The Relationship Between Standing Crop in Sedge Meadows and Summer Temperature

1974 ◽  
Vol 62 (2) ◽  
pp. 487 ◽  
Author(s):  
Eville Gorham
Climate ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 126
Author(s):  
Moon Taveirne ◽  
Laura Ekemar ◽  
Berta González Sánchez ◽  
Josefine Axelsson ◽  
Qiong Zhang

Glacier mass balance is heavily influenced by climate, with responses of individual glaciers to various climate parameters varying greatly. In northern Sweden, Rabots Glaciär’s mass balance has decreased since it started being monitored in 1982. To relate Rabots Glaciär’s mass balance to changes in climate, the sensitivity to a range of parameters is computed. Through linear regression of mass balance with temperature, precipitation, humidity, wind speed and incoming radiation the climate sensitivity is established and projections for future summer mass balance are made. Summer mass balance is primarily sensitive to temperature at −0.31 m w.e. per °C change, while winter mass balance is mainly sensitive to precipitation at 0.94 m w.e. per % change. An estimate using summer temperature sensitivity projects a dramatic decrease in summer mass balance to −3.89 m w.e. for the 2091–2100 period under climate scenario RCP8.5. With large increases in temperature anticipated for the next century, more complex modelling studies of the relationship between climate and glacier mass balance is key to understanding the future development of Rabots Glaciär.


1989 ◽  
Vol 67 (6) ◽  
pp. 1609-1617 ◽  
Author(s):  
Irene C. Wisheu ◽  
Paul A. Keddy

The applicability of a model describing the relationship between species richness and standing crop and litter was tested in each of four lakeshore habitats within Wilsons Lake, Nova Scotia. The shapes of the curves describing the species richness – standing crop relationships in the four habitats were significantly different. Standing crop and litter values were positively correlated with measured indices of soil fertility (loss on ignition and silt and clay content) and negatively correlated with disturbance as determined by the location of the shrub zone and overwinter damage to wooden pegs. Sites with high standing crop had a lower proportion of biomass composed of evergreen and isoetid species than the proportion in sites where standing crop was low. The among habitat variation observed in this study, and the variation in published values of standing crop values yielding maximum species richness, limit the accuracy of predictions from this model. Steps for refinement are suggested.


1974 ◽  
Vol 52 (8) ◽  
pp. 1947-1972
Author(s):  
K. A. Kershaw

The relationship of the sedge meadows lying between raised-beach ridges at the Pen Island site in NW Ontario is described using principal-component analysis. Three major trends are detected following moss hummock formation, depth of water table, and pH. The data also show a progressive sequence from the young meadows with few hummocks and high pH to the older meadows where marked hummock formation has occurred and where the overall pH is lower. Six noda have subsequently been extracted as the central plant associations characteristic of the area.


1983 ◽  
Vol 61 (6) ◽  
pp. 1207-1213 ◽  
Author(s):  
Candace Galen ◽  
Peter G. Kevan

Plants of Polemonium viscosum have either sweet- or skunky-scented flowers. In this paper we examine the relationship between floral scent and visitation by the principal pollinator, Bombus kirbyellus. Field observations of nectar collecting bumblebee queens showed that bees visited plants with sweet-scented flowers significantly more often than those with skunky scent and tended to visit more flowers per inflorescence of sweet than of skunky scent. These observations agree with results from preference tests with captive bees foraging under controlled conditions on enclosed arrays of the two scent morphs. In experimental trials, bee orientation on the initial visit to the array and on visits between plants within the array favored sweet-scented inflorescences. Bees moved on the grid in such a way that skunky-scented nearest neighbors were undervisited, while sweet-scented flowers were visited more often than expected. In one set of trials, sucrose solution was added to flowers in order to compensate for natural standing crop variation. This treatment did not reduce bumblebee preference for the sweet scent morph nor alter the movement patterns of bees on the grid. Hence, in this system, floral visitation pattern appears to be influenced more strongly by scent than by nectar level.


Author(s):  
Giulia Zacchello ◽  
Svenja Bomers ◽  
Cecilia Böhme ◽  
Froukje Postma ◽  
Jon Agren

The timing of germination is a key life-history trait in plants, which is strongly affected by the strength of seed dormancy. Continental-wide variation in seed dormancy has been related to differences in climate and the timing of conditions suitable for seedling establishment. However, for predictions of adaptive potential and consequences of climatic change, information is needed regarding the extent to which seed dormancy varies within climatic regions and the factors driving such variation We planted 17 Italian and 28 Fennoscandian populations of Arabidopsis thaliana in the greenhouse and at two field sites in Italy and Sweden. To identify possible drivers of among-population variation in seed dormancy, we examined the relationship between seed dormancy and climate at the sites where populations were originally sampled. Seed dormancy was on average stronger in the Italian compared to the Fennoscandian populations, but also varied widely within both regions. Estimates of seed dormancy in the three maternal environments were positively correlated, but seeds had on average stronger dormancy when produced in the greenhouse than at the two field sites. Among Fennoscandian populations, seed dormancy tended to increase with increasing summer temperature and decreasing precipitation at the site of origin. In the smaller sample of Italian populations, no significant association was detected between mean seed dormancy and climate at the site of origin. The correlation between seed dormancy and climatic factors in Fennoscandia suggests that at least some of the among-population variation is adaptive and that climate change will affect selection on this trait.


1984 ◽  
Vol 62 (11) ◽  
pp. 2370-2374 ◽  
Author(s):  
B. Freedman

For 765 stems of plants that spanned eight orders of magnitude of aboveground dry weight (DWT) and three orders of magnitude of stem diameter (DIAM), a plot of log10DWT vs. log10DIAM was highly linear, with an r2 value of 0.997 and a slope of 2.6. The value of this slope may be related to the minimum diameters that are required by upright plants to withstand the horizontal forces of drag that arc exerted at high wind speeds. The multispecies biomass regression gave a similar estimate of the standing crop of a conifer stand to that computed using species- and site-specific tree regressions, indicating the possible general use of such equations in estimating the standing crops of terrestrial ecosystems.


Vegetatio ◽  
1988 ◽  
Vol 79 (1-2) ◽  
pp. 99-106 ◽  
Author(s):  
Dwayne R. J. Moore ◽  
Paul A. Keddy

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