SREL Reprint #2285
Soil resource heterogeneity effects on early succession
Beverly Collins and Gary Wein
Heterogeneous soil resources may cause vegetation heterogeneity on abandoned fields and
grasslands. We tested effects of resource enrichment and heterogeneity at scales from a
single plant to small plot community on vegetation composition and rate of early
succession on two fields. Enriched plots of three heterogeneity scales were established by
fertilizing alternate trenched subplots. Unenriched plots were established with trenched
but unfertilized subplots as controls for trenching heterogeneity. Vegetation was censused
every other year for six years. We asked if nutrient enrichment or heterogeneity affects
vegetation diversity or rate of succession, and if resource effects change over time.
Species richness was lower in fertilized plots on both fields. Species turnover reflected
an early gain of species on one field and loss on the other. Turnover differed between
enriched and unenriched plots, but not over heterogeneity scales. Plot enrichment, but not
heterogeneity, influenced initial abundance and establishment of a dominant, Ambroslo
trifido, on one field and the later dominant Solidogo oltissimo on the other
field. Ambroslo responses slowed, and Solidogo responses increased,
succession on enriched plots. There was a weak trend of increasing strength of soil
resource effects over time in both fields. We found no strong evidence that vegetation
tracks soil resource heterogeneity of the patch sizes, arrangement, and contrast tested.
However, differential growth of the dominant species and richness of minor taxa between
enriched and unenriched plots created vegetation heterogeneity on both fields through
early succession.
SREL Reprint #2285
Collins, B. and G. Wein. 1998. Soil resource heterogeneity effects on early succession. OIKOS 82:238-245.
