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Journal of Ecology (2004) 92, 505–511 [ABSTRACT FROM AUTHOR]

Characterizes the Potentilla rupestris, a biological flora of the British Isles. Geographical and altitudinal distribution; Habitat; Communities; Response to biotic factors; Response to environment; Phenology; Floral and seed characters; Herbivory and disease; History.

Tests the hypothesis that physiological integration is most advantageous in a heterogenous habitat using the clonal species Potentilla simplex. Comparison of the performance of intact and disconnected clones growing in artificial habitat types differing in nutrient status; Effect of increasing patchiness of the land on the benefits of resources sharing.

Tests the hypothesis that clonal plants may benefit from their ability to share resources between connected ramets experiencing contrasting levels of resource supply. Use of clones of Potentilla reptans and P. Anserina; Benefits of integration to the two species; Benefits due to mutual support of connected clone-parts growing in shaded and unshaded patches.

Examines the herb Potentilla simplex to determine whether newly-produced ramets are continuously dependent on other parts of the clone and whether clones consist of completely interdependent primary stolons. Significant difference in survivorship and growth of the severed stolon segments across treatments; Independence of individual primary stolons of P. simplex.

(1) Potentilla anserina is a stoloniferous plant in which the daughter ramets become independent during their first year of life Ramets of P. anserina behave in four different ways They may be inactive flowering only, stolon-producing only, or both flowering and stolon-producing. The relationships between ramet size and type of behaviour, and transition probabilities between behavioural states during four successive years were derived from a field study of P. anserina on a Baltic seashore meadow. (2) Ramet behaviour and mortality were significantly size related. The results suggest that flowers and stolons are initiated when the physiological condition of ramets has reached some internal resource threshold. The size relationships form the basis for inferring phenotypically-expressed costs of different behaviour patterns from transition probabilities. (3) Several transition probabilities varied significantly between years, but some patterns of variation emerged. Inactive ramets which changed behaviour usually became 'flowering only' next year. There were no indications that reproduction per se incurred any costs for ramets. Flowering ramets had the greatest probability of flowering the following year In contrast, stolon production had negative consequences both for survivorship and for future reproduction of ramets. (4) Simulations of a matrix model yielded different population growth rates (1.05, 0.91 and 0.68) during the study years. Simulated stable state distributions differed from the observed ones which also vaned significantly between years Population growth rate was most sensitive to alterations in transitions from inactive to stoloniferous ramets, but these transitions are not common in the real population. Elasticity analysis revealed that growth rate instead depends mainly on survivorship of inactive ramets, and transitions from ramets which were flowering only. In addition, population growth rate depends much more on vegetative propagation than on... [ABSTRACT FROM AUTHOR]

(1) Changes in species composition, live standing crop and plant litter have been measured in a salt marsh at La Pérouse Bay, Manitoba in the presence of a grazer (the lesser snow goose, Anser caerulescens caerulescens) and when the grazer is excluded. (2) The composition of vegetation in exclosures (5 m ⊗ 5 m) changed rapidly. After five years sixteen species of higher plants were present in the oldest exclosure compared with six species in an adjacent (control) grazed area. Dicotyledons, such as Potentilla egedii and Plantago maritime, increased in frequency in the absence of grazing, and Carex subspathacea replaced Puccinellia phryganodes as the dominant graminoid. (3) New species, which appeared in the exclosure, were present in ungrazed areas elsewhere in the marsh. However, the frequency of these species in the exclosures was different from that in ungrazed areas. (4) The grazer is a generalist in its selection of forage species. The removal of geese leads to extensive clonal growth of species, such as Potentilla egedii, which are unable to tolerate heavy grazing and trampling, unlike Carex and Puccinellia. (5) Within a season the standing crop of vegetation was highest in exclosures erected one or two years previously. Litter accumulated in exclosures. The ratio of maximum standing crop to litter fell from »4 : 1 to «2 :1 as communities aged in the absence of grazing. (6) Cessation of grazing leads to rapid changes in the structure and composition of the community. The vegetation within an exclosure was poorly grazed when the fence was removed after two years. [ABSTRACT FROM AUTHOR]

The article offers information on the plant Potentilla fruticosa L. It is described as a deciduous, branched shrub, the branches are white, pubescent in their first year, becoming brown and glabrous in their second, with the bark beginning to flake off in the second and third years. Both erect and prostrate branches are present in the mature plant, the latter being able to root adventitiously, according to the author. It states that population studies and cultivation experiments have shown that the English species of the plant have longer apical leaflets than the Irish.