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The Jena Experiment – More than 10 years of weeding and mowing



The Jena Experiment is one of the longest-running biodiversity experiments in Europe. Over the past 10 years, the members of our Jena Experiment consortium have been using the field site in Jena for more than 1500 documented field-activities and measurements to understand the role of biodiversity for the functioning of ecosystems. The more we learn about our model grassland ecosystem the more we see the interdependence of plants, soil, atmosphere, climate, consumers and land-use management. This is only possible because of the scientific diversity of the members of the consortium. Our team studies a great variety of phenomena that affect ecological processes, networks and strategies of organisms.


TBE_Bodenstein

In this short overview we summarize different views and research results that are necessary to achieve our research goals, which are based in several areas of natural sciences. Most of our work focuses on abiotic and biotic relationships, including species like decomposers (earthworms, arthropods and microbes), producers (plants), and consumers (herbivorous arthropods or parasitoids). As an example, we collected and analyzed several hundreds of kilograms of plant material and soil samples in our experiments so far. After we got more and more data, we also got more puzzle pieces and promising ideas how to arrange those.

  • Most impressive results have shown positive impact of high diverse communities on ecosystem functioning and productivity. Roscher et al. (2005) as well as Marquard et al. (2009) showed higher productivity in diverse mixtures that is directly related to higher bioenergy rates (Khalsa et al. 2012). Surprisingly, increasing diversity from one to 16 species had the same positive effect on biomass production than the addition of fertilizers, applied in standard agronomic amounts (Weigelt et al. 2009).

  • Progressive climate change and carbon storage in soil prompted us to focus on the capacity of carbon storage in soil and its relationship to the diversity of the plant communities. Our soil-diggers found that higher species diversity increases carbon storage rates in soil (Steinbeiss et al. 2008, Eisenhauer et al. 2010).

  • Colleagues around Eisenhauer (2011) found strong relationship between higher plant species richness and soil fauna. We found the same effect on aboveground consumers. In other words, aboveground and belowground organisms like our highly diverse plant communities and assemble more complex networks than in low diverse plots (Scherber et al. 2010, Rzanny et al. 2012 and 2012a, Ebeling et al. 2011). For instance, on high-diversity plots we found much higher bee activity, likely having important consequences for pollination (Ebeling et al. 2008, 2012).

  • Oelmann et al (2011a) found that our diverse plant communities are better in soil N storage that improves soil fertility and reduces fertilizing needs. Further they concluded that increasingly closed N cycling with increasing plant diversity reduces the negative impact of agricultural N leaching on groundwater resources (Oelmann et al. 2007a, b, Oelmann et al. (2011b). Rosenkranz et al. (2012) found that under species-rich plant communities microbial activity was favored resulting in a faster nutrient cycle.

  • Increasing plant diversity has not only been shown to increase stability in plant productivity in space and time (Weigelt et al. 2008, Roscher et al. 2011), but to increase stability in many ecosystem processes (Proulx et al. 2010).

  • We further assessed invasiveness of species while our high diverse communities showed more resistance against plant invasion processes (Petermann et al. 2010, Roscher et al. 2009, Roscher et al. 2013).

  • After collection of many variables, we put all pieces together: Allan et al. (2013) found that the plant diversity value is important for roughly 45% of the ecosystem processes we measured. However, we are working to detect the mechanisms that are currently unclear.

  • Here, people currently found that high functional and phylogenetic diversity is more important than simple species richness (soil biota - Milcu et al. 2013) and plant productivity (Roscher et al. 2012) .

So, the research goes on, and there are numerous collaborations between participating scientists. Nevertheless, the Jena Experiment is an open platform for researchers and the consortium is very happy getting new collaborators. More than 100 active researchers and more than 2000 research helpers from more than 40 different nations have contributed to the Jena Experiment since 2002 exploring flora, fauna, soil, nutrient flow, water regime, species networks and strategies, etc..

Currently, we want to know more about these strategies in different communities. Therefore, we established a new experiment in 2010 using plant traits as proxy for differential plant tactics (Fig. 1) influencing plant-plant interactions, plant-consumer interactions, nutrient cycling, and many more.

References

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Allan E., Jenkins T., Fergus A.J.F., Roscher C., Fischer M., Petermann J., Weisser W.W., Schmid B. (2013) Experimental plant communities develop phylogenetically overdispersed abundance distributions during assembly. Ecology, 94, 465-477.

Ebeling, A., Klein, A.M., Schumacher, J., Weisser, W.W., Tscharntke, T. (2008) How does plant richness affect pollinator richness and temporal stability of flower visits? Oikos, 117, 1808-1815.

Ebeling, A., Klein, A. M., Tscharntke, T. (2011) Plant-flower visitor interaction webs: Temporal stability and pollinator specialization increases along an experimental plant diversity gradient. Basic and Applied Ecology, 12, 300-309.

Ebeling, A., Klein, A. M., Weisser, W.W., Tscharntke, T. (2012) Multitrophic effects of experimental changes in plant diversity on cavity-nesting bees, wasps, and their parasitoids. Oecologia, 169, 453-465.

Eisenhauer N., Bessler H., Engels C., Gleixner G., Habekost M., Milcu A., Partsch S., Sabais A.C.W., Scherber C., Steinbeiss S., Weigelt A., Weisser W.W., Scheu S. (2010) Plant diversity effects on soil microorganisms support the singular hypothesis. Ecology, 91, 485-496.

Eisenhauer N., Milcu A., Sabais A.C.W., Bessler H., Brenner J., Engels C., Klarner B., Maraun M., Partsch S, Roscher C., Schonert F., Temperton V.M., Thomisch K., Weigelt A., Weisser W.W., Scheu S. (2011) Plant diversity surpasses plant functional groups and plant productivity as driver of soil biota in the long term. PlosOne 6, e16055.

Khalsa J., Fricke T., Weisser W.W., Weigelt A., Wachendorf M. (2012) Effects of functional groups and species richness on biomass constituents relevant for combustion: results from a grassland diversity experiment. Grass and Forage Science, 67 (4), 569-588.

Marquard, E., Weigelt, A., Temperton, V. M., Roscher, C., Schumacher, J., Buchmann, N., Fischer, M., Weisser, W.W., Schmid, B. (2009) Plant species richness and functional composition drive overyielding in a 6-year grassland experiment. Ecology, 90, 3290-3302.

Milcu A., Allan E., Roscher C., Jenkins T., Meyer S.T., Flynn D.F.B., Bessler H., Buscot F., Engels C., Gubsch M., König S., Lipowsky A., Loranger J., Renker C., Scherber C., Schmid B., Thébault E., Wubet T., Weisser W.W., Scheu S., Eisenhauer N. (2013) Functionally and phylogenetically diverse plant communities key to soil biota. Ecology, http://dx.doi.org/10.1890/12-1936.1

Oelmann Y., Wilcke W., Temperton V.M., Buchmann N., Roscher C., Schumacher J., Schulze E.-D., Weisser W.W. (2007a) Soil and plant nitrogen pools as related to plant diversity in an experimental grassland. Soil Science Society of America Journal, 71, 720-729

Oelmann Y., Kreutziger Y., Temperton V.M., Buchmann N., Roscher C., Schumacher J., Schulze E.D., Weisser W.W., Wilcke W. (2007b) Nitrogen and phosphorus budgets in experimental grasslands of variable diversity. Journal of Environmental Quality, 36, 396-407.

Oelmann Y., Buchmann N., Gleixner G., Habekost M., Roscher C., Rosenkranz S., Schulze E.-D., Steinbeiss S., Temperton V.M., Weigelt A., Weisser W.W., Wilcke W. (2011a) Plant diversity effects on above- and belowground N pools in temperate grassland ecosystems: development in the first five years after establishment. Global Biogeochemical Cycles 25 (2), DOI: 10.1029/2010GB003869

Oelmann Y, Richter AK, Roscher C, Rosenkranz S, Temperton VM, Weisser WW, Wilcke W (2011b) Does plant diversity influence phosphorus cycling in experimental grasslands? Geoderma, 167-68, 178-187.

Petermann J.S., Fergus A.J.F., Roscher C., Turnbull L.A., Weigelt A., Schmid B. (2010) Biology, chance or history? The predictable re-assembly of temperate grassland communities. Ecology, 91, 408-421.

Proulx R., Wirth C., Voigt W., Weigelt A., Roscher C., Attinger S., Baade J., Barnard R.L., Buchmann N., Buscot F., Eisenhauer N., Fischer M., Gleixner G., Halle S., Hildebrandt A., Kowalski E., Kuu A., Lange M., Milcu A., Niklaus P.A., Oelmann Y., Rosenkranz S., Sabais A., Scherber C., Scherer-

Lorenzen M., Scheu S., Schulze E.-D., Schumacher J., Schwichtenberg G., Soussana J.-F., Temperton V.M., Weisser W.W., Wilcke W., Schmid B. (2010) Diversity promotes temporal stability across levels of ecosystem organization in experimental grassland. PlosOne 5, e13382.

Roscher C., Beßler H., Oelmann Y., Engels C., Wilcke W., Schulze E.-D. (2009) Resources, recruitment limitation and invader species identity determine pattern of spontaneous invasion in experimental grasslands. Journal of Ecology, 97, 32-47.

Roscher C., Fergus A.J.F., Petermann J.S., Buchmann N., Schmid B., Schulze E.-D. (2013) What happens to the sown species if a biodiversity experiment is not weeded? BAAE, 14 (3), 187-198.

Roscher C., Schumacher J., Gubsch M., Lipowsky A., Weigelt A., Buchmann N., Schmid B., Schulze E.-D. (2012) Using plant functional traits to explain diversity-productivity relationships. PlosOne 7, e36760.

Roscher, C., Temperton, V. M., Scherer-Lorenzen, M., Schmitz, M., Schumacher, J., Schmid, B., Buchmann, N., Weisser, W. W. & Schulze, E. D. (2005) Overyielding in experimental grassland communities - irrespective of species pool or spatial scale. Ecology Letters, 8, 419-429.

Roscher C., Weigelt A., Proulx R., Marquard E., Schumacher J., Weisser W.W., Schmid B. (2011) Identifying population- and community-level mechanisms of diversity-stability relationships in experimental grasslands. Journal of Ecology, 99, 1460-1469.

Rosenkranz S., Wilcke W., Eisenhauer N., Oelmann Y. (2012) Net ammonification as influenced by plant diversity in experimental grasslands. Soil Biology & Biochemistry, 48, 78-87.

Rzanny M., Voigt W. (2012) Complexity of multitrophic interactions in a grassland ecosystem depends on plant species diversity. Journal of Animal Ecology, 81, 614-627.

Rzanny M., Kuu A., Voigt W. (2012a) Bottom-up and top-down forces structuring consumer communities in an experimental grassland. Oikos, DOI: 10.1111/j.1600-0706.2012.00114.x.

Scherber C., Eisenhauer N., Weisser W. W., Schmid B., Voigt W., Fischer M., Schulze E. D., Roscher C., Weigelt A., Allan E., Beßler, H., Bonkowski, M., Buchmann N., Buscot F., Clement L.W., Ebeling A., Engels C., Halle S., Kertscher I., Klein A.M., Koller R., König S., Kowalski E., Kummer V., Kuu, A., Lange, M., Lauterbach D., Middelhoff C., Migunova V.D., Milcu A., Müller R., Partsch S., Petermann J.S., Renker C., Rottstock T., Sabais A., Scheu S., Schumacher J., Temperton V.M., Tscharntke T. (2010) Bottom-up effects of plant diversity on multitrophic interactions in a biodiversity experiment. Nature, 468, 553-556.

Steinbeiss S., Beßler H., Engels C., Temperton V.M., Buchmann N., Roscher C., Kreutziger Y., Baade J., Habekost M., Gleixner G. (2008) Plant diversity positively affects short-term soil carbon storage in experimental grasslands. Global Change Biology, 14, 2937-2949.

Weigelt A., Schumacher J., Roscher C., Schmid B. (2008) Does biodiversity increase spatial stability in plant community biomass? Ecology Letters, 11 (4): 338-347.

Weigelt A., Weisser W.W., Buchmann N., Scherer-Lorenzen M. (2009) Biodiversity for multifunctional grasslands: equal productivity in high-diversity low-input and low-diversity high-input systems. Biogeosciences, 6, 1695-1706.