Succession and biomass allocation as controlled by Sphagnum in an Alaskan peatland

1985 ◽  
Vol 63 (9) ◽  
pp. 1500-1507 ◽  
Author(s):  
J. O. Luken ◽  
W. D. Billings ◽  
K. M. Peterson
Keyword(s):  
Net Primary Production ◽  
Vascular Plant ◽  
Adventitious Shoot ◽  
Leaf Biomass ◽  
Stem Density ◽  
Turnover Rates ◽  
Ledum Palustre ◽  
Rubus Chamaemorus ◽  
Shoot Production ◽  
Leaf Turnover

The vascular plant vegetation on active Sphagnum hummocks, on senescent hummocks, and in hollows of an Alaskan peatland was measured in several ways. Aboveground biomass and net primary production were greatest on senescent hummocks. Growth of hummock-forming Sphagnum mosses caused a significant increase in stem density and adventitious shoot production of Ledum palustre and Andromeda polifolia, while Vaccinium vitis-idaea showed a decrease in stem density; Rubus chamaemorus was unaffected. Overgrowth of vascular plants by Sphagnum resulted in significantly higher leaf/stem ratios in most of the shrub species. In addition, leaf turnover rates of the evergreen shrubs were modified. The growth of Sphagnum hummocks leads to a developmental stage in the vascular vegetation in which a large amount of structural biomass is present relative to leaf biomass. The rate of microsuccessional change in hummock–hollow complexes appears to be relatively high, at least in comparison to those macrosuccessional processes associated with permafrost formation and melting.

scholarly journals Plant traits and environment: floating leaf blade production and turnover of waterlilies

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3212 ◽  
Author(s):  
Peter F. Klok ◽  
Gerard van der Velde
Keyword(s):  
Plant Traits ◽  
Vegetation Period ◽  
Leaf Biomass ◽  
Leaf Life Span ◽  
Turnover Rates ◽  
Leaf Production ◽  
Nuphar Lutea ◽  
Nymphaea Alba ◽  
Floating Leaves ◽  
Floating Leaf

Floating leaf blades of waterlilies fulfill several functions in wetland ecosystems by production, decomposition and turnover as well as exchange processes. Production and turnover rates of floating leaf blades of three waterlily species, Nuphar lutea (L.) Sm., Nymphaea alba L. and Nymphaea candida Presl, were studied in three freshwater bodies, differing in trophic status, pH and alkalinity. Length and percentages of leaf loss of marked leaf blades were measured weekly during the growing season. Area and biomass were calculated based on leaf length and were used to calculate the turnover rate of floating leaf blades. Seasonal changes in floating leaf production showed that values decreased in the order: Nymphaea alba, Nuphar lutea, Nymphaea candida. The highest production was reached for Nuphar lutea and Nymphaea alba in alkaline, eutrophic water bodies. The production per leaf was relatively high for both species in the acid water body. Nymphaea candida showed a very short vegetation period and low turnover rates. The ratio Total potential leaf biomass/Maximum potential leaf biomass (P/Bmax) of the three species ranged from 1.35–2.25. The ratio Vegetation period (Period with floating leaves)/Mean leaf life span ranged from 2.94–4.63, the ratio Growth period (Period with appearance of new floating leaves)/Vegetation period from 0.53–0.73. The clear differences between Nymphaea candida versus Nuphar lutea and Nymphaea alba, may be due to adaptations of Nymphaea candida to an Euro-Siberic climate with short-lasting summer conditions.

scholarly journals Synthetic Constraint of Soil C Dynamics Using 50 Years of 14C and Net Primary Production (NPP) in a New Zealand Grassland Site

Radiocarbon ◽  
2013 ◽  
Vol 55 (2) ◽  
pp. 1071-1076 ◽  
Author(s):  
W Troy Baisden ◽  
E D Keller
Keyword(s):  
Time Series ◽  
New Zealand ◽  
Net Primary Productivity ◽  
Net Primary Production ◽  
Turnover Rates ◽  
Full Data ◽  
Soil System ◽  
Soil C ◽  
Plant Soil ◽  
C Cycle

Time-series radiocarbon measurements have substantial ability to constrain the size and residence time of the soil C pools commonly represented in ecosystem models. 14C remains unique in its ability to constrain the size and turnover rate of the large stabilized soil C pool with roughly decadal residence times. The Judgeford soil, near Wellington, New Zealand, provides a detailed 11-point 14C time series enabling observation of the incorporation and loss of bomb 14C in surface soil from 1959–2002. Calculations of the flow of C through the plant-soil system can be improved further by combining the known constraints of net primary productivity (NPP) and 14C-derived C turnover. We show the Biome-BGC model provides good estimates of NPP for the Judgeford site and estimates NPP from 1956–2010. Synthesis of NPP and 14C data allows parameters associated with the rapid turnover “active” soil C pool to be estimated. This step is important because it demonstrates that NPP and 14C can provide full data-based constraint of pool sizes and turnover rates for the 3 pools of soil C used in nearly all ecosystem and global C-cycle models.

scholarly journals Particle Bombardment of Apple Leaf Explants Influences Adventitious Shoot Formation

HortScience ◽  
1994 ◽  
Vol 29 (12) ◽  
pp. 1536-1538 ◽  
Author(s):  
P. Gercheva ◽  
R.H. Zimmerman ◽  
L.D. Owens ◽  
C. Berry ◽  
F.A. Hammerschlag
Keyword(s):  
Shoot Regeneration ◽  
Particle Bombardment ◽  
Dark Period ◽  
Leaf Explants ◽  
Adventitious Shoot ◽  
Shoot Formation ◽  
Regeneration Medium ◽  
Adventitious Shoot Formation ◽  
Shoot Production ◽  
And Control

Shoot regeneration from apple (Malus domestica Borkh.) leaf explants following particle bombardment at various acceleration pressures was studied. Basal leaf segments of micropropagated `Royal Gala' apple were bombarded with 1 μm gold particles, accelerated using helium pressures of 4.5, 6.2, 7.6, 9.3, or 13.8 MPa (650–2000 psi), and cultured on shoot regeneration medium consisting of N6 salts supplemented with 10 μM TDZ for 5, 10, or 20 days in darkness. Bombarded and control explants exhibited 63% to 100% shoot regeneration. With a 5-day dark period, average shoot production per explant ranged from 6.1 to 14; bombardments of 4.5 and 6.2 MPa significantly increased shoot production over the controls. With a 10-day dark period, average shoot production per explant ranged from 9.1 to 22 following bombardment at 9.3 and 6.2 MPa, respectively. Following bombardment at 6.2 MPa, 75% of the explants produced more than 20 regenerants per explant. With a 20-day dark period, average shoot production per explant ranged from 8.9 to 19 following bombardment at 13.8 MPa and following no bombardment, respectively. Shoot production per explant was significantly less than the controls following bombardments ranging from 6.2 to 13.8 MPa. Shoot production was highest per explant with particle bombardment at 6.2 MPa followed by incubation in darkness for 10 days. Chemical name used: thidiazuron (TDZ).

The primary production of aldabra atoll, with reference to habitats used by Giant Tortoises

1983 ◽  
Vol 302 (1109) ◽  
pp. 167-199 ◽  
Keyword(s):  
Primary Production ◽  
Standing Crop ◽  
Single Species ◽  
Structural Heterogeneity ◽  
Turnover Rates ◽  
Net Production ◽  
Wooded Area ◽  
Leaf Turnover ◽  
Scrub Forest

This paper reports on the seasonal changes of standing crop and production in habitats used by a high-density population of giant tortoises on Aldabra atoll. The study had two main aims: first to investigate the primary production of a raised coral atoll (to our knowledge the first such study) and secondly to provide base data for a study of the interactions of a large reptilian herbivore (the giant tortoise) with its food supply and environment. Environmental heterogeneity made it necessary to measure separately the standing crop and the above-ground net production of different components of the vegetation; these components were usually single species or small groups of species of plants. Measurements of these components were then combined with cover data for the same components in selected places to illustrate the seasonal and spatial variability of primary production on Aldabra. Standing crop biomasses were estimated from harvest samples. Methods for production estimates varied with the component studied, but included harvest difference methods, repeated clipping of the same plots and direct measurement of leaf turnover rates on marked shoots. These methods are compared where appropriate. Net annual above-ground production varied between plant types from 3165 kJ per square metre of plant for ‘tortoise turf’ to 47700 kJ m -2 for Cyperus ligularis , a robust perennial sedge. Total above-ground annual net production of different habitat types (bare ground and rocks between plants being taken into account) varied from 9100 kJ m -2 in a thinly wooded area with high tortoise turf cover (‘open mixed scrub’) to 28200 kJ m -2 in an area of thick scrub forest (‘groves’). The seasonality of production and standing crop also varied considerably between habitats, owing to the role of different components of the ground layer and shrub cover. These results are discussed in terms of the roles of environmental and structural heterogeneity in setting primary production and of the tortoises themselves in their interactions with the vegetation via trampling and grazing. The effect of this heterogeneity on sampling strategies and results is also assessed.

scholarly journals Impacts of mixed-grazing on root biomass and belowground net primary production in a temperate desert steppe

2019 ◽  
Vol 6 (2) ◽  
pp. 180890 ◽  
Author(s):  
Zhanyi Wang ◽  
Jing Jin ◽  
Yanan Zhang ◽  
Xiaojuan Liu ◽  
Yongling Jin ◽  
...  
Keyword(s):  
Primary Production ◽  
Root Biomass ◽  
Net Primary Production ◽  
Single Species ◽  
Community Diversity ◽  
Root Turnover ◽  
Turnover Rates ◽  
Large Herbivores ◽  
Growing Seasons ◽  
Belowground Net Primary Production

The impacts of large herbivores on plant communities differ depending on the plants and the herbivores. Few studies have explored how herbivores influence root biomass. Root growth of vegetation was studied in the field with four treatments: sheep grazing alone (SG), cattle grazing alone (CG), mixed grazing with cattle and sheep (MG) and no grazing (CK). Live and total root biomasses were measured using the root ingrowth core and the drilling core, respectively. After 2 years of grazing, total root biomass showed a decreasing trend while live root biomass increased with time during the growing seasons. Belowground net primary production (BNPP) among the treatments varied from 166 ± 32 to 501 ± 88 g m −2 and root turnover rates (RTR) varied from 0.25 ± 0.05 to 0.70 ± 0.11 year −1 . SG had the greatest BNPP and RTR, while the CG had the smallest BNPP and RTR. BNPP and RTR of the MG treatment were between those of the CG and SG treatments. BNPP and RTR of the CK were similar to MG treatment. Compared with other treatments, CG had a greater impact on dominant tall grasses species in communities. SG could decrease community diversity. MG eliminated the disadvantages of single-species grazing and was beneficial to community diversity and stability.

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