Abstract:

Aims Current knowledge about tree distributions in species-rich communities is almost exclusively derived from tropical rain forests. The Natural Reserve of Mao’ershan Mountain has complicated landforms and high biodiversity, including relic plants. Our objective was to analyze distribution patterns and regeneration conditions of two relic plants to find survival conditions and coexistence mechanisms.
Methods Using a stem map of two 1 hm² permanent plots at different altitudes in the Mao’ershan Mountain Natural Reserve, we analyzed the distribution pattern, regeneration condition and size distribution of two relic plants: Tsuga chinensis var. tchekiangensis and Fagus longipetiolata. Spatial patterns were analyzed by R program. Confidence intervals were generated from 999 Monte Carlo simulations under the null hypothesis of complete spatial randomness.
Important findings Regeneration conditions and size distribution of both species determined no new individuals had appeared in six years. Diameter at breast height (DBH) classes for 2002 and 2008 were inverse J type for F. longipetiolata and normal distribution for T. chinensis var. tchekiangensis. Both species have regeneration problems. There were fewer individuals of T. chinensis than F. longipetiolata. Continuously sampling data to analyze spatial point pattern using the relative neighborhood density showed that both species had different distribution patterns at different scales. Fagus longipetiolata were significantly aggregated at scales <11 m, as did T. chinensis at scales from 2 to 20 m. Fagus longipetiolata was widely distributed in its plot, while T. chinensis was distributed in the southwest of the plot. Integrative measures should be adopted to protect both relic species from regeneration difficulties, such as local protection, artificially aided regeneration and ex-situ conservation to increase their populations and enlarge their areas of distribution.

Key words: Fagus longipetiolata, point pattern, regeneration, relative neighborhood density, relic plants, Tsuga chinensis var. tchekiangensis