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Within a forest, differences in landform spatial variation (i.e., geomorphic settings: valley, slope, and ridge) could affect the species richness and distribution present at a particular site. Previous studies have confirmed that plant species richness and biomass changes after a hurricane and such values can vary among geomorphic settings. Understory vegetation, including ferns, herbs, climbers, graminoids, and shrubs, accounts for more than two thirds of flora in tropical ecosystems, but there is limited information of the effect of hurricanes on these communities. We evaluated the structure and composition of understory vegetation in a post-hurricane forest in relation to geomorphic settings. This study was conducted in El Verde Research Area in the Luquillo Experimental Forest, Puerto Rico. We established 1-m2 plots within three geomorphic settings: riparian valley, slope, and ridge. Within each plot we identified species, estimated percent of cover, and collected biomass samples. Additionally, we estimated species accumulation curves and analyzed species composition among geomorphic settings using multivariate ordination. The relative species abundance of vegetation life-forms was similar among geomorphic settings, but graminoids and climbers exhibited differences in species composition. Higher forest understory biomass and percent vegetation cover was observed at this immediate post-hurricane period than what was reported pre-hurricane. The understory of valley areas had a more distinct species composition than what was observed among ridge and slope areas. The understory vegetation patterns observed would need to be followed through time and among the landforms to confirm the hurricane disturbances effects at these understory scale.
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Diversity – volume relationships: adding structural arrangement and volume to species – area relationships across forest macrosystems
The species – area relationship (SAR) is a common pattern in which diversity increases with the area sampled, but ecosystems are three‐dimensional (3D) and diversity – volume relationships (DVRs) may exist in ecosystems that vary substantially in their vegetation volume. We tested whether forest vegetation volume, as a 3D extension of area in SARs, was a significant predictor of taxonomic (species) and structural (arrangement) diversity in five groups of organisms across the National Ecological Observatory Network (NEON). Vegetation volume and four structural arrangement metrics within the area of NEON plots were measured using NEON's discrete return lidar. Species richness was measured as the number of species within the respective NEON plot sampling area for understory plants, trees, breeding land birds, small mammals, and ground beetles. We found that volume negatively predicted understory plants and positively predicted tree and beetle species richness across the USA forest macrosystem, but not bird and small mammal species richness. Furthermore, volume was a significant predictor of several metrics that describe the internal and external heterogeneity of vegetation in forests (structural arrangement) within the ecosystem across the USA forest macrosystem. There were several significant within site‐level relationships, but not at all sites, between volume and species richness or structural arrangement in organism groups. Our study indicates that previous work that has focused on a 2D conceptualization of habitat can be expanded to 3D habitat space, but that the strength and the positive or negative direction of DVRs may vary taxonomically or geographically.
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- Award ID(s):
- 2212859
- PAR ID:
- 10474291
- Publisher / Repository:
- Ecography
- Date Published:
- Journal Name:
- Ecography
- Volume:
- 2023
- Issue:
- 10
- ISSN:
- 0906-7590
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1111/ecog.06723
