SEARCH

SEARCH BY CITATION

Keywords:

  • Big Thicket;
  • Death rate;
  • Demographic variability;
  • Disturbance;
  • Light;
  • Permanent plot;
  • Recruitment rate;
  • Regeneration;
  • Understorey
  • Correll & Johnston (1970) except for basket oak;
  • which is recognized as Quercus michauxii Nutt. and cherrybark oak;
  • to which the name Quercus falcata Michx. var. pagodaefolia Ell. is applied

Abstract. How much temporal variation in recruitment, mortality and change in size class occurs in the sapling layer of mature temperate forests in the absence of large-scale exogenous disturbance? Using 15 years of data from a flood-plain forest in Big Thicket National Preserve, we found that year-to-year variation in demographic parameters was greater than we originally expected. Death rates were generally more variable than recruitment rates, and were much more variable for large saplings than for small ones. Small saplings of the 10 most common species had at least one year when they experienced two to eight times their long-term mean recruitment and death rates. Large saplings had at least one year when they experienced three to 10 times their long-term mean death rates and at least one year with two to seven times the long-term mean recruitment rate. Temporal patterns in sapling death rates were related to flooding patterns, while temporal patterns in recruitment were related to the Palmer Drought Severity Index, an indicator of drought severity and soil moisture availability. We also identified apparently synchronous patterns of demographic response among less flood-tolerant species which differed from the responses of more flood-tolerant species. We demonstrated the effects of both climatic variation and light variation in affecting stand-wide sapling demographics in a forest where canopy gaps are important for regeneration, and where chronic understorey disturbance favours growth over survivorship as a sapling strategy.