf area, wood density, seed mass and maximum height) for tree and shrub species. To account for stochastic and habitat filtering effects, we fitted spatial point processes for the 23 more abundant species in the plot, which confirmed that all species responded to plot scale habitat filtering and 14 were dispersal-limited. We tested the hypothesis that facilitative interactions would be prevalent in this dry forest. For this, we compared the distribution of taxonomic (TD), functional (FD) and phylogenetic (PD) diversity in the neighborhood of the studied species with the diversity expected under a null model combining habitat filtering and stochastic assembly. We found that in the fine spatial scales where species interactions are expected to occur (i.e., neighborhoods of 1–20 m) eight species did not show any significant pattern for TD, FD or PD. Eleven species showed evidences of facilitation (i.e., accumulated more TD than expected) but in some cases the facilitated neighborhoods had more FD or PD than expected, suggesting the joint effect of facilitation and competition based on niche differences. One species showed less TD than expected, accompanied by lower FD and higher PD, suggesting competition based on fitness differences. Our study shows that in this dry tropical forest, where abiotic stress is prevalent, the assembly of diversity is controlled by environmental heterogeneity and both facilitative and competitive biotic processes, all of them acting simultaneously and at the same scale in the same neighborhoods.