Effects of Inundation, Nutrient Availability and Plant Species Diversity on Fine Root Mass and Morphology Across a Saltmarsh Flooding Gradient

Banning of grazing is a widely used means of restoring degraded rangeland in China. However, little is known about the time required to restore degraded alpine meadows through the use of a grazing ban. Height and cover of individual plant species and total cover, herbage mass and root mass of each plot of a grazing ban and communal free-grazing alpine meadows in Northern Tibet were examined. Soil samples were also collected and total organic carbon, microbial biomass carbon, total phosphorus and ammonium nitrogen contents were measured. The results showed that both the level of plant species diversity and herbage mass were higher in areas of a grazing ban than in communal free-grazing land without a grazing ban. No significant differences in root mass and soil nutrient contents were observed. There was a higher plant species diversity and herbage mass in the early years of a grazing ban but there was a subsequent decline. It is suggested that some grazing after a grazing ban may be necessary according to the dynamics of ecosystem responses with time.

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Mean age of carbon in fine roots from temperate forests and grasslands with different management

Biogeosciences Discussions ◽

10.5194/bgd-10-5671-2013 ◽

2013 ◽

Vol 10 (3) ◽

pp. 5671-5700 ◽

Cited By ~ 3

Author(s):

E. Solly ◽

I. Schöning ◽

S. Boch ◽

J. Müller ◽

S. A. Socher ◽

...

Keyword(s):

Species Diversity ◽

Plant Species ◽

Fine Roots ◽

Fine Root ◽

Plant Species Diversity ◽

Soil Conditions ◽

Perennial Species ◽

Temperate Grasslands ◽

Organic C ◽

The Mean

Abstract. Fine roots are the most dynamic portion of a plant's root system and a major source of soil organic matter. By altering plant species diversity and composition, soil conditions and nutrient availability, and consequently belowground allocation and dynamics of root carbon (C) inputs, land-use and management changes may influence organic C storage in terrestrial ecosystems. In three German regions we measured fine root radiocarbon (14C) content to estimate the mean time since C in root tissues was fixed from the atmosphere in 54 grassland and forest plots with different management and soil conditions. Although root biomass was on average greater in grasslands 5.1 ± 0.8 g (mean ± SE, n = 27) than in forests 3.1 ± 0.5 g (n = 27), the mean age of C in fine roots in forests averaged 11.3 ± 1.8 yr and was significantly older and more variable compared to grasslands 1.7 ± 0.4 yr. We further found that management affects the mean age of fine root C in temperate grasslands mediated by changes in plant species diversity and composition. Fine root mean C age is positively correlated to plant diversity (r = 0.65) and to the number of perennial species (r = 0.77). In temperate grasslands the mean age of fine root C is also influenced by the study region mainly driven by differences in soil characteristics and climate which reflect in plant composition variations, with averages of 0.7 ± 0.1 yr (n = 9) on mostly organic sandy soils in northern Germany and of 1.8 ± 0.3 yr (n = 9) and 2.6 ± 0.3 (n = 9) in more silty and clayey soils respectively in central and southern Germany. Our results indicate an internal redistribution of C in perennial species and suggest linkages between fine root C age and management in grasslands. These findings improve our ability to predict and model belowground C fluxes across broader spatial scales.

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Mean age of carbon in fine roots from temperate forests and grasslands with different management

Biogeosciences ◽

10.5194/bg-10-4833-2013 ◽

2013 ◽

Vol 10 (7) ◽

pp. 4833-4843 ◽

Cited By ~ 30

Author(s):

E. Solly ◽

I. Schöning ◽

S. Boch ◽

J. Müller ◽

S. A. Socher ◽

...

Keyword(s):

Species Diversity ◽

Plant Species ◽

Fine Roots ◽

Fine Root ◽

Plant Species Diversity ◽

Soil Conditions ◽

Organic Soils ◽

Perennial Species ◽

Organic C ◽

The Mean

Abstract. Fine roots are the most dynamic portion of a plant's root system and a major source of soil organic matter. By altering plant species diversity and composition, soil conditions and nutrient availability, and consequently belowground allocation and dynamics of root carbon (C) inputs, land-use and management changes may influence organic C storage in terrestrial ecosystems. In three German regions, we measured fine root radiocarbon (14C) content to estimate the mean time since C in root tissues was fixed from the atmosphere in 54 grassland and forest plots with different management and soil conditions. Although root biomass was on average greater in grasslands 5.1 ± 0.8 g (mean ± SE, n = 27) than in forests 3.1 ± 0.5 g (n = 27) (p < 0.05), the mean age of C in fine roots in forests averaged 11.3 ± 1.8 yr and was older and more variable compared to grasslands 1.7 ± 0.4 yr (p < 0.001). We further found that management affects the mean age of fine root C in temperate grasslands mediated by changes in plant species diversity and composition. Fine root mean C age is positively correlated with plant diversity (r = 0.65) and with the number of perennial species (r = 0.77). Fine root mean C age in grasslands was also affected by study region with averages of 0.7 ± 0.1 yr (n = 9) on mostly organic soils in northern Germany and of 1.8 ± 0.3 yr (n = 9) and 2.6 ± 0.3 (n = 9) in central and southern Germany (p < 0.05). This was probably due to differences in soil nutrient contents and soil moisture conditions between study regions, which affected plant species diversity and the presence of perennial species. Our results indicate more long-lived roots or internal redistribution of C in perennial species and suggest linkages between fine root C age and management in grasslands. These findings improve our ability to predict and model belowground C fluxes across broader spatial scales.

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