Nitrogen and phosphorus tissue concentrations in 41 wetland plants : a comparison across habitats and functional groups

1. Increased nutrient loading to wetlands often results in an increase in emergent plant biomass and a decrease in species diversity. While these patterns are broadly predictable, the underlying mechanisms are unknown. We tested two related hypotheses by growing plants under standardized conditions: (1) emergent plants typical of infertile wetlands have higher tissue nutrient contents than plants from fertile wetlands and (2) plants belonging to different functional groups (ruderal, interstitial and matrix) have different tissue nutrient contents. 2. Concentrations of N and P in above-ground phytomass were measured for 41 plant species, from contrasting kinds of wetlands, after one season of growth in excess fertilizer (NPK in ratios 7:11:27 and 15:0:0). Tissue nutrient concentrations ranged from 0.25 to 2.14% dry weight for N and from 0.13 to 1.07% dry weight for P. 3. There was no significant difference in nutrient content between plants from infertile sites and plants from fertile sites. However, plants with «ruderal» life history traits (e.g. annual or functional annual/fast-growing) had significantly lower N and P tissue concentrations than plants having «interstitial» or «matrix» life-history traits. Interstitial perennials had significantly higher N concentrations than matrix perennials. Therefore, plant functional groups are likely to respond differently to eutrophication. 4. Plant size, estimated by maximum species biomass, explained 67% (r 2 =0.67, P<0.001, n=31) of the variation in N tissue concentrations but only 5% of the variation in P tissue concentrations

[1]  H. Cole,et al.  Element constitution of selected aquatic vascular plants from Pennsylvania: Submersed and floating leaved species and rooted emergent species☆ , 1973 .

[2]  Rf Williams.  The Effects of Phosphorus Supply on The Rates of Intake of Phosphorus and Nitrogen and Upon Certain Aspects of Phosphorus Metabolism in Gramineous Plants , 1948 .

[3]  P. Keddy.  A pragmatic approach to functional ecology , 1992 .

[4]  Rare,et al.  Rare vascular plants in Canada : our natural heritage , 1990 .

[5]  Paul A. Keddy,et al.  FERTILITY AND DISTURBANCE GRADIENTS: A SUMMARY MODEL FOR RIVERINE MARSH VEGETATION' , 1988 .

[6]  R. B. Bradstreet.  The Kjeldahl Method for Organic Nitrogen , 1965 .

[7]  Roderick Hunt,et al.  Relative growth-rate: its range and adaptive significance in a local flora. , 1975 .

[8]  F. Salisbury,et al.  The Vascular Plants , 1970 .

[9]  P. Keddy,et al.  Species richness – standing crop relationships along four lakeshore gradients: constraints on the general model , 1989 .

[10]  P. Keddy.  Effects of competition from shrubs on herbaceous wetland plants: a 4-year field experiment , 1989 .

[11]  Céline Boutin,et al.  A functional classification of wetland plants , 1993 .

[12]  F. Chapin,et al.  Seasonal movement of nutrients in plants of differing growth form in an Alaskan tundra ecosystem: implications for herbivory. , 1980 .

[13]  J. P. Grime,et al.  Evidence for the Existence of Three Primary Strategies in Plants and Its Relevance to Ecological and Evolutionary Theory , 1977, The American Naturalist.

[14]  P. Keddy,et al.  Conservation of wetlands: do infertile wetlands deserve a higher priority? , 1989 .

[15]  J. P. Grime,et al.  A QUANTITATIVE ANALYSIS OF SHOOT PHENOLOGY AND DOMINANCE IN HERBACEOUS VEGETATION , 1977 .

[16]  H. Nassery.  PHOSPHATE ABSORPTION BY PLANTS FROM HABITATS OF DIFFERENT PHOSPHATE STATUS , 1969 .

[17]  H. L. Boston,et al.  Productivity, Growth and Photosynthesis of Two Small `Isoetid' Plants, Littorella Uniflora and Isoetes Macrospora , 1987 .

[18]  I. H. Rorison.  THE RESPONSE TO PHOSPHORUS OF SOME ECOLOGICALLY DISTINCT PLANT SPECIES , 1968 .

[19]  G. Likens,et al.  Chemical Analyses of Plant Tissues from the Hubbard Brook Ecosystem in New Hampshire , 1970 .

[20]  E. Small.  Photosynthetic rates in relation to nitrogen recycling as an adaptation to nutrient deficiency in peat bog plants , 1972 .

[21]  P. Keddy,et al.  Species richness, survivorship, and biomass accumulation along an environmemtal gradient , 1988 .

[22]  N. Grundon.  MINERAL NUTRITION OF SOME QUEENSLAND HEATH PLANTS , 1972 .

[23]  D. Clarkson.  PHOSPHORUS SUPPLY AND GROWTH RATE IN SPECIES OF AGROSTIS L. , 1967 .

[24]  A. Bradshaw,et al.  Differences between Natural Populations of Trifolium repens L. in Response to Mineral Nutrients , 1962 .

[25]  A. J. Willis.  Braunton Burrows: The Effects on the Vegetation of the Addition of Mineral Nutrients to the Dune Soils , 1963 .

[26]  J. P. Grime,et al.  MORPHOLOGICAL PLASTICITY AND MINERAL NUTRIENT CAPTURE IN TWO HERBACEOUS SPECIES OF CONTRASTED ECOLOGY. , 1987, The New phytologist.

[27]  R. L. Westerman,et al.  Alternative procedure for total phosphorus determination in plant tissue , 1987 .

[28]  J. M. Bremner.  Determination of nitrogen in soil by the Kjeldahl method , 1960, The Journal of Agricultural Science.

[29]  H. Connor,et al.  Response of four species of Chionochloa and two introduced grasses to soil amendment , 1972 .

[30]  D. Tilman.  Resource competition and community structure. , 1983, Monographs in population biology.

[31]  C. Boyd,et al.  Relationships between Cell‐Wall Fractions, Nitrogen, and Standing Crop in Aquatic Macrophytes , 1972 .

[32]  Paul A. Keddy,et al.  Biological monitoring and ecological prediction: from nature reserve management to national state of the environment indicators , 1991 .

[33]  Thomas J. Givnish,et al.  On the economy of plant form and function. , 1988 .

[34]  N. Barrow.  The response to phosphate of two annual pasture species. II. The specific rate of uptake of phosphate, its distribution and use for growth , 1975 .

[35]  P. Kuiper,et al.  Luxury consumption and specific utilization rates of three macroelements in two Taraxacum microspecies of contrasting mineral ecology , 1989 .

[36]  F. Stuart Chapin,et al.  The Nature of Nutrient Limitation in Plant Communities , 1986, The American Naturalist.

[37]  C. J. Asher,et al.  RESPONSE OF PLANTS TO PHOSPHATE CONCENTRATION IN SOLUTION CULTURE: II. RATE OF PHOSPHATE ABSORPTION AND ITS RELATION TO GROWTH , 1967 .

[38]  M. J. Chadwick,et al.  Experimental Investigations into the Mineral Nutrition of Several Grass Species: IV. Nitrogen Level , 1964 .

[39]  F. S. Chapin,et al.  The Mineral Nutrition of Wild Plants , 1980 .

[40]  P. Keddy,et al.  The conservation and management of a threatened coastal plain plant community in Eastern North America (Nova Scotia, Canada) , 1989 .

[41]  R. Jefferies.  GROWTH RESPONSES OF COASTAL HALOPHYTES TO INORGANIC NITROGEN , 1977 .

[42]  P. Kuiper,et al.  Growth rate and phosphate utilization of some Carex species from a range of oligotrophic to eutrophic swamp habitats , 1980 .