scholarly journals Herbaceous Layer Net Primary Production of Oak-Hornbeam Forest: Comparing Six Methods of Assessment Based on the Seasonal Dynamics of Biomass Increments

Ecosystems ◽  
2021 ◽  
Author(s):  
Mateusz Rawlik ◽  
Andrzej M. Jagodziński

AbstractProper estimation of the herb layer annual net primary production (ANPP) can help to appreciate the role of this layer in carbon assimilation and nutrient cycling. Simple methods of ANPP estimation often understate its value. More accurate methods take into account biomass increments of individual species but are more laborious. We conducted our study in an oak-hornbeam forest (site area 12 ha) dominated by beech in NW Poland during two growing seasons (2010 and 2011). We collected herb layer biomass from 7 to 10 square frames (0.6 × 0.6 m). We collected plant biomass every week in April and May and every two weeks for the rest of the growing season. We compared six methods of calculating ANPP. The highest current-year standing biomass (1st method of ANPP calculation) was obtained on May 15, 2010—37.8 g m−2 and May 7, 2011—41.0 g m−2. The highest values of ANPP were obtained by the 6th method based on the sum of the highest products of shoot biomass and density for individual species: 74.3 g m−2 year−1 in 2010 and 94.0 g m−2 year−1 in 2011. The spring ephemeral Anemone nemorosa had the highest share of ANPP with 50% of the total ANPP. Two summer-greens, Galeobdolon luteum and Galium odoratum, each had a ca. 10% share of ANPP. The best results of ANPP calculation resulted from laborious tracking of dynamics of biomass and density of individual shoots.

2005 ◽  
Vol 56 (3) ◽  
pp. 303 ◽  
Author(s):  
I. T. Webster ◽  
N. Rea ◽  
A. V. Padovan ◽  
P. Dostine ◽  
S. A. Townsend ◽  
...  

In this paper, the dynamics of primary production in the Daly River in tropical Australia are investigated. We used the diurnal-curve method for both oxygen and pH to calculate photosynthesis and respiration rates as indicators of whole-river productivity. The Daly River has maximum discharges during the summer, monsoonal season. Flow during the dry season is maintained by groundwater discharge via springs. The study investigated how primary production and respiration evolve during the period of low flow in the river (April–November). The relationship between primary production and the availability of light and nutrients enabled the role of these factors to be assessed in a clear, oligotrophic tropical river. The measured rate of photosynthesis was broadly consistent with the estimated mass of chlorophyll associated with the main primary producers in the river (phytoplankton, epibenthic algae, macroalgae, macrophytes). A significant result of the analysis is that during the time that plant biomass re-established after recession of the flows, net primary production proved to be ~4% of the rate of photosynthesis. This result and the observed low-nutrient concentrations in the river suggest a tight coupling between photosynthetic fixation of carbon and the microbial degradation of photosynthetic products comprising plant material and exudates.


1982 ◽  
Vol 35 (5) ◽  
pp. 572 ◽  
Author(s):  
J. L. Dodd ◽  
W. K. Lauenroth ◽  
R. K. Heitschmidt

2015 ◽  
Vol 12 (1) ◽  
pp. 51-92 ◽  
Author(s):  
M. Moreno-de las Heras ◽  
R. Diaz-Sierra ◽  
L. Turnbull ◽  
J. Wainwright

Abstract. Climate change and the widespread alteration of natural habitats are major drivers of vegetation change in drylands. A classic case of vegetation change is the shrub-encroachment process that has been taking place over the last 150 years in the Chihuahuan Desert, where large areas of grasslands dominated by perennial grass species (black grama, Bouteloua eriopoda, and blue grama, B. gracilis) have transitioned to shrublands dominated by woody species (creosotebush, Larrea tridentata, and mesquite, Prosopis glandulosa), accompanied by accelerated water and wind erosion. Multiple mechanisms drive the shrub-encroachment process, including exogenous triggering factors such as precipitation variations and land-use change, and endogenous amplifying mechanisms brought about by soil erosion-vegetation feedbacks. In this study, simulations of plant biomass dynamics with a simple modelling framework indicate that herbaceous (grasses and forbs) and shrub vegetation in drylands have different responses to antecedent precipitation due to functional differences in plant growth and water-use patterns, and therefore shrub encroachment may be reflected in the analysis of landscape-scale vegetation–rainfall relationships. We analyze the structure and dynamics of vegetation at an 18 km2 grassland-shrubland ecotone in the northern edge of the Chihuahuan Desert (McKenzie Flats, Sevilleta National Wildlife Refuge, NM, USA) by investigating the relationship between decade-scale (2000–2013) records of medium-resolution remote sensing of vegetation greenness (MODIS NDVI) and precipitation. Spatial evaluation of NDVI-rainfall relationship at the studied ecotone indicates that herbaceous vegetation shows quick growth pulses associated with short-term (previous 2 months) precipitation, while shrubs show a slow response to medium-term (previous 5 months) precipitation. We use these relationships to (a) classify landscape types as a function of the spatial distribution of dominant vegetation, and to (b) decompose the NDVI signal into partial primary production components for herbaceous vegetation and shrubs across the study site. We further apply remote-sensed annual net primary production (ANPP) estimations and landscape type classification to explore the influence of inter-annual variations in seasonal precipitation on the production of herbaceous and shrub vegetation. Our results suggest that changes in the amount and temporal pattern of precipitation comprising reductions in monsoonal summer rainfall and/or increases in winter precipitation may enhance the shrub-encroachment process in desert grasslands of the American Southwest.


1988 ◽  
Vol 66 (5) ◽  
pp. 989-997 ◽  
Author(s):  
William A. Pfitsch ◽  
L. C. Bliss

The deposition of 5–10 cm of tephra from the 1980 eruption of Mount St. Helens had no more effect than subsequent yearly weather fluctuations on the net primary production of subalpine meadows. The net primary production of areas subject to cold mudflows slowly increased as surviving plants resprouted through the eroded surface and has remained below that of tephra deposition areas. The net primary production of tephra deposition areas fluctuated dramatically (coefficient of variation = 40%) in the seven summers following the eruption. An inverse relationship between net primary production and nutrient concentration of individual species contributed to stability in aboveground nutrient pools from year to year. The dominant community members responded similarly to differences among years in summer precipitation, with little evidence of compensatory growth that would help stabilize community production. Tephra greatly inhibited seedling establishment. Species density (number of species per square metre) and diversity (H′) declined in a community having species that rely on sexual reproduction for persistence and also in experimental tephra addition plots in a more species-rich community. These results indicate that although the short-term effect of tephra deposition on net primary production was minor, the long-term consequence will be of community simplification, which will contribute to fluctuation in net primary production in response to yearly weather patterns.


1989 ◽  
Vol 5 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Mario Dantas ◽  
John Phillipson

ABSTRACTLitterfall in primary and secondary forests (‘capoeira’) in eastern Brazilian Amazonia was measured fortnightly from August 1979 to October 1980. The nutrient contents of the litter (N, P, K, Ca and Mg) were determined.Litterfall differed between the two forest types (primary forest − 8.04 t ha−1 yr−1; secondary forest − 5.04 t ha−1 yr−1). The value obtained for primary forest was similar to those reported elsewhere in Brazil (mean = 8 t ha−1 yr−1) and from other regions of S. America (mean = 7.20 t ha−1 yr−1).Prediction of net primary production from litterfall at the primary forest site gave rise to values of 14.47 and 26.53 t ha−1 yr−1. Estimates of net primary production in ‘capoeira’ ranged from 9.07 to 16.63 t ha−1 yr−1.Seasonality of litterfall was more marked in ‘capoeira’ than primary forest but in both cases was less pronounced than elsewhere in Brazil.Nutrient concentrations were highest in ‘capoeira’ litter, a finding which accords with results from other tropical sites; nevertheless input of nutrients per unit area of forest floor was greatest in the primary forest.


1990 ◽  
Vol 38 (3) ◽  
pp. 229 ◽  
Author(s):  
N Gibson

Primary production of four species of alpine cushion plants were studied over a 2-year period. The climate of these areas was found to be severe but with a high degree of variability on a seasonal and yearly basis. The growing season at the higher altitude sites generally exceeded 6 months. Net above ground primary production of the four cushion species ranged from 282 to 709 g m-2 year-1. Reproductive effort fluctuated between species and years, ranging from 0 to 30% of net above ground production. Patterns in dry matter accumulation suggest no individual species would show consistently superior growth rates under present climatic conditions. Soil moisture and soil nutrient status was found to be similar between all sites. Altitude of the sites (830-1400 m) was found to be strongly correlated with the timing of flowering and/or seed set but appeared to have little effect on net primary production.


Plant Ecology ◽  
2020 ◽  
Vol 221 (11) ◽  
pp. 1133-1142
Author(s):  
Mateusz Rawlik ◽  
Andrzej M. Jagodziński

Abstract Seasonal fluctuations of light availability, nutrient concentrations, and moisture affect plant population traits like density, standing biomass, and flowering. We analyzed seasonal changes of density and shoot biomass of the four most frequent herb species growing in an oak–hornbeam forest community, i.e., Anemone nemorosa, Ficaria verna, Galeobdolon luteum, and Galium odoratum. In 2010 and 2011 plant biomass was harvested from 7 to 10 randomly situated square sample plots (0.36 m2) in the homogenous oak–hornbeam forest community every week in the spring and every two weeks in the summer and autumn. The highest abundance of Anemone nemorosa reached over 1000 shoots per m2, of Ficaria verna 459.5 shoots per m2, of Galium odoratum 83.6 shoots per m2, and of Galeobdolon luteum 98.4 shoots per m2 (means for 2010 and 2011, based on all sample plots). We did not observe negative correlation between density and shoot biomass. Growth rates of vegetative shoot biomass amounted to 0.857 mg day−1 for Anemone nemorosa, 0.467 mg day−1 for Ficaria verna, 0.722 mg day−1 for Galium odoratum, and 0.448 mg day−1 for Galeobdolon luteum (means for 2010 and 2011). Spring ephemerals had much higher densities of shoots than summer-greens. Summer-greens reached higher biomass of individual shoots than spring ephemerals. Flowering shoots constituted only 4, 2, and 11% of all shoots for A. nemorosa, F. verna, and G. odoratum, respectively. More resource availability resulting in high shoot biomass did not translate to higher share of flowering shoots.


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