Finn Borchsenius 15-09-2015 Aarhus University Science Museums 1 What we lost during glaciations Finn Borchsenius NordGen Conference Riga, Latvia, 15. Sep. 2015
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
1
What we lost during glaciations
Finn Borchsenius
NordGen Conference
Riga, Latvia, 15. Sep. 2015
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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.
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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Temperate tree species diversity anomalySou
rce: Ricklefs&
Schlu
ter1993
570
122
23666
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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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
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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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
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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Tertiary coolingW
illis & M
cElwain
2002
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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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)
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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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
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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Severe restriction of temperate forests in Europe during Pleistocene glaciations
• Meditteranean barrier plus dry climate in S
Willis &
McElw
ain2002
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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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
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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Most taxa were lost early in Pleistocene
Pterocaryafraxinifolia
Zelkova sicula
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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Selective extinctionSvenning 2003, Ecol. Lett.
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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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.
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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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
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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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.!
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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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.!
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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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 ‐‐‐
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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Strong relationship between extinction frequency and cold tolerance
Example: European region
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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Survivors phylogenetically clustered
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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Example: Phylogenies for Angiosperm trees in Europe (left) and Asia (right) with survivors in red
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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Simulations gave similar results
Random extinction Extinction related to "survival trait" evolved by Brownian motion
Finn Borchsenius15-09-2015
Aarhus UniversityScience Museums
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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/