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- Castaño, Nicolas, et al.
(författare)
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Contrasting drivers of aboveground woody biomass and aboveground woody productivity in lowland forests of Colombia
- 2024
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Ingår i: Ecography. - 0906-7590 .- 1600-0587. ; 2024
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Tidskriftsartikel (refereegranskat)abstract
- The relative importance of abiotic and biotic factors in shaping forest biomass stocks and fluxes remains a controversial issue. Here, using data gathered from 39 1 ha plots located in flooded and terra firme mature tropical lowland forests of the Amazon and Orinoquia regions of Colombia, we evaluated the importance of climate, soil fertility, and flooding, as well as tree taxonomic/phylogenetic diversity and forest structural properties, in determining the aboveground biomass stocks (AGB; Mg ha−1) and aboveground woody productivity (AWP; Mg ha−1 year−1). Using information-theoretic multimodel inference and variance partitioning we found that forest structural features such as the number of trees with diameter at breast height ≥ 70 cm, and wood density, are the main drivers of variation in AGB. However, taxonomic diversity also contributes to AGB because it is associated with more large trees in these forests. In contrast, the key drivers of AWP in these forests were soil P and Mg concentrations, with no significant effects of diversity indices. These findings emphasize the need to include major soil cations other than N and P (e.g. Mg) in experimental studies to improve our understanding about the extent to which soil fertility can modulate increases in forest AWP due to climate change. Terra firme forests had higher AGB stocks than flooded forests, but both had similar AWP; and we found similar results for the drivers of AGB and AWP between flooded and terra firme forests. Our results provide limited evidence for strong effects of plant diversity on AGB or AWP. Therefore, we call for caution on generalizations of nature-based initiatives aiming to preserve diversity based on maximizing carbon stocks and productivity, due to the complex nature of the processes controlling carbon accumulation and carbon fluxes in tropical forests.
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| 2. |
- Zuleta, Daniel, 1990, et al.
(författare)
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Importance of topography for tree species habitat distributions in a terra firme forest in the Colombian Amazon
- 2020
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 450, s. 133-149
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To test the relative importance of topography versus soil chemistry in defining tree species-habitat associations in a terra firme Amazonian forest. Method: We evaluated habitat associations for 612 woody species using alternative habitat maps generated from topography and soil chemistry in the 25-ha Amacayacu Forest Dynamics Plot, Colombian Amazon. We assessed the ability of each habitat map to explain the community-level patterns of species-habitat associations using two methods of habitat randomization and different sample size thresholds (i.e., species’ abundance). Results: The greatest proportion of species-habitat associations arose from topographically-defined habitats (55% to 63%) compared to soil chemistry-defined (19% to 40%) or topography plus soil chemistry-defined habitats (18% to 42%). Results were robust to the method of habitat randomization and to sample size threshold. Conclusions: Our results demonstrate that certain environmental factors may be more influential than others in defining forest-level patterns of community assembly and that comparison of the ability of different environmental variables to explain habitat associations is a crucial step in testing hypotheses about the mechanisms underlying assembly. Our results point to topography-driven hydrological variation as a key factor structuring tree species distributions in what are commonly considered homogeneous Amazonian terra firme forests.
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