西双版纳热带森林动态监测样地——树种组成与空间分布格局

doi:10.3773/j.issn.1005-264x.2008.02.006

植物生态学报 ›› 2008, Vol. 32 ›› Issue (2): 287-298.DOI: 10.3773/j.issn.1005-264x.2008.02.006

西双版纳热带森林动态监测样地——树种组成与空间分布格局

兰国玉¹^,², 胡跃华¹^,², 曹敏¹^,^*(), 朱华¹, 王洪¹, 周仕顺¹, 邓晓保¹, 崔景云¹, 黄建国³, 刘林云³, 许海龙³, 宋军平³, 何有才³

1 中国科学院西双版纳热带植物园,昆明 650223
2 中国科学院研究生院,北京 100049
3 西双版纳州国家级自然保护区管理局,云南景洪 666100

收稿日期:2007-12-18 接受日期:2008-01-12 出版日期:2008-12-18 发布日期:2008-03-30
通讯作者: 曹敏
作者简介:* E-mail: caom@xtbg.ac.cn
基金资助:
中国科学院知识创新工程重要方向项目(KZCX2-YW-430-03)

ESTABLISHMENT OF XISHUANGBANNA TROPICAL FOREST DYNAMICS PLOT: SPECIES COMPOSITIONS AND SPATIAL DISTRIBUTION PATTERNS

LAN Guo-Yu¹^,², HU Yue-Hua¹^,², CAO Min¹^,^*(), ZHU Hua¹, WANG Hong¹, ZHOU Shi-Shun¹, DENG Xiao-Bao¹, CUI Jing-Yun¹, HUANG Jian-Guo³, LIU Lin-Yun³, XU Hai-Long³, SONG Jun-Ping³, HE You-Cai³

¹Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
²Graduate University of Chinese Academy of Sciences, Beijing 100049, China
³Xishuangbanna Administration of Nature Reserves, Jinghong, Yunnan 666100, China

Received:2007-12-18 Accepted:2008-01-12 Online:2008-12-18 Published:2008-03-30
Contact: CAO Min

摘要/Abstract

摘要：

西双版纳热带雨林是中国生物多样性最丰富的生态系统之一,西双版纳也被公认为国际上重要的生物多样性保护的热点地区之一。2007年,在中国科学院生物多样性委员会、加拿大Alberta大学和中国台湾东海大学等相关单位的支持下,由中国科学院西双版纳热带植物园和西双版纳州自然保护区管理局在西双版纳州勐腊县补蚌村的望天树(Shorea wantianshuea)林中建立了一块面积为20 hm²的热带森林动态监测样地,该样地是中国森林生物多样性动态监测网络建设的重要组成部分之一,其建设技术是按照美国史密森热带研究所的热带森林研究中心(Center for Tropical Forest Science, CTFS) 1980年在巴拿马Barro Colorado Island建立50 hm²样地的技术规范进行的。我们逐一测量并记录了样地中所有树干胸径大于1 cm树木的胸围,并对其挂牌标记、鉴定种名和确定坐标位置。并应用Ripley's L-Function分析了样地内4种上层优势种和12个稀有种的空间分布格局。研究结果表明:样地内共含有胸径 ≥ 1 cm的乔木95 834株,其中已经鉴定的有95 498株,占总个体数的99.65%;有乔木种类468种,隶属于213个属和70个科;另外有336个个体没有鉴定出来,仅占总个体数的0.35%。上层乔木中的望天树重要值排名第2,但具有最大的胸高断面积;中、下层的假海桐(Pittosporopsis kerrii)个体数最多,占样地内已鉴定乔木个体总数的21.90%。样地内4个上层优势种的小径阶个体数量较多,而大径阶个体数量较少,径阶分布呈倒“J”型,因此这4个种群可以维持自我更新。在分布格局上,样地内的4个上层优势树种的幼树和中龄树以聚集分布为主,而成年树则以随机分布为主。另外,大多数稀有物种也表现出聚集分布的格局。

关键词: 西双版纳, 热带雨林, 森林动态监测样地

Abstract:

Aims Tropical seasonal rain forest in Xishuangbanna is one of the most species-rich forest ecosystems in China. This area is also one of the biodiversity hotspots for conservation priorities of the world. For the purpose of monitoring long-term dynamics of tree populations, a 20-hm² plot was established in a dipterocarp forest in Mengla Nature Reserve in 2007 by Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences and Xishuangbanna Administration of Nature Reserves, in collaboration with Alberta University, Canada and Tunghai University (Taiwan, China).
Methods The construction technology and field protocol followed those applied in the establishment of the 50 hm² plot in the tropical forest of Barro Colorado Island in Panama, developed by Center for Tropical Forest Science, Smithsonian Tropical Research Institute in 1980. All free-standing trees with diameter at breast height (DBH) ≥ 1 cm were tagged, mapped, measured (girth) and identified to species in the plot. Spatial distribution patterns of four dominant canopy tree species (among different tree size classes) and 12 rare species were analyzed by using a point pattern analysis Ripley's L-function.
Important findings A total of 95 834 free-standing individuals with DBH ≥ 1 cm were recorded in the 20 hm² plot. Of which, 95 498 individuals were identified to species level. This plot included 468 species belonging to 213 genera and 70 families, except for another 336 individuals that could not be identified yet. The flora of plot was mainly composed of species in tropical families. Shorea wantianshuea that dominates the forest canopy was ranked the second in terms of importance value, although it had the largest basal area. Pittosporopsis kerrii, an understory tree species showed the highest abundance (20 918 individuals). The four canopy species had a large number of juveniles and exhibited size structures with reverse-J shape associated with continuously regenerating populations. Young trees (saplings and poles) revealed a clumped spatial distribution, but adults tended to have a random distribution. Most of the 12 rare tree species in the plot also showed aggregated distribution pattern.

Key words: Xishuangbanna, tropical rain forest, forest dynamics plot (FDP)

兰国玉, 胡跃华, 曹敏, 朱华, 王洪, 周仕顺, 邓晓保, 崔景云, 黄建国, 刘林云, 许海龙, 宋军平, 何有才. 西双版纳热带森林动态监测样地——树种组成与空间分布格局. 植物生态学报, 2008, 32(2): 287-298. DOI: 10.3773/j.issn.1005-264x.2008.02.006

LAN Guo-Yu, HU Yue-Hua, CAO Min, ZHU Hua, WANG Hong, ZHOU Shi-Shun, DENG Xiao-Bao, CUI Jing-Yun, HUANG Jian-Guo, LIU Lin-Yun, XU Hai-Long, SONG Jun-Ping, HE You-Cai. ESTABLISHMENT OF XISHUANGBANNA TROPICAL FOREST DYNAMICS PLOT: SPECIES COMPOSITIONS AND SPATIAL DISTRIBUTION PATTERNS. Chinese Journal of Plant Ecology, 2008, 32(2): 287-298. DOI: 10.3773/j.issn.1005-264x.2008.02.006

导出引用管理器 EndNote|Ris|BibTeX

链接本文: https://www.plant-ecology.com/CN/10.3773/j.issn.1005-264x.2008.02.006

https://www.plant-ecology.com/CN/Y2008/V32/I2/287

图/表 14

参考文献 24

[1]	Cao M, Zou XM, Warren M, Zhu H (2006). Tropical forests of Xishuangbanna, South China. Botropica, 38, 306-309.
[2]	Condit R (1995). Research in large, long-term tropical forest plot. Trends in Ecology and Evolution, 10, 18-22. URL PMID
[3]	Condit R (1998). Tropical forest census plots: methods and results from Barro Colorado Island, Panama and a comparison with other plot. Springer-Verlag and RG Landes Company, Berlin.
[4]	Condit R, Ashton P, Balslev H, Brokaw N, Bunyavejchewin S, Chuyong G, Co L, Dattaraja HS, Davies S, Esufali S, Ewango CEN, Foster R, Gunatilleke N, Gunatilleke S, Hernandez C, Hubbell S, John R, Kenfack D, Kiratiprayoon S, Pamela S, Hart T, Itoh A, Lafrankie JV, Liengola I, Lagunzad D, Lao S, Losos E, Magard E, Makana J, Manokaran N, Navarrete H, Nur SM, Okhubo T, Pérez R, Samper C, Seng LH, Sukumar R, Svenning JC, Tan S, Thomas D, Thompson J, Vallejo MI, Munoz GV, Valencia R, Yamakura T, Zimmerman JK (2005). Tropical tree-diversity: results from worldwide network of large plots. Biologiske Skrifter, 55, 565-582.
[5]	Condit R, Ashton PS, Baker P, Bunyavejchewin S, Gunatilleke S, Gunatilleke N, Hubbell SP, Foster RB, Itoh A, LaFrankie JV, Lee SL, Losos E, Manokaran N, Sukumar R, Yamakura T (2000). Spatial patterns in the distribution of tropical tree species. Science, 288, 1114-1118.
[6]	Connell JH (1971). On the role of natural enemies in preventing competitive exclusion in some marine animals and in rain forest trees. In: den Boer PJ, Gradwell GR eds. Dynamics of Populations. Center for Agricultural Publication and Documentation. Wageningen, The Netherlands, 298-312.
[7]	Diggle PJ (1983). Statistical analysis of spatial point patterns. Academic Press, London, UK.
[8]	Getzin S, Dean C, He F, Trofymow JA, Wiegand K, Wiegand T (2006). Spatial patterns and competition of tree species in a Douglas-fir chronosequence on Vancouver Island. Ecography, 29, 671-682.
[9]	Greig-Smith P (1983). Quantitative Plant Ecology. Blackwell Scientific Publications, London.
[10]	Hubbell SP, Foster RB (1997). Commonness and rarity in a neotropical forest: implications for tropical tree conservation. In: Soulé M ed. Conservation Biology: Science of Scarcity and Diversity. Sinauer Press, Sunderland, UK, 205-231.
[11]	Janzen DH (1970). Herbivores and the number of tree species in tropical forests. American Naturalist, 104, 501-528.
[12]	Jones EA, Chen J, Weng GJ, Hubbell SP (2005). A genetic evaluation of seed dispersal in the neotropical tree Jacaranda copaia (Bignoniaceae). American Naturalist, 166, 543-555.
[13]	Kenfack D, Thomas DW, Chuyong G, Condit R (2007). Rarity and abundance in a diverse African forest. Biodiversity and Conservation, 16, 2045-2074.
[14]	Linares-Palomino R, Alvarez SIP (2005). Tree community patterns in seasonally dry tropical forests in the Cerros de Amotape Cordillera, Tumbes, Peru. Forest Ecology and Management, 209, 261-272.
[15]	Svenning JC, Wright SJ (2005). Seed limitation in Panamanian forest. Journal of Ecology, 93, 853-862.
[16]	Wu ZY (吴征镒) (2003). Revise of areal-types of the world families of seed plants. Acta Botanica Yunnanica (云南植物研究), 25, 535-538. (in Chinese with English abstract)
[17]	Wu ZY (吴征镒), Zhou ZK (周浙昆), Li DZ (李德铢), Peng H (彭华), Sun H (孙航) (2003). The areal-types of the world families of seed plants. Acta Botanica Yunnanica (云南植物研究), 25, 245-257. (in Chinese with English abstract)
[18]	Xue JY (薛敬意), Tang JW (唐建维), Sha LQ (沙丽清), Meng Y (孟盈) (2003). Siol nutrient contents and their characteristic of seasonal change under Shorea chinensis forest in Xishuangbanna. Acta Phytoecologica Sinica (植物生态学报), 27, 373-379. (in Chinese with English abstract)
[19]	Zhang JT (张金屯) (1998). Analysis of spatial point pattern for plant species. Acta Phytoecologica Sinica (植物生态学报), 22, 344-349. (in Chinese with English abstract)
[20]	Zhu H (2006). Forest vegetation of Xishuangbanna, South China. Forestry Studies in China, 8(2), 1-27.
[21]	Zhu H, Cao M, Hu HB (2006). Geological history, flora, and vegetation of Xishuangbanna, southern Yunnan, China. Biotropica, 38, 310-317.
[22]	Zhu H (朱华), Li YH (李延辉), Xu ZF (许再富), Wang H (王洪), Li BG (李宝贵) (2001). Characteristics and affinity of the flora of Xishuangbanna, SW China. Guihaia (广西植物), 21, 127-136. (in Chinese with English abstract)
[23]	Zhu H (朱华), Wang H (王洪), Li BG (李保贵), Xu ZF (许再富) (1998). Research on the tropical seasonal rainforest of Xishuangbanna, South Yunnan. Guihaia (广西植物), 18, 371-384. (in Chinese with English abstract)
[24]	Zhu H (朱华), Zhou HX (周虹霞) (2002). A comparative study on the tropical rain forests in Xishuangbana and Hainan. Acta Botanica Yunnanica (云南植物研究), 24, 1-13. (in Chinese with English abstract)

	胸径DBH ≥ 1 cm	胸径DBH ≥ 10 cm	胸径DBH ≥ 30 cm
科数 No. of families	70	63	51
每公顷科数 No. of families·hm^-2	53.75 (2.84)	43.50 (2.4 0)	23.65 (4.48)
属数 No. of genera	213	171	119
每公顷属数 No. of genera·hm^-2	131.80 (7.80)	84.75 (5.67)	35. 0(7.98)
种数 No. of species	468	339	215
每公顷种数 No. of species·hm^-2	216.50 (15.35)	123.50 (9.83)	42.65 (8.73)
个体数 No. of individuals	95 834	12 331	2 232
每公顷个体数 No. of individuals·hm^-2	4 791.70 (659.12)	616.60 (83.97)	111.60 (26.24)
胸高断面积 Basal area	846.86	733.36	496.41
每公顷胸高断面积 Basal area·hm^-2	42.34 (8.91)	36.66 (8.92)	24.82 (8.40)

	胸径DBH ≥ 1 cm	胸径DBH ≥ 10 cm	胸径DBH ≥ 30 cm
科数 No. of families	70	63	51
每公顷科数 No. of families·hm^-2	53.75 (2.84)	43.50 (2.4 0)	23.65 (4.48)
属数 No. of genera	213	171	119
每公顷属数 No. of genera·hm^-2	131.80 (7.80)	84.75 (5.67)	35. 0(7.98)
种数 No. of species	468	339	215
每公顷种数 No. of species·hm^-2	216.50 (15.35)	123.50 (9.83)	42.65 (8.73)
个体数 No. of individuals	95 834	12 331	2 232
每公顷个体数 No. of individuals·hm^-2	4 791.70 (659.12)	616.60 (83.97)	111.60 (26.24)
胸高断面积 Basal area	846.86	733.36	496.41
每公顷胸高断面积 Basal area·hm^-2	42.34 (8.91)	36.66 (8.92)	24.82 (8.40)

序号 Rank	种名 Species name	代码 Species code	个体数 Abundance	胸高断面积 Basal area (m²)
1	假海桐Pittosporopsis kerrii	PITTKE	20 918	28.472 5
2	望天树Shorea wantianshuea	SHORWA	7 919	113.518 8
3	云树Garcinia cowa	GARCCO	4 333	19.237 6
4	蚁花Mezzettiopsis creaghii	MEZZCR	3 300	25.277
5	木奶果Baccaurea ramiflora	BACCRA	3 212	14.010 5
6	红光树Knema furfuracea	KNEMFU	3 160	11.240 5
7	染木树Saprosma ternata	SAPRTE	2 698	1.007 2
8	披针叶楠Phoebe lanceolata	PHOELA	2 409	4.425 9
9	钝叶桂Cinnamomum bejolghota	CINNBE	1 337	8.757 4
10	青藤公Ficus langkokensis	FICULA	1 337	7.636 6
11	滇毒鼠子Dichapetalum gelonioides	DICHGE	1 222	2.490 2
12	韶子Nephelium chryseum	NEPHCH	1 098	12.968 8
13	密花火筒树Leea compactiflora	LEEACO	1 051	0.343 3
	合计Total		53 994	249.386 3

序号 Rank	种名 Species name	代码 Species code	个体数 Abundance	胸高断面积 Basal area (m²)
1	假海桐Pittosporopsis kerrii	PITTKE	20 918	28.472 5
2	望天树Shorea wantianshuea	SHORWA	7 919	113.518 8
3	云树Garcinia cowa	GARCCO	4 333	19.237 6
4	蚁花Mezzettiopsis creaghii	MEZZCR	3 300	25.277
5	木奶果Baccaurea ramiflora	BACCRA	3 212	14.010 5
6	红光树Knema furfuracea	KNEMFU	3 160	11.240 5
7	染木树Saprosma ternata	SAPRTE	2 698	1.007 2
8	披针叶楠Phoebe lanceolata	PHOELA	2 409	4.425 9
9	钝叶桂Cinnamomum bejolghota	CINNBE	1 337	8.757 4
10	青藤公Ficus langkokensis	FICULA	1 337	7.636 6
11	滇毒鼠子Dichapetalum gelonioides	DICHGE	1 222	2.490 2
12	韶子Nephelium chryseum	NEPHCH	1 098	12.968 8
13	密花火筒树Leea compactiflora	LEEACO	1 051	0.343 3
	合计Total		53 994	249.386 3

序号 Rank	科名 Family	树种数 No. of species	属数 No. of genusra	个体数 No. of individuals	胸高断面积 Basal area (m²)	相对多样性 (RΔ)	相对密度(RD)	相对优势度(RA)	科重要值 (FIV)
1	茶茱萸科Icacinaceae	6	4	21 769	31.753 5	1.282 1	22.795 2	3.805 1	27.882 4
2	樟科Lauraceae	52	11	7 302	72.364 1	11.111 1	7.646 2	8.671 5	27.428 9
3	大戟科Euphorbiaceae	38	19	9 827	59.273 5	8.119 7	10.290 3	7.102 9	25.512 8
4	龙脑香科Dipterocarpaceae	1	1	7 919	113.518 0	0.213 7	8.292 3	13.603 2	22.109 2
5	壳斗科Fagaceae	14	2	2 068	106.329 2	2.991 5	2.165 5	12.741 7	17.898 6
6	桑科Moraceae	30	5	3 315	45.700 5	6.410 3	3.471 3	5.476 4	15.358 0
7	茜草科Rubiaceae	28	19	4 869	22.195 7	5.982 9	5.098 5	2.659 8	13.741 2
8	番荔枝科Annonaceae	15	7	5 010	34.790 9	3.205 1	5.246 2	4.169 1	12.620 3
9	楝科Meliaceae	17	2	1 259	56.997 0	3.632 5	1.318 4	6.830 1	11.780 9
10	杜英科Elaeocarpaceae	25	11	2 990	27.594 2	5.341 9	3.131 0	3.306 7	11.779 5
	合计 Total	226	81	66 328	570.517 518	48.290 8	69.454 86	68.366 32	186.112

西双版纳热带森林动态监测样地——树种组成与空间分布格局

ESTABLISHMENT OF XISHUANGBANNA TROPICAL FOREST DYNAMICS PLOT: SPECIES COMPOSITIONS AND SPATIAL DISTRIBUTION PATTERNS

全文

PDF (PC)

可视化

被引次数

摘要/Abstract

引用本文

使用本文

图/表 14

参考文献 24

相关文章 15

编辑推荐

Metrics

本文评价

序号 Rank	种名 Species	物种代码 Code	科名 Family	相对密度 (RD)	相对频度 (RF)	相对优势度 (RA)	重要值 (IV)
1	假海桐Pittosporopsis kerrii	PITTKE	Icacinaceae	21.904 1	0.459 9	3.411 9	25.775 9
2	望天树Shorea wantianshuea	SHORWA	Dipterocarpaceae	8.292 3	0.459 9	13.603 2	22.355 4
3	云树Garcinia cowa	GARCCO	Guttiferae	4.537 3	0.459 9	2.305 3	7.302 4
4	短刺锥Castanopsis echidnocarpa	CASTEC	Fagaceae	0.922 5	0.321 9	5.823 3	7.067 7
5	蚁花Mezzettiopsis creaghii	MEZZCR	Annonaceae	3.455 6	0.436 9	3.029	6.921 5
6	毛猴欢喜Sloanea tomentosa	SLOATO	Elaeocarpaceae	0.525 7	0.413 9	4.957 2	5.896 8
7	木奶果Baccaurea ramiflora	BACCRA	Euphorbiaceae	3.363 4	0.459 9	1.678 9	5.502 2
8	红光树Knema furfuracea	KNEMFU	Myristicaceae	3.309	0.459 9	1.347	5.115 8
9	绒毛番龙眼Pometia tomentosa	POMETO	Sapindaceae	0.502 6	0.459 9	2.826 2	3.788 7
10	披针叶楠Phoebe lanceolata	PHOELA	Lauraceae	2.522 6	0.459 9	0.530 4	3.512 8
	总计 Total			49.335 1	4.392 0	39.512 4	93.239 5

分布区类型 Areal-types	科数No. of families	百分比 Percentage
世界广布 Widespread	13	18.57
泛热带 Pantropic	38	54.29
东亚(热带亚洲至热带大洋洲)及热带南美间断 Tropical and Subtropical East Asia and (South) Tropical America disjuncted	6	8.57
旧世界热带 Old World Tropics	3	4.29
热带亚洲至热带大洋洲 Tropical Asia to Tropical Australasia Oceania	1	1.43
热带亚洲(即热带东南亚至印度-马来,太平洋诸岛) Tropical Asia=Tropical Southeast Asia+Indo-Malaya + Tropical South and Southwest Pacific Island	3	4.29
北温带 North Temperature	3	4.29
东亚及北美间断East Asia and North America disjuncted	2	2.86
东亚 East Asia	1	1.43
合计 Total	70	100.00

[1]	俞庆水倪晓凤吉成均朱江玲唐志尧方精云. 10年氮磷添加对海南尖峰岭两种热带雨林优势植物叶片非结构性碳水化合物的影响[J]. 植物生态学报, 2024, 48(预发表): 0-0.
[2]	朱华, 谭运洪. 中国热带雨林的群落特征、研究现状及问题[J]. 植物生态学报, 2023, 47(4): 447-468.
[3]	罗金环, 谭照远, 陈斌, 陈广武, 姜凯, 何奇芳, 张辉. 银合欢成功入侵热带雨林先锋群落的关键因素[J]. 植物生态学报, 2020, 44(12): 1215-1223.
[4]	黄运峰,路兴慧,臧润国,丁易,龙文兴,王进强,杨民,黄运天. 海南岛热带低地雨林刀耕火种弃耕地自然恢复过程中的群落构建[J]. 植物生态学报, 2013, 37(5): 415-426.
[5]	朱华. 云南热带季雨林及其与热带雨林植被的比较[J]. 植物生态学报, 2011, 35(4): 463-470.
[6]	李晓亮, 王洪, 郑征, 林露湘, 邓晓保, 曹敏. 西双版纳热带森林树种幼苗的组成、空间分布和旱季存活[J]. 植物生态学报, 2009, 33(4): 658-671.
[7]	谭正洪, 张一平, 于贵瑞, 宋清海, 高举明, 杨振, 孙晓敏, 赵双菊. 热带季节雨林林冠上方和林内近地层CO₂浓度的时空动态及其成因分析[J]. 植物生态学报, 2008, 32(3): 555-567.
[8]	张瑞清, 孙振钧, 王冲, 袁堂玉. 西双版纳热带雨林凋落叶分解的生态过程.Ⅲ.酶活性动态[J]. 植物生态学报, 2008, 32(3): 622-631.
[9]	郝占庆, 张健, 李步杭, 叶吉, 王绪高, 姚晓琳. 长白山次生杨桦林样地:物种组成与群落结构[J]. 植物生态学报, 2008, 32(2): 251-261.
[10]	孟令曾, 高秀霞, 陈进. 小果野芭蕉种子散布和不同时空尺度上种子被捕食格局[J]. 植物生态学报, 2008, 32(1): 133-142.
[11]	闫兴富, 曹敏. 濒危树种望天树大量结实后幼苗的生长和存活[J]. 植物生态学报, 2008, 32(1): 55-64.
[12]	于洋, 曹敏, 郑丽, 盛才余. 光对热带雨林冠层树种绒毛番龙眼种子萌发及其幼苗早期建立的影响[J]. 植物生态学报, 2007, 31(6): 1028-1036.
[13]	张志东, 臧润国. 海南岛霸王岭热带天然林景观中木本植物功能型分布的影响因素[J]. 植物生态学报, 2007, 31(6): 1092-1102.
[14]	乔秀娟, 曹敏, 林华. 西双版纳不同林龄次生植物群落优势树种的热值[J]. 植物生态学报, 2007, 31(2): 326-332.
[15]	吕晓涛, 唐建维, 何有才, 段文贵, 宋军平, 许海龙, 朱胜忠. 西双版纳热带季节雨林的生物量及其分配特征[J]. 植物生态学报, 2007, 31(1): 11-22.