CAS Workshop on Ecosystem Succession Theory and Practice of Ecological Restoration

鼎湖山退化马尾松林恢复演替进程中群落的有机质和植物多样性

(¹中国科学院华南植物研究所, 广东肇庆鼎湖山树木园 526070；²Winrock International, 1621 N. Kent St., Suite 1200, Arlington, VA 22209, USA)

摘要：通过处理（根据当地习惯收割凋落物和林下层）和保护（无任何人为干扰）样地的试验，研究了鼎湖山生物圈保护区退化马尾松 (Pinus massoniana) 林10年来的恢复演替过程中，群落的有机质和植物多样性及其对人为干扰的响应。结果表明，1990年至1995年，五年时间里由于人为干扰活动而直接从处理样地取走的有机质总量为21.21 t.hm^-2。在同一时期，保护样地林下层植物种数减少11种（20个10 × 10 m²样方，从1990年的41种减至1995年的30种），但处理样地林下层植物种数基本上维持在原来的水平，仅减少2种（20个10 × 10 m²样方，从1990年的36种减至1995年的34种）。1990年至2000年，保护样地在停止人为干扰后林下层生物量以34%-53%的年增长速率从2.23 t.hm^-2逐年提高，至1995年达到高峰（11.10 t.hm^-2），之后因与乔木层马尾松生长竞争原因而下降至9.44 t.hm^-2。地表凋落物主要来源于林下层植物且地表凋落物量变化与林下层生物量变化相类似。在整个试验过程中，保护样地和处理样地乔木层马尾松个体总数均随时间而减少，保护样地减少4.3％（20个10 × 10 m²样方，从1990年的93株减至2000年的89株），处理样地减少9.6%（20个10 × 10 m²样方，从1990年的115株减至2000年的104株）。但它们的总生物量则随时间而增加且其增加的速率随时间和样地不同而异。1990年至1995年，保护样地总生物量增加了38.3%（从 81.2 t.hm^-2 增至 112.3 t.hm^-2），较处理样地（收获林下层和凋落物）总生物量增加的百分比高4.7（33.6%，从98.8 t.hm^-2 增至 132.0 t.hm^-2）。然而，1995年至2000年，保护样地总生物量增加的百分比为29.1%（33.6%，从112.3 t.hm^-2 增至 145.0 t.hm^-2），较处理样地（1995-2000年也停止人为干扰）增加的百分比却低3.2（32.3%，从132.0 t.hm^-2 增至174.7 t.hm^-2）。可见，1990年至1995年，人为干扰活动使处理样地马尾松林乔木层生物量年平均增长量降低约1.6个百分点，即年平均约减少1.58 t.hm^-2，此量相当于每年通过林下层和凋落物收割活动而直接从林地中取走的有机质总量的34%-46%。

关键词：人为干扰；退化；恢复；演替；有机质；植物多样性；马尾松；鼎湖山

Organic matter and plant diversity of a restoring degraded pine forest in subtropical China

(¹South China Institute of Botany, Academia Sinica, Dinghu, Zhaoqing, Guangdong 526070, China; ²Winrock International, 1621 N. Kent St., Suite 1200, Arlington, VA 22209, USA)

Abstract: Dynamics of organic matter and of plant diversity in a restoring degraded pine (Pinus massoniana) forest in subtropical China was studied, in an experiment comparing harvesting (according to local practice) and control (no harvest) plots over a ten year period of 1990 to 2000. In addition, responses of organic matter and of plant diversity to human impacts in this forest was also discussed in this paper. In treatment plots, the total organic matter removed by this harvesting practice during 1990 to 1995 was 21.21 t.hm^-2. In control plots, after stopping harvesting practice the understory biomass increased at an annual rate of 34 to 53 percent during the first 5 years from 2.23 t.hm^-2 to 11.10 t.hm^-2, followed by a slight decline over the remaining 5 years from 11.10 t.hm^-2 to 9.44 t.hm^-2. During the same period, species number of understory plant decreased by 11 species in control plots from 41 to 30 in an area of 4000 m², but in treatment plots remained more or less stable, only 2 species lost from 36 to 34. The standing stock of forest floor litter was mainly composed of understory plants and reflected the pattern of understory biomass production. The number of individuals of pine trees decreased by 4.3 percent in control plots from 93 to 89 in an area of 4000 m², and decreased by 9.6 percent in treatment plots from 115 to 104. However, the biomass of pine trees in both treatment and control plots increased over time. The biomass increment of pine trees varied depending on plots and on years. From 1990 to 1995, the biomass increased by 38.3% (from 81.2 t.hm^-2 to 112.3 t.hm^-2) in control plots and was higher than that in treatment plots (33.6%), which increased from 98.8 t.hm^-2 to 132.0 t.hm^-2. From 1995 to 2000, the biomass in control plots increased by 29.1 percent (from 112.3 t.hm^-2 to 145.0 t.hm^-2) and was lower than that in treatment plots (32.2%, harvesting was also stopped during 1995-2000), which increased from 132.0 t.hm^-2 to 174.7 t.hm^-2. Thus, from 1990 to 1995, harvesting practice resulted in about 1.6 percent of biomass decrease each year in treatment plots, which was about 1.58 t.hm^-2.a^-1 and accounted for 34 to 46 percent of total organic matter removed directly each year by this harvesting practice.

Key words: human impact; degradation; restoration; succession; organic matter; plant diversity; Pinus massoniana; Dinghushan

基金项目：国家自然科学基金项目（30270283）、中国科学院知识创新工程领域前沿项目、中国科学院华南植物研究所所长基金项目和广东省自然科学基金项目（021524）资助。张佑昌、莫定升等同志参加部分野外工作，在此一并致谢。