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"Alt, Fabian"
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Above- and belowground biodiversity jointly tighten the P cycle in agricultural grasslands
2021
Experiments showed that biodiversity increases grassland productivity and nutrient exploitation, potentially reducing fertiliser needs. Enhancing biodiversity could improve P-use efficiency of grasslands, which is beneficial given that rock-derived P fertilisers are expected to become scarce in the future. Here, we show in a biodiversity experiment that more diverse plant communities were able to exploit P resources more completely than less diverse ones. In the agricultural grasslands that we studied, management effects either overruled or modified the driving role of plant diversity observed in the biodiversity experiment. Nevertheless, we show that greater above- (plants) and belowground (mycorrhizal fungi) biodiversity contributed to tightening the P cycle in agricultural grasslands, as reduced management intensity and the associated increased biodiversity fostered the exploitation of P resources. Our results demonstrate that promoting a high above- and belowground biodiversity has ecological (biodiversity protection) and economical (fertiliser savings) benefits. Such win-win situations for farmers and biodiversity are crucial to convince farmers of the benefits of biodiversity and thus counteract global biodiversity loss.
Relationships between biodiversity and phosphorus cycling and the underlying processes are complex. Here the authors analyse a biodiversity manipulation experiment and an agricultural management gradient to show how plant and mycorrhizal fungal diversity promote phosphorus exploitation.
Journal Article
General Relationships between Abiotic Soil Properties and Soil Biota across Spatial Scales and Different Land-Use Types
2012
Very few principles have been unraveled that explain the relationship between soil properties and soil biota across large spatial scales and different land-use types. Here, we seek these general relationships using data from 52 differently managed grassland and forest soils in three study regions spanning a latitudinal gradient in Germany. We hypothesize that, after extraction of variation that is explained by location and land-use type, soil properties still explain significant proportions of variation in the abundance and diversity of soil biota. If the relationships between predictors and soil organisms were analyzed individually for each predictor group, soil properties explained the highest amount of variation in soil biota abundance and diversity, followed by land-use type and sampling location. After extraction of variation that originated from location or land-use, abiotic soil properties explained significant amounts of variation in fungal, meso- and macrofauna, but not in yeast or bacterial biomass or diversity. Nitrate or nitrogen concentration and fungal biomass were positively related, but nitrate concentration was negatively related to the abundances of Collembola and mites and to the myriapod species richness across a range of forest and grassland soils. The species richness of earthworms was positively correlated with clay content of soils independent of sample location and land-use type. Our study indicates that after accounting for heterogeneity resulting from large scale differences among sampling locations and land-use types, soil properties still explain significant proportions of variation in fungal and soil fauna abundance or diversity. However, soil biota was also related to processes that act at larger spatial scales and bacteria or soil yeasts only showed weak relationships to soil properties. We therefore argue that more general relationships between soil properties and soil biota can only be derived from future studies that consider larger spatial scales and different land-use types.
Journal Article
Biodiversity at multiple trophic levels is needed for ecosystem multifunctionality
by
Morris, E. Kathryn
,
Weisser, Wolfgang W.
,
Steffan-Dewenter, Ingolf
in
631/158/2458
,
631/158/670
,
Animals
2016
Both a high number of species and abundance in multiple trophic levels are required for ecosystems to continue to provide the services humans require of them.
The importance of biodiversity in depth
Numerous experiments have shown that the loss of biodiversity within single trophic groups — groups of organisms consuming resources from a similar level in the food chain — reduces the ability of ecosystems to deliver the services on which humans depend. How the loss of biodiversity in natural ecosystems consisting of multiple interacting trophic groups affects ecosystem functioning has remained unclear. Santiago Soliveres
et al
. have compiled data on the richness and abundance of 4,600 microbial, plant and animal taxa in 150 grasslands in Germany, together with information on 14 ecosystem services. Their analysis of the data demonstrates that biodiversity across multiple trophic groups is as important for the functioning of ecosystems as land-use intensity or environmental conditions. They conclude that the preservation of high levels of richness and diversity within a wide range of taxa will be key to ensuring that ecosystems continue to deliver the services on which humans rely. The findings also inform conservation and ecosystem management strategies by highlighting the most functionally relevant organisms, which include plants, soil bacteria and herbivorous insects.
Many experiments have shown that loss of biodiversity reduces the capacity of ecosystems to provide the multiple services on which humans depend
1
,
2
. However, experiments necessarily simplify the complexity of natural ecosystems and will normally control for other important drivers of ecosystem functioning, such as the environment or land use. In addition, existing studies typically focus on the diversity of single trophic groups, neglecting the fact that biodiversity loss occurs across many taxa
3
,
4
and that the functional effects of any trophic group may depend on the abundance and diversity of others
5
,
6
. Here we report analysis of the relationships between the species richness and abundance of nine trophic groups, including 4,600 above- and below-ground taxa, and 14 ecosystem services and functions and with their simultaneous provision (or multifunctionality) in 150 grasslands. We show that high species richness in multiple trophic groups (multitrophic richness) had stronger positive effects on ecosystem services than richness in any individual trophic group; this includes plant species richness, the most widely used measure of biodiversity. On average, three trophic groups influenced each ecosystem service, with each trophic group influencing at least one service. Multitrophic richness was particularly beneficial for ‘regulating’ and ‘cultural’ services, and for multifunctionality, whereas a change in the total abundance of species or biomass in multiple trophic groups (the multitrophic abundance) positively affected supporting services. Multitrophic richness and abundance drove ecosystem functioning as strongly as abiotic conditions and land-use intensity, extending previous experimental results
7
,
8
to real-world ecosystems. Primary producers, herbivorous insects and microbial decomposers seem to be particularly important drivers of ecosystem functioning, as shown by the strong and frequent positive associations of their richness or abundance with multiple ecosystem services. Our results show that multitrophic richness and abundance support ecosystem functioning, and demonstrate that a focus on single groups has led to researchers to greatly underestimate the functional importance of biodiversity.
Journal Article
Locally rare species influence grassland ecosystem multifunctionality
by
Morris, E. Kathryn
,
Weisser, Wolfgang W.
,
Steffan-Dewenter, Ingolf
in
Agriculture
,
Biodiversity
,
Biologi
2016
Species diversity promotes the delivery of multiple ecosystem functions (multifunctionality). However, the relative functional importance of rare and common species in driving the biodiversity–multifunctionality relationship remains unknown. We studied the relationship between the diversity of rare and common species (according to their local abundances and across nine different trophic groups), and multifunctionality indices derived from 14 ecosystem functions on 150 grasslands across a land-use intensity (LUI) gradient. The diversity of above- and below-ground rare species had opposite effects, with rare above-ground species being associated with high levels of multifunctionality, probably because their effects on different functions did not trade off against each other. Conversely, common species were only related to average, not high, levels of multifunctionality, and their functional effects declined with LUI. Apart from the community-level effects of diversity, we found significant positive associations between the abundance of individual species and multifunctionality in 6% of the species tested. Species-specific functional effects were best predicted by their response to LUI: species that declined in abundance with land use intensification were those associated with higher levels of multifunctionality. Our results highlight the importance of rare species for ecosystem multifunctionality and help guiding future conservation priorities.
Journal Article
Towards the development of general rules describing landscape heterogeneity–multifunctionality relationships
by
Binkenstein, Julia
,
Böhm, Stefan
,
Weisser, Wolfgang W.
in
agricultural production
,
Biodiversity
,
biodiversity conservation
2019
Rapid growth of the world's human population has increased pressure on landscapes to deliver high levels of multiple ecosystem services, including food and fibre production, carbon storage, biodiversity conservation, and recreation. However, we currently lack general principles describing how to achieve this landscape multifunctionality. We combine theoretical simulations and empirical data on 14 ecosystem services measured across 150 grasslands in three German regions. In doing so, we investigate the circumstances under which spatial heterogeneity in a driver of ecosystem functioning (an “ecosystem‐driver,” e.g., the presence of keystone species, land‐use intensification, or habitat types) increases landscape‐level ecosystem multifunctionality. Simulations based on theoretical data demonstrated that relationships between heterogeneity and landscape multifunctionality are highly variable and can range from nonsignificant to strongly positive. Despite this variability, we could identify criteria under which heterogeneity‐landscape multifunctionality relationships were most strongly positive: this happened when multiple ecosystem services responded contrastingly (both positively and negatively) to an ecosystem‐driver. These findings were confirmed using empirical data, which showed that heterogeneity in land‐use intensity (LUI) promoted landscape multifunctionality in cases where functions with both positive (e.g., plant biomass) and negative (e.g., flower cover) responses to land use intensification were included. For example, the simultaneous provisioning of ecosystem functions related to forage production (generally profiting from land‐use intensification), biodiversity conservation and recreation (generally decreasing with land‐use intensification) was highest in landscapes consisting of sites varying in LUI. Synthesis and applications. Our findings show that there are general principles governing landscape multifunctionality. A knowledge of these principles may support land management decisions. For example, knowledge of relationships between ecosystem services and their drivers, such as land use type, can help estimate the consequences of increasing or decreasing heterogeneity for landscape‐level ecosystem service supply, although interactions between landscape units (e.g., the movement of pollinators) must also be considered. Our findings show that there are general principles governing landscape multifunctionality. A knowledge of these principles may support land management decisions. For example, knowledge of relationships between ecosystem services and their drivers, such as land use type, can help estimate the consequences of increasing or decreasing heterogeneity for landscape‐level ecosystem service supply, although interactions between landscape units (e.g., the movement of pollinators) must also be considered.
Journal Article
Phosphate Release Kinetics in Calcareous Grassland and Forest Soils in Response to H+ Addition
by
Schöning, Ingo
,
Oelmann, Yvonne
,
Wilcke, Wolfgang
in
bioavailability
,
calcareous soils
,
chalk grasslands
2013
Phosphate release kinetics in soils are of global interest because sustainable plant nutrition with phosphate will be a major concern in the future. Dissolution of phosphate‐containing minerals induced by a changing rhizosphere equilibrium through proton input is one important mechanism that releases phosphate into bioavailable forms. Our objectives were (i) to determine phosphate release kinetics during H+ addition in calcareous soils of the Schwäbische Alb, Germany, and to assess the influence of (ii) land‐use type (grassland vs. forest) and (iii) management intensity on reactive phosphate pools and phosphate release rate constants during H+ addition. Phosphate release kinetics were characterized by a large fast‐reacting phosphatepool, which could be attributed to poorly‐crystalline calcium phosphates, and a small slow‐reacting phosphate pool probably originating from carbonate‐bearing hydroxylapatite. Both reactive phosphate pools—as well as total phosphate concentrations (TP) in soil—were greater in grassland than in forest soils. In organically fertilized grassland soils, concentrations of released phosphate were higher than in unfertilized soils, likely because organic fertilizers contain poorly‐crystalline phosphate compounds which are further converted into sparingly soluble phosphate forms. Because of an enriched slow‐reacting phosphate pool, mown pastures were characterized by a more continuous slow phosphate release reaction in contrast to clear biphasic phosphate release patterns in meadows. Consequently, managing phosphate release kinetics via management measures is a valuable tool to evaluate longer‐term P availability in soil in the context of finite rock phosphate reserves on earth.
Journal Article
Phosphate Release Kinetics in Calcareous Grassland and Forest Soils in Response to H^sup +^ Addition
by
Schöning, Ingo
,
Wilcke, Wolfgang
,
Oelmann, Yvonne
in
Biodiversity
,
Calcareous soils
,
Calcium phosphates
2013
Phosphate release kinetics in soils are of global interest because sustainable plant nutrition with phosphate will be a major concern in the future. Dissolution of phosphate-containing minerals induced by a changing rhizosphere equilibrium through proton input is one important mechanism that releases phosphate into bioavailable forms. our objectives were (i) to determine phosphate release kinetics during H+ addition in calcareous soils of the Schwäbische Alb, Germany, and to assess the influence of (ii) land-use type (grassland vs. forest) and (iii) management intensity on reactive phosphate pools and phosphate release rate constants during H+ addition. Phosphate release kinetics were characterized by a large fast-reacting phosphatepool, which could be attributed to poorly-crystalline calcium phosphates, and a small slow-reacting phosphate pool probably originating from carbonate-bearing hydroxylapatite. both reactive phosphate pools-as well as total phosphate concentrations (TP) in soil-were greater in grassland than in forest soils. In organically fertilized grassland soils, concentrations of released phosphate were higher than in unfertilized soils, likely because organic fertilizers contain poorly-crystalline phosphate compounds which are further converted into sparingly soluble phosphate forms. Because of an enriched slow-reacting phosphate pool, mown pastures were characterized by a more continuous slow phosphate release reaction in contrast to clear biphasic phosphate release patterns in meadows. Consequently, managing phosphate release kinetics via management measures is a valuable tool to evaluate longer-term P availability in soil in the context of finite rock phosphate reserves on earth. [PUBLICATION ABSTRACT]
Journal Article
Locally rare species influence grassland ecosystem multifunctionality
by
Morris, E. Kathryn
,
Weisser, Wolfgang W.
,
Steffan-Dewenter, Ingolf
in
Animal ecology
,
Biodiversity
,
Biodiversity conservation
2016
Species diversity promotes the delivery of multiple ecosystem functions (multifunctionality). However, the relative functional importance of rare and common species in driving the biodiversity-multifunctionality relationship remains unknown. We studied the relationship between the diversity of rare and common species (according to their local abundances and across nine different trophic groups), and multifunctionality indices derived from 14 ecosystem functions on 150 grasslands across a land-use intensity (LUI) gradient. The diversity of above- and below-ground rare species had opposite effects, with rare above-ground species being associated with high levels of multifunctionality, probably because their effects on different functions did not trade off against each other. Conversely, common species were only related to average, not high, levels of multifunctionality, and their functional effects declined with LUI. Apart from the community-level effects of diversity, we found significant positive associations between the abundance of individual species and multifunctionality in 6% of the species tested. Species-specific functional effects were best predicted by their response to LUI: species that declined in abundance with land use intensification were those associated with higher levels of multifunctionality. Our results highlight the importance of rare species for ecosystem multifunctionality and help guiding future conservation priorities.
Journal Article
Clinical predictors of survival in patients with relapsed/refractory small-cell lung cancer treated with checkpoint inhibitors: a German multicentric real-world analysis
by
Rohde, Gernot
,
Frost, Nikolaj
,
Saalfeld, Felix C.
in
Brain cancer
,
Disease control
,
Immune checkpoint inhibitors
2022
Objectives:
Small-cell lung cancer (SCLC) is a lung malignancy with high relapse rates and poor survival outcomes. Treatment-resistant disease relapse occurs frequently and effective salvage therapies are urgently needed.
Materials and Methods:
We aimed to define efficacy and safety of checkpoint inhibitors (CPIs) in a heterogeneous population of relapsed and refractory SCLC patients in a large retrospective multicentric real-world cohort across German tertiary care centers.
Results:
A total of 111 patients from 11 treatment centers were included. Median age of all patients was 64 years, and 63% were male. Approximately one-third of all patients had poor performance status [Eastern Cooperative Oncology Group (ECOG) ⩾ 2], and 37% had known brain metastases. Patients were heavily pretreated with a median number of prior therapy lines of 2 (range, 1–8). Median follow-up of the entire cohort was 21.7 months. Nivolumab and Nivolumab/Ipilimumab were the most common regimens. Overall disease control rate was 27.2% in all patients and was numerically higher in CPI combination regimens compared with single-agent CPI (31.8% versus 23.8%; p = 0.16). Median overall survival (OS) was 5.8 months [95% confidence interval (CI), 1.7–9.9 months]. The 12- and 24-month survival rates were 31.8% and 12.7%, respectively. The 12-week death rate was 27.9%. Disease control and response rate were significantly lower in patients with liver metastases. Platinum sensitivity (to first-line treatment), metastatic burden, and lactate dehydrogenase (LDH) showed prognostic impact on survival in univariate analysis. Neutrophil-to-lymphocyte ratio (NLR) was a significant and independent predictor of survival in univariate (p = 0.01) and multivariate analyses [hazard ratio (HR), 2.1; 95% CI = 1.1–4.1; p = 0.03].
Conclusion:
CPI in patients with relapsed or refractory (R/R) SCLC is of limited value in an overall patient cohort; however, long-term survival, in particular with CPI combination strategies, is possible. Clinical characteristics allow a more differentiated subgroup selection, in particular patients with low NLR showed less benefit from CPI in R/R SCLC.
Journal Article
Complete Correction of Murine Artemis Immunodeficiency by Lentiviral Vector-Mediated Gene Transfer
2006
Artemis gene mutations are responsible for the development of a severe combined immunodeficiency [radiation-sensitive (RS) SCID] characterized by a severe B and T cell deficiency and a normal natural killer cell population. To establish the feasibility of a gene therapy approach to the treatment of RS-SCID, we generated a series of lentiviral vectors expressing human Artemis from different promoters and used them to transduce highly purified hematopoietic stem cells (HSCs) from Artemis knockout mice. HSCs transduced by the different viruses were transplanted into either lethally irradiated Rag-l-deficient animals or Artemis knockout mice treated with a nonmyeloablative dose of Busulfan. In both models, transplantation of HSCs transduced by a vector that used a murine phosphoglycerate kinase (PGK) promoter led to a complete functional correction of the immunodeficiency. Corrected animals displayed rescue of mature B cells with normal levels of serum immunoglobulins, together with complete rescue of the T cell compartment as evidenced by the presence of mature T lymphocytes in peripheral blood as well as normal values of thymocytes in thymus. Those B and T cells were capable of activation, as shown both by in vitro stimulation responses and in vivo after immune challenge. Overall, the results indicate that a gene therapy approach for RS-SCID involving the transplantation of genetically modified HSCs is indeed feasible. Furthermore, our studies suggest the possibility that nonmyeloablative conditioning regimens might be effectively used to promote engraftment of genetically modified cells in the case of diseases where standard irradiation-based myeloablative bone marrow transplantation protocols may prove problematic.
Journal Article