The effect of conspecific density, herbivory, and bamboo on seedling dynamics of a dominant oak in a Neotropical highland forest

Calderón‐Sanou, Irene; Ríos, Luis Diego; Cascante‐Marín, Alfredo; Barrantes, Gilbert; Fuchs, Eric J.

doi:10.1111/btp.12714

Cited by 8 publications

(4 citation statements)

References 72 publications

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“…Furthermore, several studies in tropical forests demonstrate that lianas can invest more in‐depth roots than in above‐ground growth during the sapling stage, increasing their ability to survive against physical damages and competition (Martínez‐Izquierdo et al, 2016; Restom & Nepstad, 2004; Schnitzer, 2005; Swaine & Grace, 2007). The ability to recover from disturbances, such as trampling or leaf consumption, might also explain why bamboos were not affected by the experimental exclusion of LMH (Buckingham et al, 2011; Calderón‐Sanou et al, 2019; Terborgh et al, 2008). Bamboos possibly have low attractiveness for herbivores, and their solid biomechanical structures, as well as vegetative regeneration and propagation, might additionally contribute to regeneration from LMH disturbance (Rother et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Large mammalian herbivores modulate plant growth form diversity in a tropical rainforest

et al. 2022

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The world’s terrestrial biomes are broadly classified according to the dominant plant growth forms that define ecosystem structure and processes. Although the abundance and distribution of different plant growth forms can be strongly determined by factors such as climate and soil composition, large mammalian herbivores have a strong impact on plant communities, thus defaunation (the local or functional extinction of large animals) has the potential to alter the compositional structure of plant growth forms in natural ecosystems. Tropical rainforests sustain a high diversity of growth forms, including trees, palms, lianas, shrubs, herbs and bamboos, all of which play important ecosystem functions. Here, we experimentally evaluate how large mammalian herbivores affect the dominance, diversity and coexistence of these major tropical forest plant growth forms, by monitoring communities of saplings on the understorey in 43 paired exclusion plots in a long‐term replicated exclusion experiment in the understorey of the Atlantic forest of Brazil. Over the course of 10 years large herbivore exclusion decreased diversity among growth forms, increased the absolute abundance of palms and trees (22% and 38% respectively) and increased the diversity of species within these two groups, to the detriment of other growth forms. Furthermore, all pairwise relationships between growth forms were positive on plots where herbivores had access, whereas several strong negative relationships emerged in plots where herbivores were excluded. This occurred despite strong background directional temporal trends affecting plant communities in both experimental treatments across the region. Synthesis. Our work indicates that the defaunation alters growth form dominance by favouring palms and trees while eroding diversity among growth forms and coexistence on a temporal scale. Large herbivore mammals promote diversity among growth forms, preventing the hyper‐dominance of trees and palms, yet without supressing the diversity of species within growth forms. We argue that large herbivore mammals affect growth forms through several non‐mutually exclusive mechanisms, including herbivory, seed dispersal and physical disturbance, as well as differential effects linked to the morphological and physiological adaptations of growth forms. We conclude that defaunation might lead to profound impacts on important ecosystem functions underpinned by growth form diversity, and result in vertical and horizontal structural simplification of tropical rainforests.

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Section: Discussionmentioning

confidence: 99%

Large mammalian herbivores modulate plant growth form diversity in a tropical rainforest

et al. 2022

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“…Q. costaricensis and H. irazuense appear to be poorly protected against ant herbivory, and in Costa Rica, they occur only at elevations higher than the ants, despite the better growth observed among the temporary surviving seedlings at lower elevations in our study (~ 2000 m a.s.l., Supporting information). Previous observations in the region suggested that survival of Q. costaricenses is often determined by herbivory (Calderón‐Sanou et al 2019). Similarly, the good survival of P. caerulea above its natural range may reflect an absence of specialized herbivores, such as the avocado moth ( Stenoma catenifer ; Luna et al 2017), though at these elevations the seedlings grow slowly.…”

Section: Discussionmentioning

confidence: 99%

Canopy openness modifies tree seedling distributions along a tropical forest elevation gradient

Mazón

Klanderud

Sheil

2022

Oikos

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In theory, canopy openings can influence tree species establishment and resulting distributions over environmental gradients, but evidence concerning the magnitude and direction of such effects remain scarce. In this study we examine how canopy openings influence seedling persistence and growth and resulting elevation range limits. We transplanted 1360 seedlings of eight woody species (trees Trichilia habanensis, Persea caerulea, Cedrela tonduzii, Cornus disciflora, Quercus salicifolia, Q. bumelioides, Q. costaricensis and the shrub Hypericum irazuense) under the forest canopy and in open areas with understorey vegetation removed in a replicated design along a 2900 m elevation gradient in Costa Rica. We recorded survival, stem diameter and height over 18 months. We used hierarchical generalized additive models to examine relationships of seedling survival and growth with elevation and treatment (inside forest versus open area). We found a clear effect of open versus forest conditions on survival across the elevation gradient for six species. Species planted into open areas with full light exposure survived 100–1000 m below (~ 0.5–5°C warmer), and in one case 300 m above (~ 1.8°C colder) their observed ranges. Above 2900 m, survival of all species was markedly greater under the forest canopy versus open sites, suggesting facilitation from the forest, as frost occurred in open areas above this elevation. The resulting upper range increased between 200 and 1160 m (~ 1–6°C colder) compared to their observed range. At lower elevations, severe insect herbivory occurred on some species likely influencing lower range limits. Open areas influenced how seedling survival and growth varied with elevation for all the studied species. All species survived and grew outside the elevation ranges where they are typically observed. We suggest that the influence of forest gaps and clearings over extended gradients offers novel insights into tree range dynamics, limits and conservation.

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“…The vegetation in the adjacent Montane Forests is dominated by oaks ( Quercus costaricensis Liebm.) with abundant epiphytes and shrubs and many species in the Ericaceae, Asteraceae, and Onagraceae [ 66 ].…”

Section: Methodsmentioning

confidence: 99%

Elevational and seasonal patterns of plant pollinator networks in two highland tropical ecosystems in Costa Rica

Cristóbal-Perez,

Barrantes,

Cascante-Marín

et al. 2024

PLoS ONE

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Many plant species in high montane ecosystems rely on animal pollination for sexual reproduction, however, our understanding of plant-pollinator interactions in tropical montane habitats is still limited. We compared species diversity and composition of blooming plants and floral visitors, and the structure of plant-floral visitor networks between the Montane Forest and Paramo ecosystems in Costa Rica. We also studied the influence of seasonality on species composition and interaction structure. Given the severe climatic conditions experienced by organisms in habitats above treeline, we expected lower plant and insect richness, as well as less specialized and smaller pollination networks in the Paramo than in Montane Forest where climatic conditions are milder and understory plants are better protected. Accordingly, we found that blooming plants and floral visitor species richness was higher in the Montane Forest than in the Paramo, and in both ecosystems species richness of blooming plants and floral visitors was higher in the rainy season than in the dry season. Interaction networks in the Paramo were smaller and more nested, with lower levels of specialization and modularity than those in the Montane Forest, but there were no seasonal differences within either ecosystem. Beta diversity analyses indicate that differences between ecosystems are likely explained by species turnover, whereas within the Montane Forest differences between seasons are more likely explained by the rewiring of interactions. Results indicate that the decrease in species diversity with elevation affects network structure, increasing nestedness and reducing specialization and modularity.

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The effect of conspecific density, herbivory, and bamboo on seedling dynamics of a dominant oak in a Neotropical highland forest

Cited by 8 publications

References 72 publications

Large mammalian herbivores modulate plant growth form diversity in a tropical rainforest

Large mammalian herbivores modulate plant growth form diversity in a tropical rainforest

Canopy openness modifies tree seedling distributions along a tropical forest elevation gradient

Elevational and seasonal patterns of plant pollinator networks in two highland tropical ecosystems in Costa Rica

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