Energy and Moisture Balances of an Alpine Tundra in Mid July

1969 ◽  
Vol 1 (4) ◽  
pp. 247 ◽  
Author(s):  
Werner H. Terjung ◽  
Ronald N. Kickert ◽  
Gerald L. Potter ◽  
Stanley W. Swarts
Keyword(s):  
Alpine Tundra

Symbiotic N2-fixation in alpine tundra: ecosystem input and variation in fixation rates among communities

Oecologia ◽  
1996 ◽  
Vol 108 (2) ◽  
pp. 345-350 ◽  
Author(s):  
William D. Bowman ◽  
James C. Schardt ◽  
Steven K. Schmidt
Keyword(s):  
N2 Fixation ◽  
Alpine Tundra ◽  
Symbiotic N2 Fixation ◽  
Tundra Ecosystem

Effects of alleviation of ecological stresses on an alpine tundra community over an eight-year period

Oikos ◽  
2002 ◽  
Vol 97 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Marie-Charlotte Nilsson ◽  
David A. Wardle ◽  
Olle Zackrisson ◽  
Anders Jäderlund
Keyword(s):  
Alpine Tundra

Responses of the Norwegian alpine Betula nana community to nitrogen fertilization

1997 ◽  
Vol 75 (1) ◽  
pp. 108-120 ◽  
Author(s):  
Jaanus Paal ◽  
Eli Fremstad ◽  
Tõnu Möls
Keyword(s):  
Nitrogen Fertilization ◽  
Nitrogen Supply ◽  
Alpine Tundra ◽  
Soil Parameters ◽  
Alpine Plant ◽  
Betula Nana ◽  
South Central ◽  
Different Types ◽  
Tissue Nitrogen ◽  
Annual Deposition

The effect of nitrogen fertilization on species cover, increment of shrubs, tissue nitrogen, and soil parameters was tested during a 3-year experiment in a low alpine plant community dominated by Betula nana in the Dovre mountains, south-central Norway. The doses used were 1.2 and 6.1 g N/m2, corresponding to 0.72 and 3.6 times, respectively, the annual deposition of nitrogen in southwest Norway. Statistical analysis using SAS ANOVA and GLM procedures were applied to different types of models. The cover of species and growth forms showed no significant response to additional nitrogen supply. The increment of shrubs was not significantly affected by the fertilization, except for the year factor. Incorporation of nitrogen into plant tissue was not evident. No effects were found on soil parameters. Key words: fertilization, alpine tundra, shrubs, nitrogen.

Nitrogen Cycling

2001 ◽  
Author(s):  
Melany C. Fisk ◽  
Paul D. Brooks
Keyword(s):  
Spatial Variation ◽  
Water Availability ◽  
Growing Season ◽  
N Cycling ◽  
Alpine Tundra ◽  
N Transformations ◽  
Cold Temperatures ◽  
Niwot Ridge ◽  
N Cycle ◽  
Large N

In this chapter, we discuss the current understanding of internal N cycling, or the flow of N through plant and soil components, in the Niwot Ridge alpine ecosystem. We consider the internal N cycle largely as the opposing processes of uptake and incorporation of N into organic form and mineralization of N from organic to inorganic form. We will outline the major organic pools in which N is stored and discuss the transfers of N into and from those pools. With a synthesis of information regarding the various N pools and relative turnover of N through them, we hope to provide greater understanding of the relative function of different components of the alpine N cycle. Because of the short growing season, cold temperatures, and water regimes tending either toward very dry or very wet extremes, the alpine tundra is not a favorable ecosystem for either production or decomposition. Water availability, temperature, and nutrient availability (N in particular) all can limit alpine plant growth (chapter 9). Cold soils also inhibit decomposition so that N remains bound in organic matter and is unavailable for plant uptake (chapter 11). Consequently, N cycling in the alpine often is presumed to be slow and conservative (Rehder 1976a, 1976b; Holzmann and Haselwandter 1988). Nonetheless, studies reveal large spatial variation in primary production and N cycling in alpine tundra across gradients of snowpack accumulation, growing season water availability, and plant species composition (May and Webber, 1982, Walker et al., 1994, Bowman, 1994, Fisk et al. 1998; chapter 9). Furthermore, evidence for relatively large N transformations under seasonal snowcover (Brooks et al., 1995a, 1998) and maintenance of high microbial biomass in frozen soils (Lipson et al. 1999a) provide a complex temporal component of N cycling on Niwot Ridge. Our discussion of N cycling on Niwot Ridge will focus on two main points: first, the spatial variation in N turnover in relation to snowpack regimes and plant community distributions; and second, the temporal variability of N transformations during both snow-free and snow-covered time periods.

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