NordGen Finn Borchsenius · 2015. 9. 18. · Finn Borchsenius 15-09-2015 Aarhus University Science...

Finn Borchsenius15-09-2015

Aarhus UniversityScience Museums

1

What we lost during glaciations

Finn Borchsenius

NordGen Conference

Riga, Latvia, 15. Sep. 2015



2

A forest in Denmark• Bolderslev Fotest, S JUtland

• 133 ha semi-natural deciduousforest with dominance of Fagus, Tilia, Fraxinus and Quercus

• 21 tree species, 8 shrubs, 6 woody climbers = 72% of Danish woody flora

Borchsen

ius et al. 2004, Plan

t. Ecol.



3

Temperate tree species diversity anomalySou

rce: Ricklefs&

Schlu

ter1993

570

122

23666



4

Predicted versus observed richness

• Asian forest communities significantly richerthan North American and European forests

Data from

Latham

&Ricklefs

1993, Oikos

Average observed richness as percent of predicted richness based on a global relation S ~AET

Asia (n=14) 157

E Am (n=7) 61

W Am (n=4) 61

Europe (n=1) 42

Two forests moved around: S~Area+AET+Region

Bialowiesa, Poland

Pukhansan, S Korea

Obs 25 82

Pre (Europe) 25 23

Pre (Am W) 31 28

Pre (Am E) 54 49

Pre (Asia E) 102 93



5

Origin of temperate deciduous forests

• Eocene: first nemoral forests poleward of 70°N – Gingko, Larix, Pseudolarix,

Metasequoia, Taxodium, Glyptostrobus, Alnus, Betula, Quercus, Juglans, Populus, Acer

– Deciduousness: winter darkness, not temperature?

Wolfe 1985 G

eophys. M

onog

r. + Mai 1995



6

Tertiary coolingW

illis & M

cElwain

2002



7

Miocene flora in Denmark

"...coastal areas ... dominated by Taxodium swamp forests that also hosted terrestrial angiosperms such as Nyssa, Betula, Alnus and ... Myricaceae. Further inland, a mixed deciduous–evergreen forest prevailed. In areas with better drained soils ..., conifer forests ... including taxa such as Pinus, Sequoia and Sciadopitys."

Larsson et a. 2011, Pal.

Pal. Pal.

Taxodium distichum (Bald cypress), Four Holes Swamp, South Carolina (from www)



8



9

Miocene-Pliocene alteration of climate zones• Loss of warm

temperate taxa in Europe and W North America

• Increasingsummer droughtand expansion of mediterranentype climate

From Mai 1995



10

Severe restriction of temperate forests in Europe during Pleistocene glaciations

• Meditteranean barrier plus dry climate in S

Willis &

McElw

ain2002



11

Neogene extinctions by region• Heavy losses from

Europe and W North America

• Moderate losses in E North America, little loss in E Asia

Latham

&Ricklefs

1993, Oikos



12

Most taxa were lost early in Pleistocene

Pterocaryafraxinifolia

Zelkova sicula



13

Selective extinctionSvenning 2003, Ecol. Lett.



14

Consequences for phylogenetic diversity?

• Test case: Plio- Pleistocene extinctions of north-hemispherical tree flora

• Four hypotheses:– Extinction driven by climatic cooling

– Key traits for survival phylogenetically conserved

– > Extinctions phylogenetically clustered

– > Effect stronger at high extinction rates

Eiserhardt, Borch

seniu

s et al. 2015, Ecol. Lett.



15

Effect of extinction on phylogeneticdiversity controversial

• 80% of the evolutionary history may besaved at 95% extinction (Nee &May 1997, Science)

• Accelerated effect, (e.g. Vamosi&Wilson (2008, Ecol. Lett.)

• Importance for conservation

Pausas

& V

erdu(2010), BioScien

ce



16

Methods I• Distribution data from Latham & Rickleffs 1993 plus updates

– 212 genera of temperate trees

– Four regions: W&E North-America; Europe; Asia

• Trait data from The Palaeoflora Database – Utescher & Mosbrugger (2013). http://www.palaeoflora.de.

Eiserhardt, Borch

seniu

s et al. 2015, Ecol. Lett.!



17

Methods II

• Phylogeny assembledusing Phylomatic (Webband Donoghue 2005), plus updates (45 studies)

• Dating performed usingBLADJ, fixing 60 internalnodes based on Bell et al. (2010)

Eiserhardt, Borch

seniu

s et al. 2015, Ecol. Lett.!



18

Phylogenetic diversity measures

• Faith phylogenetic diversity(PD)

• Mean Pairwise Divergencetime (MPD)

• Net Relatedness Index (NRI)– Webb et al. 2002, Annu. Rev.

Ecol. Syst.

• Both statistical analyses and simulations

NRI +++ NRI ‐‐‐



19

Strong relationship between extinction frequency and cold tolerance

Example: European region



20

Survivors phylogenetically clustered



21

Example: Phylogenies for Angiosperm trees in Europe (left) and Asia (right) with survivors in red



22

Simulations gave similar results

Random extinction Extinction related to "survival trait" evolved by Brownian motion



23

Conclusions• Climate driven extinction in the past

led to a disproportionately large lossof evolutionary history– Ongoing climate change

– E.g. selection on dispersal traits?

• European forests not onlydepapuperate in species, but evenstronger in evolutionary historyrepresented– Relationship between functional trait

diversity and ecosystem functioning, e.g. Allan et al. 2011 PNAS

http://w

ww

.techn

ology.org

/2013/08/06/deep-past-offers-clu

es-into-clim

ate-driven-biotic-sh

ifts/

NordGen Finn Borchsenius · 2015. 9. 18. · Finn Borchsenius 15-09-2015 Aarhus University Science...

Documents

Transcript of NordGen Finn Borchsenius · 2015. 9. 18. · Finn Borchsenius 15-09-2015 Aarhus University Science...