Laserfiche WebLink
<br />11 <br />~~ <br />in response pattern, using the term `nutrient-rich' to describe the <br />pattern opposite to that which he found. <br />"This suggests that there may be qualitative differences <br />between secondary succession on a poor soil and that on <br />a rich soil. After an initial period of transient <br />dynamics, successional dynamics on a poor soil may depend <br />mainly on the slow displacement of one species by another <br />as nutrients accumulate, much as has been reported for <br />several primary successions. In contrast, for secondary <br />successions on rich soils, it is likely that colonization <br />rates and maximal growth rates could be major <br />determinants of the successional sequence, because rapid <br />colonization and rapid growth could allow species to <br />attain periods of transient dominance during the time <br />required for more slowly growing species to arrive in a <br />habitat and attain the biomass needed to displace them." <br />(Tilman 1987:213) <br />We feel that our results indicate the pattern suggested by Tilman <br />(1987) for secondary succession on rich soils, but that such a <br />pattern is characteristic not only of nutrient-rich soils but also <br />of most soils with intermediate N levels since our soils were not <br />particularly high in soil N (Table 2). <br />We also feel that the dominance shift from rapidly growing <br />annuals to slower-growing herbaceous perennials, at least on our <br />site, is not caused by a simple competitive displacement of the <br />