Carole Ampe

Ecology, management and monitoring of grey dunes in Flanders

Grey dunes are a priority habitat type of the European Union Habitats Directive and demand special attention for conservation and management. Knowledge of the ecology of coastal grey dunes can contribute to this policy. Dune grassland succession is initiated by fixation and driven by the complex of soil formation (humus accumulation) and vegetation development. Leaching and mobilization of CaCO3. which are important in nutrient dynamics, complicate the picture. At present, grass- and scrub encroachment greatly overrules these fine scaled soil processes and causes substantial loss of regional biodiversity. Belgium has an international responsibility in grey dune conservation because of the limited range of its characteristic vegetation, flora and fauna. As biomass removal seems essential in grassland preservation, grazing is an important management tool. Evaluation of management measures focuses on biodiversity measurements on the levels of landscape, community and species.

Management of the Belgian coast: opinions and solutions.

Since the beginning of the 20th century the Belgian coast has undergone important changes of which an overview is presented here. To determine the view of the Belgian public on the Belgian coast and in order to obtain their opinions and solutions to the problems along the Belgian coast, a questionnaire survey was conducted with a total of 100 respondents divided into five groups, all active in the coastal zone. The five groups included (1) politicians on various levels of authority, (2) coastal entrepreneurs and business people, (3) naturalists and scientists, (4) coastal residents and (5) tourists. Coastal zone problems, as perceived by the different groups, and their solutions are discussed. Former municipalities, in particular, were held responsible for the current coastal problems. Most respondents were skeptic about the application of recent juridical instruments (e.g. the Dune Decree), the structural plans and their power to protect the remaining natural areas. The root of the problems seems to lie in lack of coordination and communication between different authorities responsible for the coastal zone.

Morphological characterisation of humus forms in recent coastal dune ecosystems in Belgium and northern France

Abstract The morphology of humus profiles, developed on recent sandy coastal dune ecosystems, is studied on macro- and microscale. Humus and soil profiles were described, sampled and analysed. Undisturbed, oriented samples were taken from the surface horizons for micromorphological study. The soils are situated in the National Biological Reserve of the Opal Coast, Merlimont, France and near De Haan, Belgium. On both sites, the parent material consists of aeolian calcareous sand. Surface horizons, however, are decarbonated due to leaching processes. In Merlimont, the sequence consists of two profiles, one under Pinus nigra ssp. laricio and one under Populus nigra ssp. nigra , characterised by a Resimor 1 /Dysmoder 2 and Rhizomull 1 /Mesomull 2 humus type, respectively. At the De Haan site, three profiles under Quercus robur , Populus ssp. and P. nigra var. austriaca are investigated. The humus types are respectively Mullmoder 1 to Mull/Dysmull 2 , Mull 1 / Oligomull 2 , Mormoder 1 /Dysmoder 2 . Differences among the humus profiles are related to presence/absence among the L-, F-, H- and A-horizons, structure, rooting, presence of hyphae, sclerotia and excrements. Macromorphologically, the difference between humus profiles under coniferous and deciduous forest/grassland is evident by thicker L-, F and/or H-horizons under coniferous trees. The microstructure of the L- and F-horizons shows a loose packing of subhorizontally oriented needles. The microstructure of the H-horizons varies from intergrain microaggregate to locally weak crumb. The microstructure of the surface mineral horizon of all profiles is mainly intergrain microaggregate, sometimes single grain and exceptionally bridged grain. Intimate mixing and complexation of organic matter to the mineral fraction into aggregates is very limited in the A-horizons. All A-horizons, irrespective of the humus type, are to some degree characterised by a “pepper and salt” appearance. The horizon symbol “H+E” is introduced to label this morphology. The Mull humus forms under deciduous trees are indicative of rather intense mesofauna activities. The absence of a crumb structure in the A-horizon of these soils could be due to the fast disintegration of earthworm casts in these sandy soils with no clay or silt fraction.