Climate, niche evolution, and diversification of the “bird‐cage” evening primroses (Oenothera, sections Anogra and Kleinia)

Margaret Evans, Post-doc; YIBS, EEB, Yale UniversityStephen Smith, PhD student; EEB, Yale UniversityRachel Flynn, Undergraduate; Yale UniversityMichael Donoghue, Professor; Peabody Museum, EEB,

Yale University

plant diversity~300,000 species

Explanations for plant diversity:Evolutionary vs.Climatic

High elevation or latitude,meadows, prairies

evening primroses (Oenothera, sections Anogra and Kleinia)

Low elevation, Sonoran Desert

Mid elevation, foothills

19 taxaWestern North America

two endangered species

Oenothera californica ssp. eurekensisEureka Dunes, Death Valley National Park

Origins?

Stem date ~ 9 my

Evolutionary radiation during the Quaternary, Pleistocene

glacial-interglacial climatic fluctuations, migration, vicariance

Crown date ~ 0 my

…How old is this diversity?

Qualitatively,Occupy a diversity of habitats/climates (deserts to alpine meadows)Radiated in the last ~1 million years

Approach:Combine niche models

phylogenetic information time scale

Quantify and visualize niche evolution

To understand speciation/diversification in relation to climate

Origins?How has the evolution of this group been influenced by climate?

Step 1:Characterize extant species’ climatic tolerances

locality data from herbarium specimen

Quantify and visualize niche evolution

Georeferenced locality data

+

Environmental layers

herbarium specimens

19 Bioclim variables (temperature, precipitation)

Predicted species distribution

algorithm

Where the species is

What the environment is like there

Where you should find the species on the landscape

Species Distribution Modeling

Maxent

Maxent output

Probability Distribution -predicted suitability of the landscape

cumulative probability of occurrence

Probability Distribution -predicted suitability of the landscape

Characterize extant species’ climatic tolerances

predicted occupancy of a climatic niche dimension

sum probabilities according to the

climate data

niche occupancy profiles

Characterize extant species’climatic tolerances

Step 2:Phylogenetic relationships?

Step 1:Characterize extant species’ climatic tolerances

6 gene regions(one nuclear, five cp)~6500 bpBayesian analysis

Phylogeny (topology) Dating (time scale)

Step 2: Phylogenetic relationshipsStep 1: Characterize extant species’ climatic tolerances

Step 3: Reconstruct evolution of climatic tolerances

Brownian motion model of evolution•weighted mean of daughters•(weights inversely proportional to the branch lengths)

3 2 9 5 2

3

22

11

4 46

2.5

75.9

5.3

Step 2: Phylogenetic relationshipsStep 1: Characterize extant species’ climatic tolerances

Step 3: Reconstruct evolution of climatic tolerances

Brownian motion model of evolution•weighted mean of daughters•(weights inversely proportional to the branch lengths)

Two issues:Intraspecific variabilityPhylogenetic uncertainty

samples from climate profiles

samples from posterior distribution of trees

3 2 9 5 2

3

22

11

4 46

2.5

75.9

5.3

reconstruct the evolution of ecological niches

ecological radiation

evolution of ecological niches

ecological radiation

summer rain vs. summer drought

evolution of ecological niches

ecological radiation

summer rain vs. summer drought

freezing temperatures

Niches have evolved quite a bit: summer rain vs. summer droughtfreezing temperatures

Climatic heterogeneity of WNA has been template for niche evolutionThis niche evolution and diversification occurred in last 1 my

spatio‐temporal climatic heterogeneity, and adaptation to it, probably played a role in generating diversity

Evans, Smith, Flynn, and Donoghue. in revision.

The American Naturalist.

conceptual models for speciation in response to climate change

conceptual models for speciation in response to climate change

Biodiversity “pump” hypothesis

Migration of an ancestor similar to O. californica ssp. avita or O. neomexicana

Leaving behind O. arizonicaO. californica ssp. eurekensisO. californica ssp. californica

Other hotspots of plant diversity explained by spatio-climatic heterogeneity??

Explanations for plant diversity:Evolution andClimate

We can use niche modeling and phylogenetic information to estimate or “reconstruct” evolution of climatic tolerances (niche evolution).

Infer: what were the climatic tolerances of ancestors?

Make inference on the role of climate in diversification, speciation.

Summary

Might evolution in response to climate change mitigate predictions about biodiversity loss?  

slope=rate

Evans, Smith, Sytsma and Donoghue. in prep.

How fast must evolution be, and how does that compare to past rates of evolution?