Suchergebnisse

Während der durch das El-Niño-Phänomens ausgelösten Dürre im Jahr 2015 haben verheerende Waldbrände Indonesien weltweit in die Schlagzeilen gebracht. Die Waldbrände, die zumindest teilweise auf die Brandrodung von Regenwäldern für Plantagen zurückzuführen sind, haben die Debatte über die Nachhaltigkeit des weltweit am meisten gehandelten Pflanzenöls, des Palmöls, verschärft. Doch trotz intensiver Diskussionen um die Nachhaltigkeit von Palmöl, hat sich vor Ort bisher wenig geändert. Insbesondere verhindert die inkonsequente Durchsetzung von Umweltgesetzen eine nachhaltigere Produktion von Palmöl. Gleichzeitig expandiert die Palmölindustrie in Lateinamerika und Westafrika. Für Kleinbauern ist die Ölpalme eine attraktive Nutzpflanze. Sie verlangt weniger Arbeitseinsatz als andere Nutzpflanzen und ermöglicht so Landwirten Einkommen außerhalb der Landwirtschaft zu generieren. Während der Verlust der Artenvielfalt und Treibhausgasemissionen als Folge der Ausweitung der Palmölproduktion bereits diskutiert werden, findet die Degradation lokaler Wasserressourcen bisher wenig Beachtung. Der vorliegende Artikel untersucht daher, warum es durch die Ausweitung der Plantagen zu einer Veränderung des Wasserkreislaufes kommen kann. Dafür stützt es sich auf neueste interdisziplinäre Forschungsergebnisse (Merten et al., 2016). Darüber hinaus werden Auflagen für das Wassermanagement in privaten Nachhaltigkeitsstandards und nationalen Vorschriften diskutiert. Die Ergebnisse der ökohydrologischen Messungen auf Ölpalmplantagen sowie Beobachtungen indonesischer Kleinbauern deuten darauf hin, dass großflächige Ölpalmmonokulturen langfristig negative Auswirkungen auf kleinbäuerliche Anbausysteme und die Wasserversorgung ländlicher Gemeinden haben. Unsere Studie zeigt, dass die lokale Bevölkerung seit Ölpalmen vermehrt angebaut werden, über Wassermangel während der Trockenzeit klagt; sich Überschwemmungen häufen; intensiv bewirtschaftete Monokulturen starke Bodendegradation verursachen, sodass Niederschlag schnell oberflächlich abfließt und die Grundwasserneubildung reduziert wird. Zudem zeigt sich, dass Ölpalmen den lokalen Wasserkreislauf stärker beeinflussen als andere Nutzpflanzen. Auf Grundlage dieser Erkenntnisse geben wir folgende Empfehlungen: Die Europäische Union (EU) sollte für sämtliche Palmölprodukte verbindliche Nachhaltigkeitsstandards einführen. In Umweltverträglichkeitsprüfungen (UVP) und Nachhaltigkeitsstandards sollte Wasser- und Bodenmanagement eine größere Bedeutung beigemessen werden. Nachhaltigkeitsstandards für Agrokraftstoffe sollten besser überwacht werden. Bei Nichteinhaltung der Standards, sollte die EU ein zeitweiliges Verbot der Nutzung von Palmöl für die Herstellung von Agrokraftstoffen in Erwägung ziehen.

During El Niño in 2015, devastating forest fires in Indonesia directed international attention towards land use changes and deforestation on the archipelago. At least partially a result of clearing land for plantation estates, those fires spurred debate about the sustainability of palm oil, which is the most traded vegetable oil. Recently, seven European governments signed the Amsterdam Declaration. Its signatories, including Germany, committed themselves to helping the private sector to achieve a fully sustainable palm oil supply chain by 2020. Despite progress made in talks on sustainability, little is visible on the ground. To the contrary, as the Indonesian case shows, that palm oil expansions can cause soil and water resources to degrade. Especially weak law enforcement poses a major challenge to a sustainable production of oil palm. At the same time, the oil palm business has been expanding rapidly in Latin America and West Africa. For smallholders oil palm cultivation is an attractive land use option that requires little labour input and allows them to engage in off-farm income activities. Current discussions about the ecological impacts of expanding palm oil production focus on how it destroys primary forest and peatlands, increases greenhouse gas (GHG) emissions and reduces biodiversity. Little attention has been paid to concerns that oil palm plantations severely impact local water resources and increase flood risks. This briefing paper makes use of a recent interdisciplinary publication (Merten et al., 2016) and extensive fieldwork to analyse the way expanding palm oil production impacts the hydrological cycle. It also discusses water management criteria in certification schemes and national regulations. Measurements of eco-hydrological processes and observations of Indonesian farmers indicate that large-scale oil palm monoculture has long-term negative consequences for smallholder farming systems and the water supplies of rural communities. Our interdisciplinary study has revealed that: local populations report water shortages in dry seasons in the wake of new oil palm plantations; expanding oil palm plantations leads to more frequent floods; intensive monoculture plantation systems severely degrade the soil, impeding the recharge of groundwater reservoirs and increasing surface runoff; and oil palm cultivation impacts the local hydrological cycle more severely than other crops. Based on these findings we recommend that: The European Union (EU) should set mandatory sustainability standards for all palm oil products. Water and soil management should have prominent roles in environmental impact assessments and sustainability standards. Sustainability standards for agrofuels should be better monitored. If compliance cannot be guaranteed, the EU should consider a temporary ban on using palm oil for agrofuel production.

By mediating evapotranspiration processes, plant canopies play an important role in the terrestrial water cycle and regional climate. Substantial uncertainties exist in modeling canopy water interception and related hydrological processes due to rainfall forcing frequency selection and varying canopy traits. Here we design a new time interpolation method "zero" to better represent convective-type precipitation in tropical regions. We also implement and recalibrate plant functional type-specific interception parameters for rainforests and oil palm plantations, where oil palms express higher water interception capacity than forests, using the Community Land Model (CLM) versions 4.5 and 5.0 with CLM-Palm embedded. Reconciling the interception scheme with realistic precipitation forcing produces more accurate canopy evaporation and transpiration for both plant functional types, which in turn improves simulated evapotranspiration and energy partitioning when benchmarked against observations from our study sites in Indonesia and an extensive literature review. Regional simulations for Sumatra and Kalimantan show that industrial oil palm plantations have 18-27% higher transpiration and 15-20% higher evapotranspiration than forests on an annual regional average basis across different ages or successional stages, even though the forests experience higher average precipitation according to reanalysis data. Our land-only modeling results indicate that current oil palm plantations in Sumatra and Kalimantan use 15-20% more water (mean 220 mm or 20 Gt) per year compared to lowland rainforests of the same extent. The extra water use by oil palm reduces soil moisture and runoff that could affect ecosystem services such as productivity of staple crops and availability of drinking water in rural areas. ; European Commission Erasmus Mundus FONASO Doctorate fellowship; German Research Foundation (DFG) [990, KN 582/8-1]; European Union [SC5-01-2014, 641816]; US Department of Agriculture National Institute of Food and Agriculture Hatch Project [HAW01136-H]; National Science Foundation [DBI-1052875] ; Open access journal ; This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.

Land-use transitions can enhance the livelihoods of smallholder farmers but potential economic-ecological trade-offs remain poorly understood. Here, we present an interdisciplinary study of the environmental, social and economic consequences of land-use transitions in a tropical smallholder landscape on Sumatra, Indonesia. We find widespread biodiversity-profit trade-offs resulting from land-use transitions from forest and agroforestry systems to rubber and oil palm monocultures, for 26,894 aboveground and belowground species and whole-ecosystem multidiversity. Despite variation between ecosystem functions, profit gains come at the expense of ecosystem multifunctionality, indicating far-reaching ecosystem deterioration. We identify landscape compositions that can mitigate trade-offs under optimal land-use allocation but also show that intensive monocultures always lead to higher profits. These findings suggest that, to reduce losses in biodiversity and ecosystem functioning, changes in economic incentive structures through well-designed policies are urgently needed.