植物竞争对3种移植树苗生长的影响

doi:10.17521/cjpe.2005.0096

摘要/Abstract

摘要：

在植物幼苗生长过程中,总是受到包括地下根竞争在内的各种竞争影响。植物间的竞争主要同有效光辐射、水分和各种营养相关。当外来植物侵入森林群落时,可能受到群落中其它植物竞争的影响。该文通过移植尾叶桉(Eucalyptus urophylla)、大叶相思(Acacia auriculaeformis)两种外来种和本地种荷木(Schima superba)幼苗,挖沟排除根竞争和砍树创造林窗来排除地上竞争的野外实验,研究植物竞争对幼苗生长的影响。有根竞争时,荷木、尾叶桉和大叶相思幼苗的生物量和净初级生产力均小于没有根竞争时,可见地下根竞争对3种幼苗生长有抑制性影响。尾叶桉、大叶相思和荷木3种幼苗受到的总竞争强度分别是0.357 9、0.338 3和0.198 9,受到的地下根竞争强度则分别是0.104 3、0.053 04和0.118 8,受到的地上竞争强度则分别是0.285 1、0.277 0和0.090 85。尾叶桉和大叶相思两种幼苗受到的总竞争强度间的差异不显著,但都显著大于荷木;3种幼苗受到的地上竞争强度间的差异同总竞争强度情况相似;尾叶桉和荷木两种幼苗受到的地下根竞争强度间的差异不显著,但都显著大于大叶相思。地上竞争对阳性树种尾叶桉和大叶相思两种幼苗的生长影响大,而地下根竞争则对耐阴性强的荷木幼苗影响大。尾叶桉和大叶相思两种外来种幼苗受到的总竞争强度均大于本地种荷木幼苗,这反映了这两种外来树种侵入次生林这样的群落受到竞争影响大。

关键词: 竞争强度, 生物量, 净初级生产力, 植物外来种

Abstract:

Juvenile plants usually compete with the established vegetation within a community. Competition among plants takes place both aboveground and belowground. Aboveground competition primarily involves a single resource, light. In contrast to aboveground competition, plants compete for a broad range of soil resources, including water and many essential mineral nutrients that differ in molecular size, valence, oxidation state, and mobility within the soil. Of particular interest is the intensity of competition by invasive exotic plants and how this varies among species. We used a field experiment to measure the intensity of competition on juvenile trees in a secondary forest community with infertile soil on an island in South China. We separated competition into above- and belowground components in the field. We reduced aboveground competition by felling large trees to create a treefall gap and removed belowground competition by trenching. We created three neighborhood treatments: roots of neighbors only, shoots of neighbors only and no neighbors. Seedlings of three tree species were transplanted into the understory with and without trenches cut around plots (with roots and shoots of neighbors and with shoots of neighbors only), and single treefall gap area with and without trenches cut around plots (with roots of neighbors only and with no neighbors). The species used included two exotic species, Eucalyptus urophylla and Acacia auriculaeformis, and one native species, Schima superba. We measured the biomass, net primary productivity (NPP), and total competitive intensity in above- and belowground components over a two-year period.
The biomass and NPP in the plots without root competition were greater than those in the plots with root competition. Comparisons among the three species of seedlings showed that the intensity of total competition was greater for E. urophylla and A. auriculaeformis and lower for S. superba. Difference in the intensity of aboveground competition among the three tree species showed the same pattern as that of intensity of total competition. However, the intensity of belowground competition was the greatest for S. superba and the lowest for A. auriculiformis. Results based on the average of the three species showed that seedlings of the exotic trees, such as E. urophylla, A. auriculiformis, were also influenced by competition with established vegetation within the community during the invasion process. The intensity of total competition on the two exotic species, E. urophylla and A. auriculaeformis, were significantly greater than on the native species, S. superba. These results suggest that competition might pose a greater impact on the two exotic species when they invade a secondary forest community with a complex structure.

Key words: Intensity of competition, Biomass, Net primary productivity, Exotic plants

向言词, 彭少麟, 彭秀花, 蔡锡安, 饶兴权. 植物竞争对3种移植树苗生长的影响. 植物生态学报, 2005, 29(5): 724-729. DOI: 10.17521/cjpe.2005.0096

XIANG Yan-Ci, PENG Shao-Lin, PENG Xiu-Hua, CAI Xi-An, RAO Xing-Quan. MEASURES OF PLANT COMPETITION AMONG THREE SPECIES OF TRANSPLANTED TREE SEEDLINGS. Chinese Journal of Plant Ecology, 2005, 29(5): 724-729. DOI: 10.17521/cjpe.2005.0096

导出引用管理器 EndNote|Ris|BibTeX

链接本文: https://www.plant-ecology.com/CN/10.17521/cjpe.2005.0096

https://www.plant-ecology.com/CN/Y2005/V29/I5/724

图/表 8

图1 林窗中竞争对幼苗生物量的影响 E: 尾叶桉Eucalyptus urophylla A: 大叶相思Acacia auriculaeformis S: 荷木Schima superba ■: 无地下根竞争No belowground competition □: 地下根竞争 Belowground competition

Fig.1 Impacts of competition on the biomass of seedlings in gap

图2 乔木层下竞争对幼苗生物量的影响 E, A, S, ■, □: 同图1 See Fig.1

Fig.2 Impacts of competition on the biomass of seedlings under the canopy layer

图3 林窗中竞争对幼苗净初级生产力的影响 E, A, S, ■, □: 同图1 See Fig.1

Fig.3 Impacts of competition on the net primary productivity (NPP)of seedlings in gap

图4 乔木层下竞争对幼苗净初级生产力的影响 E, A, S, ■, □: 同图1 See Fig.1

Fig.4 Impacts of competition on the net primary productivity (NPP) of seedlings under the canopy layer

图5 幼苗受到的总竞争强度 E, A, S: 同图1 See Fig.1

Fig.5 Intensity of total competition on seedlings

图6 幼苗受到的地下竞争强度 E, A, S: 同图1 See Fig.1

Fig.6 Intensity of belowground competition on seedlings

图7 幼苗受到的地上竞争强度 E, A, S: 同图1 See Fig.1

Fig.7 Intensity of aboveground competition on seedlings

图8 幼苗受到的地下竞争强度和地上竞争强度的对比 ■:地下竞争 Belowground competition □:地上竞争 Aboveground competition E, A, S: 同图1 See Fig.1

Fig.8 Comparison between intensity of below- and aboveground competition on seedlings

参考文献 16

[1]	Callaway RM, Aschehoug ET (2000). Invasive plants versus their new and old neighbors: a mechanism for exotic invasion. Science, 290,521-523. DOI URL PMID
[2]	Coomes DA, Grubb PJ (1998). Responses of juvenile trees to above- and belowground competition in nutrient-starved Amazonian rain forest. Ecology, 79,768-782.
[3]	Coomes DA, Grubb PJ (2000). Impacts of root competition in forests and woodlands: a theoretical framework and review of experiments. Ecological Monographs, 70,171-207.
[4]	Fahey TJ, Hughes JW (1994). Fine root dynamics in a northern hardwood forest ecosystem, Hubbard Brook Experimental Forest, NH. Journal of Ecology, 82,533-548.
[5]	Huang JH(黄建辉), Han XG (韩兴国), Chen LZ (陈灵芝) (1999). Advances in the research of fine root biomass in forest ecosystem. Acta Ecologica Sinica (生态学报), 19,270-277. (in Chinese with English abstract)
[6]	Latham PE (1992). Co-occurring tree species change rank in seedling performance with resource varied experimentally. Ecology, 73,2129-2144.
[7]	Lewis SL, Janner TEV (2000). Effects of above- and belowground competition on growth and survival of rain forest tree seedlings. Ecology, 81,2525-2538.
[8]	Liao LP(廖利平), Chen CY (陈楚莹), Zhang JW (张家武), Gao H(高洪) (1995). Turnover of fine root in pure and mixed Cunninghamia lanceolata and Michelia macclurei forests. Chinese Journal of Applied Ecology (应用生态学报), 5,7-10. (in Chinese with English abstract)
[9]	McNaughton SJ, Banyikwa FF, McNaughton MM (1998). Root biomass and productivity in a grazing ecosystem:the serengeti. Ecology, 79,587-592.
[10]	Runkle JR (1982). Pattern of disturbance in some old-growth mesic forests of eastern North America. Ecology, 63,1533-1546.
[11]	Shan JP (单建平), Tao DL (陶大立), Wang M (王淼), Zhao SD (赵士洞) (1993). Fine roots turn-over in a broad-leaved Korean pine forest of Changbai Mountain. Chinese Journal of Applied Ecology (应用生态学报), 4,241-245. (in Chinese with English abstract)
[12]	Strutt LT, Keddy PA (1996). Above- and belowground competition intensity in two contrasting wetland plant communities. Ecology, 77,259-270.
[13]	Wilson SD, Tilman D (1991). Components of plant competition along a productivity gradient. Ecology, 72,1050-1065.
[14]	Wilson SD, Tilman D (1993). Plant competition and resource availability in response to disturbance and fertilization. Ecology, 74,599-611.
[15]	Zhang XQ(张小全), Wu KH(吴可红), Murach D (2000). A review of methods for fine-root production and turnover of trees. Acta Ecologica Sinica (生态学报), 20,875-883. (in Chinese with English abstract)
[16]	Zhou HC (周厚诚), Ren H(任海), Xiang YC (向言词), Peng SL(彭少麟), Li P(李萍) (2001). The changes of soil in the process of vegetation restoration in Nanao Island,Guangdong. Tropical Geography (热带地理), 21,6-10. (in Chinese with English abstract)