Nachhaltigkeitsbewertung von Bodennutzungen und Bodenfunktionen

Böden stehen im Spannungsfeld verschiedener Ziele der nachhaltigen Entwicklung. Neben der Produktivität als Beitrag zur Ernährungssicherheit geht es um den Erhalt der Funktionsfähigkeit terrestrischer Ökosysteme und um den Beitrag zum Klimaschutz durch Kohlenstoffspeicherung und Verminderung von Treibhausgasemissionen. Eine Nachhaltigkeitsbewertung erfordert die Analyse, wie Bodenfunktionen sich durch das Management von Böden verändern, und welche Folgen für die Ziele der nachhaltigen Entwicklung entstehen. Im Rahmen des Forschungsprogramms „BonaRes – Boden als nachhaltige Ressource für die Bioökoonomie“ haben wir einen analytischen Rahmen entwickelt, um die Wirkungen von Bodenbewirtschaftungen und Bodenfunktionen auf Nachhaltigkeitsziele zu bewerten und Trade-offs zu identifizieren. Während die systemischen Wechselwirkungen zwischen Bodenbewirtschaftung und Bodenfunktionen Gegenstand einer anderen Arbeitsgruppe sind, geht es hier um die Wechselwirkungen zwischen den natürlichen und gesellschaftlichen Systemen. Der Bewertungsansatz nutzt das DPSIR (Driver-Pressure-State-Impact-Response) Konzept als Grundstruktur und kombiniert die beiden komplementären Ansätze der Ökosystemleistungen und der Ressourceneffizienz miteinander. Die Verbindung zwischen Bodenfunktionen und Nachhaltigkeitszielen wird damit für verschiedene Zeit- und Raumdimensionen abbildbar. Wir stellen den analytischen Rahmen vor und geben erste Beispiele für seine Anwendung

A systemic approach for modeling soil functions

The central importance of soil for the functioning of terrestrial systems is increasingly recognized. Critically relevant for water quality, climate control, nutrient cycling and biodiversity, soil provides more functions than just the basis for agricultural production. Nowadays, soil is increasingly under pressure as a limited resource for the production of food, energy and raw materials. This has led to an increasing demand for concepts assessing soil functions so that they can be adequately considered in decision-making aimed at sustainable soil management. The various soil science disciplines have progressively developed highly sophisticated methods to explore the multitude of physical, chemical and biological processes in soil. It is not obvious, however, how the steadily improving insight into soil processes may contribute to the evaluation of soil functions. Here, we present to a new systemic modeling framework that allows for a consistent coupling between reductionist yet observable indicators for soil functions with detailed process understanding. It is based on the mechanistic relationships between soil functional attributes, each explained by a network of interacting processes as derived from scientific evidence. The non-linear character of these interactions produces stability and resilience of soil with respect to functional characteristics. We anticipate that this new conceptional framework will integrate the various soil science disciplines and help identify important future research questions at the interface between disciplines. It allows the overwhelming complexity of soil systems to be adequately coped with and paves the way for steadily improving our capability to assess soil functions based on scientific understanding

Understanding and managing freshwater recreational fisheries as complex adaptive social-ecological systems

The state of knowledge on the science and management of freshwater recreational fisheries is reviewed, with the objective of integrating insights from disparate fields such as fisheries science, environmental complexity theory, common-pool-resource theory, and resilience theory. First, freshwater recreational fisheries are characterized as complex adaptive social-ecological systems (SESs). Subsequently, two interrelated frameworks, drawing on the Ostrom framework for the analysis of SESs and adaptive management as key foundations, are presented. These frameworks are useful to structure the complexity and apprehend the various feedbacks and links inherent in any particular recreational fisheries system. Moreover, the frameworks help to identify operational management strategies in the face of substantial social-ecological uncertainty. It is concluded that to understand and manage freshwater recreational fisheries as complex adaptive SESs, a sustained shift from disciplinary to inter- and sometimes transdisciplinary research as well as a focus on flexible, adaptive and generally enabling rather than command-and-control type governance and management are needed. Understanding and managing recreational fisheries as complex adaptive SESs will benefit from an increasing focus on (i) managing social-ecological feedbacks and processes, (ii) managing critical slow variables that either drive the system or maintain it in potentially undesirable states, and (iii) managing and maintaining social and ecological diversity. It is hoped that the frameworks presented in this article may guide future interdisciplinary inquiry to manage for sustainability by building resilience

Landscape simplification promotes weed seed predation by carabid beetles (Coleoptera: Carabidae)

Weeds constitute major constraints for farmers by reducing crop yield and quality. However, weeds are managed effectively using herbicides, but this may cause harmful effects on human health and the environment. In an experiment on weed seed predation, we tested the biological control potential of carabid beetles to combat weeds in the absence of herbicides. Seeds from three common weed species were placed in cereal fields on conventional and organic farms located along a landscape complexity gradient (area annual crops within 1 km) in two distinct regions in Sweden. Carabid beetles were sampled in the same fields using pitfall traps. Neither carabid species richness nor seed removal was related to organic farming. Seed removal was significantly related to carabid species richness and both carabid species richness and seed removal was higher in landscapes with large total area of annual crops, although the evenness of the carabid communities was lower. The carabid genera with strongest positive relationship to seed removal differed between regions (Trechus in Uppland and Pterostichus in Scania), as did the preference for the different weed seed species. This study concludes that carabid species richness contributes to weed seed predation and that large scale landscape context explains more variation in the carabids' responses than local farming practices