Biomass distribution of two subalpine dwarf-shrubs in relation to soil moisture and nutrient content (original) (raw)
Related papers
Leaf structure vs. nutrient relationships vary with soil conditions in temperate shrubs and trees
Acta Oecologica, 2003
Often there are significant positive interspecific relationships between leaf area per unit dry mass (SLA) and foliar phosphorus and nitrogen concentrations ([P] and [N]). Most of these studies have been conducted on moderately acidic soils, and little is known of the generality of these relations as potentially affected by soil characteristics. We investigated foliage mineral composition in relation to leaf structure in a wooded meadow on calcareous alkaline soil, in a bog on strongly acidic soil, and in a flood plain on moderately acidic soil. Foliar nutrient contents and fertilization experiments indicated that foliage physiological activity was co-limited by both P and N availabilities in the wooded meadow, by P in the bog, and by N in the flood plain. In the wooded meadow and in the bog, there were positive relationships between SLA and P concentration ([P]), and no relationship between SLA and nitrogen concentration [N]. Given that the fraction of support tissues generally increases with decreasing SLA, the requirement for mineral nutrients is lower at low SLA. Thus, these contrasting relations between mineral nutrients and SLA suggest that P was distributed in a more "optimal" manner among the leaves with varying structure than N in P-limited communities. In the flood plain, SLA was positively related to both [P] and [N], possibly manifesting a strategy to cope with N limitations by enhancing N turnover, and accordingly, greater P requirement for nucleic acid formation in N-limited soils. Total variation in foliar structural and chemical characteristics was similar in all sites, and was mainly determined by variation among the species. Part of this variability was explained by life form and plant size. [P] was higher in trees than in shrubs, and [P] and P/N ratio increased with increasing total plant height, indicating that P nutrition was improved relative to N nutrition with increasing plant size. Since the capture of less mobile soil elements such as P is dependent on extensive root systems, but not that of readily mobile and temporarily variable elements such as N, this correlation was attributed to more extensive root systems in larger plants. Our study indicates that foliar structure vs.
Nitrogen and Phosphorus Resorption in Two Sympatric Deciduous Species Along an Elevation Gradient
2012
Quelques traits foliaires (concentrations en N et P, N/P ratio, surface foliaire specifique, temps moyen de residence de l'azote et du phosphore (MRTN et MRTP) et resorption foliaire) ont ete etudies chez deux especes decidues sympatriques (Arnelanchier rotundifolia (Lam.) Dum.-Courset subsp. rotundifolia et Rhamnus oleoides L. subsp. graecus) qui sont les especes les plus caracteristiques de la vegetation steppique et rupicole le long d'un gradient altitudinal et cela pour determiner quels traits foliaires sont lies a l'efficience (NRE et PRE) et a la capacite (NRP et PRP) en azote et phosphore. Des differences statistiquement significatives ont ete trouvees le long du gradient altitudinal entre les deux especes pour ce qui concerne le N/P ratio des feuilles vertes, NRE, MRTN, MRTP et la longevite foliaire. NRE etait sous les valeurs-seuils des especes decidues pour A. rotundifolia subsp. rotundifolia bien que PRE etait plus eleve que les valeurs-seuils. Tant NRE que PR...
Geoderma, 2009
Nitrogen-fixing plants alter the chemical properties of the soil beneath plant canopies, particularly by concentrating nitrogen-rich organic matter. We hypothesize that the presence of a legume canopy inside a plot will more greatly influence the spatial structure of soil nitrogen (N) than phosphorus (P). We also investigated whether the effects of legume individuals on the soil properties beneath their canopies might be mediated by soil texture and water availability. Thus, we expected that the local effect of a legume canopy would be more conspicuous in nutrient-poor sandy soils than in nutrient-rich loamy soils. Moreover, the spatial pattern should differ during the wet (winter) and dry seasons (summer) because the microbial processes driving nutrient cycling are sensitive to water availability. To test these hypotheses, square plots (4 m × 4 m or 3 m × 3 m) were placed around isolated mature individuals of Adenocarpus viscosus in two pine forest stands of the Canary Islands (Spain) with contrasting soil textures (loamy and sandy soil). The spatial pattern and scale of microbial biomass-N (MB-N), dissolved organic-N (DON), and inorganic-N and -P fractions (NH 4 -N, NO 3 -N and PO 4 -P) were analyzed with geostatistical methods for two sampling dates (summer and winter). Soil variables with spatial structure demonstrated a greater spatial dependence in the loamy than sandy soil, with the exception of MB-N during summer. Except for NH 4 -N and NO 3 -N in winter plots, the spatial range was also lower in the sandy than the loamy soil. The legume canopy only had a clear effect on the spatial pattern of winter NH 4 -N, NO 3 -N, and DON in the sandy soil; no dependence was observed for PO 4 -P on the legume canopy in both soil types. Our results suggest that the presence of A. viscosus individuals may be an important source of spatial heterogeneity in the N content of the soil in these forests. However, soil texture and water content modulated the magnitude of the legume canopy effect on the spatial distribution of these N forms beneath canopies.
2010
We determined concentrations of major nutrients in the vegetation of six habitat types (hummock, scrub, lawn, fen meadow, hollow and marginal stream), spanning a broad range of environmental conditions as regards water-table depth and water chemistry, in five mires on the southern Alps of Italy. Our study was based on chemical analyses of living tissues of plant species, grouped into growth-form based plant functional types (PFTs). We aimed at assessing to what extent the observed differences in tissue nutrient content were accounted for by community composition (both in terms of species and PFTs) and by habitat. Nutrient concentrations were overall lowest in Sphagnum mosses and highest in forbs, although the latter showed large variations presumably due to heterogeneity in mechanisms and adaptations for acquiring nutrients among species within this PFT. Nutrient content patterns in the other three PFTs varied greatly in relation to individual nutrients, with evergreen shrubs showing low nitrogen (N) concentrations, graminoids showing high N concentrations but low potassium (K) and magnesium (Mg) concentrations and deciduous shrubs showing rather high phosphorus (P) concentrations. Habitat accounted for a modest fraction of variation in tissue concentration of all nutrients except P. We concluded that the nutrient status of mire vegetation is primarily controlled by community composition and structure although habitat does exert a direct control on P concentration in the vegetation, presumably through P availability for plant uptake.
Annals of Forest Science, 2001
The objective of this study was to assess the effects of base cation (Ca, Mg, K) and phosphorous (P) fertilization on the vascular ground vegetation in mature European beech and sessile oak stands located on acid brown soils. Two types of treatment were applied next to control plots (dolomite lime, dolomite lime + natural phosphate + potassium sulphate). Specific richness, total cover (%), equitability coefficient as well as the Ecological Group of the ground vegetation were studied. Four years after dolomite application, new Ndemanding and ruderal species appeared and increased the specific richness. The natural phosphate application combined with potassium sulphate positively influenced the emergence of new mesotrophic plant species. In the beech stands the total cover tended to increase while in the oak stand the equitability coefficient decreased. The specific richness of the initial acidophilous vegetation remained unchanged but the total cover decreased. Differences between the response of the ground vegetation in the oak and the beech stands were attributed to a difference in stand density. base cation / phosphorous / acid brown soil / plant diversity / ecological group Résumé -Effets de la fertilisation sur les plantes vasculaires du sous-bois dans des peuplements de hêtre (Fagus sylvatica L.) et de chêne sessile (Quercus petraea (Matt.) Lieb.). L'objectif de cette étude est d'évaluer les effets d'une fertilisation en cations basiques (Ca, Mg, K) et P sur les plantes vasculaires du sous-bois dans des peuplements adultes de hêtre et de chêne sessile situés sur des sols bruns acides. Deux types de traitement ont été appliqués et comparés à un témoin (dolomie, dolomie + phosphate naturel + sulfate de potassium). La richesse spécifique, le recouvrement total, le coefficient d'équitabilité ainsi que les groupes écologiques de la végétation au sol ont été étudiés. Quatre ans après l'application de dolomie, de nouvelles espèces nitrophiles et rudérales apparaissent, augmentant ainsi la richesse spécifique. Le phosphate naturel combiné au sulfate de potassium influence positivement l'émergence de nouvelles espèces mésophiles. Dans les peuplements de hêtre, le recouvrement total tend à s'accroître et dans le peuplement de chêne le coefficient d'équitabilité diminue. La richesse spécifique de la végétation initiale acidophile reste inchangée mais le recouvrement total diminue. Des différences entre la réponse de la végétation au sol dans les peuplements de chêne et de hêtre ont été mises en évidence et ont été attribuées à la différence de densité de peuplement. cation basique / phosphore / sol brun acide / diversité floristique / groupe écologique Ann. For. Sci. 58 (2001) 829-842 829
© 2003 Springer-Verlag Natural 15 N Abundance of Plants and Soil N in a Temperate
2014
Measurement of nitrogen isotopic composition ( � 15 N) of plants and soil nitrogen might allow the characteristics of N transformation in an ecosystem to be detected. We tested the measurement of � 15 N for its ability to provide a picture of N dynamics at the ecosystem level by doing a simple comparison of � 15 N between soil N pools and plants, and by using an existing model. � 15 Nof plants and soil N was measured together with foliar nitrate reductase activity (NRA) and the foliar NO 3 pool at two sites with different nitrification rates in a temperature forest in Japan. � 15 N of plants was similar to that of soil NO 3
BMC Ecology
Background Alpine alder vegetation acts upon the nearby grass and dwarf shrub vegetation by the nitrogen supply from the symbiotic bacteria Frankia alni of Alnus viridis. This has been studied in two transects concerning plant distribution, plant diversity, nitrate concentration in soil and photosynthetic performance of specific marker plants. Results Away from the alder stand, a band of some meters was dominated by Calamagrostis varia which then was followed by alpine dwarf shrub vegetation. Nitrate in the soil showed a concentration decrease away from the alder stand leading to values near the detection limit in the dwarf shrub zone. Within these three zones, plant species were distributed according to their N-index, given in the ecological literature. Three dominant species, Calamagrostis varia, Rhododendron ferrugineum and Vaccinium myrtillus were examined at sites of different N-availability in the horizontal transect for their photosynthetic performance, by measuring the promp...
Functional Ecology, 2002
Leaf morphology at the site/species level should reflect environmental constraints on plant growth. One of the oldest controversies in ecology is the environmental basis for sclerophylly. The dominant view (Beadle's theory) is that it has a nutritional, rather than a drought, basis, especially low phosphorus. 2. Using leaf mass per area (LMA) as an index of sclerophylly, we assessed its relationship with leaf phosphorus (P) and nitrogen (N) along extensive rainfall gradients in southwestern Australia and the Cape of South Africa. Leaf 13 C/ 12 C discrimination (∆ 13 C), as an index of intrinsic water-use efficiency, was also examined in the Cape. All Hakea species (Proteaceae) were sampled at 10 sites in Australia (96 species), and all Proteaceae at 14 sites in the Cape (82 species). All were evergreen shrubs with iso(bi)lateral leaves. 3. In each region there was a strong (inverse) curvilinear relationship between mean LMA per site and mean annual rainfall and ∆ 13 C, but none with mean P or N on a mass basis (although P and N on an area basis declined with rainfall). The Cape study was a particularly good test of Beadle's theory, as P varied as much between sites as rainfall, and more between sites than within sites. 4. Leaf thickness and dry density were not as well correlated with rainfall as LMA, and leaf area and mass showed no relationship with rainfall. Area and mass had much greater variation within sites than between sites, limiting their value in plant-environment studies, while LMA was the most site-stable of the eight leaf attributes measured, except for ∆ 13 C. 5. For all species considered individually in each region, there was a similar pattern as the site level, with LMA most strongly correlated (negatively) with rainfall and ∆ 13 C and (positively) with leaf thickness, but no consistent relationship with P, N or density. 6. We conclude that when water and nutrient supply vary independently in the field, rainfall (as an index of water status) and ∆ 13 C may be more closely correlated (inversely) with level of sclerophylly than nutrient status among evergreens, so that the role of sclerophylly as a drought adaptation warrants further consideration.
Physiologia Plantarum, 1992
Boot, R. G. A., Schildwacht, P. M. and Lambers, H. 1992. Partitioning of nitrogen and biomass at a range of N-addition rates and their consequences for growth and gas exchange in two perennial grasses from inland dunes. -Physiol. Plant. 86: 152-160. This paper describes the effects of nitrogen supply on the partitioning of biomass and nitrogen of Agrostis vinealis (L.) Schreber and Corynephorus canescens (L.) Beauv., two perennial grasses of dry, nutrient-poor inland dunes, and their consequences for growth and gas exchange. At a given plant nitrogen concentration (PNC) the two species allocate the same relative amount of dry matter and nitrogen to their leaves. However, A. vinealis allocates more dry matter and nitrogen to its roots and less to its above-ground support tissue than C. canescens. Both the leaf weight ratio and leaf nitrogen ratio increase with increasing PNC. Despite species-specific <tffereBces in growth form and leaf morphology, the leaf area ratio and specific leaf atw of the two species are similar, both at high and low PNC. At intermediate nitrogen supply, and thus intermediate PNC, however, A. vinealis has a higher leaf area ratio and specific leaf area than C. canescens. The two species exhibit a similar positive relationship when either the rate of net photosynthesis or the rate of shoot respiration are eompared to the leaf nitrogen concentration, all expressed per unit leaf weight. The rate of net photosynthesis per unit leaf nitrogen (PNUE) of the two species increases with decreasing leaf nitrogen concentration per unit leaf weight. C. canescens has a higher PNUE at low, and a lower PNUE at high leaf nitrogen concentration per unit leaf weight than A. vinealis. At non-limiting nitrogen supply, A. vinealis has a higher nitrogen productivity and net assimilation rate and a similar PNC and leaf area ratio as compared to C canescens, which explains the higher relative growth rate (RGR,^) of .4. vinealis. At growth-limiting nitrogen supply C. canescens achieves a similar relative growth rate at a lower PNC than A. vinealis.