广西靖西西南桦天然林种子雨的时空动态

doi:10.3724/SP.J.1258.2012.00729

摘要/Abstract

摘要：

以一片西南桦(Betula alnoides)天然林和一个西南桦独立单株为研究对象, 通过收集散种期内与林分或母树不同距离的种子以及测定风速和风向, 研究了西南桦群落和个体水平上种子雨的时空动态及其与风速和风向的关系。结果表明: 群落水平上, 西南桦种子散布的初始期、高峰期、消退期分别历时11天、32天和40天, 而个体水平上则为9天、25天和26天。高峰期内群落和个体水平的散种量分别占其总量的83.1%和68.7%, 而且白天的种子雨密度高于夜间; 西南桦个体白天种子雨密度最大的时段为12:00-16:00, 与此时段内风速较高有关。在个体水平上, 距离母树0-30 m范围内散落的种子占总散种量的79.6%; 而在群落水平上, 距离林缘0-45 m范围内集中了总散种量的81.2%。西南桦种子散布具有方向性, 无论个体还是群落水平上不同方向间种子雨密度差异极显著(p < 0.01), 与散种期内的主要风向有关; 而且种子雨密度与风速亦呈极显著正相关关系。研究结果将有助于揭示西南桦天然更新动态和更新机制, 亦为开展西南桦人工促进天然更新提供理论依据。

关键词: 西南桦群落和个体, 种子散布, 种子雨, 空间异质性, 时空动态

Abstract:

Aims Our objective was to study spatiotemporal dynamics of seed dispersal of Betula alnoides and analyze its correlation with wind speed and wind direction at community and individual levels.
Methods Seed dispersal was investigated for a natural forest and an isolated tree of B. alnoides. We set seven sample lines 100 to 355 m long in or around the natural forest. One seed trap was placed every 5 m, and seeds were collected every two days. We set eight sample lines (east, southeast, south, southwest, west, northwest, north, northeast) around the isolated tree. Three seed traps were placed every 5 m from 0 to 50 m and every 10 m from 60 to 150 m, and seeds were collected each day. Wind speed and wind directions were measured at two sites. Seed rain density was calculated.
Important findings The seed rain lasted 83 and 60 days at the community and individual levels, respectively. The starting, fastigium and subsiding stages of seed dispersal lasted 11, 32 and 40 days for the community and 9, 25 and 26 days for the isolated individual. Seeds dispersed at the fastigium stage accounted for 83.1% and 68.7% of all seeds collected at the community and individual levels, respectively. Seed rain density was higher during the day than at night, and the highest seed rain density by day occurred at 12:00-16:00. At the individual level, seed rain density decreased with increasing distance from the maternal tree, and 79.6% of seeds were collected in the area of 0-30 m around the maternal tree. Seed rain density at the community level also decreased with longer distance from the forest edge, and 79.6% of seeds were collected in the area of 0-45 m around the forest edge. The seed rain density was significantly different among directions (p < 0.01), which was affected by wind direction. Seed rain density was also positively affected by wind speed (p < 0.05).

Key words: Betula alnoides community and individual, seed dispersal, seed rain, spatial heterogeneity, spatiotemporal dynamics

郭俊杰, 赵志刚, 欧景莉, 沙二, 林开勤, 曾杰, 徐大平. 广西靖西西南桦天然林种子雨的时空动态. 植物生态学报, 2012, 36(8): 729-738. DOI: 10.3724/SP.J.1258.2012.00729

GUO Jun-Jie, ZHAO Zhi-Gang, OU Jing-Li, SHA Er, LIN Kai-Qin, ZENG Jie, XU Da-Ping. Spatiotemporal dynamics of seed rain in natural forest of Betula alnoides in Jingxi County, Guangxi, China. Chinese Journal of Plant Ecology, 2012, 36(8): 729-738. DOI: 10.3724/SP.J.1258.2012.00729

导出引用管理器 EndNote|Ris|BibTeX

链接本文: https://www.plant-ecology.com/CN/10.3724/SP.J.1258.2012.00729

https://www.plant-ecology.com/CN/Y2012/V36/I8/729

图/表 11

图1 个体水平上种子雨密度的时间变化。

Fig. 1 Temporal dynamics of seed rain density at individual level.

图2 群落水平上种子雨密度的时间变化。

Fig. 2 Temporal dynamics of seed rain density at community level.

表1 西南桦种子散布的时间变化(平均值±标准误差)

Table 1 Temporal dynamics of Betula alnoides seed dispersal (mean ± SE)

地点 Site	阶段 Stage	持续时间 Duration	日种子雨密度 (粒?m^-2?d^-1) SRD per day (seed?m^-2?d^-1)^*	落种比例 Percentage of seed dispersed (%)	白天种子雨密度(粒?m^-2) SRD at daytime (seed?m^-2)^*	夜间种子雨密度(粒?m^-2) SRD at night (seed?m^-2)^*	昼夜落种比例 Percentage of seed dispersed at daytime vs night (%)
斑块I (个体水平) Patch I (individual level)	初始期Starting	2月16日至24日 Feb. 16 to 24	3.71 ± 0.04	3.4%
	高峰期Fastigium	2月25日至3月21日 Feb. 25 to Mar. 21	27.23 ± 0.21	68.7%	9.49 ± 1.57	6.34 ± 0.58	59.9%/40.1%
	消退期 Subsiding	3月22日至4月16日 Mar. 22 to Apr. 16	10.65 ± 0.06	27.9%
斑块II (群落水平) Patch II (community level)	初始期 Starting	2月14日至24日 Feb. 14 to 24	14.38 ± 0.06	4.9%
	高峰期 Fastigium	2月25日至3月28日 Feb. 25 to Mar. 28	83.12 ± 0.72	83.1%	395.28 ± 109.07	145.31 ± 28.85	73.1%/26.9%
	消退期 Subsiding	3月29日至5月7日 Mar. 29 to May 7	9.59 ± 0.06	12.0%

图3 斑块I白天单株种子雨密度与风速的动态变化(平均值±标准误差)。

Fig. 3 Dynamics of seed rain density (SRD) at individual level and mean wind speed (MWS) at daytime in Patch I (mean ± SE).

图4 个体水平上种子雨密度随方向的变化(平均值±标准误差)。

Fig. 4 Dynamics of seed rain density (SRD) at individual level among directions (mean ± SE).

图5 个体水平上种子雨密度随距母树距离的变化。

Fig. 5 Dynamics of seed rain density at individual level with increasing distance from maternal tree.

图6 个体水平上不同方向种子雨密度随距母树距离的变化。

Fig. 6 Dynamics of seed rain density (SRD) at individual level with increasing distance from maternal tree in different directions.

表2 西南桦林分外不同方向种子雨密度的变化

Table 2 Dynamics of seed rain density in different directions outside Betula alnoides stand

方向 Direction	样线¹⁾ Sample line¹⁾	收集的种子数(粒)²⁾ Number of seeds collected (seed)²⁾	种子雨密度(粒?m^-2) Seed rain density (seed?m^-2)
南侧 South side	A, B, C	94.67	482.13
北侧 North side	A, B, C	562.67	2 107.09
东侧 East side	K	165.00	1 000.40
西侧 West side	G	296.00	991.78
东南侧 Southeast side	D	131.00	641.52
东北侧 Northeast side	F	239.00	1 449.07
西南侧 Southwest side	H	382.00	1 621.26

图7 林分外不同方向种子雨密度随距林缘距离的变化。

Fig. 7 Dynamics of seed rain density (SRD) with distance from stand edge outside stand in different directions.

图8 斑块I个体水平种子雨密度随风向、风速的变化。

Fig. 8 Dynamics of seed rain density at individual level with wind directions or wind speed in Patch I.

图9 西南桦林分种子雨密度随风向、风速的变化。试验中西北方向因小山包阻挡而未观测, 为了方向的对称, 遂取7个方向的平均值作“Mean”方向。

Fig. 9 Dynamics of seed rain density with wind direction or wind speed in the stand of Betula alnoides. The direction of “Mean”, as means of seven directions, was inserted since seed dispersal on northwest side of the stand was not measured due to existence of a steep hill.

参考文献 34

[1]	Aldrich PR, Hamrick JL (1998). Reproductive dominance of pasture trees in a fragmented tropical forest mosaic. Science, 281, 103-105.
[2]	Bittencourt JVM, Sebbenn AM (2007). Patterns of pollen and seed dispersal in a small, fragmented population of the wind-pollinated tree Araucaria angustifolia in southern Brazil. Heredity, 99, 580-591.
[3]	Bullock JM, Clarke RT (2000). Long distance seed dispersal by wind: measuring and modelling the tail of the curve. Oecologia, 124, 506-521.
[4]	Chang CS, Bongarten B, Hamrick JL (1998). Genetic structure of natural populations of black locust (Robinia pseudoacacia L.) at Coweeta, North Carolina. Journal of Plant Research, 111, 17-24.
[5]	Chen XM (陈香茗), Zhao XH (赵秀海), Xia FC (夏富才), Wang L (王蕾), Chen BB (陈贝贝) (2011). Spatiotemporal dynamics of seed rain of Tilia amurensis in forest stands in Changbai Mountain. Journal of Northeast Forestry University (东北林业大学学报), 39(1), 7-10. (in Chinese with English abstract)
[6]	Dow BD, Ashley MV (1996). Microsatellite analysis of seed dispersal and parentage of saplings in bur oak, Quercus macrocarpa. Molecular Ecology, 5, 615-627.
[7]	Ellison AM, Parker JN (2002). Seed dispersal and seedling establishment of Sarracenia purpurea (Sarraceniaceae). American Journal of Botany, 89, 1024-1026.
[8]	Epperson BK (1992). Spatial structure of genetic variation within populations of forest trees. New Forests, 6, 257-278.
[9]	García C, Jordano P, Godoy JA (2007). Contemporary pollen and seed dispersal in a Prunus mahaleb population: patterns in distance and direction. Molecular Ecology, 16, 1947-1955.
[10]	Gorchov DL, Cornejo F, Ascorra C, Jaramillo M (1993). The role of seed dispersal in the natural regeneration of rain forest after strip-cutting in the Peruvian Amazon. Vegetatio, 107/108, 339-349.
[11]	Hamrick JL, Murawski DA, Nason JD (1993). The influence of seed dispersal mechanisms on the genetic structure of tropical tree populations. Vegetatio, 107/108, 281-297.
[12]	Han YZ (韩有志), Wang ZQ (王政权) (2002). Spatial pattern of Manchurian ash seed dispersal in secondary hardwood forests. Acta Phytoecologica Sinica (植物生态学报), 26, 51-57. (in Chinese with English abstract)
[13]	Harper JL (1977). Population Biology of Plants. Academic Press, London.
[14]	Heuertz M, Vekemans X, Hausman F, Palada M, Hardy OJ (2003). Estimating seed vs. pollen dispersal from spatial genetic structure in the common ash. Molecular Ecology, 12, 2483-2495.
[15]	Houle G (1998). Seed dispersal and seedling recruitment of Betula alleghaniensis: spatial inconsistency in time. Ecology, 79, 807-818.
[16]	Janzen DH (1970). Herbivores and the number of tree species in tropical forests. The American Naturalist, 104, 501-528.
[17]	Kimmel TM, do Nascimento LM, Piechowski D, Sampaio EVSB, Rodal MJN, Gottsberger G (2010). Pollination and seed dispersal modes of woody species of 12-year-old secondary forest in the Atlantic forest region of Pernambuco, NE Brazil. Flora, 205, 540-547.
[18]	Levin SA, Muller-Landau HC, Nathan R, Chave J (2003). The ecology and evolution of seed dispersal: a theoretical perspective. Annual Review of Ecology Evolution and Systematics, 34, 575-604. (in Chinese with English abstract)
[19]	Mceuen AB, Curran LM (2004). Seed dispersal and recruitment limitation across spatial scales in temperate forest fragments. Ecology, 85, 507-518.
[20]	Nathan R, Katul GG, Horn HS, Thomas SM, Oren R, Avissar R, Pacala SW, Levin SA (2002). Mechanisms of long- distance dispersal of seeds by wind. Nature, 418, 409-413.
[21]	Nathan R, Katul GG, Bohrer G, Kuparinen A, Soons MB, Thompson SE, Trakhtenbrot A, Horn HS (2011). Mechanistic models of seed dispersal by wind. Theoretical Ecology, 4, 113-132.
[22]	Nathan R, Muller-Landau HC (2000). Spatial patterns of seed dispersal, their determinants and consequences for recruitment. Tree, 15, 278-285. DOI URL
[23]	Okubo A, Levin SA (1989). A theoretical framework for data analysis of wind dispersal of seeds and pollen. Ecology, 70, 329-338. DOI URL
[24]	Portnoy S, Willson MF (1993). Seed dispersal curves behavior of the tail of the distribution. Evolutionary Ecology, 7, 25-44. DOI URL
[25]	Schurr FM, Steinitz O, Nathan R (2008). Plant fecundity and seeddispersal in spatially heterogeneous environments: models, mechanisms and estimation. Journal of Ecology, 96, 628-641. DOI URL
[26]	Willson MF, Traveset A (2000). The ecology of seed dispersal. In: Fenner M ed. Seeds: The Ecology of Regeneration in Plant Communities. CAB International, Wallingford. 85-110.
[27]	Xu JW (许建伟), Shen HL (沈海龙), Zhang XL (张秀亮), Zhang P (张鹏), Huang J (黄剑) (2010). Sorbus pohuashanensis seed dispersal and germination and their relationships with population natural regeneration. Chinese Journal of Applied Ecology (应用生态学报), 21, 2536-2544. (in Chinese with English abstract)
[28]	Yang YF (杨允菲), Bai YP (白云鹏), Li JD (李建东), Li L (李丽) (2010). Spatial patterns of seed dispersal in Hemiptelea davidii woodland in Keerqin sandyland, China. Chinese Journal of Applied Ecology (应用生态学报), 21, 1967-1973. (in Chinese with English abstract)
[29]	Yu SL (于顺利), Lang NJ (郎南军), Peng MJ (彭明俊), Zhao L (赵琳), Guo YQ (郭永清), Zheng K (郑科), Zhang LX (张立新), Wen SL (温绍龙), Li H (李晖) (2007). Research advances in seed rain. Chinese Journal of Ecology (生态学杂志), 26, 1646-1652. (in Chinese with English abstract)
[30]	Zeng J (曾杰), Weng QJ (翁启杰), Zheng HS (郑海水) (2001). Study on the seed storage of Betula alnoides. Forest Research (林业科学研究), 14, 430-434. (in Chinese with English abstract)
[31]	Zeng J (曾杰), Zheng HS (郑海水), Gan SM (甘四明), Bai JY (白嘉雨) (2005). Phenotypic variation in natural populations of Betula alnoides in Guangxi, China. Science Silvae Sinicae (林业科学), 41(2), 59-65. (in Chinese with English abstract) DOI URL
[32]	Zhang YB (张玉波), Li JW (李景文), Zhang H (张昊), Zou DL (邹大林), Wu FP (武逢平), Cheng CL (程春龙), Li JQ (李俊清), Li SY (李帅英) (2005). Spatiotemporal patterns of seed dispersal in Populus euphratica. Acta Ecologica Sinica (生态学报), 25, 1994-2000. (in Chinese with English abstract)
[33]	Zhao ZG (赵志刚), Cheng W (程伟), Guo JJ (郭俊杰), Zeng J (曾杰), Lai JY (赖家业) (2011). Inflorescence growth and flowering phenology of Betula alnoides. Forest Research (林业科学研究), 4, 385-389. (in Chinese with English abstract)
[34]	Zou L (邹莉), Xie ZQ (谢宗强), Li QM (李庆梅), Zhao CM (赵常明), Li CL (李传龙) (2007). Spatial and temporal pattern of seed rain of Abies fargesii in Shennongjia Nature Reserve, Hubei. Biodiversity Science (生物多样性), 15, 500-509. (in Chinese with English abstract) DOI URL