@article{BluethgenDormannPratietal.2012, author = {Bl{\"u}thgen, Nico and Dormann, Carsten F. and Prati, Daniel and Klaus, Valentin H. and Kleinebecker, Till and Hoelzel, Norbert and Alt, Fabian and Boch, Steffen and Gockel, Sonja and Hemp, Andreas and M{\"u}ller, J{\"o}rg and Nieschulze, Jens and Renner, Swen C. and Sch{\"o}ning, Ingo and Schumacher, Uta and Socher, Stephanie A. and Wells, Konstans and Birkhofer, Klaus and Buscot, Francois and Oelmann, Yvonne and Rothenw{\"o}hrer, Christoph and Scherber, Christoph and Tscharntke, Teja and Weiner, Christiane N. and Fischer, Markus and Kalko, Elisabeth K. V. and Linsenmair, Karl Eduard and Schulze, Ernst-Detlef and Weisser, Wolfgang W.}, title = {A quantitative index of land-use intensity in grasslands integrating mowing, grazing and fertilization}, series = {Basic and applied ecology : Journal of the Gesellschaft f{\"u}r {\"O}kologie}, volume = {13}, journal = {Basic and applied ecology : Journal of the Gesellschaft f{\"u}r {\"O}kologie}, number = {3}, publisher = {Elsevier}, address = {Jena}, issn = {1439-1791}, doi = {10.1016/j.baae.2012.04.001}, pages = {207 -- 220}, year = {2012}, abstract = {Land use is increasingly recognized as a major driver of biodiversity and ecosystem functioning in many current research projects. In grasslands, land use is often classified by categorical descriptors such as pastures versus meadows or fertilized versus unfertilized sites. However, to account for the quantitative variation of multiple land-use types in heterogeneous landscapes, a quantitative, continuous index of land-use intensity (LUI) is desirable. Here we define such a compound, additive LUI index for managed grasslands including meadows and pastures. The LUI index summarizes the standardized intensity of three components of land use, namely fertilization, mowing, and livestock grazing at each site. We examined the performance of the LUI index to predict selected response variables on up to 150 grassland sites in the Biodiversity Exploratories in three regions in Germany(Alb, Hainich, Schorlheide). We tested the average Ellenberg nitrogen indicator values of the plant community, nitrogen and phosphorus concentration in the aboveground plant biomass, plant-available phosphorus concentration in the top soil, and soil C/N ratio, and the first principle component of these five response variables. The LUI index significantly predicted the principal component of all five response variables, as well as some of the individual responses. Moreover, vascular plant diversity decreased significantly with LUI in two regions (Alb and Hainich). Inter-annual changes in management practice were pronounced from 2006 to 2008, particularly due to variation in grazing intensity. This rendered the selection of the appropriate reference year(s) an important decision for analyses of land-use effects, whereas details in the standardization of the index were of minor importance. We also tested several alternative calculations of a LUI index, but all are strongly linearly correlated to the proposed index. The proposed LUI index reduces the complexity of agricultural practices to a single dimension and may serve as a baseline to test how different groups of organisms and processes respond to land use. In combination with more detailed analyses, this index may help to unravel whether and how land-use intensities, associated disturbance levels or other local or regional influences drive ecological processes.}, language = {en} } @article{TuerkeAndreasGossneretal.2012, author = {T{\"u}rke, Manfred and Andreas, Kerstin and Gossner, Martin M. and Kowalski, Esther and Lange, Markus and Boch, Steffen and Socher, Stephanie A. and M{\"u}ller, J{\"o}rg and Prati, Daniel and Fischer, Markus and Meyh{\"o}fer, Rainer and Weisser, Wolfgang W.}, title = {Are gastropods, rather than ants, important dispersers of seeds of myrmecochorous forest herbs?}, series = {The American naturalist : a bi-monthly journal devoted to the advancement and correlation of the biological sciences}, volume = {179}, journal = {The American naturalist : a bi-monthly journal devoted to the advancement and correlation of the biological sciences}, number = {1}, publisher = {Univ. of Chicago Press}, address = {Chicago}, issn = {0003-0147}, doi = {10.1086/663195}, pages = {124 -- 131}, year = {2012}, abstract = {Seed dispersal by ants (myrmecochory) is widespread, and seed adaptations to myrmecochory are common, especially in the form of fatty appendices (elaiosomes). In a recent study, slugs were identified as seed dispersers of myrmecochores in a central European beech forest. Here we used 105 beech forest sites to test whether myrmecochore presence and abundance is related to ant or gastropod abundance and whether experimentally exposed seeds are removed by gastropods. Myrmecochorous plant cover was positively related to gastropod abundance but was negatively related to ant abundance. Gastropods were responsible for most seed removal and elaiosome damage, whereas insects (and rodents) played minor roles. These gastropod effects on seeds were independent of region or forest management. We suggest that terrestrial gastropods can generally act as seed dispersers of myrmecochorous plants and even substitute myrmecochory, especially where ants are absent or uncommon.}, language = {en} } @article{SocherPratiBochetal.2012, author = {Socher, Stephanie A. and Prati, Daniel and Boch, Steffen and M{\"u}ller, J{\"o}rg and Klaus, Valentin H. and H{\"o}lzel, Norbert and Fischer, Markus}, title = {Direct and productivity-mediated indirect effects of fertilization, mowing and grazing on grassland species richness}, series = {The journal of ecology}, volume = {100}, journal = {The journal of ecology}, number = {6}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0022-0477}, doi = {10.1111/j.1365-2745.2012.02020.x}, pages = {1391 -- 1399}, year = {2012}, abstract = {Recent declines in biodiversity have given new urgency to questions about the relationship between land-use change, biodiversity and ecosystem processes. Despite the existence of a large body of research on the effects of land use on species richness, it is unclear whether the effects of land use on species richness are principally direct or indirect, mediated by concomitant changes in ecosystem processes. Therefore, we compared the direct effects of land use (fertilization, mowing and grazing) on species richness with indirect ones (mediated via grassland productivity) for grasslands in central Europe. We measured the richness and above-ground biomass in 150 grassland plots in 3 regions of Germany (the so-called Biodiversity Exploratories). We used univariate and structural equation models to examine direct and indirect land-use effects. The direct effects of mowing (-0.37, effect size) and grazing (0.04) intensity on species richness were stronger compared with the indirect effects of mowing (-0.04) and grazing (-0.01). However, the strong negative effect of fertilization (-0.23) on species richness was mainly indirect, mediated by increased productivity compared with the weak direct negative effect (-0.07). Differences between regions in land-use effects showed five times weaker negative effects of mowing (-0.13) in the region with organic soils (Schorfheide-Chorin), strong overall negative effects of grazing (-0.29) for the region with organic soils opposed to a similar strong positive effect (0.30) in the Hainich-Dun region, whereas the Schwabische Alb region displayed a five times weaker positive effect (0.06) only. Further, fertilization effects on species richness were positive (0.03) for the region with organic soils compared to up to 25 times stronger negative effects in the other two regions. Synthesis. Our results clearly show the importance of studying both direct and indirect effects of land-use intensity. They demonstrate the indirect nature, via productivity, of the negative effect of fertilization intensity on plant species richness in the real-world context of management-induced gradients of intensity of fertilization, mowing and grazing. Finally, they highlight that careful consideration of regional environments is necessary before attempting to generalize land-use effects on species diversity.}, language = {en} } @article{NaetherFoeselNaegeleetal.2012, author = {N{\"a}ther, Astrid and F{\"o}sel, B{\"a}rbel U. and N{\"a}gele, Verena and W{\"u}st, Pia K. and Weinert, Jan and Bonkowski, Michael and Alt, Fabian and Oelmann, Yvonne and Polle, Andrea and Lohaus, Gertrud and Gockel, Sonja and Hemp, Andreas and Kalko, Elisabeth K. V. and Linsenmair, Karl Eduard and Pfeiffer, Simone and Renner, Swen and Sch{\"o}ning, Ingo and Weisser, Wolfgang W. and Wells, Konstans and Fischer, Markus and Overmann, J{\"o}rg and Friedrich, Michael W.}, title = {Environmental factors affect acidobacterial communities below the subgroup level in Grassland and Forest Soils}, series = {Applied and environmental microbiology}, volume = {78}, journal = {Applied and environmental microbiology}, number = {20}, publisher = {American Society for Microbiology}, address = {Washington}, issn = {0099-2240}, doi = {10.1128/AEM.01325-12}, pages = {7398 -- 7406}, year = {2012}, abstract = {In soil, Acidobacteria constitute on average 20\% of all bacteria, are highly diverse, and are physiologically active in situ. However, their individual functions and interactions with higher taxa in soil are still unknown. Here, potential effects of land use, soil properties, plant diversity, and soil nanofauna on acidobacterial community composition were studied by cultivation-independent methods in grassland and forest soils from three different regions in Germany. The analysis of 16S rRNA gene clone libraries representing all studied soils revealed that grassland soils were dominated by subgroup Gp6 and forest soils by subgroup Gp1 Acidobacteria. The analysis of a large number of sites (n = 57) by 16S rRNA gene fingerprinting methods (terminal restriction fragment length polymorphism [T-RFLP] and denaturing gradient gel electrophoresis [DGGE]) showed that Acidobacteria diversities differed between grassland and forest soils but also among the three different regions. Edaphic properties, such as pH, organic carbon, total nitrogen, C/N ratio, phosphorus, nitrate, ammonium, soil moisture, soil temperature, and soil respiration, had an impact on community composition as assessed by fingerprinting. However, interrelations with environmental parameters among subgroup terminal restriction fragments (T-RFs) differed significantly, e.g., different Gp1 T-RFs correlated positively or negatively with nitrogen content. Novel significant correlations of Acidobacteria subpopulations (i.e., individual populations within subgroups) with soil nanofauna and vascular plant diversity were revealed only by analysis of clone sequences. Thus, for detecting novel interrelations of environmental parameters with Acidobacteria, individual populations within subgroups have to be considered.}, language = {en} } @article{MuellerKlausKleinebeckeretal.2012, author = {M{\"u}ller, J{\"o}rg and Klaus, Valentin H. and Kleinebecker, Till and Prati, Daniel and H{\"o}lzel, Norbert and Fischer, Markus}, title = {Impact of Land-Use intensity and productivity on bryophyte diversity in agricultural grasslands}, series = {PLoS one}, volume = {7}, journal = {PLoS one}, number = {12}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0051520}, pages = {9}, year = {2012}, abstract = {While bryophytes greatly contribute to plant diversity of semi-natural grasslands, little is known about the relationships between land-use intensity, productivity, and bryophyte diversity in these habitats. We recorded vascular plant and bryophyte vegetation in 85 agricultural used grasslands in two regions in northern and central Germany and gathered information on land-use intensity. To assess grassland productivity, we harvested aboveground vascular plant biomass and analyzed nutrient concentrations of N, P, K, Ca and Mg. Further we calculated mean Ellenberg indicator values of vascular plant vegetation. We tested for effects of land-use intensity and productivity on total bryophyte species richness and on the species richness of acrocarpous (small \& erect) and pleurocarpous (creeping, including liverworts) growth forms separately. Bryophyte species were found in almost all studied grasslands, but species richness differed considerably between study regions in northern Germany (2.8 species per 16 m(2)) and central Germany (6.4 species per 16 m(2)) due environmental differences as well as land-use history. Increased fertilizer application, coinciding with high mowing frequency, reduced bryophyte species richness significantly. Accordingly, productivity estimates such as plant biomass and nitrogen concentration were strongly negatively related to bryophyte species richness, although productivity decreased only pleurocarpous species. Ellenberg indicator values for nutrients proved to be useful indicators of species richness and productivity. In conclusion, bryophyte composition was strongly dependent on productivity, with smaller bryophytes that were likely negatively affected by greater competition for light. Intensive land-use, however, can also indirectly decrease bryophyte species richness by promoting grassland productivity. Thus, increasing productivity is likely to cause a loss of bryophyte species and a decrease in species diversity.}, language = {en} } @article{LeimuKlossFischer2012, author = {Leimu, Roosa and Kloss, Lena and Fischer, Markus}, title = {Inbreeding alters activities of the stress-related enzymes chitinases and beta-1,3-Glucanases}, series = {PLoS one}, volume = {7}, journal = {PLoS one}, number = {8}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0042326}, pages = {7}, year = {2012}, abstract = {Pathogenesis-related proteins, chitinases (CHT) and beta-1,3-glucanases (GLU), are stress proteins up-regulated as response to extrinsic environmental stress in plants. It is unknown whether these PR proteins are also influenced by inbreeding, which has been suggested to constitute intrinsic genetic stress, and which is also known to affect the ability of plants to cope with environmental stress. We investigated activities of CHT and GLU in response to inbreeding in plants from 13 Ragged Robin (Lychnis flos-cuculi) populations. We also studied whether activities of these enzymes were associated with levels of herbivore damage and pathogen infection in the populations from which the plants originated. We found an increase in pathogenesis-related protein activity in inbred plants from five out of the 13 investigated populations, which suggests that these proteins may play a role in how plants respond to intrinsic genetic stress brought about by inbreeding in some populations depending on the allele frequencies of loci affecting the expression of CHT and the past levels of inbreeding. More importantly, we found that CHT activities were higher in plants from populations with higher levels of herbivore or pathogen damage, but inbreeding reduced CHT activity in these populations disrupting the increased activities of this resistance-related enzyme in populations where high resistance is beneficial. These results provide novel information on the effects of plant inbreeding on plant-enemy interactions on a biochemical level.}, language = {en} } @article{KlausKleinebeckerBochetal.2012, author = {Klaus, Valentin H. and Kleinebecker, Till and Boch, Steffen and M{\"u}ller, J{\"o}rg and Socher, Stephanie A. and Prati, Daniel and Fischer, Markus and Hoelzel, Norbert}, title = {NIRS meets Ellenberg's indicator values prediction of moisture and nitrogen values of agricultural grassland vegetation by means of near-infrared spectral characteristics}, series = {Ecological indicators : integrating monitoring, assessment and management}, volume = {14}, journal = {Ecological indicators : integrating monitoring, assessment and management}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1470-160X}, doi = {10.1016/j.ecolind.2011.07.016}, pages = {82 -- 86}, year = {2012}, abstract = {Ellenberg indicator values are widely used ecological tools to elucidate relationships between vegetation and environment in ecological research and environmental planning. However, they are mainly deduced from expert knowledge on plant species and are thus subject of ongoing discussion. We researched if Ellenberg indicator values can be directly extracted from the vegetation biomass itself. Mean Ellenberg "moisture" (mF) and "nitrogen" (mN) values of 141 grassland plots were related to nutrient concentrations, fibre fractions and spectral information of the aboveground biomass. We developed calibration models for the prediction of mF and mN using spectral characteristics of biomass samples with near-infrared reflectance spectroscopy (NIRS). Prediction goodness was evaluated with internal cross-validations and with an external validation data set. NIRS could accurately predict Ellenberg mN, and with less accuracy Ellenberg mF. Predictions were not more precise for cover-weighted Ellenberg values compared with un-weighted values. Both Ellenberg mN and mF showed significant and strong correlations with some of the nutrient and fibre concentrations in the biomass. Against expectations, Ellenberg mN was more closely related to phosphorus than to nitrogen concentrations, suggesting that this value rather indicates productivity than solely nitrogen. To our knowledge we showed for the first time that mean Ellenberg indicator values could be directly predicted from the aboveground biomass, which underlines the usefulness of the NIRS technology for ecological studies, especially in grasslands ecosystems.}, language = {en} }