Change in Primary Production in Lake Kasumigaura(1986-1989)Accompanied by Transition of Dominant Species.

1991 ◽  
Vol 52 (3) ◽  
pp. 173-187 ◽  
Author(s):  
Noriko TAKAMURA ◽  
Morihiro AIZAKI
Ecosystems ◽  
2009 ◽  
Vol 12 (5) ◽  
pp. 760-776 ◽  
Author(s):  
Matteo Campioli ◽  
Anders Michelsen ◽  
Andreas Demey ◽  
Annemie Vermeulen ◽  
Roeland Samson ◽  
...  

Author(s):  
William D. Bowman ◽  
Melany C. Fisk

The production of biomass by plants is of central importance to energy, carbon, and nutrient fluxes in ecosystems. Knowledge of the spatial and temporal variation of production and the underlying biotic and physical controls on this variation are central themes in ecosystem science. The goals of this chapter are to present the estimates of spatial patterns in above- and belowground production associated with the major community types found on Niwot Ridge and other alpine areas of the southern Rocky Mountains and to examine the likely environmental causes and underlying mechanisms responsible for spatial and temporal variation in production as elucidated by experimental and observational studies. Rates of primary production and standing crops of plant biomass are low in alpine tundra relative to other ecosystem types (Lieth and Whittaker 1975; Zak et al. 1994). However, within communities (i.e., at the plot level), there is large variation in rates of production, the degree of biotic control over response to environmental change, and the principal environmental constraints of primary production. As a result, the alpine is one of the most dynamic ecosystems for research. For example, there is a tenfold difference in annual aboveground production between the most and least productive sites with continuous plant cover on Niwot Ridge. In addition, the high plant diversity is a source of potential variation in physiological and developmental control of plant response to the environment. Dominant species include sedges, grasses, shrubs, and forbs, among which are N2-fixing Trifolium species. Nearly all of the dominant species may be mycorrhizal. Soil moisture, a driving force for many biotic processes, may vary by an order of magnitude between wet and dry sites following prolonged periods of drought. Thus the alpine tundra of Niwot Ridge, which might appear superficially homogeneous, in fact has complex physical and biotic gradients. This spatial variation prevents simple generalizations about single limiting resources or climatic driving forces determining spatial and temporal variation in productivity. Billings (1973) defined the mesotopographic gradient as a working unit for describing the alpine landscape, as it encompasses the full range of snow accumulation and associated microclimates and thus biological diversity.


Author(s):  
Kazuhiro KOMATSU ◽  
Megumi NAKAGAWA ◽  
Kenji TSUCHIYA ◽  
Ayato KOHZU ◽  
Ryuichiro SHINOHARA ◽  
...  

1976 ◽  
Vol 33 (5) ◽  
pp. 1175-1187 ◽  
Author(s):  
W. M. Pomeroy ◽  
J. G. Stockner

Construction of a river training dyke at Squamish, B.C., has resulted in strong salinity, water transparency, and sedimentation gradients across the estuary face which have significantly affected the distribution and primary production of benthic algae. The estuary west of the dyke is now a very unstable habitat for algal colonization and growth. During river freshet, heavy sedimentation and salinities less than 3‰ make algal survival difficult. At other times of the year, a salinity range of up to 25‰ is common over a tidal cycle. Algae in this area are generally strongly euryhaline, the dominant species being Enteromorpha minima, Rhizoclonium riparium, and Vaucheria dichotoma; mean production is 0.6 g Cm−2 day−1. The eastern portion of the estuary has a more stable benthic environment; lower sedimentation and higher salinity result in greater species diversity, biomass, and primary production. Dominant species are E. minima, Ulva lactuca, Pylaiella littoralis, and a variety of diatom communities. These algae tend to be weakly euryhaline, with optimum salinities between 15 and 30‰. Mean production is 2.2 g C m−2 day−1. Recent intrusion of Fucus vesiculosus strongly indicates that the eastern estuary is developing into a more marine habitat.Primary production of benthic algae is maintained by the wax and wane of low light and high light favoring species. Annual production estimates of 215 g C m−2 approximate those for estuaries at similar latitudes.


1985 ◽  
Vol 7 (3) ◽  
pp. 303-312 ◽  
Author(s):  
Noriko Takamura ◽  
Toshio Iwakuma ◽  
Masayuki Yasuno

1991 ◽  
Vol 63 (2) ◽  
pp. 115-130
Author(s):  
Päivi Halinen ◽  
Mikko Raatikainen

The total weed seed storage in the plough layer of 20 cm was 93 965 seeds/m2, of which 36 taxa were defined. The proportion of seeds of annual and winter annual species in soil was 89.6 %. The number of rye seeds emerging in autumn was 614 per m2 and weeds 224 per m2. The total number of weeds was 381/ m2 when the calculation was based on the time of maximal appearance. 0.3 % of the total amount of weeds emerged. Rye and Elymus repens were the dominant species in the above-ground vegetation, whereas the biomass of the other weeds remained poorly developed because of marked shading from these two. The maximum biomass of the living above-ground vegetation, 614 g/m2, was achieved in the middle of August (12. VIII). Net above-ground primary production, measured by the harvesting method, was 664 g/m2 · year and underground production 190 g/m2 · year, giving a total production of vegetation and detritus of 854 g/ m2 · year. The net efficiency of the primary producers was 0.7 %.


1987 ◽  
Vol 48 (Special) ◽  
pp. 13-38 ◽  
Author(s):  
Noriko TAKAMURA ◽  
Toshio IWAKUMA ◽  
Masayuki YASUNO

Sign in / Sign up

Export Citation Format

Share Document