Category Archives: Biodiversity

The Value of Species Diversity in Grasslands

By Sergei Schaub

Background

Grasslands cover a large portion of the global land area and are essential for global food security and the agricultural economy. Grasslands provide many ecosystem services in addition to forage production, such as biodiversity, pollination, carbon sequestration, and outdoor recreation. Changes in agricultural production, biodiversity loss, and climate change (and with it, for example, increased droughts) are putting increasing pressure on grasslands and grassland-based production. This increasing pressure requires farmers to make adjustments.

Farmers have several instruments at their disposal to adapt their grasslands, including the choice of (plant) species diversity. Species diversity can increase yields and grassland stability, as well as species diversity can reduce the adverse effects of weather extremes (e.g., droughts). A key challenge is to quantify these species diversity benefits for farmers economically. These realities gave rise to the central question of my dissertation: ‘What is the value of species diversity for farmers in grasslands?’.

What evidence is useful for policymaking?

In my thesis1, I showed that species diversity can increase yields while it did overall not negatively affect forage quality, both in intensively managed grasslands and managed semi-natural grasslands. Thus, species diversity can increase revenues from milk production. Additionally, I found that species diversity can reduce production risk in intensively managed grasslands. These benefits of species diversity were also present under climate change conditions, i.e., increasing drought probability. Therefore, my thesis results show that species diversity can be an economically relevant production factor and that the increasing species diversity in grasslands can contribute to sustainable intensification of grassland-based production. Additionally, other studies indicated that species diversity can also support other important ecosystem services and functions (e.g., biodiversity, pollination, and cultural ecosystem services), which I did not consider in my thesis. One key challenge to benefit from species diversity (and especially for semi-natural grasslands) will be to develop management systems that allow maintaining plant diversity over time in more intensively managed grasslands.

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Innerhalb von vier terrestrischen Planetengrenzen ist es möglich, zehn Milliarden Menschen zu ernähren

Die Studie Feeding ten billion peole is possible within four terrestrial planetary boundaries (Gerten et al. 2020) gibt Anlass zur Hoffnung. Die Erde kann 10 Millionen Menschen ernähren, aber nicht nur mit den Methoden einer effizienten Landwirtschaft. Es braucht andere Massnahmen, damit wir die grossen Probleme von industriellen Monokulturen und Massentierhaltung überwinden, sonst sind die Ernteverluste wegen einer weiteren Überschreitung der globalen Grenzen bei den natürlichen Ressourcen unausweichlich. Die Agrarökologie wird hier eine grosse Rolle spielen.

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Viele landwirtschaftliche Subventionen in der Schweiz wirken sich negativ auf die Biodiversität aus

Um den Biodiversitätsverlust zu bremsen, finanzieren der Bund und die Kantone verschiedenen biodiversitätsfördernde Massnahmen. Mit einem Vielfachen dieser Beträge werden Aktivitäten finanziert, die Lebensräume und Arten direkt oder indirekt schädigen. Insgesamt 207 Subventionen in verschienden Bereichen sind es die ganz, teilweise oder indirekt Biodiversität schädigen. Zu dieser Schlussfolgerung kommt eine Untersuchung zusammen mit WSL und in Zusammenarbeit mit dem Forum Biodiversität, aus welcher ein Faktenblatt des SCNAT hervorgegangen ist (Gubler et al., 2020).

Darin werden im Bereich der Landwirtschaft einige Verbesserungen der Subventionspraxis vorgeschlagen, um biodiversitätsschädigende Subventionen bis 2020 zu beseitigen, schrittweise abzubauen oder umzugestalten.

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Principles for participation in competing demands for land use

Global demand for agricultural products is competing with scarce land resources and environmental protection especially biodiversity protection and the increasing thread of shortages of water and nutrients. How can we ensure biodiversity and ecosystem protection in fragile habitats if we struggle to satisfy the demand of the world population for food, energy and housing?

Ten principles for a landscape approach to reconciling agriculture, conservation, and other competing land uses (Sayer et al., 2013) can help to guide the process of decision-making in the landscape context. These principles emphasize that we will need a people-centred approach applied at landscape scales and a focus on multifunctional landscapes. The principles in short:

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Maintaining Plant Biodiversity in Cities

Using Urban Design for a Better Green Infrastructure in Zurich

By Kevin Vega

What evidence was useful for policymaking?

Understanding the effects of urban design on plant species composition in cities is essential to maintaining biodiversity overall, promoting urban resilience in the face of climate change, and improving life quality for a city’s residents. Functional ecosystems can benefit pollinators, reduce urban flooding, and improve air quality –all while looking aesthetically pleasing.

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How can biodiversity-ecosystem function research (BEF) be used to inform ecosystem managers and policy-makers?

Ecosystem researchers currently do different types of BEF research. How can these studies be used in policymaking? A recent analysis with involvement of Prof. Nina Buchmann from ETH Zurich and member of PSC came up with recommendations:

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How can policymakers decide if protected areas (=PA) in the Alps will be able to secure high-species richness under climate future change?

Protected areas like the Swiss National Park should conserve native plant and animal species in the Alps now and in the future. With upcoming climate change the habitats of species shift and the spatial distribution of alpine biodiversity is changing.

Can researchers predict if protected areas can uphold conservation goals under these changing conditions? How can policymakers decide if they need to update the boundaries of existing protected areas or if new ones need to be created in specific areas to conserve alpine biodiversity?

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Dramatic Loss of Food Plants for Insects

The diversity of food plants for insects in the canton of Zurich has dramatically decreased over the past 100 years or so. This means that bees, flies and butterflies are increasingly deprived of their food base, a team of researchers from the Universities of Bonn and Zurich (Reto Nyffler, Michael Kessler) and the Swiss Federal Institute for Forest, Snow and Landscape Research WSL has demonstrated. The results are transferable to the whole of Central Europe, with minor regional restrictions.

Source: https://www.media.uzh.ch/en/Press-Releases/2020/Loss-of-Plants.html

Stefan Abrahamczyk, Thomas Wohlgemuth, Michael Nobis, Reto Nyffeler, Michael Kessler: Shifts in food plant abundance for flower-visiting insects between 1900 and 2017 in the canton of Zurich, Switzerland, Ecological Applications, 23 April 2020. DOI: 10.1002/eap.2138