Competition and coexistence in grassland codominants: responses to neighbour removal and resource availability

2004 ◽  
Vol 82 (4) ◽  
pp. 450-460 ◽  
Author(s):  
Andrea M Silletti ◽  
Alan K Knapp ◽  
John M Blair
Keyword(s):  
Tallgrass Prairie ◽  
Competitive Exclusion ◽  
Net Photosynthesis ◽  
Andropogon Gerardii ◽  
Sorghastrum Nutans ◽  
Konza Prairie ◽  
Plant Removal ◽  
Anthropogenic Alterations ◽  
Prairie Plant

We examined the role of interspecific competition in the regulation of abundance and coexistence of the dominant grasses in tallgrass prairie using a removal experiment with Andropogon gerardii Vitman and Sorghastrum nutans L. Nash, two of the most abundant grasses in tallgrass prairie. Plant removal treatments (using foliar herbicide), applied to 0.3-m2 plots at the Konza Prairie Biological Station (northeast Kansas, USA), included removal of all A. gerardii, removal of all S. nutans, and no removal. To determine whether soil fertility altered the outcome, we included a fertilizer addition treatment (10 g N·m–2) fully crossed with the removal treatments. Andropogon gerardii removal resulted in significantly increased net photosynthesis, stomatal conductance, and tiller mass in S. nutans. Sorghastrum nutans removal had little effect on A. gerardii, suggesting asymmetric competition. Fertilizer significantly increased tiller mass and flowering stalk production in S. nutans, but had little effect on A. gerardii. The ability of A. gerardii to suppress the performance of S. nutans is consistent with the greater abundance of A. gerardii over much of the tallgrass prairie, while the ability of S. nutans to take advantage of increased resources may be one mechanism by which it avoids competitive exclusion. Because of the greater variability in the performance of S. nutans than in that of A. gerardii, any natural or anthropogenic alterations to this grassland that lead to shifts in dominance between these species may affect ecosystem productivity and stability.Key words: Andropogon gerardii, competition, grassland, neighbour removal, photosynthesis, Sorghastrum nutans, tallgrass prairie.

The Keystone Role of Bison in North American Tallgrass Prairie

BioScience ◽  
1999 ◽  
Vol 49 (1) ◽  
pp. 39 ◽  
Author(s):  
Alan K. Knapp ◽  
John M. Blair ◽  
John M. Briggs ◽  
Scott L. Collins ◽  
David C. Hartnett ◽  
...  
Keyword(s):  
Tallgrass Prairie ◽  
North American

scholarly journals Biological Control and Mitigation of Aflatoxin Contamination in Commodities

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 104
Author(s):  
Ferenc Peles ◽  
Péter Sipos ◽  
Szilvia Kovács ◽  
Zoltán Győri ◽  
István Pócsi ◽  
...  
Keyword(s):  
Biological Control ◽  
Secondary Metabolites ◽  
Competitive Exclusion ◽  
Aflatoxin Contamination ◽  
Post Harvest ◽  
Physical Chemical ◽  
Synthetic Chemicals ◽  
Ruminal Degradation

Aflatoxins (AFs) are toxic secondary metabolites produced mostly by Aspergillus species. AF contamination entering the feed and food chain has been a crucial long-term issue for veterinarians, medicals, agroindustry experts, and researchers working in this field. Although different (physical, chemical, and biological) technologies have been developed, tested, and employed to mitigate the detrimental effects of mycotoxins, including AFs, universal methods are still not available to reduce AF levels in feed and food in the last decades. Possible biological control by bacteria, yeasts, and fungi, their excretes, the role of the ruminal degradation, pre-harvest biocontrol by competitive exclusion or biofungicides, and post-harvest technologies and practices based on biological agents currently used to alleviate the toxic effects of AFs are collected in this review. Pre-harvest biocontrol technologies can give us the greatest opportunity to reduce AF production on the spot. Together with post-harvest applications of bacteria or fungal cultures, these technologies can help us strictly reduce AF contamination without synthetic chemicals.

Interspecific nutrient transfer in a tallgrass prairie plant community

1996 ◽  
Vol 83 (2) ◽  
pp. 180-184 ◽  
Author(s):  
Laura E. Fischer Walter ◽  
David C. Hartnett ◽  
Barbara A. D. Hetrick ◽  
A. Paul Schwab
Keyword(s):  
Plant Community ◽  
Tallgrass Prairie ◽  
Nutrient Transfer ◽  
Prairie Plant

scholarly journals Effects of Fire and Large Herbivores on Canopy Nitrogen in a Tallgrass Prairie

2019 ◽  
Vol 11 (11) ◽  
pp. 1364 ◽  
Author(s):  
Bohua Ling ◽  
Edward J. Raynor ◽  
Douglas G. Goodin ◽  
Anthony Joern
Keyword(s):  
Spatial Variability ◽  
Nitrogen Content ◽  
Tallgrass Prairie ◽  
High Nitrogen Content ◽  
High Nitrogen ◽  
Grazing History ◽  
One Year ◽  
Canopy Nitrogen

This study analyzed the spatial heterogeneity of grassland canopy nitrogen in a tallgrass prairie with different treatments of fire and ungulate grazing (long-term bison grazing vs. recent cattle grazing). Variogram analysis was applied to continuous remotely sensed canopy nitrogen images to examine the spatial variability in grassland canopies. Heterogeneity metrics (e.g., the interspersion/juxtaposition index) were calculated from the categorical canopy nitrogen maps and compared among fire and grazing treatments. Results showed that watersheds burned within one year had higher canopy nitrogen content and lower interspersions of high-nitrogen content patches than watersheds with longer fire intervals, suggesting an immediate and transient fire effect on grassland vegetation. In watersheds burned within one year, high-intensity grazing reduced vegetation density, but promoted grassland heterogeneity, as indicated by lower canopy nitrogen concentrations and greater interspersions of high-nitrogen content patches at the grazed sites than at the ungrazed sites. Variogram analyses across watersheds with different grazing histories showed that long-term bison grazing created greater spatial variability of canopy nitrogen than recent grazing by cattle. This comparison between bison and cattle is novel, as few field experiments have evaluated the role of grazing history in driving grassland heterogeneity. Our analyses extend previous research of effects from pyric herbivory on grassland heterogeneity by highlighting the role of grazing history in modulating the spatial and temporal distribution of aboveground nitrogen content in tallgrass prairie vegetation using a remote sensing approach. The comparison of canopy nitrogen properties and the variogram analysis of canopy nitrogen distribution provided by our study are useful for further mapping grassland canopy features and modeling grassland dynamics involving interplays among fire, large grazers, and vegetation communities.

Composition and soil–environment analysis of prairies on Walpole Island, southwestern Ontario

1987 ◽  
Vol 65 (11) ◽  
pp. 2410-2419 ◽  
Author(s):  
D. Faber-Langendoen ◽  
P. F. Maycock
Keyword(s):  
Tallgrass Prairie ◽  
Panicum Virgatum ◽  
Sandy Loam ◽  
Poa Pratensis ◽  
Sorghastrum Nutans ◽  
Environment Analysis ◽  
Calamagrostis Canadensis ◽  
Species Lists ◽  
Fragaria Virginiana ◽  
Profile Characteristics

Extensive prairie communities on Walpole Island Indian Reserve in Lake St. Clair, southwestern Ontario, were sampled for vegetation and soil profile characteristics. Two hundred and fifty-two species were found in the 20 stands. Dominant grasses included Calamagrostis canadensis, Andropogon gerardii, Sorghastrum nutans, Panicum virgatum, Poa pratensis, and Spartina pectinata. Dominant forbs were Pycnanthemum virginianum, Liatris spicata, Fragaria virginiana, Lysimachia quadriflora, and Viola papilionacea. Stands were ordered along a recognized moisture–substrate gradient divided into four segments; dry-mesic sandy, mesic sandy loam, wet-mesic sandy loam, and wet loam. Many species showed preferences for certain regions of the gradient. Species richness ranged between 44 and 91 species per stand. The composition of the vegetation was summarized for the four segments, using prevalent species lists. Effectiveness of the direct gradient analysis was assessed by ordination using reciprocal averaging and polar ordination. Percent sand, percent organic matter, and depth of A horizon were significant correlates of the primary axis. Frequent burning of the prairie by the Indians has effectively maintained these prairies. The composition of the Walpole Island prairies is similar to those in Michigan, Illinois, and Wisconsin, forming part of the eastern tallgrass prairie.

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