Ecological and Evolutionary Interactions between Reproduction of Beech Fagus silvatica and Seed Eating Animals

Publication Type:Journal Article
Year of Publication:1985
Authors:Nilsson, SG
Date Published:1985
ISBN Number:00301299
Keywords:Corvidae, Fringilla, Fringilla montifringilla, Fringillidae, Garrulus, Garrulus glandarius
Abstract:Patterns of beech seed production, seedling establishment, sapling densities, and sapling mortalities were studied in several forests dominated by different tree species. In a beech dominated forest, seed production and seedling establishment were negatively correlated in space. Seedlings became established mainly where there was least canopy coverage of mature beeches. Vertebrate seed predation was low in a year with an abundant seed crop but relatively higher in a year with a moderate crop. In the latter year predispersal insect seed predation was about 39%. I suggest that mast seeding in trees is more effective in reducing seed predation by insects than by vertebrates. Data in the literature support this prediction. The mortality rates of saplings and small trees of beech and oak were higher below mature trees of their own species than below trees of other species. In a spruce forest without mature oaks and beeches there was a high density and low mortality of saplings and small trees of the latter two species. Evidence suggests that the jay Garrulus glandarius had dug down the acorns and beech nuts. The jay appears to store beech mast only when no acorns are available. This situation occurred in the study area in 3 out of 13 years. The jay seems to be one of the species that could have dispersed the beech northwards during the Holocene. Several features of beech mast (morphology, chemistry, time of availability) seem to have evolved as adaptations to vertebrate (probably bird) dispersal. Apart from the brambling, a finch that does not disperse the beech, no bird species appear to be especially adapted to feed on beech mst. However, when available, mast profoundly affects the population dynamics of several bird species.
Short Title:Oikos
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