Plant quality and primary productivity modulate plant biomass responses to the joint effects of grazing and fertilization in a mesic grassland

2021 ◽  
Author(s):  
Sofía Campana ◽  
Laura Yahdjian
Keyword(s):  
Primary Productivity ◽  
Plant Biomass ◽  
Plant Quality ◽  
Joint Effects ◽  
Mesic Grassland

Resource selection in a high-altitude rangeland equid, the kiang (Equus kiang): influence of forage abundance and quality at multiple spatial scales

2014 ◽  
Vol 92 (3) ◽  
pp. 239-249 ◽  
Author(s):  
Antoine St-Louis ◽  
Steeve D. Côté
Keyword(s):  
High Altitude ◽  
Resource Selection ◽  
Large Scale ◽  
Plant Biomass ◽  
Spatial Scales ◽  
Plant Quality ◽  
The Tibetan Plateau ◽  
Higher Plant ◽  
Feeding Site ◽  
Spatial And Temporal Scales

Herbivores foraging in arid and seasonal environments often face choices between plant patches varying in abundance and nutritional quality at several spatial and temporal scales. Because of their noncompartmented digestive system, equids typically rely on abundant forage to meet their nutrient requirements. In forage-limited environments, therefore, scarcity of food resources represents a challenge for wild equids. We investigated hierarchical resource-selection patterns of kiangs (Equus kiang Moorcroft, 1841), a wild equid inhabiting the high-altitude steppes of the Tibetan Plateau, hypothesizing that vegetation abundance would be the main factor driving resource selection at a large scale and that plant quality would influence resource selection at finer scales. We investigated resource-selection patterns at three spatial levels (habitat, feeding site, and plant (vegetation groups, i.e., grasses, sedges, forbs, and shrubs)) during summer and fall. At the habitat level, kiangs selected both mesic and xeric habitats in summer and only xeric habitats (plains) during fall. At the feeding-site level, feeding sites had higher plant biomass and percentage of green foliage than random sites in the same habitats. At the plant level, grasses were selected over forbs and shrubs, and sedges were used in proportion to their availability during all seasons. Our results indicate that resource-selection patterns in kiangs vary across scales and that both forage abundance and quality play a role in resource selection. Plant quality appeared more important than hypothesized, possibly to increase daily nutrient intake in forage-limited and highly seasonal high-altitude rangelands.

scholarly journals Differential Responses of Plant Primary Productivity to Nutrient Addition in Natural and Restored Alpine Grasslands in the Qinghai Lake Basin

2021 ◽  
Vol 12 ◽  
Author(s):  
Chunli Li ◽  
Yonghui Li ◽  
Xinwei Li ◽  
Li Ma ◽  
Yuanming Xiao ◽  
...  
Keyword(s):  
Plant Community ◽  
Primary Productivity ◽  
Plant Biomass ◽  
Growing Season ◽  
N Deposition ◽  
Qinghai Lake ◽  
Lake Basin ◽  
N Addition ◽  
Alpine Grasslands ◽  
Qinghai Lake Basin

Climate, land-use changes, and nitrogen (N) deposition strongly impact plant primary productivity, particularly in alpine grassland ecosystems. In this study, the differential responses of plant community primary productivity to N and phosphorus (P) nutrient application were investigated in the natural (NG) and “Grain for Green” restored (RG) alpine grasslands by a continuous 3-year experiment in the Qinghai Lake Basin. N addition only significantly promoted plant aboveground biomass (AGB) by 42% and had no significant effect on belowground biomass (BGB) and total biomass (TB) in NG. In comparison with NG, N addition elevated AGB and BGB concurrently in RG by 138% and 24%, respectively, which further significantly increased TB by 41% in RG. Meanwhile, N addition significantly decreased BGB and the AGB ratio (R/S) both in NG and RG. Compared with N addition, P addition did not perform an evident effect on plant biomass parameters. Additionally, AGB was merely negatively influenced by growing season temperatures (GST) under the N addition treatment in NG. AGB was negatively associated with GST but positively related to growing season precipitation (GSP) in RG. By contrast, changes in the R/S ratio in RG were positively correlated with GST and negatively related to GSP. In sum, the results revealed that plant community biomass exhibited convergent (AGB and R/S) and divergent (BGB and TB) responses to N addition between NG and RG. In addition, the outcomes suggested that climate warming would enhance plant biomass allocation to belowground under ongoing N deposition, and indicated the significance of precipitation for plant growth and AGB accumulation in this restored alpine grassland ecosystem.

scholarly journals Effects of plant evolution on nutrient cycling couple aboveground and belowground processes

2016 ◽  
Author(s):  
Nicolas Loeuille ◽  
Tiphaine Le Mao ◽  
Sébastien Barot
Keyword(s):  
Nutrient Uptake ◽  
Functional Traits ◽  
Primary Productivity ◽  
Ecosystem Functioning ◽  
Plant Biomass ◽  
Plant Evolution ◽  
Mineral Nutrient ◽  
Belowground Processes ◽  
Total Plant Biomass ◽  
Total Plant

AbstractPlant strategies for nutrient acquisition and recycling are key components of ecosystem functioning. How the evolution of such strategies modifies ecosystem functioning and services is still not well understood. In the present work, we aim at understanding how the evolution of different phenotypic traits link aboveground and belowground processes, thereby affecting the functioning of the ecosystem at different scales and in different realms. Using a simple model, we follow the dynamics of a limiting nutrient inside an ecosystem. Considering trade-offs between aboveground and belowground functional traits, we study the effects of the evolution of such strategies on ecosystem properties (amount of mineral nutrient, total plant biomass, dead organic matter and primary productivity) and whether such properties are maximized. Our results show that when evolution leads to a stable outcome, it minimizes the quantity of nutrient available (following Tilman's R* rule). We also show that considering the evolution of aboveground and belowground functional traits simultaneously, total plant biomass and primary productivity are not necessarily maximized through evolution. The coupling of aboveground and belowground processes through evolution may largely diminish predicted standing biomass and productivity (extinction may even occur), and impact the evolutionary resilience (ie, the return time to previous phenotypic states) of the ecosystem in face of external disturbances. We show that changes in plant biomass and their effects on evolutionary change can be understood by accounting for the links between nutrient uptake and mineralization, and for indirect effects of nutrient uptake on the amount of detritus in the system.

scholarly journals Photothermal Ratio Affects Plant Quality in `Freedom' Poinsettia

2002 ◽  
Vol 127 (1) ◽  
pp. 20-26 ◽  
Author(s):  
Bin Liu ◽  
Royal D. Heins
Keyword(s):  
Thermal Energy ◽  
Plant Biomass ◽  
Radiant Energy ◽  
Dry Weight ◽  
Plant Quality ◽  
Greenhouse Crops ◽  
Degree Day ◽  
Stem Strength ◽  
Plant Stem

Light (radiant energy) and temperature (thermal energy) affect quality of greenhouse crops. Radiant energy drives photosynthesis and, consequently, plant biomass accumulation. Thermal energy is the primary environmental factor driving developmental rate. The concept of a photothermal ratio (PTR), the ratio of radiant energy [moles of photosynthetic (400 to 700 nm) photons/m2] to thermal energy (degree-day), was proposed to describe the balance between plant growth and plant development in greenhouse crops. The objective of this study was to quantify the effect of PTR during vegetative (PTRv) or reproductive (PTRr) phases on finished plant quality of `Freedom' poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch). In Expt. 1, plants were grown under 27 combinations of three constant temperatures (19, 23, or 27 °C), three daily light integrals (DLIs) as measured by the number of photosynthetic (400 to 700 nm) photons (5, 10, or 20 mol·m-2·d-1), and three plant spacings (15 × 15, 22 × 22, or 30 × 30 cm) from pinch to the start of short-day flower induction, and then moved to a common PTR until anthesis. In Expt. 2, plants were grown under a common PTR during the vegetative stage and then moved to combinations of three DLIs (5, 10, or 15 mol·m-2·d-1) and three plant spacings (25 × 25, 30 × 30, or 35 × 35 cm) at a constant 20 °C from the start of short days until anthesis. Both PTRr and PTRv affected final plant dry weight (DW). All components of DW (total, stem, leaf, and bract) increased linearly as PTRr increased, and responded quadratically to PTRv, reaching a maximum when PTRv was 0.04 mol/degree-day per plant. Stem strength depended more on PTRv than PTRr. When PTRv increased from 0.02 to 0.06 mol/degree-day per plant, stem diameter increased ≈24%, while stem strength increased 75%. The size of bracts and cyathia increased linearly as PTRr increased, but was unaffected by PTRv. When PTRr increased from 0.02 to 0.06 mol/degree-day per plant, bract area, inflorescence diameter, and cyathia diameter increased 45%, 23%, and 44%, respectively.

scholarly journals Herbivory in a Spatially Heterogeneous Environment- Pikas Ochotona princeps and High Alpine Vegetation

1994 ◽  
Vol 18 ◽  
pp. 131-134
Author(s):  
Jon Moen ◽  
Tarja Oksanen ◽  
Nancy Huntly
Keyword(s):  
Growth Rate ◽  
Landscape Ecology ◽  
Spatial Heterogeneity ◽  
Primary Productivity ◽  
Plant Biomass ◽  
Grazing Pressure ◽  
Trophic Levels ◽  
Plant Production ◽  
Heterogeneous Environment ◽  
And Function

Landscape ecology has been very influential in developing tools for describing both structure (e.g. the distribution and sizes of patches) and function (i.e. the flow among patches) of heterogeneous environments (Turner 1989, Turner & Gardner 1991). This approach has shown that spatial heterogeneity on a landscape level may influence many types of ecological processes (Kolasa & Pickett 1991, Wiens et al. 1993). However, it is also clear that landscape structure and function must be described from an organism-centered view (Kolasa & Pickett 1991), which invites the use of population dynamic hypotheses, and presents the challenging task of merging population ecology with landscape ecology. Standard, non-spatial, predator-prey models predict that the grazing pressure in a given area is related to primary productivity (Oksanen et al. 1981). The model assumes that the number of dynamically important trophic levels is dependent on primary productivity and, in its simplest form, it can be outlined as follows: In extremely unproductive areas (e.g. boulder-fields), plant biomass is too low to sustain mammalian herbivores. In undisturbed areas, plants will thus eventually deplete their resources and compete. In moderately productive areas (e.g.arctic and alpine heaths), plant production is high enough to sustain herbivores, albeit at low densities, lower than what is needed for efficient predators to have a positive growth rate. Uncontrolled by predation, these herbivores are predicted to exert a strong grazing pressure on the vegetation. In more productive areas (e.g. tall herb meadows), plant production is high enough to sustain both herbivores and predators. With herbivores controlled by predation, plants will experience a low grazing pressure, and competition will be an important structuring factor for the plants. According to these models, a productivity gradient from extremely barren areas to productive areas should contain a zone of strong grazing pressure at intermediate productivities. A re­analysis using two types of patches with different primary productivity (T. Oksanen 1990) shows that the exact predictions depend on the proportion of these two patches in the habitat. Predation pressure could be high (and thus grazing pressure low) in a patch of intermediate productivity if it is embedded in a matrix of more productive patches, and, reversely, a productive patch might have a high grazing pressure if it is embedded in a matrix of less productive patches. These predictions parallel those of the source-sink model of Pulliam (1988) where a habitat where the consumer has a high growth rate "exports" juveniles to a habitat where the consumer growth rate is lower or even negative, thus creating a higher grazing pressure in the latter habitat than would have been possible without this continuous restocking of individuals. The general conclusion from these models is that grazing pressure may vary between patches both as a consequence of differences in productivity and also because of the spatial arrangements of patches. Any comprehensive understanding of the interactions between herbivores and plants in a heterogeneous environment must thus be based on experiments and observations that explicitly take the spatial heterogeneity of the study area into account.

scholarly journals Mathematical model for Plant-Insect interaction with dynamic response to PAD4-BIK1 interaction and effect of BIK1 inhibition

2017 ◽  
Author(s):  
Sanjay ◽  
Sabahuddin Ahmad ◽  
M. I. Siddiqi ◽  
Khalid Raza
Keyword(s):  
Mathematical Model ◽  
Plant Defense ◽  
Defense Mechanism ◽  
Plant Biomass ◽  
Plant Quality ◽  
Predator Prey Model ◽  
Enhanced Production ◽  
Interaction System ◽  
Plant Defense Mechanism ◽  
Plant Insect Interaction

AbstractPlant-insect interaction system has been a widely studied model of the ecosystem. Attempts have long been made to understand the numerical behaviour of this counter system and make improvements in it from initial simple analogy based approach with predator-prey model to the recently developed mathematical interpretation of plant-insect interaction including concept of plant immune interventions Caughley and Lawton (1981). In our current work, we propose an improvement in the model, based on molecular interactions behind plant defense mechanism and it’s effect on the plant growth and insect herbivory. Motivated from an interaction network of plant biomolecules given by Louis and Shah (2014) and extending the model of Chattopadhyay, et al (2001), we propose here a mathematical model to show how plant insect interaction system is governed by the molecular components inside. Insect infestation mediated induction of Botrytis Induced Kinase-1 (BIK-1) protein causes inhibition of Phyto Alexin Deficient-4 (PAD4) protein. Lowered PAD4, being responsible for initiating plant defense mechanism, results in degraded plant immune potential and thus causes loss of plant quality. We adapt these interactions in our model to show how they influence the plant insect interaction system and also to reveal how silencing BIK-1 may aid in enhanced production of plant biomass by increasing plant immunity mediated by increase in PAD4 and associated antixenotic effects. We hypothesize the significance of BIK-1 inhibition which could result in the improvement of the plant quality. We explain the interaction system in BIK-1 inhibition using mathematical model. Further, we adopted the plethora of computational modeling and simulations techniques to identify the mechanisms of molecular inhibition.

Influence of shrub encroachment on aboveground net primary productivity and carbon and nitrogen pools in a mesic grassland

2004 ◽  
Vol 82 (9) ◽  
pp. 1363-1370 ◽  
Author(s):  
Michelle S Lett ◽  
Alan K Knapp ◽  
John M Briggs ◽  
John M Blair
Keyword(s):  
Tallgrass Prairie ◽  
Primary Productivity ◽  
Aboveground Biomass ◽  
Net Primary Productivity ◽  
Shrub Encroachment ◽  
Organic C ◽  
Mesic Grassland ◽  
C And N ◽  
Cornus Drummondii ◽  
The Impact

The clonal shrub Cornus drummondii C.A. Mey. is rapidly increasing in cover and displacing mesic grassland species in the central USA as a consequence of fire suppression. We assessed the impact of C. drummondii on carbon (C) and nitrogen (N) pools and C fluxes in a tallgrass prairie in eastern Kansas, USA, through a comparison of both burned and unburned C. drummondii islands with open grassland areas. Allometric equations relating C. drum mondii foliage and wood biomass to basal stem diameter were developed to estimate aboveground biomass and net primary productivity (ANPP) of C. drummondii. Within C. drummondii islands, ANPP was 496 ± 45 g C·m–2·year–1, nearly three times that within open grassland (167 ± 13 g C·m–2·year–1). As a result of greater aboveground biomass, aboveground C and N storage within shrub islands (3270 ± 466 g C·m–2, 37.9 ± 5.3 g N·m–2) was substantially greater than that within open grassland (241 ± 33 g C·m–2, 6.1 ± 0.8 g N·m–2). No change in soil organic C or total N to 10-cm depth was evident; however, soil CO2 flux was significantly reduced in C. drummondii islands relative to the open grassland. The storage of C in aboveground biomass of C. drummondii represents a significant short-term increase in C storage relative to open grassland. However, potential alterations in belowground processes must be quantified before the long-term net effect of shrub encroachment on C and N pools within this mesic grassland can be determined.Key words: aboveground biomass, Cornus drummondii, net primary productivity, shrub encroachment, tallgrass prairie.

Studies on Standing Crop Biomass and Primary Productivity of Horse Gram in Jharkhand

2020 ◽  
Vol 6 (02) ◽  
Author(s):  
PRAMOD KUMAR Budiman ◽  
RAGHUNATH PRASAD ◽  
R RK SINHA ◽  
SANJEEV KUMAR ◽  
ANIL KUMAR SINGH
Keyword(s):  
Primary Productivity ◽  
Standing Crop ◽  
Net Primary Productivity ◽  
Plant Biomass ◽  
Sigmoidal Curve ◽  
Standing Dead ◽  
Total Plant Biomass ◽  
Total Plant ◽  
Final Harvest ◽  
Crop Biomass

The standing crop biomass in different plant compartments was found to be variable with the age of the crop. The total plant biomass of ageing plant indicated a sigmoidal curve in three varieties of Birsa Kulthi–1, Birsa Kulthi–2 and Birsa Kulthi–3. The total plant biomass was recorded to be 115.53 g/m2 (Birsa Kulthi–1), 92.85 g/m2 (Birsa Kulthi–2) and 72.42 g/m2 (Birsa Kulthi–3) at final harvest i.e. 105 days. Contribution of stem and leaves to the total plant biomass has increased between 15 and 90 days. Infl./pod biomass per cent as found to be increasing throughout. Standing dead biomass was maximum 9.40 per cent (Birsa Kulthi–1), 8.97 per cent (Birsa Kulthi–2) and 6.53 per cent (Birsa Kulthi–3) at final harvest i.e. 105 days. Peak values for current increments in biomass were observed at 90 days in Birsa Kulthi–1 and 105 days in Birsa Kulthi–2 and Birsa Kulthi–3. The peak values for net primary productivity were found to be highest at 90 days for Birsa Kulthi–1 and 105 days harvest for Birsa Kulthi–2 and Birsa Kulthi–3.

Net aerial primary production of a James Bay, Ontario, salt marsh

1982 ◽  
Vol 60 (7) ◽  
pp. 1060-1067 ◽  
Author(s):  
Walter A. Glooschenko ◽  
Nancy S. Harper
Keyword(s):  
Salt Marsh ◽  
Primary Productivity ◽  
Aboveground Biomass ◽  
Plant Biomass ◽  
Dry Weight ◽  
Intertidal Flat ◽  
James Bay ◽  
Juncus Balticus ◽  
Puccinellia Phryganodes ◽  
The Mean

Aboveground plant biomass and litter measurements were made at four intervals between mid-June and late August 1977 on a subarctic salt marsh located at North Point on the southwestern shore of James Bay, Ontario. We sampled six salt marsh zones ranging from a lower intertidal flat dominated by the grass Puccinellia phryganodes to the edge of willow thickets characterized by Juncus balticus.Peak aboveground biomass was reached in nearly all zones by early August, and ranged from 119.3 to 240.4 g dry weight∙m−2. Litter accumulated in all zones except the lower two zones which were subjected to tidal flows. The highest zone where Juncus balticus occurred had the highest litter mass, 572.8 g dry weight∙m−2, while the lowest, 24.7 g∙m−2, occurred in the lowest zone. Estimates of net aerial primary productivity using Smalley's method ranged from 119.3 g∙m−2 in the upper salt marsh to 384.0 g∙m−2 in the zone dominated by Juncus balticus. The mean marsh net aerial primary productivity was 227.7 g∙m−2 which was low compared with other salt marsh data. The 1977 aboveground biomass was lower in 1976, probably as a result of a cooler summer.

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