Recruitment of fleshy-fruited species under different shrub species: Control by under-canopy environment
Kollmann, Johannes ; Grubb, Peter J.
In: Ecological Research, 1999, vol. 14, no. 1, p. 9-21
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- Seedling densities and the mortality of fleshy-fruited species under 10 European tall-shrub species and the tree Sorbus aria were analyzed in 10-year-old experimental scrub for one growing season. The mean total densities of seedlings of 18 fleshy-fruited species differed under the different ‘hosts', being highest under Crataegus monogyna, Viburnum opulus and Rosa canina (24-20 m−2); intermediate under Sorbus aria, Rhamnus catharticus, Cornus sanguinea, Ligustrum vulgare and Juniperus communis (17-12 m−2); and lowest under Euonymus europaeus, Viburnum lantana and Prunus spinosa (10-9 m−2). This ranking was similar for the 11 planted species and for nine bird-dispersed, non-planted species which invaded the site, notably Hedera helix and Solanum dulcamara. Within the experimental scrub as a whole mortality of seedlings differed significantly among species, being highest in those with the smallest number of recruits. Mortality ranged from 94% and 89% for Solanum dulcamara and Viburnum opulus to 26% for Hedera helix and Ligustrum vulgare. The mean mortality across all species of seedlings did not differ significantly between host species, although it was slightly higher under Juniperus and Cornus (56%, 53%) and lower under Viburnum lantana and Rhamnus (42%, 41%). In four species, the mortality of seedlings was significantly higher under conspecific adults. Mean topsoil water content after a dry spell was negatively correlated with the diffuse site factor (DSF). The mean density of accumulated seedlings of the most abundant seedling species (Hedera) was positively correlated with the topsoil water content. Densities of other species showed no strong correlations with either topsoil water content or DSF. The probable factors controlling recruitment are discussed