Burning history, time of burning, and year effects on plant community structure and heterogeneity in Fescue Prairie

Botany ◽  
2010 ◽  
Vol 88 (1) ◽  
pp. 1-12 ◽  
Author(s):  
D. V. Gross ◽  
J. T. Romo
Keyword(s):  
Community Structure ◽  
Species Composition ◽  
Spatial Heterogeneity ◽  
Plant Community ◽  
Canopy Cover ◽  
Plant Functional Groups ◽  
Plant Community Structure ◽  
Temporal Heterogeneity ◽  
Spatial And Temporal Heterogeneity ◽  
Festuca Hallii

Structure, as well as spatial and temporal heterogeneity in plant species composition were studied in a Festuca hallii (Vasey) Piper – dominated Prairie in Canada for 6 years following burning before, during, or after the growing season on sites burned 1× or 3×. Structure, spatial heterogeneity, and temporal heterogeneity were never (P > 0.05) influenced by the time of burning. Diversity and richness of graminoids, perennial forbs, and shrubs fluctuated among years after burning, but were unaffected by burning history. Excepting shrubs, canopy cover of plant functional groups positively correlated with precipitation. After a single burn, spatial heterogeneity in species composition increased with years after burning, indicating plant communities were becoming patchier, whereas those burned 3× did not change predictably through time. Spatial heterogeneity in species composition between consecutive years was positively correlated, but temporal heterogeneity in species composition did not correlate with spatial heterogeneity. Burning history and precipitation appear important in controlling the plant community structure and spatial heterogeneity in species composition in Fescue Prairie.

scholarly journals Livestock exclosure with consequent vegetation changes alters photo-assimilated carbon cycling in a <i>Kobresia</i> meadow

2013 ◽  
Vol 10 (11) ◽  
pp. 17633-17661 ◽  
Author(s):  
J. Zou ◽  
L. Zhao ◽  
S. Xu ◽  
X. Xu ◽  
D. Chen ◽  
...  
Keyword(s):  
Community Structure ◽  
Carbon Cycling ◽  
Plant Community ◽  
Plant Functional Groups ◽  
Ecosystem Functions ◽  
Plant Community Structure ◽  
Soil System ◽  
Plant Soil ◽  
Ecosystem Carbon ◽  
Aboveground Productivity

Abstract. Livestock exclosure has been widely used as an approach for grassland restoration. However, the effects of exclosure on grassland are controversial and can depend on many factors, such as the grassland ecosystem types, evolutionary history and so on. In this study, we conduct field experiments to investigate the variations of ecosystem function in response to livestock exclosure in a Kobresia humilis meadow under six years grazing exclosure on the Qinghai-Tibetan plateau. We focused on two ecosystem functions: plant community structure and ecosystem carbon cycling. The plant aboveground productivity, plant diversity and the composition of plant functional groups of the meadow were addressed as the indicators of the plant community structure. The 13C isotope pulse labeling technique was applied to evaluate the alterations of ecosystem carbon cycling during the short-term. The results showed that the plant community structure was changed after being fenced for six years, with significantly decreased aboveground productivity, species loss and varied composition of the four plant functional groups (grasses, sedges, legumes and forbs). Using the pulse labeling technique, we found a lower cycling rate of 13C in the plant–soil system of the fenced plots compared with the grazed sites during the first 4 days after labeling. A higher proportion of 13C amount recovered in the plant–soil system were migrated into soil as root exudates immediately after labeling at both fenced and control grazed sites, with significantly lower proportion in the fenced site, coinciding with the lower loss of 13C in soil respiration. Thirty-two days after labeling, 37% of recovered 13C remained in the soil of the fenced plots, with significant differences compared to the grazed plots (47%). In addition, less 13C (5% vs. 7%) was lost by soil respiration in the fenced plots during the chase period of 32 d. Overall, our study suggested that livestock exclosure had negative effects on the two ecosystem functions investigated, and the effects on 13C cycling and sequestrations in the soil were in response to variations in community structures, especially the suppression of forbs and legumes in the fenced site.

scholarly journals Field <sup>13</sup>CO<sub>2</sub> pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a <i>Kobresia</i> meadow

2014 ◽  
Vol 11 (16) ◽  
pp. 4381-4391 ◽  
Author(s):  
J. Zou ◽  
L. Zhao ◽  
S. Xu ◽  
X. Xu ◽  
D. Chen ◽  
...  
Keyword(s):  
Community Structure ◽  
Carbon Cycling ◽  
Plant Community ◽  
Lower Proportion ◽  
Plant Functional Groups ◽  
Plant Community Structure ◽  
Soil System ◽  
Plant Soil ◽  
Ecosystem Carbon ◽  
Aboveground Productivity

Abstract. Livestock exclosure has been widely used as an approach for grassland restoration. However, the effects of exclosures on grasslands are controversial and can depend on many factors, such as the grassland ecosystem types, evolutionary history and so on. In this study, we conduct field experiments to investigate the variations of the ecosystem function in response to livestock exclosure in a Kobresia humilis meadow with 6 years of grazing exclosure on the Qinghai–Tibetan Plateau. We focused on two ecosystem functions: plant community structure and ecosystem carbon cycling. The plant aboveground productivity, plant diversity and the composition of plant functional groups of the meadow were addressed as the indicators of the plant community structure. The 13C isotope pulse labeling technique was applied to evaluate the alterations of ecosystem carbon cycling during a short term. The results showed that the plant community structure was changed after being fenced in for 6 years, with significantly decreased aboveground productivity, species loss and varied composition of the four plant functional groups (grasses, sedges, legumes and forbs). Using the pulse labeling technique, we found a lower cycling rate of 13C in the plant–soil system of the fenced plots compared with the grazed sites during the first 24 h after labeling. A higher proportion of recovered 13C in the plant–soil system migrated into the soil as root exudates immediately after labeling at both fenced and control grazed sites, with a significantly lower proportion in the fenced site, coinciding with the lower proportion of 13C lost from soil respiration. Thirty-two days after labeling, 37% of the recovered 13C remained in the soil of the fenced plots, with significant differences compared to in the grazed plots (47%). In addition, less 13C (5 vs. 7%) was lost by soil respiration in the fenced plots during the chase period of 32 days. Overall, our study suggests that livestock exclosures have negative effects on the plant community structure and partitioning patterns of the photoassimilated carbon in the Kobresia meadow, and the effects on photoassimilated carbon cycling are likely to result from the variations of community structures in the ecosystem.

scholarly journals Altitudinally coordinated pattern of plant community structure in the Shivapuri National Park, Nepal

1970 ◽  
Vol 18 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Shalik Ram Sigdel
Keyword(s):  
Community Structure ◽  
Species Diversity ◽  
Plant Species ◽  
Plant Community ◽  
National Park ◽  
Climatic Factors ◽  
Flower Colour ◽  
Basal Area ◽  
Plant Community Structure ◽  
Closed Canopy

Study on plant community structure was undertaken in different altitudinal ranges of Shivapuri National Park. The general objective of this study is to analyse different plant community structure in Shivapuri National Park with regards to altitudinal variation. The forest was divided into three distinct altitudinal ranges on the basis of dominancy. In each altitudinal range standard quadrats method was applied for vegetation analysis. The highest number of species was found in site II. All the ecological parameters of the plant species were higher in site II except Basal Area of tree that was highest in site III. The pattern of distribution of plant species was not uniform according to altitude. At higher elevation, the forest was mature with almost closed canopy and trees were large; so the tree density was low. Species richness was highest in site II. Species diversity among tree and shrub species was higher in site I. But for herb species diversity was higher in site II for both seasons. Such type of variations may be due to nature of soil i.e. acidity, nutrient availability and other micro-climatic factors. The most noteworthy thing was that variation in flower colour of Rhododendron arboreum i.e. deep scarlet at low altitude, but it gradually changed into pinkish white as altitude increased. Key words: Altitude, Density, Plant community, Species diversity doi: 10.3126/banko.v18i1.2161 Banko Janakari, Vol. 18, No. 1, 11-17

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