skip to main content


Title: Integrating historical biogeography and environmental niche evolution to understand the geographic distribution of Datureae
Premise

The distributions of plant clades are shaped by abiotic and biotic factors as well as historical aspects such as center of origin. Dispersals between distant areas may lead to niche evolution when lineages are established in new environments. Alternatively, dispersing lineages may exhibit niche conservatism, moving between areas with similar environmental conditions. Here we test these contrasting hypotheses in the Datureae clade (Solanaceae).

Methods

We used maximum likelihood methods to estimate the ancestral range of Datureae along with the history of biogeographic events. We then characterized the niche of each taxon using climatic and soil variables and tested for shifts in environmental niche optima. Finally, we examined how these shifts relate to the niche breadth of taxa and clades within Datureae and the degree of overlap between them.

Results

Datureae originated in the Andes and subsequently expanded its range to North America and non‐Andean regions of South America. The ancestral niche, and that of mostDaturaandTrompettiaspecies, is dry, whileBrugmansiaspecies likely shifted toward a more mesic environment. Nonetheless, most Datureae present moderate to high overlap in niche breadth today.

Conclusions

The expansion of Datureae into North America was associated with niche conservatism, with dispersal into similarly dry areas as occupied by the ancestral lineage. Subsequent niche evolution, including the apparent shift to a mesic niche inBrugmansia, diversified the range of habitats occupied by species in the tribe Datureae but also led to significant niche overlap among the three genera.

 
more » « less
Award ID(s):
1413855
NSF-PAR ID:
10371232
Author(s) / Creator(s):
 ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
American Journal of Botany
Volume:
106
Issue:
5
ISSN:
0002-9122
Page Range / eLocation ID:
p. 667-678
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract Aim

    While the floras of eastern Asia (EA) and eastern North America (ENA) share numerous genera, they have drastically different species richness. Despite an overall similarity in the quality of their temperate climates, the climate of EA is more spatially heterogeneous than that of ENA. Spatial environmental heterogeneity has been found to play a key role in influencing species richness in some regions. Here, we tested the following hypotheses: (a) EA species will occupy larger climatic niches than their ENA congeners, (b) congeners of EA‐ENA disjunct genera will occupy statistically equivalent climatic niches, and (c) congeners of EA‐ENA disjunct genera will occupy more similar climatic niches than expected by their respective physiographic context.

    Location

    North America and Asia.

    Time period

    Present.

    Major taxa studied

    Seed plants.

    Methods

    Predictions generated by ecological niche models (ENMs) were compared for 88 species across 31 EA‐ENA disjunct genera. ENM predictions were assessed for geographic and ecological breadth. Tests for niche equivalency and similarity were performed for congeneric species pairs to determine if species of disjunct genera have experienced niche conservatism or divergence.

    Results

    EA species tend to occupy greater amounts of climatic niche space than their close relatives in ENA. Over two‐thirds of the conducted niche comparisons show that EA‐ENA congeners either occupy equivalent climatic niche space within these broader climatic regimes or occupy non‐equivalent niches that are as similar as expected given their physiographic contexts.

    Main conclusions

    EA species tend to occupy larger climatic niches, and congeners of EA‐ENA disjunct genera tend to occupy equivalent/similar niche space within their respective distributions, with differences in occupied niches possibly due to their respective physiographic contexts, highlighting how niche‐neutral processes and niche conservatism may affect the distributions of disjunct species.

     
    more » « less
  2. Abstract Aim

    We investigate the evolutionary mechanisms that allow morphologically convergent lineages to share the same geographical space. We compared the evolutionary events that occurred along the diversification ofKarawataandAechmeasubgen.Chevalierain the Atlantic Forest by (a) verifying whether the climatic niches and habitats ofKarawataandChevalieraare similar; (b) testing whether the two groups had the same pattern of colonization in the Atlantic Forest; and (c) evaluating whether they had the same evolutionary dynamics of environmental space occupation.

    Location

    Brazilian Atlantic Forest

    Taxon

    KarawataandAechmeasubgen.Chevaliera(Bromeliaceae: Bromelioideae)

    Methods

    We explored differences in evolutionary dynamics betweenKarawataandChevalieraby (a) analyzing their divergence times using Bayesian inference with a relaxed molecular clock; (b) estimating ancestral ranges and habitats with Dispersion Extinction Cladogenesis Lagrange and Statistical Dispersal Vicariance analyses; (c) testing climatic niche similarity, equivalency and overlap using principal component analysis; and, (d) evaluating shifts in speciation dynamics using Bayesian Analysis of Macroevolutionary Mixtures.

    Results

    KarawataandChevalieramost likely originated in the Pliocene and diversified during the Pleistocene. The two clades originated in ombrophilous forests and shared a similar environmental space. However,KarawataandChevalierashow different dynamics in the occupation of geographical and environmental spaces.

    Main Conclusions

    Our results suggest that the São Francisco and Jequitinhonha Rivers acted as geographical barriers forKarawataandChevaliera. Differences in spatial and environmental evolutionary dynamics have allowed the two groups to occupy similar habitats as well as environmental and geographical spaces in the Brazilian Atlantic Forest.

     
    more » « less
  3. Abstract Aim

    Historical processes that shaped current diversity patterns of seaweeds remain poorly understood. Using Dictyotales, a globally distributed order of brown seaweeds as a model, we test if historical biogeographical and diversification patterns are comparable across clades. Dictyotales contain some 22 genera, three of which,Dictyota,LobophoraandPadina, are exceptionally diverse. Specifically, we test whether the evolutionary processes that shaped the latitudinal diversity patterns in these clades are in line with the tropical conservatism, out‐of‐the‐tropics or diversification rate hypotheses.

    Location

    Global coastal benthic marine environments.

    Taxon

    Dictyotales (Phaeophyceae).

    Methods

    Species diversity was inferred using DNA‐based species delineation, addressing cryptic diversity and circumventing taxonomic problems. A six‐gene time‐calibrated phylogeny, distribution data of 3,755 specimens and probabilistic modelling of geographical range evolution were used to infer historical biogeographical patterns. The phylogeny was tested against different trait‐dependent models to compare diversification rates for different geographical units as well as different thermal affinities.

    Results

    Our results indicate that Dictyotales originated in the Middle Jurassic and reach a current peak of species diversity in the Central Indo‐Pacific. Ancestral range estimation points to a southern hemisphere origin of Dictyotales corresponding to the tropical southern Tethys Sea. Our results demonstrate that diversification rates were generally higher in tropical regions, but increased diversification rates in different clades are driven by different processes. Our results suggest that three major clades underwent a major diversification burst in the early Cenozoic, withDictyotaandPadinaexpanding their distribution into temperate regions whileLobophoraretained a predominantly tropical niche.

    Main conclusions

    Our results are consistent with both the tropical conservatism hypothesis, in which clades originate and remain in the tropics (Lobophora), and the out‐of‐the‐tropics scenario, where taxa originate and expand towards the temperate regions while preserving their presence in the tropics (Dictyota,Padina).

     
    more » « less
  4. Abstract Aim

    Due to the sessile nature of flowering plants, movements to new geographical areas occur mainly during seed dispersal. Frugivores tend to be efficient dispersers because animals move within the boundaries of their preferable niches, so seeds are more likely to be transported to environments that are similar to where the parent plant occurs. However, this efficiency can result in less opportunity for niche shifts over macroevolutionary time, ‘trapping’ plant lineages in particular climatic conditions. Here we test this hypothesis by analysing the role that the interaction with frugivores play in changing dynamics of climatic niche evolution in five clades of flowering plants.

    Location

    Global.

    Taxon

    The flowering plant families Apocynaceae, Ericaceae, Melastomataceae, Rosaceae and Solanaceae.

    Methods

    We model climatic niche evolution as a variable parameter Ornstein–Uhlenbeck process. However, rather than assuming regimes a priori, we use a hidden Markov model (HMM) to infer the complex evolutionary history associated with different modes of seed dispersal. In addition to allowing for a more accurate picture of the regimes, the use of HMMs allows partitioning the variance of climatic niche evolution to include dynamics independent of our focal character.

    Results

    Lineages dispersed by frugivores tend to have warmer and wetter climatic optima and are generally associated with areas where potential for vegetation growth is higher. However, lineages distributed in more mesic habitats, such as rainforests, are generally associated with slower rates of climatic niche evolution regardless of their mode of seed dispersal.

    Main Conclusions

    Characteristics of the abiotic environment may facilitate the evolution of some types of plant–animal interactions. Association with frugivores is an important modulator of how plants move in space, but its impact on their climatic niche evolution appears to be indirect. Seed dispersal by frugivores may facilitate the establishment of lineages in closed canopy biomes, but the general slower rates of climatic niche evolution in these habitats are possibly related to other general aspects of the ‘mesic syndrome’ rather than the behaviour of the animals that disperse their seeds.

     
    more » « less
  5. Premise

    Despite the fast pace of exploration of the patterns and processes influencing Neotropical plant hyperdiversity, the taxa explored are mostly from large groups that are widely distributed, morphologically diverse, or economically important. Vochysiaceae is an example of an undersampled taxon, providing an excellent system for investigating Neotropical biogeography. We present a phylogenomics‐based hypothesis of species relationships in Vochysiaceae to investigate its evolutionary history through space and time.

    Methods

    We inferred a phylogeny for 122 species from Vochysiaceae and seven other families of Myrtales. Fossils from four myrtalean families were used to estimate the divergence times within Vochysiaceae. Historical biogeography was estimated using ancestral range probabilities and stochastic mapping.

    Results

    Monophyly of all genera was supported except forQualea, which was split byRuizteraniainto two clades. Vochysiaceae originated ~100 mya, splitting into an Afrotropical and a Neotropical lineage ~50 mya, and its ancestral range is in the area currently occupied by the Cerrado.

    Conclusions

    The most recent common ancestor of Vochysiaceae + Myrtaceae had a West Gondwanan distribution, supporting a South American + African ancestral range of Vochysiaceae. On a global scale, geographic range reduction was the principal biogeographic event. At a finer scale, initial range reduction was also important and the Cerrado region was the most ancestral area with multiple colonization events to the Amazon, Central America, and the Atlantic Forest. Colonization events occurred from open areas to forest vegetation, an unusual finding regarding the evolution of plants in the Neotropics.

     
    more » « less