JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. We analysed the germination of 91 herbaceous species in response to a temperature gradient, and to alternating temperatures and stratification (chilling). A principalcomponents analysis revealed that the species were distributed along two statistically independent axes, the first of which primary represented the optimal temperature for germination and the second the rate of germination. 2 These results were further related to data on species replacement during 25 years of succession in grassland after the cessation of fertilizer application but with continued hay making. Separate successional sequences were distinguished for the dry parts and the wet parts of the fields Changes in canopy structure were studied by counting gaps and mapping light at the soil surface. 3 Changes in species composition of species present at the different stages were related to the changes in the germination attributes during the succession towards nutrient-poor grassland. The productive grassland was characterized by rapidly germinating species and in the wetter parts, by those germinating at low temperatures. This might enable these species to escape from light competition by germinating in the autumn or winter, i.e. soon after seed set. The species from the less productive, more open stages germinated more slowly, and responded more clearly to stratification and alternating temperatures. It is therefore likely that germination of most seeds of these species is delayed until the following summer. 4 The importance of the observed interspecific differences in germination characteristics in relation to the observed changes in vegetation structure as an explanation for species replacement during succession is discussed. British Ecological Society

With the intensification of agricultural practices, formerly species rich marginal grassland communities of high botanical value in the Netherlands have been fertilized or manured since the first part of the twentieth century. This type of land use resulted in a dramatic decrease of the original plant species-richness. In the early 1970's yearly nutrient input to many of these grasslands was ceased as a nature management practice, while hay-cropping was continued. This type of grassland management is carried out to decrease overall nutrient supplying ability of the soil to plant cover in order to restore their original high botanical richness. The effect of this management on the type and the extent of nutrient deficiency was studied by comparing the short-term shoot responsiveness of undisturbed turfs to added nutrients and the nutrient status of fieldgrown dominants of four hay-field communities which were not fertilized for 3, 7, 20 or 25 years.Contrary to expectation, hay-cropping without input of additional nutrients did not impose an increase of species-richness of grassland on gley podzol. During early vegetation change strong inadequacy of N supply and moderate inadequacy of K supply by the soil regulate (shoot) growth. P-deficiency was not established. Prolonged discontinuation of fertilizer application caused concomitant inadequate supplies of N, K and P. In the last field (25 years unfertilized), nutrient deficiencies could not be detected by shoot growth responses to added nutrients but only by a low nutrient status. It appeared that during this type of vegetation change N-deficiency is the most pronounced and that K-deficiency developes much more rapidly than P-deficiency. The strong decline in total aerial pool sizes of N, K and P also emphasizes these simultaneously occurring shifts.We conclude that cut grassland composition on gley podzol soil is regulated by co-deficiencies of at least the soil phytoavailable macronutrients nitrogen, potassium and phosphorus. The absence of change in plant species number is likely not regulated by the nutrient supplying ability of the soil. Seed dispersal from elsewhere seems to be the most important factor.

An important methodological problem in plant ecology concerns the way in which the type and extent of nutrient limitation in terrestrial communities should be assessed. Conclusions on nutrient limitation have been founded mainly on soil extractions, fertiliser trials and tissue nutrient concentrations. In order to avoid some of the problems associated with these methods, we employed a special technique using intact sods which rooted both in the intact soil and in a nutrient solution, from which N, P and K were omitted stepwise. The method was applied to hay-field communities which differed in their history of fertiliser application. Four fields were compared which were not fertilised for 2, 6, 19 or 45 years, while hay making continued. This was done to restore former species-rich grassland communities. We tested the hypothesis that the increase in species diversity in these grasslands was attended by an increase in the number of limiting nutrients.We observed clear shifts in the type and extent of nutrient limitation. Fields which were recently fertilised were characterised by nitrogen and potassium limitation, while phosphorus limitation increased in importance towards the later stages of succession. In the last field (45 years unfertilised) N, P and K equally limited production at the community level. These conclusions differed from those drawn from a fertiliser trial in these same four fields, which failed to detect phosphorus limitation.It is concluded that the use of this method provides a valuable extra source of information while studying relationships between nutrient limitation and species diversity in grassland communities.

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Abstract. An integrated multidisciplinary approach including descriptive and experimental research of environmental and biotic factors was used to evaluate an attempt to restore a species‐rich fen meadow, phytosociologically belonging to the Cirsio‐Molinietum. Expert judgement and preliminary research indicated that soil acidification, due to drainage in the surrounding area, caused the degeneration of the fen meadow. Flooding the meadow with surface water was applied in order to stop acidification. A small irrigated wetland (helophyte filter) was constructed to reduce nutrient availability in the surface water. Sod cutting was applied in a small area as well. The two measures were evaluated through: (1) measurements of hydrological and soil factors, (2) seed bank analysis, (3) recording species composition in permanent plots, (4) assessing the type and extent of nutrient limitation using a full‐factorial fertilization experiment, (5) assessing the effect of liming on vegetation biomass, and (6) recording the growth of three introduced fen meadow species in the liming experiment. The research was carried out in a degraded site with intact vegetation, a degraded site where the top soil was removed by sod cutting and a reference site with intact Cirsio‐Molinietum vegetation. Groundwater levels in the degraded and the stripped site differed slightly from those of the reference site but they were within the range of Cirsio‐Molinietum requirements. Groundwater quality slightly improved in the stripped site. Top‐soil removal considerably reduced the macro‐nutrient contents and caused a stronger P‐deficiency. No increase in soil pH was observed immediately after top‐soil removal. A small increase in soil pH was found after five years in the stripped site, indicating a slight recovery from acidification. Liming after top‐soil removal had little effect on the soil pH after six months but stimulated the growth of established species such as Agrostis canina. Few viable seeds of characteristic fen meadow species were present in the seed banks of both degraded and well developed fen meadow sites. The species composition after top soil removal reflected the seed bank of the degraded fen meadow and establishment of characteristic fen meadow species was poor, even after five years. The introduced species (Carex hostiana, C. panicea, Cirsium dissectum) survived during the first year in both the degraded and the stripped site. Liming initially stimulated the growth of two species, but in the second year this effect disappeared. After two years, none of the introduced species survived at the stripped site. The restoration measures failed so far, probably because acidification could not be counteracted satisfactorily. Finally, it was concluded that our multidisciplinary approach enables us to draw proper conclusions and that it is suitable for other restoration attempts as well.