Dataset Information

Historical reconstruction of climatic and elevation preferences and the evolution of cloud forest-adapted tree ferns in Mesoamerica.

ABSTRACT:

Background

Cloud forests, characterized by a persistent, frequent or seasonal low-level cloud cover and fragmented distribution, are one of the most threatened habitats, especially in the Neotropics. Tree ferns are among the most conspicuous elements in these forests, and ferns are restricted to regions in which minimum temperatures rarely drop below freezing and rainfall is high and evenly distributed around the year. Current phylogeographic data suggest that some of the cloud forest-adapted species remained in situ or expanded to the lowlands during glacial cycles and contracted allopatrically during the interglacials. Although the observed genetic signals of population size changes of cloud forest-adapted species including tree ferns correspond to predicted changes by Pleistocene climate change dynamics, the observed patterns of intraspecific lineage divergence showed temporal incongruence.

Methods

Here we combined phylogenetic analyses, ancestral area reconstruction, and divergence time estimates with climatic and altitudinal data (environmental space) for phenotypic traits of tree fern species to make inferences about evolutionary processes in deep time. We used phylogenetic Bayesian inference and geographic and altitudinal distribution of tree ferns to investigate ancestral area and elevation and environmental preferences of Mesoamerican tree ferns. The phylogeny was then used to estimate divergence times and ask whether the ancestral area and elevation and environmental shifts were linked to climatic events and historical climatic preferences.

Results

Bayesian trees retrieved Cyathea, Alsophyla, Gymnosphaera and Sphaeropteris in monophyletic clades. Splits for species in these genera found in Mesoamerican cloud forests are recent, from the Neogene to the Quaternary, Australia was identified as the ancestral area for the clades of these genera, except for Gymnosphaera that was Mesoamerica. Climate tolerance was not divergent from hypothesized ancestors for the most significant variables or elevation. For elevational shifts, we found repeated change from low to high elevations.

Conclusions

Our data suggest that representatives of Cyatheaceae main lineages migrated from Australia to Mesoamerican cloud forests in different times and have persisted in these environmentally unstable areas but extant species diverged recentrly from their ancestors.

SUBMITTER: Sosa V

PROVIDER: S-EPMC5119233 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Historical reconstruction of climatic and elevation preferences and the evolution of cloud forest-adapted tree ferns in Mesoamerica.

Sosa Victoria V Ornelas Juan Francisco JF Ramírez-Barahona Santiago S Gándara Etelvina E

PeerJ 20161116

<h4>Background</h4>Cloud forests, characterized by a persistent, frequent or seasonal low-level cloud cover and fragmented distribution, are one of the most threatened habitats, especially in the Neotropics. Tree ferns are among the most conspicuous elements in these forests, and ferns are restricted to regions in which minimum temperatures rarely drop below freezing and rainfall is high and evenly distributed around the year. Current phylogeographic data suggest that some of the cloud forest-ad ...[more]

PMID: 27896030

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Project description:Question:What is the impact of simulated historical tree litter removal on understorey plants and soil properties in a temperate deciduous forest? What is the role of seasonal timing of tree litter removal on understorey plants? Location:Podyjí National Park, Czech Republic. Methods:We conducted an experiment in a randomized complete block design of 45 plots (5 × 5 m). Each block (N = 15) consisted of one plot for each of the three treatments. Treatments consisted of (i) tree litter removal during spring, (ii) tree litter removal during autumn, or (iii) no litter removal as control treatment. These treatments were repeated for a duration of four years. In each plot we recorded the understorey plant species composition and collected soil samples prior to treatment (year 0) and in each subsequent year (years 1-4). Temporal trends in species richness were analysed using repeated measures ANOVAs. The impact of the treatments on vegetation composition over time was analysed using Principal Response Curves. Results:Total species richness per plot significantly changed over time, but this was not related to treatment. Annual species richness increased significantly, but only for the autumn treatment. Annual species also showed the highest inter-annual variation. Endangered species were not affected. When compared to the control treatment, the effect of autumn raking on species composition was stronger than the effect of spring raking. Although the amount of removed nutrients substantially exceeded ambient nitrogen input, no changes in soil conditions were detected. Conclusions:The season in which tree litter removal took place had a small but significant impact on the understorey vegetation, in particular affecting the germination and establishment of annual species. The large inter-annual variation in species richness calls for a long-term field experiment. The removal of nutrients via litter raking greatly exceeds atmospheric nutrient deposition, warranting a further investigation of litter raking as a potential tool for forest conservation.

Dataset Information

Historical reconstruction of climatic and elevation preferences and the evolution of cloud forest-adapted tree ferns in Mesoamerica.

Background

Methods

Results

Conclusions

Publications

Historical reconstruction of climatic and elevation preferences and the evolution of cloud forest-adapted tree ferns in Mesoamerica.

Similar Datasets

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