Bacca quo vadis: Regeneration niche differences among seven sympatric Vaccinium species on headlands of Newfoundland

On headlands in Newfoundland, four of the seven sympatric Vaccinium species cc-occur frequently at the quadrat level in tundra communities. We hypothe sized that differentiation at the regeneration niche level was a prerequisi te for the coexistence of these sympatric congeners. After a description an d quantification of parameters affecting whole berry and seed dispersal and those affecting seed germination, differentiation at these two levels of t he regeneration niches of the seven Vaccinia was investigated using numeric al clustering techniques. Differentiation patterns were similar in both the germination and the dispersal dendrograms; three species were most dissimi lar (viz. V. angustifolium, V. boreale and V. uliginosum), and the remainin g four were separated into single species groups at the 62% and 75% similar ity levels by the germination and dispersal dendrograms, respectively. Over all, patterns reflect divergence in dispersal mechanisms and germination ab ilities among the seven species, in support of the thesis that sympatric co ngeners have varied regeneration strategies. Differences in the germination success observed after testing natural dispersal units (e.g. seed from sea t and seed within whole berries) points to the need to conduct germination trials in ecologically relevant ways. This approach reveals how divergent r egeneration strategies are possible in species having similar, palatable ba ccate fruits (e.g. V. angustifolium and V: uliginosum) and highlights our l ack of insight into regeneration strategies of the groups. The cranberry se eds, despite germination success gauged by results from standard germinatio n protocols, exhibit no germination in trials conducted with the natural di spersal unit, the whole berry.