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Sökning: WFRF:(Leuschner Christoph)

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1.
  • Drescher, Jochen, et al. (författare)
  • Ecological and socio-economic functions across tropical land use systems after rainforest conversion
  • 2016
  • Ingår i: Philosophical Transactions of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 371:1694
  • Tidskriftsartikel (refereegranskat)abstract
    • Tropical lowland rainforests are increasingly threatened by the expansion of agriculture and the extraction of natural resources. In Jambi Province, Indonesia, the interdisciplinary EFForTS project focuses on the ecological and socio-economic dimensions of rainforest conversion to jungle rubber agroforests and monoculture plantations of rubber and oil palm. Our data confirm that rainforest transformation and land use intensification lead to substantial losses in biodiversity and related ecosystem functions, such as decreased above-and below-ground carbon stocks. Owing to rapid step-wise transformation from forests to agroforests to monoculture plantations and renewal of each plantation type every few decades, the converted land use systems are continuously dynamic, thus hampering the adaptation of animal and plant communities. On the other hand, agricultural rainforest transformation systems provide increased income and access to education, especially for migrant smallholders. Jungle rubber and rubber monocultures are associated with higher financial land productivity but lower financial labour productivity compared to oil palm, which influences crop choice: smallholders that are labour-scarce would prefer oil palm while land-scarce smallholders would prefer rubber. Collecting long-term data in an interdisciplinary context enables us to provide decision-makers and stakeholders with scientific insights to facilitate the reconciliation between economic interests and ecological sustainability in tropical agricultural landscapes.
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2.
  • Clough, Yann, et al. (författare)
  • Land-use choices follow profitability at the expense of ecological functions in Indonesian smallholder landscapes
  • 2016
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • Smallholder-dominated agricultural mosaic landscapes are highlighted as model production systems that deliver both economic and ecological goods in tropical agricultural landscapes, but trade-offs underlying current land-use dynamics are poorly known. Here, using the most comprehensive quantification of land-use change and associated bundles of ecosystem functions, services and economic benefits to date, we show that Indonesian smallholders predominantly choose farm portfolios with high economic productivity but low ecological value. The more profitable oil palm and rubber monocultures replace forests and agroforests critical for maintaining above- and below-ground ecological functions and the diversity of most taxa. Between the monocultures, the higher economic performance of oil palm over rubber comes with the reliance on fertilizer inputs and with increased nutrient leaching losses. Strategies to achieve an ecological-economic balance and a sustainable management of tropical smallholder landscapes must be prioritized to avoid further environmental degradation.
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3.
  • Coners, Heinz, et al. (författare)
  • Evapotranspiration and water balance of high-elevation grassland on the Tibetan Plateau
  • 2016
  • Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694. ; 533, s. 557-566
  • Tidskriftsartikel (refereegranskat)abstract
    • High-elevation grasslands of the Cyperaceae Kobresia pygmaea cover nearly half a million km2 on the Tibetan Plateau. As a consequence of climate change, precipitation patterns in this monsooninfluenced region may change with possible consequences for grassland productivity. Yet, not much is known about the water cycle in this second largest alpine ecosystem of the world. We measured the evapotranspiration of a high-elevation Kobresia pasture system at 4400 m a.s.l. in the south-eastern part of the plateau in two summers using three different approaches, weighable micro-lysimeters, eddy covariance measurements, and water balance modeling with the soil–plant–atmosphere transfer model SEWAB. In good agreement among the three approaches, we found ET rates of 4–6 mm d-1 in moist summer periods (June–August) and 2mmd-1 in dry periods, despite the high elevation and a leaf area index of only 1. Measured ET rates were comparable to rates reported from alpine grasslands at 1500–2500 m a.s.l. in temperate mountains, and also matched ET rates of managed lowland grasslands in the temperate zone. At the study site with 430 mm annual precipitation, low summer rainfall reduced ET significantly and infiltration into the subsoil occurred only in moist periods. Our results show that the evapotranspiration of high-elevation grasslands at 4400 m can be as high as in lowland grasslands despite large elevational changes in abiotic and biotic drivers of ET, and periodic water shortage is likely to influence large parts of the Tibetan Kobresia pastures.
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4.
  • Dantonello, Tobias M, et al. (författare)
  • Cooperative trial CWS-91 for localized soft tissue sarcoma in children, adolescents, and young adults.
  • 2009
  • Ingår i: Journal of clinical oncology : official journal of the American Society of Clinical Oncology. - 1527-7755. ; 27:9, s. 1446-55
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To improve risk-adapted therapy for localized childhood soft tissue sarcoma within an international multicenter setting. PATIENTS AND METHODS: Four hundred forty-one patients younger than 21 years with localized rhabdomyosarcoma and rhabdomyosarcoma-like tumors (ie, extraosseous tumors of the Ewing family, synovial sarcoma, and undifferentiated sarcoma) were eligible. Therapy was stratified according to postsurgical stage, histology, and tumor site. In unresectable tumors, treatment was further adapted depending on response to induction chemotherapy, TN classification, tumor size and second-look surgery. A novel five-drug combination of etoposide, vincristine, dactinomycin, ifosfamide, and doxorubicin (EVAIA) was evaluated for high-risk patients, but cumulative chemotherapy dosage and treatment duration were reduced for the remaining individuals as compared with that of the previous trial CWS-86. Hyperfractionated accelerated radiotherapy (HART) was recommended at doses of either 32 or 48 Gy. RESULTS: At a median follow-up of 8 years, 5-year event-free survival (EFS) and overall (OS) survival for the entire cohort was 63% +/- 4% and 73% +/- 4%, respectively (all survival rates in this abstract are calculated and displayed with +/-95% CI). EFS/OS rates by histology were 60% +/- 5%/72% +/- 5% in rhabdomyosarcoma, 62% +/- 10%/69% +/- 10% for Ewing tumors of soft tissues, 84% +/- 12%/90% +/- 10% for synovial sarcoma, and 67% +/- 38%/83% +/- 30% for undifferentiated sarcoma, respectively. Response to one cycle of the five-drug combination EVAIA was similar to that of the four-drug combination VAIA used in CWS-86. Two hundred twelve patients with rhabdomyosarcoma underwent radiation (EFS, 66% +/- 6%); 53 of those patients had a favorable risk profile and received 32 Gy of HART (EFS, 73% +/- 12%). TN classification, tumor site, tumor size, histology, and age were prognostic in univariate analysis. CONCLUSION: Improved risk stratification enabled decreased therapy intensity for selected patients without compromising survival. Intensified chemotherapy with EVAIA did not improve outcome of localized high-risk rhabdomyosarcoma.
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5.
  • Dantonello, Tobias M., et al. (författare)
  • Initial patient characteristics can predict pattern and risk of relapse in localized rhabdomyosarcoma
  • 2008
  • Ingår i: Journal of Clinical Oncology. - 1527-7755. ; 26:3, s. 406-413
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose Evaluation of primary tumor-, treatment-, and patient-related factors predicting relapse pattern, risk, and survival after relapse with the aim to design a risk-adapted, tumor- directed surveillance program for patients with localized rhabdomyosarcoma (RMS). Patients and Methods One thousand one hundred sixty-four patients with nonmetastatic RMS achieved complete remission at the end of multimodal therapy in the consecutive trials of the Cooperative Weichteilsarkom Studiengruppe (CWS)-81, CWS-86, CWS-91, and CWS-96 between 1980 and 2002 ( median follow-up, 5 years). Three hundred thirty-seven of these individuals developed either locoregional, metastatic, or combined relapses. Predictive factors for relapse, its pattern, and postrelapse survival were analyzed. Results Age, histology, tumor size, tumor site, postsurgical stage, and omission of radiotherapy were identified as factors associated with an increased relapse risk in multivariate analyses. Relapse rates did not differ among the CWS trials. Median time to relapse was 1.43 years from first diagnosis ( range, 0.13 to 13.5 years). There were 217 locoregional, 72 metastatic, and 48 combined recurrences. Only two patients developed metastases more than 4 years after diagnosis, and both had combined recurrences. Five-year postrelapse survival was 24%. Patient subsets with consistent relapse pattern, risk, and postrelapse survival rates were identified on the basis of histologic subtype and tumor size. Conclusion Initial patient and tumor characteristics predict pattern and risk of relapse and also correlate with postrelapse survival probabilities. In localized RMS, tumor- directed follow-up should focus on the primary site. Screening for metastatic relapse may not be necessary more than 4 years after diagnosis. The identification of subgroups with distinctive pattern and risk of relapse may be used to develop risk-adapted, tumor- directed guidance for detection of recurrent disease in localized RMS.
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6.
  • Dantonello, Tobias M., et al. (författare)
  • Survival following disease recurrence of primary localized alveolar rhabdomyosarcoma
  • 2013
  • Ingår i: Pediatric Blood & Cancer. - : Wiley. - 1545-5009 .- 1545-5017. ; 60:8, s. 1267-1273
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Recurrences in primary localized alveolar rhabdomyosarcoma (RMA) are common. Post-relapse survival is poor. We evaluated prognostic factors including relapse treatment in patients with recurrent RMA. Methods Relapses occurred in 115/235 patients with nonmetastatic RMA treated in four consecutive CWS-trials after achievement of a complete remission. Sufficient information about post-relapse treatment and outcome could be obtained in 99 patients and was retrospectively analyzed. Results Nine of 99 patients received no salvage therapy and died after a median of 2 months. The remaining 90 patients received multimodal relapse treatment including mandatory chemotherapy. Recurrences were grossly resected in 39 patients; 57 patients received radiation. At a median follow-up from relapse of 8 years, 20 patients were alive and disease-free (5-year post-relapse survival [PROS] 21.3 +/- 8). All surviving patients apart from a single individual had an isolated, circumscribed recurrence. Sixteen of 20 survivors were treated with adequate local relapse therapy (ALRT, i.e., either complete resection or gross resection+radiation). Survival in the subgroup of 27 individuals with circumscribed recurrences and ALRT was significantly better (PROS 53.7 +/- 19) compared with disseminated recurrences and/or tumors treated without ALRT. Absence of primary lymph node involvement, circumscribed relapses, ALRT, and achievement of a second CR were identified as independent favorable risk factors. Conclusion Post-relapse survival for primary localized RMA is generally poor. However, certain patient groups differed significantly in their likelihood of survival and 50% of patients with circumscribed relapses treated with ALRT survived. These findings may form the basis for an evidence-based risk-stratification for recurrent disease including relapse treatment. 
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7.
  • Miehe, Georg, et al. (författare)
  • The Kobresia pygmaea ecosystem of the Tibetan highlands – Origin, functioning and degradation of the world's largest pastoral alpine ecosystem: Kobresia pastures of Tibet
  • 2019
  • Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 648, s. 754-771
  • Tidskriftsartikel (refereegranskat)abstract
    • With 450,000 km2 Kobresia (syn. Carex) pygmaea dominated pastures in the eastern Tibetan highlands are the world's largest pastoral alpine ecosystem forming a durable turf cover at 3000–6000 m a.s.l. Kobresia's resilience and competitiveness is based on dwarf habit, predominantly below-ground allocation of photo assimilates, mixture of seed production and clonal growth, and high genetic diversity. Kobresia growth is co-limited by livestock-mediated nutrient withdrawal and, in the drier parts of the plateau, low rainfall during the short and cold growing season. Overstocking has caused pasture degradation and soil deterioration over most parts of the Tibetan highlands and is the basis for this man-made ecosystem. Natural autocyclic processes of turf destruction and soil erosion are initiated through polygonal turf cover cracking, and accelerated by soil-dwelling endemic small mammals in the absence of predators. The major consequences of vegetation cover deterioration include the release of large amounts of C, earlier diurnal formation of clouds, and decreased surface temperatures. These effects decrease the recovery potential of Kobresia pastures and make them more vulnerable to anthropogenic pressure and climate change. Traditional migratory rangeland management was sustainable over millennia, and possibly still offers the best strategy to conserve and possibly increase C stocks in the Kobresia turf.
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8.
  • Schuldt, Bernhard, et al. (författare)
  • How adaptable is the hydraulic system of European beech in the face of climate change-related precipitation reduction?
  • 2015
  • Ingår i: New Phytologist. - : Wiley. - 1469-8137 .- 0028-646X.
  • Tidskriftsartikel (refereegranskat)abstract
    • Climate warming will increase the drought exposure of many forests world-wide. It is not well understood how trees adapt their hydraulic architecture to a long-term decrease in water availability. We examined 23 traits characterizing the hydraulic architecture and growth rate of branches and the dependent foliage of mature European beech (Fagus sylvatica) trees along a precipitation gradient (855-594 mm yr(-1) ) on uniform soil. A main goal was to identify traits that are associated with xylem efficiency, safety and growth. Our data demonstrate for the first time a linear increase in embolism resistance with climatic aridity (by 10%) across populations within a species. Simultaneously, vessel diameter declined by 7% and pit membrane thickness (Tm ) increased by 15%. Although specific conductivity did not change, leaf-specific conductivity declined by 40% with decreasing precipitation. Of eight plant traits commonly associated with embolism resistance, only vessel density in combination with pathway redundancy and Tm were related. We did not confirm the widely assumed trade-off between xylem safety and efficiency but obtained evidence in support of a positive relationship between hydraulic efficiency and growth. We conclude that the branch hydraulic system of beech has a distinct adaptive potential to respond to a precipitation reduction as a result of the environmental control of embolism resistance.
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9.
  • Sutcliffe, Laura M. E., et al. (författare)
  • Harnessing the biodiversity value of Central and Eastern European farmland
  • 2015
  • Ingår i: Diversity & distributions. - : Wiley. - 1366-9516 .- 1472-4642. ; 21:6, s. 722-730
  • Tidskriftsartikel (refereegranskat)abstract
    • A large proportion of European biodiversity today depends on habitat provided by low-intensity farming practices, yet this resource is declining as European agriculture intensifies. Within the European Union, particularly the central and eastern new member states have retained relatively large areas of species-rich farmland, but despite increased investment in nature conservation here in recent years, farmland biodiversity trends appear to be worsening. Although the high biodiversity value of Central and Eastern European farmland has long been reported, the amount of research in the international literature focused on farmland biodiversity in this region remains comparatively tiny, and measures within the EU Common Agricultural Policy are relatively poorly adapted to support it. In this opinion study, we argue that, 10years after the accession of the first eastern EU new member states, the continued under-representation of the low-intensity farmland in Central and Eastern Europe in the international literature and EU policy is impeding the development of sound, evidence-based conservation interventions. The biodiversity benefits for Europe of existing low-intensity farmland, particularly in the central and eastern states, should be harnessed before they are lost. Instead of waiting for species-rich farmland to further decline, targeted research and monitoring to create locally appropriate conservation strategies for these habitats is needed now.
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