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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.. Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecology.Abstract. This paper reports on patterns in plant-mediated processes that determine the rate of nutrient cycling in temperate fens and bogs. We linked leaf-level nutrient dynamics with leaf-litter decomposition and explored how the observed patterns were reflected in nutrient cycling at the ecosystem level. Comparisons were made among growth forms (evergreen and deciduous shrubs and trees, graminoids and Sphagnum mosses) and between mire types (fens and bogs). A literature review showed that the predominant growth form was more important as a determinant of leaf-level nutrient-use efficiency (NUE) than mire type (fen vs. bog). Evergreens had the highest N and P use efficiency. The growth form differences in NUE were mainly determined by differences in N and P concentrations in mature leaves and not by differences in resorption efficiency from senescing leaves. Sphagnum leaves had lower N and P concentrations than the other growth forms, but because of a lack of data on nutrient resorption efficiency the NUE of these mosses could not be calculated. Nitrogen use efficiency did not differ among fen and bog species, whereas bog species had a higher P use efficiency than fen species. However, a complete evaluation of mire-type or growth-form effects on NUE is only possible when data become available about nutrient resorption from senescing Sphagnum leaves. As leaf-level NUE is negatively correlated with leaf-litter nutrient concentrations, there is a direct link between NUE and litter decomposition rate. Rates of litter decomposition of Sphagnum mosses are lower than in the other growth forms, but there is still much speculation about possible reasons. The role of litter chemistry of Sphagnum mosses (including decay inhibitors and decay-resistant compounds) in de-composition especially warrants further study. The strongly deviating nutritional ecology of Sphagnum mosses clearly distinguishes fens and bogs from other ecosystems. Moreover, N and P concentrations in mature leaves from vascular plant species from fens and bogs are in almost all cases lower and leaf-level N use efficiency is higher than in species from other ecosystems, irrespective of the growth form considered.Both literature data and data from a comparative study on soil nutrient cycling in temperate fens and bogs in the United States (Maryland), The Netherlands, and Poland showed that nutrient mineralization did not differ clearly between fens and bogs. The comparative study further showed that cellulose decomposition in bogs was lower than in fens and that nutrient mineralization was higher in forested than in ...

The conservation or restoration of seminatural vegetation often involves measures that influence the availability of nutrients and consequently the plant species composition. The ability to predict effects of modified nutrient availability on species composition would therefore help to choose appropriate management strategies. The aim of this study was to test whether short‐term effects of nitrogen or phosphorus enrichment can be predicted from nutrient ratios in plant biomass. At 11 species‐rich sites in Dutch fens and dune slacks, small plots were fertilized with N, P, N + P, or not fertilized (control). The aboveground biomass, N and P concentrations, and N:P ratios were compared between fertilized and control plots for all sufficiently abundant plant populations in the summers preceding and following fertilization. Of 121 populations, only 45 had their biomass enhanced significantly by fertilization. Populations enhanced by P fertilization had on average higher biomass N:P ratios than those enhanced by N, due to higher N and lower P concentrations. However, N:P ratios did not differ among populations enhanced by N, N + P, or neither nutrient. High biomass N:P ratios (>20) therefore indicated that a plant population would probably respond to P‐fertilization, but low or intermediate N:P ratios (<20) did not indicate whether the population would respond to N or N + P fertilization. The predictive value of N:P ratios was not higher if only species from one site or only species with the same growth form were considered. It is concluded that N:P ratios are not suitable to predict how changed nutrient supply will affect plant species composition, especially in the long term. However, results suggest that biomass N:P ratios do reflect the relative availability of N and P to plants and may indicate the degree of N or P deficiency experienced by a plant population even more reliably than fertilization experiments. N:P ratios can be used to investigate how the relative availability of N and P influences various ecological processes and how it is affected by human impacts or management. Corresponding Editor: E. A. Holland.

Agriculture has been carried out in several types of (former) wetlands for millennia, with crop fields on river floodplain soils and rice fields as major examples. However, intensive agricultural use of drained/reclaimed peatlands has been shown to lead to major problems because of the oxidation and subsidence of the peat soil. This does not only lead to severe carbon dioxide emissions, but also results in low-lying land which needs to be protected against flooding. Developments in South-East Asia, where vast areas of tropical peatlands are being converted into oil palm plantations, are of great concern in this respect. Although more flood-tolerant cultivars of commercial crop species are being developed, these are certainly not suitable for cultivation in wetlands with prolonged flooding periods, but rather will survive relatively short periods of waterlogging in normally improved agricultural soils. From a sustainability perspective, reclamation of peatlands for agriculture should be strongly discouraged. The opportunities for agriculture in naturally functioning floodplains should be further investigated. The development and use of crop cultivars with an even stronger flood tolerance could form part of the sustainable use of such floodplain systems. Extensive use of wetlands without drastic reclamation measures and without fertilizer and pesticides might result in combinations of food production with other wetland services, with biodiversity remaining more or less intact. There is a need for research by agronomists and environmental scientists to optimize such solutions.