Dirk Vrebos

Evaluation of the accuracy of land-use based ecosystem service assessments for different thematic resolutions.

The demand for pragmatic tools for mapping ecosystem services (ES) has led to the widespread application of land-use based proxy methods, mostly using coarse thematic resolution classification systems. Although various studies have demonstrated the limited reliability of land use as an indicator of service delivery, this does not prevent the method from being frequently applied on different institutional levels. It has recently been argued that a more detailed land use classification system may increase the accuracy of this approach. This research statistically compares maps of predicted ES delivery based on land use scoring for three different thematic resolutions (number of classes) with maps of ES delivery produced by biophysical models. Our results demonstrate that using a more detailed land use classification system does not significantly increase the accuracy of land-use based ES assessments for the majority of the considered ES. Correlations between land-use based assessments and biophysical model outcomes are relatively strong for provisioning services, independent of the classification system. However, large discrepancies occur frequently between the score and the model-based estimate. We conclude that land use, as a simple indicator, is not effective enough to be used in environmental management as it cannot capture differences in abiotic conditions and ecological processes that explain differences in service delivery. Using land use as a simple indicator will therefore result in inappropriate management decisions, even if a highly detailed land use classification system is used.

Making the Most of Our Land: Managing Soil Functions from Local to Continental Scale

The challenges of achieving both food security and environmental sustainability have resulted in a confluence of demands on land within the European Union (EU): we expect our land to provide food, fibre and fuel, to purify water, to sequester carbon, and provide a home to biodiversity as well as external nutrients in the form of waste from humans and intensive livestock enterprises. All soils can perform all of these five functions, but some soils are better at supplying selective functions. Functional Land Management is a framework for policy-making aimed at meeting these demands by incentivising land use and soil management practices that selectively augment specific soil functions, where required. Here, we explore how the demands for contrasting soil functions, as framed by EU policies, may apply to very different spatial scales, from local to continental scales. At the same time, using Ireland as a national case study, we show that the supply of each soil function is largely determined by local soil and land use conditions, with large variations at both local and regional scales. These discrepancies between the scales at which the demands and supply of soil functions are manifested, have implications for soil and land management: while some soil functions must be managed at local (e.g. farm or field) scale, others may be offset between regions with a view to solely meeting national or continental demands. In order to facilitate the optimisation of the delivery of soil functions at national level, to meet the demands that are framed at continental scale, we identify and categorise 14 policy and market instruments that are available in the EU. The results from this inventory imply that there may be no need for the introduction of new specific instruments to aid the governance of Functional Land Management. We conclude that there may be more merit in adapting existing governance instruments by facilitating differentiation between soils and landscapes.

Tussocks : biogenic silica hot-spots in a riparian wetland

Understanding the factors determining the size and extent of Si cycling in wetlands is important, as more and more research shows they interact strongly within riverine Si fluxes. One key factor is the size of the ecosystem Si reservoir, which strongly depends on the occurrence of organisms specialized in biological Si processing. Our study was aimed to test whether tussocks, a common growth form of sedges, can efficiently retain biogenic silica. As such, they take advantage of efficient recycling of a private Si stock, providing them with a competitive advantage. We showed that tussock development caused a patch-like distribution of biogenic silica (BSi) in wetlands. While in a managed wetland (where tussocks are absent) BSi was uniformly distributed over surface layers, tussock development in an unmanaged wetland strongly interfered with BSi distribution. A mosaic of BSi richer inter-tussock soils and BSi poorer soils under tussocks developed, resulting from the active uplift of Si into the tussock from soil below the tussocks. Tussocks affected the role of wetlands as silica hot-spots and biogenic Si sinks near rivers. This implies that future studies should focus on quantifying the effect of tussock development, and human management, on system scale BSi storage.

The impact of land use and spatial mediated processes on the water quality in a river system

River systems are highly complex, hierarchical and patchy systems which are greatly influenced by both catchment surroundings and in-stream processes. Natural and anthropogenic land uses and processes affect water quality (WQ) through different pathways and scales. Understanding under which conditions these different river and catchment properties become dominant towards water chemistry remains a challenge. In this study we analyzed the impact of land use and spatial scales on a range of WQ variables within the Kleine Nete catchment in Belgium. Multivariate statistics and spatial descriptors (Morans and Asymmetric Eigenvector Maps) were used to assess changes in water chemistry throughout the catchment. Both land use and complex mixes of spatial descriptors of different scales were found to be significantly associated to WQ parameters. However, unidirectional, upstream-downstream changes in water chemistry, often described in river systems, were not found within the Kleine Nete catchment. As different sources and processes obscure and interact with each other, it is generally difficult to understand the correct impact of different pollution sources and the predominant pathways. Our results advocate for WQ management interventions on large and small scales where needed, taking the predominate pathways in to account.

Ecosystem Service Assessments: Science or Pragmatism?

Abstract This chapter challenges the capability of the ecosystem service to obtain sustainable development beyond awareness raising, based on the urgency to deliver sound results for implementation versus the large uncertainties inherent in the different research fields involved and their integration. The authors identify ten main sources of uncertainty that may affect policy and management decisions, and propose three independent strategies for individual researchers, commissioners and stakeholders to account for methodological risks and best practices in methodologies, dissemination, or application of results, even under restricted budgets or project goals. The chapter argues for a clear and transparent ecosystem services research policy on methodology development, uncertainty acknowledgment, and communication.This chapter challenges the capability of the ecosystem service to obtain sustainable development beyond awareness raising, based on the urgency to deliver sound results for implementation versus the large uncertainties inherent in the different research fields involved and their integration. The authors identify ten main sources of uncertainty that may affect policy and management decisions, and propose three independent strategies for individual researchers, commissioners and stakeholders to account for methodological risks and best practices in methodologies, dissemination, or application of results, even under restricted budgets or project goals. The chapter argues for a clear and transparent ecosystem services research policy on methodology development, uncertainty acknowledgment, and communication.