Edu Dorland

KWR Water Research Institute · Water systems and technology

Flooding of stream valleys is occurring more frequently and at more sites. This may lead to the deposition of nutrient rich sludge in Natura 2000 habitats adjacent to these streams, such as alluvial forests, resulting in loss of biodiversity. To improve our understanding of the effects of flooding in these ecosystems, weconducted a mesocosm experim...

Hoge fosfaatbeschikbaarheid in voormalige landbouwpercelen belemmert natuurbeheerders bij het omvormen van deze terreinen naar natuurgebieden. Het opbrengen van ijzerrijk drinkwaterslib verlaagt de fosforbeschikbaarheid en lijkt daarom een goed alternatief voor gronden waar afgraven van de fosfaatrijke toplaag geen optie is.

Both nitrogen (N) and phosphorus (P) enrichment are known to impact plant diversity globally. Recent studies suggest that P enrichment may be as important, or even more important, as a driver of terrestrial plant species loss as N enrichment. However, the generality and relative contribution of these critical nutrients to species losses remains unc...

Natuurbeheerders zitten soms in hun maag met percelen die vanwege hun landbouwkundig verleden een hoge fosfaatlast kennen, omdat dit de ontwikkeling van waardevolle natuur belemmert. Afgraven is duur, uitmijnen tijdrovend, maar wat dan? Kan hergebruik van ijzerrijk drinkwaterslib uitkomst bieden? De eerste resultaten van veldproeven met dit restpro...

Topography–climate–vegetation–runoff relationships are important issues in hydrological studies. In this paper, based on analyzing water isotope characteristics of river water, the influence of these variables on the relative contribution of rain to river water was investigated during one rain event in the Heishui Valley of the upper Yangtze River...

Nutrient pollution presents a serious threat to biodiversity conservation. In terrestrial ecosystems, the deleterious effects of nitrogen pollution are increasingly understood and several mitigating environmental policies have been developed. Compared to nitrogen, the effects of increased phosphorus have received far less attention, although some s...

Reduction in the species richness of acid grasslands along a gradient of atmospheric nitrogen (N) deposition has previously been demonstrated in the UK (Stevens, Dise, Mountford, Gowing, Science 303:1876–1879, 2004). Further surveys of acid grasslands in the UK confirm this relationship. This chapter reports an examination of the relationship acros...

Emissions and deposition of ammonia and nitrogen oxides have strongly increased since the 1950s. This has led to significant changes in the nitrogen (N) cycle, vegetation composition and plant diversity in many ecosystems of high conservation value in Europe. As a consequence of different regional pollution levels and of the increased importance of...

In Europe and, increasingly, the rest of the world, the key policy tool for the control of air pollution is the critical load, a level of pollution below which there are no known significant harmful effects on the environment. Critical loads are used to map sensitive regions and habitats, permit individual polluting activities, and frame internatio...

There is a growing evidence base demonstrating that atmospheric nitrogen deposition presents a threat to biodiversity and ecosystem function in acid grasslands in Western Europe. Here, we report the findings of a workshop held for European policy makers to assess the perceived importance of reactive nitrogen deposition for grassland conservation, i...

This data set consists of vascular plant and bryophyte species composition and plant and soil biogeochemical data from 153 acid grasslands located in the Atlantic biogeographic region of Europe. Data were collected between 2002 and 2007. The grasslands all belong to the Violion caninae association and were managed by grazing or cutting but had not...

Question: High atmospheric nitrogen (N) deposition has been shown to affect productivity and species composition of terrestrial ecosystems. This study focused on the differential effects of the two inorganic N forms in atmospheric deposition (i.e. ammonium and nitrate).Methods and location: Nutrient addition experiments were carried out during 4 ye...

Question: Which environmental variables affect floristic species composition of acid grasslands in the Atlantic biogeographic region of Europe along a gradient of atmospheric N deposition?Location: Transect across the Atlantic biogeographic region of Europe including Ireland, Great Britain, Isle of Man, France, Belgium, The Netherlands, Germany, No...

While it is well established that ecosystems display strong responses to elevated nitrogen deposition, the importance of the ratio between the dominant forms of deposited nitrogen (NH(x) and NO(y)) in determining ecosystem response is poorly understood. As large changes in the ratio of oxidised and reduced nitrogen inputs are occurring, this oversi...

Droge heischrale graslanden zijn zeer gevoelig voor verzuring en vermesting als gevolg van atmosferische depositie van zwavel- en stikstofverbindingen. De stikstofdepositie neemt de laatste jaren iets af, maar tegelijk blijken stikstofaccumulatie en verzuring in de bodem van grotere betekenis te zijn dan eerst gedacht. Dit blijkt zelfs reden te zij...

• This paper seeks to determine whether N-deposition has a negative impact on the species richness of calcareous grasslands at a European wide scale. • 100 calcareous grasslands across the Atlantic region of Europe were sampled in one season. Species composition and richness of vegetation communities were compared to some key environmental drivers...

A survey of 153 acid grasslands from the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is changing plant species composition and soil and plant-tissue chemistry. Across the deposition gradient (2-44 kg N ha(-1) yr(-1)) grass richness as a proportion of total species richness increased whereas forb richness decre...

Evidence from an international survey in the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is reducing plant species richness in acid grasslands. Across the deposition gradient in this region (2-44 kg N ha(-1) yr(-1)) species richness showed a curvilinear response, with greatest reductions in species richness wh...

Question: Can combined sod cutting and liming successfully restore species composition of degraded wet heaths? Location: The Netherlands. Methods: The effects of sod cutting with or without liming on plant species composition were studied in two degraded wet heath areas. Seeds and seedlings of Arnica montana were put out in the treated plots to tes...

Our study investigates the negative impact of nitrogen (N) deposition on species richness in acidic grasslands, based on a temporal comparison of vegetation data spanning a period of almost 70 years. We compiled a large data base of plots assigned to the Violion caninae grassland type, composed of managed, but unfertilized semi-natural grasslands o...

Current restoration measures of degraded, acidified heathland ecosystems have not always been successful in the Netherlands. Positive effects of a restored hydrology are often counteracted by acidification of the soil and the local groundwater system. Liming of the heathlands in the catchment of moorland pools might contribute to the restoration of...

The effects of increasing ammonium concentrations in combination with different pH levels were studied on five heathland plant species to determine whether their occurrence and decline could be attributed to ammonium toxicity and/or pH levels. Plants were grown in growth media amended with four different ammonium concentrations (10, 100, 500 and 10...

Soils of wet heathlands have lost their buffering capacity as a result of acidification, eutrophication, and desiccation. Many characteristic plant species have disappeared from these ecosystems because of the unfavourable soil conditions. Restoration projects should aim at counteracting the negative effects of acidification in particular. Blocking...

The effects of sod cutting, a common restoration measure to remove excess nutrients from grass-dominated heathlands, on nitrification were studied in dry and wet Dutch heathlands and in incubation experiments. In the field, soil ammonium and nitrate concentrations were measured after treatment by sod cutting, with or without additional liming. Pote...

Summary 1. Restoration of formerly species-rich wet heaths and matgrass swards has not always been successful. The constraints on this restoration process are not yet fully understood and need further investigation, particularly the accumulation of ammonium in the soil after sod cutting, i.e. the removal of the vegetation and topsoil layer. This ac...

Reduced light availability as a consequence of changed management is considered to be the main cause of the rapid decline of Ophrys insectifera L. in The Netherlands. Cessation of coppicing of woodlands and increased growth of shade-tolerant understorey species have decreased light conditions in the habitat of this endangered species. To restore su...

: Long-term demographic data have been analyzed to establish possible costs of flowering in the terrestrial orchid Spiranthes spiralis (L.) Chevall. in The Netherlands. Costs of flowering can be expressed as individual plant performance and flowering frequency in relation to the generative or vegetative status in the following year. Flowering in in...