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The spatial pattern of recruitment and seedling survival was studied in an ant-dispersed sedge (Carex pilulifera L.) in a forest clearing in Denmark. Seedlings were generally more aggregated than juvenile and adult plants. Recruitment distances were skewed towards larger values. While 72% plants of presumably ant-dispersed origin survived for 5 years, only 13% auto-dispersed plants were still alive, predominantly as persistent seedlings. The survivorship showed a negative exponential decrease (Deevey type II) with an expected half-life of 17 months for auto-, and 10 years for ant-dispersed plants. Growth-rate and fecundity were significantly larger for ant-dispersed plants than for auto-dispersed plants. Computer simulation was used to test three different dispersal models and two mortality types on the recruitment pattern observed in the field. The simulations confirmed the importance of ant dispersal for recruitment, but gave no conclusive evidence for evaluating recruitment from ant-nests. High mortality levels, comparable to observed predation levels, were needed to simulate field conditions. Density-dependent mortality proved more powerful than distance-dependent mortality in the simulations. Results are discussed in the context of current hypotheses of seed dispersal. While the directed dispersal hypothesis could not be rejected, results were generally more favourable to the escape hypothesis.

The timing of seed fall was studied in a guild of seven ant-dispersed forest herbs in NE-Zealand, Denmark. It is demonstrated, that the seed fall curves of Carex pilulifera, Melica uniflora and Luzula multiflora are remarkably different, representing logistic, hyperbolic, and linear relationships, respectively. The influence of environmental factors, and the significance to dispersal and predation, is discussed. It is suggested, that the three types of curves represent different strategies of seed fall. Simple, and explanded models of seed fall rate indicate that the density of seeds available to ants was more than 20 times greater for C. pilulifera than for M. uniflora. The observed phenological overlap of dispersal periods in the guild conformed to random expectations. Thus, the competition hypothesis was rejected, as there were no indications of a shift in phenology resulting from interspecific competition for the dispersal vector.

Seed predation of the myrmecochorous Carex pilulifera (Cyperaceae) was studied in a wood land area in NE Zealand, Denmark. Experiments demonstrated that predation by mice, Sylvaemus flavicollis, and ground beetles, Harpalus fuliginosus, reduced the seed pool of a C. pilulifera population by approx. 21% and 65%, respectively. The use of exclosure experiments in studies of predation is discussed and criticized. Evidence indicated only a small degree of competitive interaction between the two predator species and between predators and seed-dispersing ants. The possible evolutionary consequences of predation for seed set, dispersal, and phenology are discussed. Although the study indicated that the number of seeds surviving in soil decreased exponentially with time, the presence of a persistent seed bank in C. pilulifera was demonstrated.

Seed dispersal of the myrmecochorous Carex pilulifera (Cyperaceae) was studied in a wood land area in NE Zealand, Denmark. Nearly all seeds fell within a distance of 40 cm from the center of the parental plants. Ant dispersal of seeds was predominantly by Myrmica ruginodis. Data on foraging activity and seed transport into and out of the ant nest is presented. The resulting dispersal distances were between 0 and 1.4 m from Carex plants. It is suggested that the secondary relocation of seeds from the ant nest is of primary importance to the recruitment of seedlings. Formicarium experiments confirmed the myrmecochorous status of C. pilulifera, and demonstrated the function of the elaiosome and the attraction of fresh diaspores. Data on removal rates and ant activity is also presented and discussed. The study indicated that for a period the ant colony was nourished almost exclusively by C. pilulifera diaspores in the field. Information concerning M. ruginodis is presented, and the ant-seed mutualism is discussed.