Isselstein, Johannes

[["dc.bibliographiccitation.firstpage","157"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Applied Ecology and Environmental Research"],["dc.bibliographiccitation.lastpage","166"],["dc.bibliographiccitation.volume","9"],["dc.contributor.author","Beyschlag, W."],["dc.contributor.author","Assaf, Taher A."],["dc.contributor.author","Isselstein, Johannes"],["dc.date.accessioned","2017-09-07T11:46:39Z"],["dc.date.available","2017-09-07T11:46:39Z"],["dc.date.issued","2011"],["dc.description.abstract","Despite the fact that several experiments have been conducted to explore the biodiversity-productivity relationship in synthesized and natural plant communities, the results obtained were contradictory and no clear consensus has been reached. Recent experiments that surveyed mature natural plant communities have investigated this relationship across environmental gradients, where biotic and/or abiotic factors are correlated with the observed diversity and productivity levels. We studied the effect of plant diversity on ecosystem productivity in agriculturally managed (managed at a low intensity with moderate level of disturbance) and natural (no history of management) grasslands at a within-site scale in order to minimize the confounding effect of environmental factors. We tested the effects of two diversity measures (species richness and species evenness) on productivity within- and across-sites scale. Our results indicated that this relationship was different between the natural and the managed grasslands and varied according to the diversity measure. Species richness only poorly explained the variation in productivity for the managed grasslands, while the variations in system productivity were better explained by species evenness. Interestingly, our results from the natural low productive, species poor grassland are in agreement with the results obtained from the recent experiments that artificially manipulated diversity levels and found an asymptotic increase in productivity along with increasing species richness. Our results provide additional evidence of the complex behavior that measures of species diversity that combine several aspects of diversity such as species evenness, species identity as well as the interactions among the species may be better determinants of the response of the ecosystem to biodiversity."],["dc.format.extent","10"],["dc.identifier.doi","10.15666/aeer/0902_157166"],["dc.identifier.fs","583229"],["dc.identifier.gro","3149241"],["dc.identifier.isi","000295719900004"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/8590"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5897"],["dc.language.iso","en"],["dc.notes.intern","Isselstein Crossref Import"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.publisher","Corvinus Univ Budapest"],["dc.relation.issn","1589-1623"],["dc.relation.issn","1785-0037"],["dc.rights.access","openAccess"],["dc.subject","biodiversity; ecosystem productivity; evenness; dry acidic grasslands; managed grasslands; species richness"],["dc.subject.ddc","630"],["dc.title","The Relationship Between Plant Diversity and Productivity in Natural and in Managed Grasslands"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e0210623"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","PLOS ONE"],["dc.bibliographiccitation.volume","14"],["dc.contributor.author","Tonn, Bettina"],["dc.contributor.author","Porath, Ina"],["dc.contributor.author","Lattanzi, Fernando A."],["dc.contributor.author","Isselstein, Johannes"],["dc.date.accessioned","2019-07-09T11:50:08Z"],["dc.date.available","2019-07-09T11:50:08Z"],["dc.date.issued","2019"],["dc.description.abstract","Nitrogen stable isotope (15N) natural abundance is widely used to study nitrogen cycling. In grazed ecosystems, urine patches are hot-spots of nitrogen inputs, losses, and changes in δ15N. Understanding δ15N dynamics in urine-affected vegetation is therefore crucial for accurate inferences from 15N natural abundance in grasslands. We hypothesized that leaf δ15N following urine deposition varies with time and plant functional group. Specifically, we expected (i) short-term decreases in δ15N due to foliar absorption of 15N-depleted volatilized ammonia, (ii) followed by increases in δ15N due to uptake of 15N-enriched soil inorganic nitrogen, and (iii) that the magnitude of these changes is less in legumes than in grasses. The latter should be expected because ammonia absorption depends on leaf nitrogen concentration, which is higher in legumes than grasses, and because biological nitrogen fixation will modify the influence of urine-derived nitrogen on δ15N in legumes. We applied cattle urine to a mixture of Lolium perenne and Trifolium repens in a pot experiment. Nitrogen concentration and δ15N were determined for successive leaf cohorts and bulk biomass either 17 (early) or 32 (late) days after urine application. Early after urine application, leaves of L. perenne were 15N-depleted compared to control plants (δ15N 0.1 vs. 5.8‰, respectively), but leaves of T. repens were not (-1.1 vs. -1.1‰, respectively). Later, both species increased their δ15N, but T. repens (4.5‰) less so than L. perenne (5.9‰). Vegetation sampled within and outside urine patches in the field further supported these results. Our findings confirm that foliar ammonia uptake can substantially decrease grass foliar δ15N, and that in both grass and legume the direction of the δ15N response to urine changes over time. Temporal dynamics of plant δ15N at urine patches therefore need to be explicitly addressed when 15N natural abundance is used to study nitrogen cycling in grazed grasslands."],["dc.identifier.doi","10.1371/journal.pone.0210623"],["dc.identifier.pmid","30650124"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/15865"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/59707"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1932-6203"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.subject.ddc","630"],["dc.title","Urine effects on grass and legume nitrogen isotopic composition: Pronounced short-term dynamics of δ15N"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","1774"],["dc.bibliographiccitation.firstpage","389"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Maydica"],["dc.bibliographiccitation.lastpage","397"],["dc.bibliographiccitation.volume","56"],["dc.contributor.author","Kayser, Manfred"],["dc.contributor.author","Isselstein, Johannes"],["dc.contributor.author","Müller, Jürgen"],["dc.date.accessioned","2017-09-07T11:51:52Z"],["dc.date.available","2017-09-07T11:51:52Z"],["dc.date.issued","2011"],["dc.description.abstract","For economical and environmental reasons nitrogen management is of major importance in growing silage maize (Zea mays L). However, studies to improve N management are often restricted to fertilization measures. Therefore we investigated management effects besides fertilization on nitrogen utilization in two field experiments over two years on an eutrophic sandy soil. Experiment 1 examined the effect of row distance (0.35 m and 0.70 m) and harvesting time (premature, mid September; common practice, beginning of October, late harvest, end of October) in a two-way factorial design. In experiment 2 five maize varieties, differing in habitus and characteristic of ripening, were grown using a one-way factorial design. Nitrate leaching over winter was determined by the suction cup method. The row distance showed no significant effect neither on the soil mineral nitrogen content (SMN) in autumn nor on the amount of nitrate leaching. However, SMN and nitrate leaching were affected by the harvest time with significantly lower values for the early harvest. In the second experiment significant differences among genotypes were found with nitrate leaching rates between 52 and 77 kg NO3-N ha(-1). We conclude that the effects of harvesting time and variety on nitrate leaching were related to the stage of maturity of silage maize at harvest. Nitrate leaching during winter was lower when maize plants where prevented from sustained metabolic activity in autumn, either by premature harvest as shown in experiment 1 or by enhanced physiological ripening as in experiment 2."],["dc.format.extent","10"],["dc.identifier.fs","585063"],["dc.identifier.gro","3148087"],["dc.identifier.isi","000303962300010"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/8608"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5434"],["dc.language.iso","en"],["dc.notes.intern","Migrated from goescholar"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","2279-8013"],["dc.rights.access","openAccess"],["dc.subject","silage maize; nitrate leaching; soil mineral nitrogen (SMN); row distance; harvesting date"],["dc.subject.ddc","630"],["dc.title","Silage maize (Zea mays L) ripening behaviour affects nitrate leaching over following winter"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]