摘要:

AbstractA statistical model for the survival (potential) niche size of submerged macrophytes is related to fluctuating water levels. Designated as the spatial survival niche model (SSN), this model describes the potential niche by means of a product of spatio‐temporal mortality functions. The SSN model enables quantitative estimates of the niche's width, central location, and percentile points.The model is corroborated by an extensiveIsoëtes lacustrisL. data set from 17 Norwegian lakes, which included hydro‐electric lakes (hydrolakes) as well as non‐impacted lakes. The close fit between model prediction and the macrophyte's actual spatial performance is remarkable and encouraging from an impact assessment point o

ISSN:0020-9309    

DOI:10.1002/iroh.19880730202

出版商:Akademie Verlag, Berlin    

年代:1988

数据来源: WILEY

摘要:

AbstractDifferent features of the limnology of Tomahawk Lagoon, a shallow, hypertrophic New Zealand lake were studied for varying periods between 1964 and 1986. Surveys in 10 years revealed a strong positive correlation between the winter black swan population and the biomass of macrophytes which in turn in a shorter study was inversely related to the abundance of phytoplankton. A regression model was developed relating the winter maximum swan population to phytoplankton productivity in the previous summer. The model worked well for another very shallow lake, but less well for a third lake with a mean depth greater than the feeding reach of swans.No general mechanism could be established for suppression of phytoplankton when macrophytes were abundant, though the effect was large. Suppression of macrophytes in other years is attributed to shading by phytoplankton. The decline of one algal bloom was related to nitrogen deficiency followed by intense zooplankton grazing. Another was ended by the optical effects of a large flood‐borne silt inflow and flushing of phytoplankton. Empirical models relating chlorophyllato phosphorus or nitrogen, and zooplankton biomass to chlorophyllaor phosphorus do not work well for this lake, and the general problems of modelling shallow highly eutrophic lakes are discusse

ISSN:0020-9309    

DOI:10.1002/iroh.19880730203

出版商:Akademie Verlag, Berlin    

年代:1988

数据来源: WILEY

摘要:

AbstractIn the search for the causes of diatom assemblage distribution, a combination of two multivariate analyses has been used. Principal component analysis and canonical correlation analysis have allowed us to find suitable relationships between biological and physicochemical parameters. As a result, water salinity and pollution have appeared as the two main factors which determine diatom assemblage distribution. Reservoirs act as discruptors of the water characteristics, and have an improving effect in the two above factors, which leads to a different diatom community.

ISSN:0020-9309    

DOI:10.1002/iroh.19880730204

出版商:Akademie Verlag, Berlin    

年代:1988

数据来源: WILEY

摘要:

AbstractThe distribution of macrophytes and the biomass development during the summer was studied in the slightly acidified Lake Änketjärn in western Sweden. The submerged cyperidJuncus bulbosus, which has been reported to expand in acidifying lakes, covered almost 50% of the lake area. The most denseJuncusvegetation was found at 1.5 m on loose, highly organic sediment. BesidesJ. bulbosusthe vegetation was characterized by Nympheids,Carex rostrataandC. lasiocarpa(approximately equally important in the stands),Equisetum fluviatileandLobelia dortmanna, species which showed a quite distinct zonation with dept

ISSN:0020-9309    

DOI:10.1002/iroh.19880730205

出版商:Akademie Verlag, Berlin    

年代:1988

数据来源: WILEY

摘要:

Adenine Nucleotides and Phytoplanktonic Primary Production in Two Lakes in FranceThe adenine nucleotides concentrations and photosynthetic assimilation of phytoplankton were established during two annual sampling seasons for two lakes with different nutrients concentrations (Lakes Pavin and Aydat). Intensive photosynthetic assimilation of phytoplankton led to a limited but real evolution of the pool of adenine nucleotides towards forms less charged with high energy phosphate bond (ADP and AMP). This evolution is seen as a consequence of the ATP hydrolysis in the process of cell biosynthesis.

ISSN:0020-9309    

DOI:10.1002/iroh.19880730206

出版商:Akademie Verlag, Berlin    

年代:1988

数据来源: WILEY

摘要:

Changes in the Population Dynamics ofGammarus tigrinusSEXTON (Crustacea: Amphipoda) as Expression of Sublethal Effects by Reciprocal Interactions of Temperature and Cadmium Enriched FoodThe population dynamics ofGammarus tigrinusSEXTON were studied in a flow‐through system under semi‐natural conditions over a period of 9 months. Elevated temperatures and Cadmiumenriched food alter lifespan of generations, growth rate, number of individuals and time to reach maturity, even before elevated Cadmium concentrations can be detected in the animals. Reciprocal interactions of Cadmium intake via food and/or water can be modified by the experimental design, because it depends on the experimental animals, on the Cadmium concentration and on the temperature regime with constant or cyclic conditi

ISSN:0020-9309    

DOI:10.1002/iroh.19880730207

出版商:Akademie Verlag, Berlin    

年代:1988

数据来源: WILEY

摘要:

AbstractWANGERSKYand WANGERSKY'S(1980, 1981, 1983) Manna models on algal patchiness and competition are essentially stochastic models. Analysis of their phase‐spatial properties, however, reveals complementary, deterministic features: interspecific competition is relatively ineffective because of the high degree of compartmentalization of resource supply and consumption; the probability of consumption in a given place at a given time is largely independent of the rate of consumption in other place

ISSN:0020-9309    

DOI:10.1002/iroh.19880730208

出版商:Akademie Verlag, Berlin    

年代:1988

数据来源: WILEY

摘要:

AbstractThe number of species of caridean, brachyuran and anomuran decapods increases from high to low latitudes in both hemispheres. This is shown to be due mainly to changes in the abundance of small species. Possible explanations for these variations in abundance are discussed. The other infraorders of decapods are confined to mid and low latitudes.

ISSN:0020-9309    

DOI:10.1002/iroh.19880730209

出版商:Akademie Verlag, Berlin    

年代:1988

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19880730210

出版商:Akademie Verlag, Berlin    

年代:1988

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19880730212

出版商:Akademie Verlag, Berlin    

年代:1988

数据来源: WILEY