Jh. Ges, Naturkde. Württemberg | 152. Jahrgang l Stuttgart, 15. Dezember 1996 |
Ausgezeichnet mit dem „Walter-Schall-Preis“ 1995 der Gesellschaft für
Naturkunde in Württemberg
Unterschiede der Regenerationsnische endozoochorer
Arten
Jon JOHANNES KOLLMANN, Zürich
Mit 1 Abbildung und 6 Tabellen
1. Summary
This study deals with the dispersal ecology of 18 Central European fleshy-fruited
species (2 trees, 11 shrubs, 5 woody vines and herbs). Several processes of dispersal
which determine the regeneration niche of these species were investigated over a
two-year period in SW-Germany: transport of seed by birds, seed predation by rodents,
seed bank, germination and establishment.
Although dispersal phenology of most species was staggered, broad overlap
among the species occurred due to fruiting periods of 3-5 months. Seed rain of
fleshy-fruited species was observed throughout the year with highest records from
August to November and minimum values in May. Fruit on offer was used more or
less as available, but some species were apparently preferred by birds leading to a
more effective dispersal of seeds (Cornus sanguinea, Hedera helix, Sambucus nigra).
Choice experiments in mature scrub on seed predation by mice (Apodemus sylvaticus,
A. flavicollis, Clethrionomys glareolus) revealed preferences for large seeds
(Prunus spinosa) compared with small ones (Sambucus nigra); mechanically protected
seeds (Crataegus laevigata) und poisonous species were also less attractive (Euonymus
europaeus). The ranking of the species in the choice experiment was supported
by results on the percentage of destroyed seeds in soil samples. Small-seeded
species were most common in the soil seed bank (Rubus fruticosus agg., Sambucus
nigra, Solanum dulcamara), whereas large-seeded species were never found (Prumnus
avium, P. spinosa, Viburnum lantana). Large differences in species composition and
frequency were observed between seed rain and seed bank. Dormancy and germinability
were also appreciably different among species, and this was also true for germination
and establishment of seedlings in the field.
The fleshy-fruited species investigated have the same mode of dispersal by passerine
birds, most of them have a similar growth form (the shrub species) and coexist
in the same habitat. Based on the principle of competitive exclusion one
would postulate ecological separation of the species to maintain this coexistence.
The observed differences in the regeneration niche contribute to the separation of
the species and can explain some differences in their abundance.
2. Zusammenfassung
Unterschiede der Ausbreitungsökologie endozoochorer Arten wurden über zwei
Jahre in SW-Deutschland untersucht, wobei sich die Untersuchungen nicht auf die
Ih. Ges. Naturkde. Württ. 152 (1996)
