Weidedüngung in einer ecuadorianischen Bergregenwaldregion – Möglichkeit der Degradationsminderung?

Aufgrund wachsenden Bevölkerungsdruckes wird in der Bergregenwaldregion Süd-Ecuadors immer mehr Wald in Weideflächen überführt. Weidegräser langjährig genutzter Weiden werden jedoch durch den tropischen Adlerfarn mit seinem ausgeprägten Rhizomsystem verdrängt. Durch die Kombination aus Verdrängung des Grases und der Nährstoffakkumulation/geringe Rückführung pflanzenverfügbarer Nährstoffe durch den Farn (Potthast et al. 2010) degradieren die Weideflächen zunehmend und führen zu ihrer Aufgabe und erneuter Waldrodung. Um den Einfluss von Düngerapplikation auf Quantität und Qualität des Weidegrases, verfügbare Bodennährstoffe sowie bodenbiologische Indikatoren zu untersuchen, wurde 2007 ein Feldexperiment auf 2000m Höhe auf einer aktiven Weide initiiert. Auf einer Fläche von 0.5 ha-1 wurden jeweils 6 Plots (25 m²): Kontrolle (X), Urea (N), Rockphosphat (P) und Kombination (NP) angelegt. Die Düngergaben von 50 kg N ha-1 a-1 sowie 10 kg P ha-1 a-1 wurden auf drei Düngetermine im Jahr verteilt. Die Grasbiomasseproduktion der Plots wurde alle 2-3 Monate bestimmt. Plotbezogen wurden bodenbiologische (mikrobielle Biomasse C und N, PLFA-Analyse, Netto-N Mineralisation) sowie geochemische Analysen (pH-Wert, PO4-P (NH4F); NO3-N, NH4-N (KCl)) durchgeführt. Die Urea-Düngung bewirkte eine Erhöhung der Grasbiomasseproduktion, wobei mit 11.3 Mg ha-1 a-1 die NP Variante 2 Mg ha-1 a-1 mehr Biomasse produzierte als X und P. Neben einer erhöhten Verfügbarkeit an PO4-P im Oberboden auf P-gedüngten Flächen konnte auch ein erhöhter Gesamtphosphorgehalt der Grasbiomasse nachgewiesen werden. Die Düngung hatte keinen Einfluss auf die Höhe der mikrobiellen Biomasse zeigte aber eine Veränderung der mikrobiellen Gemeinschaftsstruktur (signifikanter Anstieg des Pilzmarkers 18:2n6,9c). Die Untersuchungen zeigen, dass durch eine Kombinationsdüngung (NP) dem Boden wichtige Pflanzennährstoffe zur Aufnahme in die Grasbiomasse zugeführt werden, welche die Bodenqualität im Untersuchungszeitraum erhalten und den potentiell verfügbaren Wuchsraum des Farnes verringern konnten. Eine Weidedegradation kann dadurch zumindest momentan vermieden werden. Eine moderate Kombinationsdüngung stellt somit einen ersten Schritt zu einem nachhaltigen Weidemanagement in der Bergregenwaldregion Süd-Ecuadors dar

Effekte von pflanzenbürtigem DOM und P-Düngung auf Nährstoffumsatzprozesse in Böden genutzter und verlassener Weiden Südecuadors

Um landnutzungsbedingte Veränderungen der organischen Bodensubstanz (SOM) sowie der Nährstoffe und den daraus folgenden Implikationen für die Bodenfunktionen abzuschätzen zu können ist das Verständnis von Mechanismen der C-Transformation eine Voraussetzung. Gelöste organische Substanz (DOM) ist eine C-Fraktion mit hoher Bioverfügbarkeit und trägt substantiell zu Nährstoffumsetzungen und Zersetzungsprozessen bei. Eine wichtige Quelle für DOM ist Pflanzenstreu. Im Untersuchungsgebiet in Südecuador wird das Weidegras (Setaria sphacelata, C4 Pflanze) im Laufe der Weidenutzung durch den Tropischen Farn (Pteridium arachnoideum, C3 Pflanze) verdrängt und diese unproduktiven Weiden werden aufgegeben. In einem 28 tägigen Inkubationsexperiment wurden die Effekte von gras- bzw. farnbürtigem DOM mit und ohne Zugabe von PO4-P auf die mikrobielle Gemeinschaft (Aktivität, Biomasse, Struktur (PLFA)) in aktiven (aW) bzw. verlassenen Weideböden (vW) untersucht. Am Ende der Inkubation zeigten alle Mikrokosmen denen DOM zugegeben wurde einen Anstieg des mikrobiell gebundenen C und P um den Faktor 1.2-1.3 und 1.3-2.0 im Vergleich zu den Kontrollen. Der Effekt war deutlicher nach Zugabe von Gras-DOM als nach Farn-DOM. Ein signifikanter zusätzlicher Effekt nach P-Zugabe war im Einzelfall festzustellen. Die ?13-C-Signatur des mineralisierten C zeigte eine präferentielle Nutzung des DOM-C bei gleichzeitiger Nutzung des SOM-C an. Dabei wurden Priming Effekte beobachtet. Die DOM-Zugabe hatte nicht nur einen Einfluß auf Aktivität und Biomasse der mikrobiellen Gemeinschaft sondern auch auf deren Struktur. Die Ergebnisse zeigen, dass die biologische Abbaubarkeit des zugegebenen DOM und die Interaktionen mit den Organismen von dessen Qualität und dem biochemischen Zustand der Böden abhängen

Compositional diversity of rehabilitated tropical lands supports multiple ecosystem services and buffers uncertainties

High landscape diversity is assumed to increase the number and level of ecosystem services. However, the interactions between ecosystem service provision, disturbance and landscape composition are poorly understood. Here we present a novel approach to include uncertainty in the optimization of land allocation for improving the provision of multiple ecosystem services. We refer to the rehabilitation of abandoned agricultural lands in Ecuador including two types of both afforestation and pasture rehabilitation, together with a succession option. Our results show that high compositional landscape diversity supports multiple ecosystem services (multifunction effect). This implicitly provides a buffer against uncertainty. Our work shows that active integration of uncertainty is only important when optimizing single or highly correlated ecosystem services and that the multifunction effect on landscape diversity is stronger than the uncertainty effect. This is an important insight to support a land-use planning based on ecosystem services

Compositional diversity of rehabilitated tropical lands supports multiple ecosystem services and buffers uncertainties

High landscape diversity is assumed to increase the number and level of ecosystem services. However, the interactions between ecosystem service provision, disturbance and landscape composition are poorly understood. Here we present a novel approach to include uncertainty in the optimization of land allocation for improving the provision of multiple ecosystem services. We refer to the rehabilitation of abandoned agricultural lands in Ecuador including two types of both afforestation and pasture rehabilitation, together with a succession option. Our results show that high compositional landscape diversity supports multiple ecosystem services (multifunction effect). This implicitly provides a buffer against uncertainty. Our work shows that active integration of uncertainty is only important when optimizing single or highly correlated ecosystem services and that the multifunction effect on landscape diversity is stronger than the uncertainty effect. This is an important insight to support a land-use planning based on ecosystem services

Accounting for multiple ecosystem services in a simulation of land‐use decisions: Does it reduce tropical deforestation?

Conversion of tropical forests is among the primary causes of global environmental change. The loss of their important environmental services has prompted calls to integrate ecosystem services (ES) in addition to socio-economic objectives in decisionmaking. To test the effect of accounting for both ES and socio-economic objectives in land-use decisions, we develop a new dynamic approach to model deforestation scenarios for tropical mountain forests. We integrate multi-objective optimization of land allocation with an innovative approach to consider uncertainty spaces for each objective. These uncertainty spaces account for potential variability among decisionmakers, who may have different expectations about the future. When optimizing only socio-economic objectives, the model continues the past trend in deforestation (1975–2015) in the projected land-use allocation (2015–2070). Based on indicators for biomass production, carbon storage, climate and water regulation, and soil quality, we show that considering multiple ES in addition to the socio-economic objectives has heterogeneous effects on land-use allocation. It saves some natural forest if the natural forest share is below 38%, and can stop deforestation once the natural forest share drops below 10%. For landscapes with high shares of forest (38%–80% in our study), accounting for multiple ES under high uncertainty of their indicators may, however, accelerate deforestation. For such multifunctional landscapes, two main effects prevail: (a) accelerated expansion of diversified non-natural areas to elevate the levels of the indicators and (b) increased landscape diversification to maintain multiple ES, reducing the proportion of natural forest. Only when accounting for vascular plant species richness as an explicit objective in the optimization, deforestation was consistently reduced. Aiming for multifunctional landscapes may therefore conflict with the aim of reducing deforestation, which we can quantify here for the first time. Our findings are relevant for identifying types of landscapes where this conflict may arise and to better align respective policies

Dipeptidyl-peptidase 3 and IL-6: potential biomarkers for diagnostics in COVID-19 and association with pulmonary infiltrates

Coronavirus SARS-CoV-2 spread worldwide, causing a respiratory disease known as COVID-19. The aim of the present study was to examine whether Dipeptidyl-peptidase 3 (DPP3) and the inflammatory biomarkers IL-6, CRP, and leucocytes are associated with COVID-19 and able to predict the severity of pulmonary infiltrates in COVID-19 patients versus non-COVID-19 patients. 114 COVID-19 patients and 35 patients with respiratory infections other than SARS-CoV-2 were included in our prospective observational study. Blood samples were collected at presentation to the emergency department. 102 COVID-19 patients and 28 non-COVID-19 patients received CT imaging (19 outpatients did not receive CT imaging). If CT imaging was available, artificial intelligence software (CT Pneumonia Analysis) was used to quantify pulmonary infiltrates. According to the median of infiltrate (14.45%), patients who obtained quantitative CT analysis were divided into two groups (> median: 55 COVID-19 and nine non-COVID-19, ≤ median: 47 COVID-19 and 19 non-COVID-19). DPP3 was significantly elevated in COVID-19 patients (median 20.85 ng/ml, 95% CI 18.34–24.40 ng/ml), as opposed to those without SARS-CoV-2 (median 13.80 ng/ml, 95% CI 11.30–17.65 ng/ml; p < 0.001, AUC = 0.72), opposite to IL-6, CRP (each p = n.s.) and leucocytes (p < 0.05, but lower levels in COVID-19 patients). Regarding binary logistic regression analysis, higher DPP3 concentrations (OR = 1.12, p < 0.001) and lower leucocytes counts (OR = 0.76, p < 0.001) were identified as significant and independent predictors of SARS-CoV-2 infection, as opposed to IL-6 and CRP (each p = n.s.). IL-6 was significantly increased in patients with infiltrate above the median compared to infiltrate below the median both in COVID-19 (p < 0.001, AUC = 0.78) and in non-COVID-19 (p < 0.05, AUC = 0.81). CRP, DPP3, and leucocytes were increased in COVID-19 patients with infiltrate above median (each p < 0.05, AUC: CRP 0.82, DPP3 0.70, leucocytes 0.67) compared to infiltrate below median, opposite to non-COVID-19 (each p = n.s.). Regarding multiple linear regression analysis in COVID-19, CRP, IL-6, and leucocytes (each p < 0.05) were associated with the degree of pulmonary infiltrates, as opposed to DPP3 (p = n.s.). DPP3 showed the potential to be a COVID-19-specific biomarker. IL-6 might serve as a prognostic marker to assess the extent of pulmonary infiltrates in respiratory patients

Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation