Ungrazed salt marsh has well connected soil pores and less dense sediment compared with grazed salt marsh: a CT scanning study. (30th October 2020)

• Record Type: Journal Article
• Authors: Keshta, Amr; Koop-Jakobsen, Ketil; Titschack, Jürgen; Mueller, Peter; Jensen, Kai; Baldwin, Andrew; Nolte, Stefanie
• Is Part Of: Estuarine, coastal and shelf science. Volume 245(2020)
• Publication Date: 2020-10-30
• Subjects: Livestock -- Land-use managment -- Soil ecosystem services -- Wadden sea -- Computed tomography -- Soil macroporosity; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2020.106987
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: Salt marshes provide various ecosystem functions and services including flooding protection, wildlife habitats, and carbon storage. These functions and services could, however, be strongly impacted by anthropogenic activities such as livestock grazing – a common practice in the Wadden Sea salt marshes located in North west of Europe. To assess the impact of grazing on soil parameters, a total number of eight soil cores (⌀: 18 cm; L: 50 cm) were collected in areas with and without livestock grazing, and scanned using a Computed Tomography (CT) to characterize soil parameters including soil macroporosity, sediment density, and pores connectivity. Subsequently, sub-samples were taken for determination of soil moisture content (%) and bulk density (g cm −3 ). To account for the impact of grazing on soil drainage after tidal inundations, water table relative to soil surface was monitored during two flooding events. Our results demonstrated that grazed salt marsh has higher top-soil bulk density, and lower macroporosity and pore connectivity, than ungrazed marsh, due to soil compaction by livestock grazing. Moreover, grazed marsh has slower water drainage and that might keep the soil waterlogged for a longer period of time which has implications on lowering decomposition rate due to lower soil redox. This study provides evidence that grazing alters physical soil parameters in salt marsh. Consequently, grazing needs to be accounted for when evaluating how land use impacts ecosystem services and functions including carbon sequestration. Graphical abstract: Image 1 Highlights: Using minimally non-destructive X-ray CT analyses allows identification of soil parameters in undisturbed soil zones. Grazed salt marshes have lower soil macroporosity and higher density than ungrazed salt marshes. Ungrazed salt marshes have higher drainage rate than grazed saltmarshes.