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Abstract High alpine regions are threatened but understudied ecosystems that harbor diverse endemic species, making them an important biome for testing the role of environmental factors in driving functional trait‐mediated community assembly processes. We tested the hypothesis that plant community assembly along a climatic and elevation gradient is influenced by shifts in habitat suitability, which drive plant functional, phylogenetic, and spectral diversity. In a high mountain system (2400–3500 m) Región Metropolitana in the central Chilean Andes (33°S, 70°W). We surveyed vegetation and spectroscopic reflectance (400–2400 nm) to quantify taxonomic, phylogenetic, functional, and spectral diversity at five sites from 2400 to 3500 m elevation. We characterized soil attributes and processes by measuring water content, carbon and nitrogen, and net nitrogen mineralization rates. At high elevation, colder temperatures reduced available soil nitrogen, while at warmer, lower elevations, soil moisture was lower. Metrics of taxonomic, functional, and spectral alpha diversity peaked at mid‐elevations, while phylogenetic species richness was highest at low elevation. Leaf nitrogen increased with elevation at the community level and within individual species, consistent with global patterns of increasing leaf nitrogen with colder temperatures. The increase in leaf nitrogen, coupled with shifts in taxonomic and functional diversity associated with turnover in lineages, indicate that the ability to acquire and retain nitrogen in colder temperatures may be important in plant community assembly in this range. Such environmental filters have important implications for forecasting shifts in alpine plant communities under a warming climate.
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This content will become publicly available on August 25, 2026
Consequences of deforestation on functional community structure reverse at high elevations
Functional diversity is expected to decrease following land conversion. Empirically, however, the consequences of such changes are highly variable. One possible explanation is that the magnitude and direction of functional diversity change depends on how agricultural land conversion interacts with the original determinants of community assembly (e.g., temperature and elevation gradients). We compared the functional structure of 50 Anolis lizard communities on the island of Hispaniola in both forested and deforested habitats along an elevation gradient, as elevation often determines community composition. We used morphological measurements of body size, limb and tail length, and toepad width to capture ecomorphological aspects of functional diversity. These traits are strongly linked to habitat use which has been shown to be the primary axis of niche partitioning in anoles. We found that deforestation had little effect on functional (morphological) richness at low elevations but increased functional richness and evenness at high elevations, where natural communities are depauperate due to thermal constraints. Simultaneously, deforestation reduced spatial turnover and eliminated morphologically peripheral species. These results suggest that how land conversion affects communities depends on whether it relaxes or reinforces a community’s dominant environmental filters: at high elevations, as deforestation increases daytime temperatures, the filters that typically shape these communities are relaxed, allowing them to functionally resemble low elevation communities. While this enriches high-elevation communities, it also removes morphologically unique species and homogenizes diversity across elevations. Our results highlight that how land conversion reorganizes the functional structure of a community depends on that community’s environmental context.
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- Award ID(s):
- 2055486
- PAR ID:
- 10645256
- Publisher / Repository:
- The American Naturalist
- Date Published:
- Journal Name:
- The American Naturalist
- ISSN:
- 0003-0147
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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