ringvorlesung bef 2014

Biodiversity research in the framework of the JenaExperiment

Lionel [email protected]

Lehrstuhl fur Terrestrische OkologieTechnische Universitat Munchen

3rd, November 2014

Lionel Hertzog (TUM) About Biodiversity 03/11/2014 1 / 33

Outline

What is biodiversity?

Global biodiversity loss

Ecosystems and ecosystem function

Biodiversity and Ecosystem function research

The Jena experiment

Results from the Jena experiment


Biodiversity


Biodiversity

CBD definition (Art. 2): the variability among living organisms from allsources, including, ’inter alia’, terrestrial, marine, and other aquaticecosystems, and the ecological complexes of which they are part: thisincludes diversity within species, between species and of ecosystems.


Biodiversity

Most of the species out there are still undescribed


Biodiversity loss

Biodiversity is declining

Butchard et al (2010) Science


Biodiversity loss

Biodiversity decline is due to various factors


Ecosystems

CBD definition (Art. 2): Ecosystem means a dynamic complex of plant,animal and micro-organism communities and their non-living environmentinteracting as a functional unitLikens (1992): An ecosystem is defined as a spatially explicit unit of theEarth that includes all of the organisms, along with all components of theabiotic environment within its boundaries


Ecosystem functions

Hooper (2005): Ecosystem function is a broad term that encompasses (...)ecosystem properties, ecosystem goods and ecosystem services.

Ecosystem properties include both size of compartments (eg pools ofmaterials like organic matter) and rates of process (eg fluxes ofmaterials among compartments).

Ecosystem goods are those ecosystem properties that have directmarket values (eg food, timber ...).

Ecosystem services are those properties of ecosystems that eitherdirectly or indirectly benefit human (eg clean air, pollination ...)


Biodiversity Ecosystem function

Species are responsible for ecosystem functioning, if theirnumber/functional groups decline what will happen to the ecosystemfunctions?


Biodiversity-ecosystem function

1 No relation: Functioncontroled by abiotic factoror species dominance

2 Linear relation: Samplingeffect, positive interaction(complementarity orfacilitation)

3 Asymptotic relation:Diversity effect strongeronce communities aregreatly impoverished

4 Negative relation:Pathogens/ parasitisminfection rates increases withtheir diversity



How to explore these hypothesis:

Observational vs experimental approach

field vs laboratory experiment

which system: grassland, forest, marine ...

Random vs targeted species loss



Cedar Creek (MN, USA) biodiversity experiment from 1994



Jena experiment (TH, DE) from 2002



BEF China, tree diversity experiment from 2009



Marine mesocosm ie Emmerson et al (2001) Nature



Climate chambers, microcosms ie Naeem and Li (1997) Nature


The Jena experiment


The weeding

Three times per year, hand-weeding of the experimental plot to maintain targetspecies richness.


The weeding

Before After


The weeding


Mowing

Mowing of the fieldsite twice per year inJune and September


Aboveground plant biomass

Abovegroundproductivity

2 sampling peryear in May andAugust

2 samples perplot 20x50cm

Sorted by species

Dried and thenweighted


Aboveground plant biomass

Plant productivityincreases withspecies richness

Plant productivityincreases withfunctional grouprichness

Slopes are varyingover time

Complementarityeffect becomestronger over time

Marcquard et al (2009) Ecology


Belowground plant biomass

Belowgroundproductivity

One sample per year

Soil core 0-50cm

Roots washed, dried for72h

Weighting of roots


Aboveground-Belowground biomass

Ravenek et al (2014) Oikos

Diversity effect only 4 years after experiment onset

No support for vertical root differentiation, negative plant-soilfeedbacks at low diversity


Root/Shoot biomass

Bessler et al (2009) Ecology

Root/shoot biomasslower in mixture thanexpected frommonocultures

Overyielding ofaboveground biomass islinked to this deviationfrom expected R/S ratio

Species-rich communitiesinvest less inbelowground organs


Pathogens resistance

Latz et al (2012) Journal of Ecology

Bacteria producinganti-fungal compoundsincrease in abundancewith plant speciesrichness

Positive indirectplant-soil feedback, maycontribute to explainsome other results


Carbon storage

Measurement of soil carbon concentrationOne sample every two yearsDepth from 0 to 30 cm


Carbon storage

Carbon storage increaseswith plant diversity after4 years of the experiment

Higher plant diversitymitigate carbon loss indeep soil layers

System with high plantdiversity might act ascarbon sink and mitigatepart of human CO2

emission.Steinbeiss et al (2008) Global Change Biology


N cycle

Increase in the positiveeffect of plant diversityon aboveground Nstorage

Diverse mixture reducenitrate in the soil in theearly years, in later yearsdiversity increaseammoniumconcentration

High diverse mixturereduce fertilization needand reduce N leaching togroundwater

Oelmann et al (2011) Global Biogeochemicalcycles


What I do


Potential project

http://www.ecology.uni-jena.de/praktika_bachelor_master_

themen_institut_oekologie.html


http://www.ecology.uni-jena.de/praktika_bachelor_master_themen_institut_oekologie.html

http://www.ecology.uni-jena.de/praktika_bachelor_master_themen_institut_oekologie.html

ringvorlesung bef 2014

Environment

ecosystem properties

ecosystem goods

ecosystem services

ecosystem functionshooper

ecosystem functionbiodiversity

biodiversity research

biodiversitylionel hertzog

boundarieslionel hertzog