ARTÍCULO

Distribution patterns of the subtropical evergreen broad-leaved forests of southwestern China, as compared with those of the eastern Chinese subtropical regions

C. Q. TANG (唐勤)

Institute of Ecology and Geobotany, Yunnan University, CN-650091 Kunming, China

E-mail: cindytang@ynu.edu.cn

Editors: M.-X. Ren & J. López-Pujol

ABSTRACT
Distribution patterns of the subtropical evergreen broad-leaved forests of southwestern China, as compared with those of the eastern Chinese subtropical regions.—This paper analyzes the geographic distribution patterns of the subtropical evergreen broad-leaved forests of southwestern China, and compares with other subtropical regions in the east of China in terms of forest types, pertinent species, and spatial distribution along latitudinal, longitudinal and altitudinal gradients. In general, for both the western and the eastern subtropical regions, the evergreen broad-leaved forests are dominated by species of Castanopsis, Lithocarpus, Cyclobalanopsis (Fagaceae), Machilus, Cinnamomum (Lauraceae), Schima (Theaceae), Manglietia, and Michelia, (Magnoliaceae), while in southwestern China there are more diverse forest types including semi-humid, monsoon, mid-montane moist and humid evergreen broad-leaved forests, but only monsoon and humid forests in the east. The Yunnan area has more varied species of Lithocarpus or Cyclobalanopsis or Castanopsis as dominants than does eastern China, where the chief dominant genus is Castanopsis. The upper limits of the evergreen broad-leaved forests are mainly 2400–2800 m in western Yunnan and western Sichuan, much higher than in eastern China (600–1500, but 2500 m in Taiwan). Also discussed are the environmental effects on plant diversity of the evergreen broad-leaved forest ecosystems exemplified by Yunnan and Taiwan.
KEYWORDS: dominant species; environmental gradient; forest type; plant diversity; spatial distribution; succession.

Patrones de distribución de los bosques subtropicales perennifolios de hoja ancha del suroeste de China en comparación con aquellos de las regiones subtropicales del este de China

RESUMEN
Patrones de distribución de los bosques subtropicales perennifolios de hoja ancha del suroeste de China en comparación con aquellos de las regiones subtropicales del este de China.— En este trabajo se analiza los patrones de distribución geográfica de los bosques subtropicales perennifolios de hoja ancha del suroeste de china, y se comparan con los de otras regiones subtropicales del este de China en términos de tipología de bosque, especies relevantes, y distribución espacial a lo largo de un gradiente latitudinal, longitudinal y altitudinal. De manera general, los bosques perennifolios de hoja ancha de la regiones subtropicales tanto orientales como occidentales presentan dominancia de especies de Castanopsis, Lithocarpus, Cyclobalanopsis (Fagaceae), Machilus, Cinnamomum (Lauraceae), Schima (Theaceae), Manglietia y Michelia (Magnoliaceae); sin embargo, mientras que en el suroeste de China hay más diversidad de tipos de bosques perennifolios de hoja ancha —húmedos, semi-húmedos, monzónicos y montanos húmedos—, en el este del país la variedad de tipos se limita a dos: monzónicos y húmedos. El área de Yunnan tiene una mayor variedad de especies dominantes de los géneros Lithocarpus, Cyclobalanopsis y Castanopsis, mientras que en este de China el género dominante es casi invariablemente Castanopsis. El límite altitudinal superior de los bosques perennifolios de hoja ancha se sitúa en 2400-2800 m para el oeste de las provincias de Yunnan y Sichuan, muy superior a lo que sucede en el este del país (entre 600 y 1500 m, aunque para Taiwan el límite alcanza los 2500 m). En último lugar se discuten los efectos medioambientales sobre la diversidad de especies vegetales de los bosques perennes de hoja ancha, y se proporcionan ejemplos de Yunnan y Taiwan.
PALABRAS CLAVE: distribución espacial; diversidad de especies vegetales; especies dominantes; gradiente medioambiental; sucesión; tipo de bosque.

摘要
中国西南部亚热带常绿阔叶林分布格局，并与中国东部亚热带常绿阔叶林之比较。— 本文分析了中国西南部亚热带常绿阔叶林类型，植物群落及优势物种在经度、纬度、海拔梯度上的分布格局，并且与中国亚热带东部（此文把中国西南部以东的中国亚热带均称为中国东部）的常绿阔叶林进行了深入比较。西南部及东部亚热带常绿阔叶林一般是以栲属、石栎属、青冈属（壳斗科），润楠属、樟属 （樟科），木荷属（茶科），木莲属、含笑属（木兰科）的物种为优势种。西南部有更多样的森林类型，含半湿润，季风，中山湿性和湿润亚热带常绿阔叶林，而东部只有季风和湿润亚热带常绿阔叶林。位于西南部的云南比中国东部有更多样的石栎属、青冈属及栲属优势物种，而东部的主要优势属只有栲属。在滇西和川西，常绿阔叶林分布的海拔上限主要是在2400-2800 m， 比中国东部常绿阔叶林分布的海拔上限（600-1500 m，台湾例外在2500 m）高很多。本文还以云南与台湾为例，阐述了西南部及东部常绿阔叶林生态系统中植物多样性在环境及植物演替梯度上的分布格局。
关键词：优势种；环境梯度；森林类型；植物多样性；空间分布；演替。

CONTENIDOS

INTRODUCTIONTop

Subtropical evergreen broad-leaved forests (hereafter EBLFs) refer to lauro-fagaceous evergreen forests, also known as lucidophylls or laurophylls, referring to their often glossy leaves. These forests, dominated by the genera Castanopsis (D. Don) Spach, Lithocarpus Blume, Cyclobalanopsis Oerst. (Fagaceae), Machilus Rumph. ex Nees (Lauraceae), Schima Reinw. ex Blume (Theaceae), Manglietia Blume, Michelia L. (Magnoliaceae), and Distylium Siebold & Zucc. (Hamamelidaceae) are almost exclusively confined to southern, southwestern, and southeastern mainland China, Taiwan, southwestern Japan, southern Korea, and some mountain regions of Vietnam, Laos, Thailand, Myanmar, India, Bhutan, and Nepal (Kira, 1991Kira, T. 1991. Forest ecosystems of east and southeast Asia in a global perspective. Ecological Research 6: 185–200. http://dx.doi.org/10.1007/BF02347161; Ohsawa, 1993Ohsawa, M. 1993. Latitudinal pattern of mountain vegetation zonation in southern and eastern Asia. Journal of Vegetation Science 4: 13‒18. http://dx.doi.org/10.2307/3235728; Tagawa, 1995Tagawa, H. 1995. Distribution of lucidophyll oak-laurel forest formation in Asia and other areas. Tropics 5: 1–40. http://dx.doi.org/10.3759/tropics.5.1; Song, 1995Song, Y.-C. 1995. On the global position of the evergreen broad-leaved forests of China. In: Box, E. O., Peet, R. K., Masuzawa, T., Yamada, I., Fujiwara, K. & Maycock, P. F. (Eds.), Vegetation science in forestry. Global perspective based on forest ecosystems of East and Southeast Asia. Papers from four symposia from the International Congress of Ecology, Yokohama 1990. Kluwer Academic Publishers, Dordrecht: 69–84.; Li, 1997Li, C. 1997. 亚洲东部常绿阔叶林的分布 [Distribution of evergreen broad-leaved forests in East Asia]. Natural Resources 2: 37‒46 [in Chinese].; Tang & Ohsawa, 2009Tang, C. Q. & Ohsawa, M. 2009. Ecology of subtropical evergreen broad-leaved forests of Yunnan, southwestern China as compared to those of southwestern Japan. Journal of Plant Research 122: 335–350. http://dx.doi.org/10.1007/s10265-009-0221-0; Song, 2013Song, Y.-C. (Ed.) 2013. 中国常绿阔叶林分类，生态，保育 [Evergreen broad-leaved forests in China, classification-ecology-conservation]. Science Press, Beijing [in Chinese].; Tang et al., 2013Tang, C. Q., Chiou, C.-R., Lin, C.-T. et al. 2013. Plant diversity patterns in subtropical evergreen broad-leaved forests of Yunnan and Taiwan. Ecological Research 28: 81–92. http://dx.doi.org/10.1007/s11284-012-1002-0). Climatic delimitation of Asian regions has been discussed by investigators (Wolfe, 1979Wolfe, J. A. 1979. Temperature parameters of humid to mesic forests of eastern Asia and relation to forests of other regions of the northern hemisphere and Australasia. (Geological Survey Professional Paper, 1106). United States Government Printing Office, Washington. ; Ohsawa, 1990Ohsawa, M. 1990. An interpretation of latitudinal patterns of forest limits in south and east Asian mountains. Journal of Ecology 78: 326‒339. http://dx.doi.org/10.2307/2261115, 1993Ohsawa, M. 1993. Latitudinal pattern of mountain vegetation zonation in southern and eastern Asia. Journal of Vegetation Science 4: 13‒18. http://dx.doi.org/10.2307/3235728; Kira, 1991Kira, T. 1991. Forest ecosystems of east and southeast Asia in a global perspective. Ecological Research 6: 185–200. http://dx.doi.org/10.1007/BF02347161; Box, 1995Box, E. O. 1995. Climatic relations of East and Southeast Asia. In: Box, E. O., Peet, R. K., Masuzawa, T., Yamada, I., Fujiwara, K. & Maycock, P. F. (Eds.), Vegetation science in forestry. Global perspective based on forest ecosystems of East and Southeast Asia. Papers from four symposia from the International Congress of Ecology, Yokohama 1990. Kluwer Academic Publishers, Dordrecht: 23‒55.) who have emphasized the seasonal variations in temperature of the monsoon system as the principal determinant of plant distribution patterns. Ohsawa (1995Ohsawa, M. 1995. Latitudinal comparison of altitudinal changes in forest structure, leaf-type and species richness in humid Asia. Vegetatio 121: 3‒10. http://dx.doi.org/10.1007/BF00044667) has provided an explicit template to depict zonal climate-forest patterns along latitudinal and altitudinal gradients in East Asia. As to latitude, southwestern China (SW China including Yunnan, Sichuan, Guizhou provinces and Chongqing Municipality, 21º 08′ 32′′–34º 20′ N, 97º 30′–110º 10′ E) (Fig. 1) falls into the transitional forest zone from tropical mountain to temperate mountain zonation (Fig. 2).

Figure 1. SW China and major mountain ranges of China. [View full size] [Descargar tamaño completo]

Figure 2. Altitudinal and latitudinal vegetation zonation scheme for East Asia (Ohsawa, 1995Ohsawa, M. 1995. Latitudinal comparison of altitudinal changes in forest structure, leaf-type and species richness in humid Asia. Vegetatio 121: 3‒10. http://dx.doi.org/10.1007/BF00044667). The mountains located between 20º and 30º(33º) N show a transitional zonation pattern; the lower two zones are comparable to the lower two of the tropical zonation (tropical lowland and tropical lower montane), and the upper two zones are comparable to those of the temperate zonation (temperate lower montane and temperate upper montane). The tropical upper montane zone is not found north of 20º–30º(33º) N, while the tropical lower montane zone reaches down to sea level and so becomes also the temperate lowland zone. Thus the zonation between 20º and 30º(33º) N includes tropical lowland, tropical lower montane/temperate lowland, temperate lower montane, and temperate upper montane zones (Ohsawa, 1990Ohsawa, M. 1990. An interpretation of latitudinal patterns of forest limits in south and east Asian mountains. Journal of Ecology 78: 326‒339. http://dx.doi.org/10.2307/2261115, 1995Ohsawa, M. 1995. Latitudinal comparison of altitudinal changes in forest structure, leaf-type and species richness in humid Asia. Vegetatio 121: 3‒10. http://dx.doi.org/10.1007/BF00044667). [View full size] [Descargar tamaño completo]

Primary EBLFs once covered most of the subtropical areas of East Asia, but are now greatly diminished as a result of human activities. A recent study found only 5% of China’s total land area to be covered by natural EBLFs (Chen, 1995Chen, W. L. 1995. The present status of degraded ecosystems in China. In: Chen, L. Z. & Chen, W. L. (Eds.), 中国退化生态系统研究 [Degraded ecosystems in China]. China Science and Technology Press, Beijing: 16–23 [in Chinese].). In the subtropical regions of China, extensive secondary forests have recently been grown on land used for agriculture or firewood production from the 19th to the middle 20th century, but remnants of the natural EBLFs are still found in remote isolated areas, on steep slopes, in nearly inaccessible or protected areas in nature reserves, and around temples. China, especially Yunnan, is home to the most diversified subtropical EBLFs to be found in East Asia (Tang & Ohsawa, 2009Tang, C. Q. & Ohsawa, M. 2009. Ecology of subtropical evergreen broad-leaved forests of Yunnan, southwestern China as compared to those of southwestern Japan. Journal of Plant Research 122: 335–350. http://dx.doi.org/10.1007/s10265-009-0221-0; Tang, 2010Tang, C. Q. 2010. Subtropical montane evergreen broad-leaved forests of Yunnan, China: diversity, succession dynamics, human influence. Frontiers of Earth Science in China 4: 22–32. http://dx.doi.org/10.1007/s11707-009-0057-x; Tang et al., 2013Tang, C. Q., Chiou, C.-R., Lin, C.-T. et al. 2013. Plant diversity patterns in subtropical evergreen broad-leaved forests of Yunnan and Taiwan. Ecological Research 28: 81–92. http://dx.doi.org/10.1007/s11284-012-1002-0).

In this paper the aim is to present an overview of the distribution patterns of the subtropical EBLFs across SW China as compared with all the Chinese subtropical regions to the east.

CLIMATE OF THE SUBTROPICAL EBLFsTop

China’s subtropical regions are bounded to the north by a line running between the Huai River and the Qinling Mountains (35º N), with a southern limit approaching the Tropic of Cancer. Eastward the subtropics extend to the coastlands and the islands of the East China Sea, the South China Sea and Taiwan; the westward limit is the Chinese national border, extending from the eastern slope of the Tibetan Plateau to southern Yunnan. The subtropical zone thus spans 11–12º from north to south, 28º from east to west (Wu, 1980Wu, Z. Y. (Ed.) 1980. 中国植被 [The vegetation of China]. Science Press, Beijing [in Chinese].). China’s subtropical region is divided into three different zones: (1) the southern subtropics (transitional tropics), extending from latitude 22º to 24º or 25º N; (2) the middle subtropics, which lie between 24º or 25º N and 31º or 32º N; and (3) the northern subtropics (transitional subtropics) which cover from 31º or 32º N to 34º or 35º N (Hou, 1983Hou, X.-Y. 1983. Vegetation of China with reference to its geographical distribution. Annals of the Missouri Botanical Garden 70: 509–548. http://dx.doi.org/10.2307/2992085). SW China is located at subtropical latitudes often distinguished as north, middle, and south subtropical (Fig. 3). A small part of southernmost Yunnan falls into the tropical zone. According to altitude, climates in SW China include tropical, subtropical, temperate, alpine and frigid. The climate is dominated by the Asian monsoon system, including the southwestern monsoon (the summer monsoon of India), the East Asian summer monsoon, and the East Asian winter monsoon, with dry continental winds in winter and moist oceanic winds in summer (Fig. 4). In China, generally the oceanic monsoon season begins earlier and ends later in the south than in the north, giving the south a longer rainy season and milder winter winds (Guo & Werger, 2010Guo, K. & Werger, M. J. A. 2010. Effect of prevailing monsoons on the distribution of beeches in continental East Asia. Forest Ecology and Management 259: 2197–2203. http://dx.doi.org/10.1016/j.foreco.2009.11.034). In general, Chinese regions east of ca. 103º E are strongly influenced by the East Asian monsoon, while the regions to the west are affected by the Indian monsoon.

Figure 3. Climate divisions of China. 1: Cold-temperate humid; 2: Middle-temperate humid, 3: Middle-temperate subhumid; 4: South-temperate humid; 5: South-temperate subhumid; 6: South-temperate subdry; 7: North-subtropical humid; 8: Middle subtropical humid; 9: South-subtropical humid; 10: Middle-subtropical subhumid and plateau; 11: Tropical humid; 12: Middle-temperate subdry; 13: Middle-temperate dry; 14: Middle-temperate alpine subdry; 15: South-temperate dry; 16: Plateau (dry and subdry). Modified from NCNWC (1984NCNWC (The Normal College of Northwest China) 1984. 中国自然地理地图集 [Maps of the Natural Geography of China]. Department of Geography, Normal College of Northwest China, Lanzhou & Special Publications Map Office, Beijing [in Chinese].) and Winkler & Wang (1993Winkler, M. G. & Wang, P. K. 1993. The Late-Quaternary vegetation and climate of China. In: Wright Jr., H. E., Kutzbach, J. E., Webb III, T., Ruddiman, W. F., Street-Perrott, F. A. & Bartlein, P. J. (Eds.), Global climates since the last glacial maximum. University of Minnesota Press, Minneapolis: 221–261. ). [View full size] [Descargar tamaño completo]

Figure 4. Three monsoon winds in China. [View full size] [Descargar tamaño completo]

Song (2013Song, Y.-C. (Ed.) 2013. 中国常绿阔叶林分类，生态，保育 [Evergreen broad-leaved forests in China, classification-ecology-conservation]. Science Press, Beijing [in Chinese].) offers the general information on the climate of the EBLFs. The annual temperature difference between the warmest and coldest months is smaller in the west (10–14ºC) than in the east (14–27ºC). In Holdridge’s life zone system (1947Holdridge, L. R. 1947. Determination of world plant formations from simple climatic data. Science 105: 367–368. http://dx.doi.org/10.1126/science.105.2727.367), bio-temperature (the sum of temperatures >0ºC, if mean monthly temperature >30ºC is calculated as 30ºC) ranges from 12 to 24ºC for the EBLF. In the subtropical EBLF region of China, the bio-temperature is 15–22ºC.

Kira (1945Kira, T. 1945. A new classification of climate in eastern Asia as the basis of agriculture geography. Horticultural Institute, Kyoto University, Kyoto [in Japanese].) has proposed a warmth index (WI) and a coldness index (CI) for vegetation zones in East Asia, as follows: WI (ºC) = Ʃ(t − 5) ∙ months; CI (ºC) = Ʃ(5 − t′) ∙ months; t is the mean monthly temperature ≥5ºC and t′ is the mean monthly temperature ≤5ºC. In Japan, a WI of 85‒180ºC ∙ months and a CI of −10‒0ºC ∙ months correspond to the EBLF distribution, and a CI of −10ºC is a decisive northern limit for the EBLF (Kira, 1945Kira, T. 1945. A new classification of climate in eastern Asia as the basis of agriculture geography. Horticultural Institute, Kyoto University, Kyoto [in Japanese].; Hattori & Nakanishi, 1985Hattori, T. & Nakanishi, S. 1985. On the distributional limits of the lucidophyllous forest in the Japanese Archipelago. The Botanical Magazine, Tokyo 98: 317–333. http://dx.doi.org/10.1007/BF02488498). In China, a WI of 125ºC and a CI of −5ºC determine the northern limit of the EBLF distribution; a WI of 135ºC, and a CI of −2ºC correspond to the northern limit of the EBLF zone (Song, 2013Song, Y.-C. (Ed.) 2013. 中国常绿阔叶林分类，生态，保育 [Evergreen broad-leaved forests in China, classification-ecology-conservation]. Science Press, Beijing [in Chinese].).

In China, the annual precipitation for the EBLF in the eastern region ranges from 1100 to 1700 mm, and is between 800–1000 mm in most areas of the western region (such as central and northern Yunnan and northwestern Guizhou). However, due to the complexity of the topography and varying elevations, the annual rainfall is ca. 1500–1800 mm in southern Yunnan, though it reaches 1500–2800 mm (but 3673 mm in Bapo, Dulongjiang) in some localities of western Yunnan, but in deep river valleys and on lee slopes it is just ca. 600–800 mm. In the western region, 80–90% of the annual precipitation falls from May to October, and the dry season is much more pronounced from November to April as compared with the east. The mean annual potential evapotranspiration for the subtropical EBLF region is ca. 800–1200 mm, and it is greater in the west than in the east. The Sichuan Basin area has the lowest evapotranspiration (Gao et al., 2006Gao, G., Chen, D., Ren, G., Chen, Y. & Liao, Y. 2006. Spatial and temporal variations and controlling factors of potential evapotranspiration in China: 1956–2000. Journal of Geographical Sciences 16: 3–12. http://dx.doi.org/10.1007/s11442-006-0101-7).

TYPES OF THE SUBTROPICAL EBLFsTop

Li (1997Li, C. 1997. 亚洲东部常绿阔叶林的分布 [Distribution of evergreen broad-leaved forests in East Asia]. Natural Resources 2: 37‒46 [in Chinese].) divided the EBLF of East Asia into four regions: the Japanese, eastern Chinese, western Chinese, and western Chinese sclerophyllous distribution regions. The evergreen sclerophyllous forest should be considered apart from the subtropical EBLF, because the morphology, physiognomy, and structure of their leaves are different. The subtropics from 33º to 35º N constitute a transitional zone from EBLFs to deciduous broad-leaved forests. Zhu (2013Zhu, H. 2013. Geographical elements of seed plants suggest the boundary of the tropical zone in China. Palaeogeography, Palaeoclimatology, Palaeoecology 386: 16–22. http://dx.doi.org/10.1016/j.palaeo.2013.04.007) considered a line at ca. 22º 30′ N to be the northern biogeographic boundary of the tropical zone in southern China. The evergreen broad-leaved forest of southernmost Yunnan is considered to be a tropical montane evergreen broad-leaved forest (Zhu, 2007Zhu, H. 2007. 论滇南西双版纳的森林植被分类 [On the classification of forest vegetation in Xishuangbanna, southern Yunnan]. Acta Botanica Yunnanica 29: 377–387 [in Chinese].; Zhu & Yan, 2009Zhu, H. & Yan, L.-C. 2009. Biogeographical affinities of the flora of southeastern Yunnan, China. Botanical Studies 50: 467–475. ). The subtropical EBLFs exclude northern tropical rain forests, which are basically tropical in nature but with some obvious transitional characteristics from tropical to subtropical floras, and are found at low altitudes in southernmost Yunnan (e.g. Xishuangbanna in S Yunnan, Xilongshan and Daweishan in SE Yunnan, Nangunhe in SW Yunnan). But here I do include the tropical montane evergreen broad-leaved forest of S, SE and SW Yunnan so as to take into account the altitudinal transition from the tropical rain forest to the subtropical EBLF. Song (2013Song, Y.-C. (Ed.) 2013. 中国常绿阔叶林分类，生态，保育 [Evergreen broad-leaved forests in China, classification-ecology-conservation]. Science Press, Beijing [in Chinese].) asserted that the subtropical EBLF of China corresponds to the region from 23º to 33º N and from 98º to 123º E. In fact, within Yunnan the forest extends west to ca. 97º 32′ E (e.g. Dulongjiang), and within Tibet it extends to 95º E (e.g. Chayu and Motuo in Yarlung Zangbo River). The most eastern longitude is 122º E in Taiwan. In sum, 95º–122º E is the longitudinal range of the EBLF within China. The distribution range of EBLFs in China is proposed in Fig. 5.

Figure 5. Distribution of subtropical evergreen broad-leaved forests in China. Note: Chayu and Motuo in Yarlung Zangbo River, southern Tibet, are included in the subtropical evergreen broad-leaved forest, though in deep gorges at 100–600 m a.s.l., very limited patches of the tropical rain forest are found, dominated by Dipterocarpus C.F. Gaertn [View full size] [Descargar tamaño completo]

A detrended correspondence analysis (DCA) (Fig. 6) for the plots of natural mature EBLFs of SW China, including Yunnan, Guizhou and the Sichuan Basin, that have been free of major disturbance during the past 60 years, indicates that along Axis 2 from the low to the upper side with increasing moisture, four forest types are roughly distinguished: the semi-humid EBLF (SH), the monsoon EBLF (MS), the humid EBLF (HE) and the mid-montane moist EBLF (MM). Axis 1 may indicate a gradient of topography or soil properties.

Figure 6. Ordination of plots along the first two detrended correspondence analysis (DCA) axes for SW China. EBLF: evergreen broad-leaved forest. All plots have been free of major disturbance during the past 60 years. The analysis reveals a sequence of 4 EBLF types along Axis 2. Axis 1 may indicate a gradient of topography or soil properties. Partial data sources: Zhou (1992Zhou, Z.-X. (Ed.) 1992. 贵州森林 [The forest of Guizhou]. Guizhou Science and Technology Press, Guiyang [in Chinese].), Zuo (1995Zuo, J.-F. 1995. 黄心夜合林的调查研究 [Investigation on Michelia martinii]. Chinese Journal of Ecology 14: 27–32 [in Chinese].), Tang & Ohsawa (1997Tang, C. Q. & Ohsawa, M. 1997. Zonal transition of evergreen, deciduous and coniferous forests along the altitudinal gradient on a humid subtropical mountain, Mt. Emei, Sichuan, China. Plant Ecology 133: 63–78. http://dx.doi.org/10.1023/A:1009729027521), Li et al. (2000Li, H., Guo, H. & Dao, Z. 2000. 高黎贡山植物 [Flora of the Gaoligong Mountains]. Science Press, Beijing [in Chinese]. ), Liu & Zhong (2000Liu, J.-M. & Zhong, Z.-C. 2000. 梵净山栲树群落的种子雨、种子库及更新 [Nature of seed rain, the seed bank and regeneration of a Castanopsis fargesii community on Fanjing Mountain]. Acta Phytoeologica Sinica 24: 402‒407 [in Chinese].), Bao & Liu (2002Bao, W. & Liu, Z. 2002. 四川瓦屋山原生和次生常绿阔叶林的群落学特征 [Community features of primary and naturally secondary evergreen broad-leaved forests in Mt. Wawu in Sichuan, China]. Chinese Journal of Environmental Biology 8: 120–126 [in Chinese].), Peng et al. (2006aPeng, M.-C., Wang, C.-Y. & Dang, C.-L. 2006a. 云南药山自然保护区生物多样性及保护研究 [Studies on biodiversity and conservation in Yaoshan Nature Reserve]. Science Press, Beijing [in Chinese].), Tang et al. (2007aTang, C. Q., Li, T. & Zhu, X. 2007a. Structure and regeneration dynamics of three subtropical midmontane moist evergreen broad-leaved forests in southwestern China, with special reference to bamboo in the forest understories. Canadian Journal of Forest Research 37: 2701–2714. http://dx.doi.org/10.1139/X07-101), Tang & Ohsawa (2009Tang, C. Q. & Ohsawa, M. 2009. Ecology of subtropical evergreen broad-leaved forests of Yunnan, southwestern China as compared to those of southwestern Japan. Journal of Plant Research 122: 335–350. http://dx.doi.org/10.1007/s10265-009-0221-0), Shi et al. (2011Shi, J.-P., Chang, Y.-F., Xu, C.-D. & Zhu, H. 2011. 楚雄花椒园半湿润常绿阔叶林的群落生态学特征 [Synecological studies on the semi-humid evergreen broad-leaved forest in Huajiaoyuan Nature Reserve, Chuxiong, Yunnan]. Guihaia 31: 204–207 [in Chinese].), Tang et al. (2013Tang, C. Q., Chiou, C.-R., Lin, C.-T. et al. 2013. Plant diversity patterns in subtropical evergreen broad-leaved forests of Yunnan and Taiwan. Ecological Research 28: 81–92. http://dx.doi.org/10.1007/s11284-012-1002-0), Wang et al. (2013Wang, C.-Y., He, Z.-R. & Peng, M.-C. 2013. 独龙江流域及邻近区域植被与植物研究 [Studies on vegetation and plants in Dulongjiang (upper Irrawaddy River) watershed and adjacent area]. Science Press, Beijing [in Chinese].). [View full size] [Descargar tamaño completo]

In SW China, most significantly, four forest types are representative of the major subtropical EBLFs:

(1) the semi-humid EBLF in Yunnan, western Sichuan, and western Guizhou.

(2) the monsoon EBLF in Yunnan.

(3) the mid-montane moist EBLF in Yunnan, which I combine with the montane mossy EBLF as classified by former researchers (e.g. Wu, 1980Wu, Z. Y. (Ed.) 1980. 中国植被 [The vegetation of China]. Science Press, Beijing [in Chinese].; Wu et al., 1987Wu, Z. Y., Zhu, Y. C. & Jiang, H. C. (Eds.) 1987. 云南植被 [The vegetation of Yunnan]. Science Press, Beijing [in Chinese]. ) since their physiognomy and ecological characteristics, including various epiphytes and lianas on tree trunks and branches, are similar.

(4) the humid EBLF in the Sichuan Basin (also including Chongqing) and eastern Guizhou, having no distinctive dry season throughout the year. The humid EBLF differs from the mid-montane moist EBLF in lacking rich epiphytes and lianas on tree trunks and branches. The humid EBLF in the Sichuan Basin and eastern Guizhou is considered as the same type as the typical humid EBLF of eastern China.

The montane mossy dwarf forest as classified by former researchers (e.g. Wu, 1980Wu, Z. Y. (Ed.) 1980. 中国植被 [The vegetation of China]. Science Press, Beijing [in Chinese].; Wu et al., 1987Wu, Z. Y., Zhu, Y. C. & Jiang, H. C. (Eds.) 1987. 云南植被 [The vegetation of Yunnan]. Science Press, Beijing [in Chinese]. ; Shi & Zhu, 2009Shi, J. P. & Zhu, H. 2009. Tree species composition and diversity of tropical mountain cloud forest in the Yunnan, southwestern China. Ecological Research 24: 83–92. http://dx.doi.org/10.1007/s11284-008-0484-2), dominated by species of Rhododendron L. along with some dwarf trees of the Fagaceae, Vacciniaceae, Rosaceae, Aceraceae, grows in special topo-habitats such as near mountaintops. This is not considered a type of the subtropical EBLF in this paper.

SPATIAL DISTRIBUTION PATTERNS OF THE SUBTROPICAL EBLFsTop

Southwestern China

Yunnan

The spatial patterns of distribution of dominant evergreen broad-leaved communities along latitudes, longitudes, and altitudes in Yunnan, as represented by 22 mountains, are depicted in Fig. 7. In Yunnan, secondary forests such as coppice woods and fast-growing Pinus L. (e.g. Pinus yunnanensis Franch. and Pinus armandii Franch.) and Eucalyptus (e.g. Eucalyptus smithii R. T. Baker and Eucalyptus globulus Labill.) plantations, as well as agricultural fields are common at low altitudes, while remnants of the natural subtropical EBLF are only found in isolated mountains, on steep slopes, and temple grounds. The semi-humid EBLFs (SH) dominated by Castanopsis orthacantha Franch., Cyclobalanopsis glaucoides Schottky, Cyclobalanopsis delavayi (Franch.) Schottky, or Lithocarpus dealbatus (Hook. f. & Thomson ex Miq.) Rehder are found at (1500)1900‒2400 m in central, south-central, and eastern Yunnan, including Jizhushan, Huafushan, Shizishan, Qiongzhushi, Wuliangshan, eastern Ailaoshan, Zhujiangyuan, Laojunshan of Wenshan, Wumengshan, and Yaoshan (shan means “mountain”).

Figure 7. The spatial patterns of distribution of dominant evergreen broad-leaved communities along latitudes, longitudes, and altitudes in Yunnan. SH: Semi-humid EBLF; MS: Monsoon EBLF; MM: Mid-montane moist EBLF; Cy: Cyclobalanopsis; Ca: Castanopsis; Li: Lithocarpus; Ma: Machilus; Trig: Trigonobalanus; Mang: Manglietia; Alcim: Alcimandra Dandy; Cry: Cryptocarya R. Br.; El: Elaeocarpus L. Data sources: Peng & Dang (1998Peng, M. & Dang, C. 1998. 云南鸡足山元江栲群落和高山栲群落的群落多样性研究 [Studies on interspecific association of both Castanopsis orthacantha and Castanopsis delavayi communities on Jizu Mountain, Yunnan Province]. Acta Ecologica Sinica 18: 159‒166 [in Chinese].), Hu (1999Hu, C.-T. 1999. 龙陵小黑山大雪山自然保护区的植被类型 [Vegetation types of Xiaoheshan in the Daxue Mountain Nature Reserve, Longling]. Yunnan Forestry Investigation, Plan and Design 24: 1–7 [in Chinese].), Yang & Li (1999Yang, Y.-M. & Li, T.-S. (Eds.) 1999. 云南大围山自然保护区科学考察报告 [Integrated scientific studies of Dawei Nature Reserve, Yunnan]. Yunnan Science Press, Kunming [in Chinese].), Li et al. (2000Li, H., Guo, H. & Dao, Z. 2000. 高黎贡山植物 [Flora of the Gaoligong Mountains]. Science Press, Beijing [in Chinese]. , 2006Li, D., Tang, J.-W., Luo, C.-K., Li, J.-S. & Liu, Z.-A. 2006. 西双版纳季风常绿阔叶林的群落学特征 [Community characteristics of the monsoon evergreen broad-leaved forest in Xishuangbanna, Yunnan]. Journal of Mountain Science 24: 257–267 [in Chinese].), Peng & Wu (2001Peng, H. & Wu, Z.-Y. 2001. 无量山半湿润常绿阔叶林的区系特征及保护生物学意义 [The floristic characteristics and its significance in conservation of semi-humid evergreen broad-leaved forests in Mt. Wuliangshan]. Acta Botanica Yunnanica 23: 278‒286 [in Chinese].), Yang & Du (2004Yang, Y.-M & Du, F. (Eds.) 2004. 中国南滚河国家级自然保护区 [Nangunhe National Nature Reserve, China]. Yunnan Science Press, Kunming [in Chinese]., 2006Yang, Y.-M. & Du, F. (Eds.) 2006. 云南铜壁关自然保护区科学考察研究 [Integrated scientific studies of Tongbiguan Nature Reserve, Yunnan]. Yunnan Science Press, Kunming [in Chinese].), Wang et al. (2005Wang, J., Ma, Q.-Y., Du, F. & Yang, Y.-M. 2005. 云南大围山种子植物区系海拔梯度格局分析 [Altitudinal patterns of seed plants on Dawei Mountain, Yunnan Province, China]. Acta Phytoecologia Sinica 29: 894–900 [in Chinese]., 2013Wang, C.-Y., He, Z.-R. & Peng, M.-C. 2013. 独龙江流域及邻近区域植被与植物研究 [Studies on vegetation and plants in Dulongjiang (upper Irrawaddy River) watershed and adjacent area]. Science Press, Beijing [in Chinese].), Peng et al. (2006aPeng, M.-C., Wang, C.-Y. & Dang, C.-L. 2006a. 云南药山自然保护区生物多样性及保护研究 [Studies on biodiversity and conservation in Yaoshan Nature Reserve]. Science Press, Beijing [in Chinese].), Yang et al. (2006Yang, Y., Wu, Z.-L. & Wang, D.-S. (Eds.) 2006. 西双版纳纳板河流域国家级自然保护区 [Nabanhe Watershed National Nature Reserve, Xishuangbanna]. Yunnan Science Press, Kunming [in Chinese].), Liu & Peng (2007Liu, E.-D. & Peng, H. 2007. 永德大雪山中山湿性常绿阔叶林植物区系的初步研究 [A preliminary floristic study on the mid-montane humid evergreen broad-leaved forest of Yongde Snow Mountain, SW Yunnan, China]. Acta Botanica Yunnanica 29: 129–136 [in Chinese].), Tang & Zhu (2007Tang, C. Q. & Zhu, X. 2007. Structure and dynamics of mid-montane moist evergreen broad-leaved forest on subtropical mountains, Ailaoshan and Gaoligongshan, Yunnan, China, and the relationship between the forests and the people, with a view of future sustainability. Annual Report of Pro Natura Fund 16: 153–175.), Tang et al. (2007aTang, C. Q., Li, T. & Zhu, X. 2007a. Structure and regeneration dynamics of three subtropical midmontane moist evergreen broad-leaved forests in southwestern China, with special reference to bamboo in the forest understories. Canadian Journal of Forest Research 37: 2701–2714. http://dx.doi.org/10.1139/X07-101, 2007bTang, C. Q., Hou, X., Gao, K., Xia, T., Duan, C. & Fu, D. 2007b. Man-made versus natural forests in mid-Yunnan, southwestern China: plant diversity and initial data on water and soil conservation. Mountain Research and Development 27: 242‒249. http://dx.doi.org/10.1659/mrd.0732, 2010aTang, C. Q., Li, Y.-H. & Zhang, Z.-Y. 2010a. Species diversity patterns of natural secondary plant communities and man-made forests in a subtropical mountainous karst area, Yunnan, SW China. Mountain Research and Development 30: 244–251. http://dx.doi.org/10.1659/MRD-JOURNAL-D-10-00021.1, 2010bTang, C. Q., Zhao M.-H., Li, X.-S., Ohsawa, M. & Ou, X.-K. 2010b. Secondary succession of plant communities in a subtropical mountainous region of SW China. Ecological Research 25: 149–161. http://dx.doi.org/10.1007/s11284-009-0644-z, 2013Tang, C. Q., Chiou, C.-R., Lin, C.-T. et al. 2013. Plant diversity patterns in subtropical evergreen broad-leaved forests of Yunnan and Taiwan. Ecological Research 28: 81–92. http://dx.doi.org/10.1007/s11284-012-1002-0), Tang & Ohsawa (2009Tang, C. Q. & Ohsawa, M. 2009. Ecology of subtropical evergreen broad-leaved forests of Yunnan, southwestern China as compared to those of southwestern Japan. Journal of Plant Research 122: 335–350. http://dx.doi.org/10.1007/s10265-009-0221-0), Tang & He (2013Tang, C. Q. & He, L.-Y. 2013. Population status of the Tertiary relict Tetracentron sinense in the subtropical Ailao Mountains, Yunnan, SW China, and proposed conservation efforts. Annual Report of Pro Natura Fund 21: 141–150.). At low altitudes below the EBLF zones on these mountains, secondary forests or shrublands or plantations of conifers (such as Pinus yunnanensis and Pinus armandii) or eucalyptus, or agricultural fields are all common, while some localities along rivers support hot-dry valley vegetation; also in southern Yunnan there are some patches of tropical seasonal rain forest or tropical rain forest. At higher altitudes above the EBLFs, there are various vegetation types, such as montane mossy dwarf communities, evergreen sclerophyllous Quercus L. forests, or temperate coniferous [e.g. Tsuga dumosa (D. Don) Eichler] and broad-leaved mixed forests, or cold temperate forests, alpine scrubland, grassland, meadows. [View full size] [Descargar tamaño completo]

The monsoon EBLFs (MS) are mainly distributed at (800)1000‒1800 m in southern Yunnan (e.g. Tongbiguan, Nangunhe, Beihualin, Yongde Daxueshan, Wuliangshan, Ailaoshan, Xilongshan, Daweishan, and Xishuangbanna) and in the province’s north-west (e.g. Dulongjiang, and Fugong). Most of them are dominated by species of Castanopsis and Lithocarpus with some Trigonobalanus Forman and Cyclobalanopsis, as well as Lauraceae and Theaceae, such as Castanopsis hystrix Hook. f. & Thomson ex A. DC., Castanopsis fleuryi Hickel & A. Camus, Castanopsis calathiformis Rehder & E. H. Wilson, Lithocarpus truncatus (King ex Hook. f.) Rehder & E. H. Wilson, Lithocarpus polystachyus (Wall. ex A. DC.) Rehder, Lithocarpus fenestratus (Roxb.) Rehder, Trigonobalanus doichangensis (A. Camus) Forman, Cyclobalanopsis augustinii (Skan) Schottky, Cyclobalanopsis kerrii (Craib) Hu, Cryptocarya calcicola H. W. Li, Cryptocarya densiflora Blume, Beilschmiedia yunnanensis Hu, Schima wallichii (DC.) Korth., and Anneslea fragrans Wall.

The mid-montane moist EBLFs (MM) are distributed at (1600)1800‒2500(2800) m from the east to the west of Yunnan, and from southern to south-central, and northern Yunnan, but not in central Yunnan, as on Jizushan, Huafushan, Shizishan, and Qiongzhusi, where no such moist EBLFs grow. Compared with the former two forest types, in the mid-montane moist EBLFs are to be found, besides dominant species of Fagaceae [e.g. Cyclobalanopsis lamellosa (Sm.) Oerst., Cyclobalanopsis oxyodon (Miq.) Oerst., Cyclobalanopsis myrsinifolia (Blume) Oerst., Lithocarpus variolosus (Franch.) Chun, Lithocarpus hancei (Benth.) Rehder, Lithocarpus pachyphyllus (Kurz) Rehder, Lithocarpus xylocarpus (Kurz) Markgr., Lithocarpus echinotholus (Hu) Chun & C. C. Huang ex Y. C. Hsu & H. W. Jen, Castanopsis echidnocarpa A. DC., Castanopsis wattii (King ex Hook. f.) A. Camus, and Castanopsis remotidenticulata Hu], Lauraceae [Machilus longipedicellata Lecomte, Machilus viridis Hand.-Mazz., Cinnamomum iners Reinw. ex Blume, Phoebe faberi (Hemsl.) Chun], Theaceae (Schima khasiana Dyer, Schima argentea E. Pritz., and Schima villosa Hu) and Magnoliaceae [Manglietia kungshanensis Law, Manglietia insignis (Wall.) Blume, and Alcimandra cathcartii (Hook. f. & Thomson) Dandy] also appear as co-dominants. The mid-montane moist EBLF is characterized by abundant lianas, ferns and mosses on tree trunks and branches.

Sichuan, Guizhou, and Chongqing Municipality

Figure 8 shows the spatial patterns of distribution of dominant evergreen broad-leaved communities along latitudes, longitudes, and altitudes in Sichuan, Guizhou, and Chongqing Municipality, as represented by 21 mountains. In these areas, natural EBLFs at low altitudes have been even more severely reduced by human activities than in Yunnan. Here secondary forests, shrublands, and plantations of pines (Pinus yunnanensis in the west of Sichuan and Guizhou, Pinus massoniana Lamb. in the east of Sichuan and Guizhou as well as Chongqing) or Cunninghamia lanceolata (Lamb.) Hook. or Cryptomeria japonica (Thunb. ex L. f.) D. Don var. sinensis Miq. (formerly Cryptomeria fortunei Hooibr.) prevail. Some semi-humid EBLFs dominated by Castanopsis delavayi Franch. or Cyclobalanopsis glaucoides are found in western Sichuan (e.g. Jinyangxian, Xiaoxiangling). In these areas, the typical humid EBLFs (HE) prevail. The dominants are Castanopsis, Lithocarpus, and Cyclobalanopsis [e.g. Castanopsis carlesii (Hemsl.) Hayata var. carlesii, Castanopsis fargesii Franch., Castanopsis eyrei (Champ. ex Benth.) Tutch., Castanopsis carlesii (Hemsl.) Hayata var. spinulosa W. C. Cheng & C. S. Chao, Castanopsis platyacantha Rehder & E. H. Wilson, Lithocarpus corneus (Lour.) Rehder, Lithocarpus cleistocarpus (Seemen) Rehder & E. H. Wilson, Cyclobalanopsis oxyodon, and Cyclobalanopsis multinervis W. C. Cheng & T. Hong], and many species of Lauraceae [e.g. Phoebe neurantha (Hemsl.) Gamble, Phoebe zhennan S. K. Lee & F. N. Wei, Lindera pulcherrima (Nees) Hook. f. var. hemsleyana (Diels) H. P. Tsui, Lindera megaphylla Hemsl., Lindera pulcherrima (Nees) Hook. f. var. pulcherrima, Cinnamomum longepaniculatum (Gamble) N. Chao ex H. W. Li, Machilus pingii W. C. Cheng ex Yen C. Yang, Machilus ichangensis Rehder & E. H. Wilson, and Actinodaphne omeiensis (H. Liu) C. K. Allen], and Theaceae [Schima superba Gardner & Champ., Schima argentea, Gordonia sichuanensis H. T. Chang, and Gordonia chrysandra Cowan], and Magnoliaceae [e.g. Michelia martini (H. Lév.) Finet & Gagnep. ex H. Lév. and Manglietia fordiana Oliv.] as well as Elaeocarpaceae [e.g. Elaeocarpus japonicus Siebold & Zucc. and Elaeocarpus sylvestris (Lour.) Poir.].

Figure 8. The spatial patterns of distribution of dominant evergreen broad-leaved communities along latitudes, longitudes and altitudes in Sichuan, Chongqing and Guizhou. HE: Humid EBLF; SH: Semi-humid EBLF; Cy: Cyclobalanopsis; Ca: Castanopsis; Li: Lithocarpus; Cinn: Cinnamomum; El: Elaeocarpus. Data sources: SVEG (1980SVEG (Sichuan Vegetation Editorial Group) 1980. 四川植被 [The vegetation of Sichuan]. Sichuan People’s Press, Chengdu [in Chinese].), Yang (1983Yang, L. 1983. 梵净山黔周林的结构和动态 [The structure and dynamics of Cyclobalanopsis stewardiana forest of the Fanjingshan Mountain]. Acta Phytoecologica et Geobotanica Sinica 7: 204–214 [in Chinese].), Liu (1985Liu, Y. 1985. 四川省缙云山常绿阔叶林的数量分类 [Numerical classification to the evergreen broadleaf forest in the Jinyun Mountain, Sichuan Province]. Acta Phytoecologica et Geobotanica Sinica 9: 315‒325 [in Chinese].), Liu & Qiu (1986Liu, Z.-G. & Qiu, F.-Y. 1986. 贡嘎山地区主要植被类型和分布 [The main vegetation types and their distribution in the Gongga mountainous region]. Acta Phytoecologica et Geobotanica Sinica 10: 26‒34 [in Chinese].), Zhou (1992Zhou, Z.-X. (Ed.) 1992. 贵州森林 [The forest of Guizhou]. Guizhou Science and Technology Press, Guiyang [in Chinese].), Zuo (1995Zuo, J.-F. 1995. 黄心夜合林的调查研究 [Investigation on Michelia martinii]. Chinese Journal of Ecology 14: 27–32 [in Chinese].), He et al. (1996He, M., Zhang, J., Liu, S. & Li, W. 1996. 峨边黑竹沟地区自然植被初探 [A preliminary study on the natural vegetation of Black Bamboo Ravine in Ebian County of Sichuan]. Journal of Sichuan University (Natural Science Edition) 33: 347–350 [in Chinese].), Tang & Ohsawa (1997Tang, C. Q. & Ohsawa, M. 1997. Zonal transition of evergreen, deciduous and coniferous forests along the altitudinal gradient on a humid subtropical mountain, Mt. Emei, Sichuan, China. Plant Ecology 133: 63–78. http://dx.doi.org/10.1023/A:1009729027521), Xie & Chen (1998Xie, Z. & Chen, W. 1998. 三峡库区残存的常绿阔叶林及其意义 [The remaining evergreen broad-leaved forest and its significance in Three Gorges Reservoir Area]. Acta Phytoecologia Sinica 22: 422–427 [in Chinese].), Liu & Zhong (2000Liu, J.-M. & Zhong, Z.-C. 2000. 梵净山栲树群落的种子雨、种子库及更新 [Nature of seed rain, the seed bank and regeneration of a Castanopsis fargesii community on Fanjing Mountain]. Acta Phytoeologica Sinica 24: 402‒407 [in Chinese].), Tang & Ohsawa (2000Tang, C. Q. & Ohsawa, M. 2000. Transitional pattern of tree leaf-types from tropical to temperate forests on Mt. Emei, Sichuan, China. In: Zheng, D. & Zhu, L. (Eds.), Formation, evolution and sustainable development on the Qinghai-Tibet Plateau. Academy Press, Beijing: 397–407.), Bao & Liu (2002Bao, W. & Liu, Z. 2002. 四川瓦屋山原生和次生常绿阔叶林的群落学特征 [Community features of primary and naturally secondary evergreen broad-leaved forests in Mt. Wawu in Sichuan, China]. Chinese Journal of Environmental Biology 8: 120–126 [in Chinese].), Xu et al. (2004Xu, X., Qin, Z.-S., Liao, Y.-M., Gu, X.-D., Yang, L. & Zhao, J. 2004. 小寨子沟-片口自然保护区的植被研究 [Study on vegetation of Xiaozhaizigou-Piankou Natural Reserve]. Journal of China West Normal University (Natural Science) 25: 135–143 [in Chinese].), Xu (2005Xu, D.-Y. 2005. 大巴山自然保护区植被及其特徵的初步研究 [Preliminary investigation on the vegetation of Dabashan Nature Reserve and its characteristics]. Journal of Anhui Agriculture University 32: 332–335 [in Chinese].), Tang et al. (2007aTang, C. Q., Li, T. & Zhu, X. 2007a. Structure and regeneration dynamics of three subtropical midmontane moist evergreen broad-leaved forests in southwestern China, with special reference to bamboo in the forest understories. Canadian Journal of Forest Research 37: 2701–2714. http://dx.doi.org/10.1139/X07-101), Yang et al. (2008Yang, Y.-M., Tian, K. & He, S.-J. (Eds.) 2008. 云南文山自然保护区综合科学考察报告[Integrated scientific studies of Wenshan National Nature Reserve, Yunnan]. Science Press, Beijing [in Chinese].), Bai et al. (2012Bai, Z.-B., Zhang, H.-J. & Ren, G. 2012. 重庆四面山森林植物群落数量分类和排序 [Quantitative classification and ordination of Simian Mountains, Chongqing]. Journal of Anhui Agricultural Science 40: 14839–14843 [in Chinese].), Yang & Xie (2012Yang, X. & Xie, S. 2012. 重庆金佛山国家自然保护区山顶与山坡表土孢粉对比研究 [A comparative study on surface spore-pollen in the mountaintop and mountainside of Mt. Jinfo]. Journal of Mountain Science 30: 655–662 [in Chinese].), Yang et al. (2012Yang, C.-H., Chen, J.-Y. & Ding, F.-J. 2012. 普定县天龙山喀斯特森林群落植物多样性对比研究 [Study on the plant diversity of Karst forest community in Tianlong Mountain of Puding County]. Guizhou Forestry Science and Technology 40: 1–7 [in Chinese].), Zhang et al. (2013Zhang, Z., Hu, G., Zhu, J. & Ni, J. 2013. Aggregated spatial distributions of species in a subtropical karst forest, southern China. Journal of Plant Ecology 6: 131–140. http://dx.doi.org/10.1093/jpe/rts027). [View full size] [Descargar tamaño completo]

To summarize: in SW China, the EBLFs are mainly distributed at higher altitudes [1000‒(2400)2800 m] in the western areas of Yunnan and Sichuan, while occurring at lower altitudes [600‒1500(2000) m] toward the southern and the eastern areas (Figs. 7 and 8). Communities dominated by Castanopsis are widely distributed over the region of SW China. In Yunnan, many plant communities dominated by Lithocarpus and/or Cyclobalanopsis are conspicuous compared with those in the Sichuan Basin and eastern Guizhou.

Eastern China

In Figure 9, representing 23 mountains of eastern China, we find that the Sichuan Basin, eastern Guizhou, and eastern China share some dominant canopy tree species of Fagaceae [e.g. Castanopsis carlesii, Castanopsis fargesii, Castanopsis eyrei, Castanopsis tibetana Hance, Lithocarpus glaber (Thunb.) Nakai, Cyclobalanopsis glauca (Thunb.) Oerst., Cyclobalanopsis myrsinifolia], Lauraceae (e.g. Phoebe neurantha), Theaceae (e.g. Schima superba) and Elaeocarpaceae (e.g. Elaeocarpus sylvestris). In the understory, they often share some genera including Ilex L. (Aquifoliaceae), Lindera Thunb., Litsea Lam. (Lauraceae), Camellia L., Eurya Thunb. (Theaceae), Symplocos Jacq. (Symplocaceae), and Vaccinium L. (Ericaceae). However, these forests lack the flourishing epiphytes and lianas on tree trunks and branches, as compared to the mid-montane moist EBLF of Yunnan. Additionally, in the Yunnan area there are more types of plant communities dominated by Lithocarpus or Cyclobalanopsis or Castanopsis than in eastern China, where the chief dominant genus is Castanopsis. The upper limits of the EBLFs are mainly 600‒1500 m in eastern China (but 2500 m in Taiwan), much lower than in western Yunnan and western Sichuan (2400‒2800 m) (Fig. 10).

Figure 9. The spatial distribution patterns of dominant evergreen broad-leaved communities along latitudes, longitudes and altitudes in eastern China. MS: Monsoon EBLF; HE: Humid EBLF; Cy: Cyclobalanopsis; Ca: Castanopsis; Li: Lithocarpus; Ma: Machilus. Data sources: Chen & Su (1995Chen, B. & Su, Z. 1995. 广东八宝山常绿阔叶林物种多样性分析 [Species diversity of evergreen broad-leaved forest in Babaoshan Nature Reserve, Guangdong]. Journal of South China Agriculture University 16: 32–36 [in Chinese].), Huang et al. (1998Huang, Z., Kong, G., Zhang, Q. & Liu, S. 1998. Structure, species diversity and population dynamics of the lower subtropical evergreen broad-leaved forest in Dinghushan Biosphere Reserve. In: Sun, H.-L. (Ed.), 热带亚热带森林生态系统研究 [The study of tropical and subtropical forest ecosystem] 8. Meteorology Press, Beijing: 64–75 [in Chinese]. ), Hu et al. (2003Hu, Z., Yu, M., Ding, B., Fang, T., Qiang, H. & Chen, Q. 2003. 古田山国家级自然保护区常绿阔叶林类型及其群落物种多样性研究 [Types of evergreen broad-leaved forests and their species diversity in Gutian Mountain National Nature Reserve]. Chinese Journal of Applied and Environmental Biology 9: 341–345 [in Chinese].), Da et al. (2004Da, L.-J., Yang, Y.-C. & Song, Y.-C. 2004. 浙江天童国家森林公园常绿阔叶林主要组成种的种群结构及更新类型 [Population structure and regeneration types of dominant species in an evergreen broad-leaved forest in Tiantong National Forest Park, Zhejiang Province, China]. Acta Phytoecologica Sinica 28: 376–384 [in Chinese].), Xia & Nie (2004Xia, A.-M. & Nie, L.-Q. 2004. 安徽植被带的划分 [Discussion about the forest vegetation zonation in Anhui Province]. Journal of Wuhan Botanical Research 22: 523–528 [in Chinese].), Zheng et al. (2004Zheng, C.-Y., Liu, Z.-L. & Fang, J.-Y. 2004. 福建黄岗山东南坡和西北坡乔木物种多样性及群落特征的垂直变化 [Tree species diversity along altitudinal gradient on southeastern and northwestern slopes of Mt. Huanggang, Wuyi Mountains, Fujian, China]. Biodiversity Science 12: 63–74 [in Chinese].), Zhu et al. (2004Zhu, B., Chen, A.-P., Liu, Z.-L., Li, G.-Z. & Fang, J.-Y. 2004. 广西猫儿山植物群落物种组成、群落结构及树种多样性的垂直分布格局 [Changes in floristic composition, community structure, and tree species diversity of plant communities along altitudinal gradients on Mt. Maoer, Guangxi, China]. Biodiversity Science 12: 44–52 [in Chinese].), Huang et al. (2006Huang, Y. H., Tang, S.-Q., Lu, Z.-Y., Liang, X.-T. & Pan, Q.-D. 2006. 广西金钟山自然保护区主要植被类型的特征 [Characteristics of main vegetation types in Jinzhongshan Nature Reserve, Guangxi Province]. Journal of Tropical and Subtropical Botany 14: 499–503 [in Chinese]. ), Peng et al. (2006bPeng, H., Du, Y., Li, J., Ouyang, X. & Huang, Z. 2006b. 南岭大顶山与鼎湖山常绿阔叶林种群分布格局对比研究 [Comparison of population distribution pattern of evergreen broad-leaved forests between Nanling Dadingshan Nature Reserve and Dinghushan]. Ecology and Environment 15: 770–774 [in Chinese].), Wan (2007Wan, H. 2007. 庐山森林生态系统植物多样性及其分布格局 [Plant diversity and its distribution pattern in the forest ecosystem of Lushan Mountain]. PhD Thesis, Forestry University of Beijing, Beijing [in Chinese].), Deng et al. (2008Deng, T., Zhang, D.-G. & Chen, G.-X. 2008. 湖南小溪国家级自然保护区常绿阔叶林及其生态意义 [Characteristics of evergreen broad-leaved forest in Xiaoxi National Natural Reserve, Hunan Province and its ecological significance]. Journal of Jishou University (Natural Science Edition) 29: 87–93 [in Chinese].), Wang et al. (2009Wang, Y., Liu, Y.-Q., Yan, Q.-P., Deng, Z.-F., Wang, B., Zeng, B.-S. & Guo H. 2009. 江西大岗山常绿阔叶林群落特征研究 [A study on the community characteristics of evergreen broad-leaved forest in Dagangshan Mountains of Jiangxi Province]. Acta Agriculturae Universitatis Jiangxiensis 31: 1055–1068 [in Chinese].), Qiu et al. (2010Qiu, Z.-J., Liu, P., Liu, C.-S. & Gao, J.-G. 2010. 金华北山常绿阔叶林群落结构及优势乔木树种更新类型 [Community structure and regeneration types of dominant species in an evergreen broad-leaved forest in Mount Beishan of Jinhua, China]. Guihaia 30: 629–635 [in Chinese].), Chang et al. (2013Chang, Y., Zhong, Q., Cheng, D., Xu, C., Hu, B. & Zhang, Z. 2013. 闽西北地区不同林龄常绿阔叶混交林物种多样性比较 [Species diversity of evergreen broad-leaved mixed forest with different forest age in the north-west of Fujian province]. Ecology and Environmental Sciences 22: 955–960 [in Chinese].), Tang et al. (2013Tang, C. Q., Chiou, C.-R., Lin, C.-T. et al. 2013. Plant diversity patterns in subtropical evergreen broad-leaved forests of Yunnan and Taiwan. Ecological Research 28: 81–92. http://dx.doi.org/10.1007/s11284-012-1002-0), Yang et al. (2013Yang, Y.-F., Ding, H., Xu, H.-G. et al. 2013. 武夷山典型常绿阔叶林4 个主要植物种群点格局分析 [Point pattern analysis of four main plant populations in evergreen broad-leaved forests typical of Wuyi Mountains, Southeast China]. Journal of Ecology and Rural Environment 29: 184–190 [in Chinese].). [View full size] [Descargar tamaño completo]

Figure 10. The upper limits of EBLFs in SW China. A dot indicates the upper limit of the EBLF on its respective mountain. 1: Tongbiguan; 2: Dulongjiang; 3: Xiaoheshan in Longling; 4: Yongdedaxueshan; 5: Wuliangshan; 6: Ailaoshan; 7: Xilongshan; 8: Daweishan; 9: Wumengshan; 10: Tianlongshan in Guizhou; 11: Gonggashan; 12: Xiaoxiangling in Sichuan; 14: Siguliangshan; 15: Emeishan; 16: Jingyunshan; 17: Simianshan; 18: Maolan in Guizhou; 19: Jinfoshan; 20: Fanjingshan; 21: Kanghe on Dabashan. [View full size] [Descargar tamaño completo]

EFFECTS OF ENVIRONMENTAL FACTORS ON PLANT DIVERSITY PATTERNS IN THE SUBTROPICAL EBLFsTop

As an evidence of environmental effects on species diversity of the EBLF ecosystems, Tang et al. (2013Tang, C. Q., Chiou, C.-R., Lin, C.-T. et al. 2013. Plant diversity patterns in subtropical evergreen broad-leaved forests of Yunnan and Taiwan. Ecological Research 28: 81–92. http://dx.doi.org/10.1007/s11284-012-1002-0) provided species diversity models comparing the EBLF ecosystems of Yunnan and Taiwan (Fig. 11A, B). In Yunnan, the monsoon EBLF in the mesic-humid sites tends to have higher species richness and diversity (Fig. 11A). Along the altitudinal gradients in Taiwan, higher diversity is found in the Machilus–Castanopsis zone at the middle altitudes (500–1500 m) and in the lower Cyclobalanopsis zone at the mid-high altitude (1500–2000 m) (Fig. 11B) (see Fig. 9 for the altitudinal distribution of dominant evergreen broad-leaved tree communities in Taiwan). Species diversity, as influenced by temperature and precipitation, varies with altitude. Thus, altitude in the EBLFs of Taiwan may be a proxy for temperature, because the annual rainfall is abundant (1800–3000 mm) throughout the EBLF zone. In short, site moisture is the best predictor of species composition and diversity in the EBLFs of Yunnan, while temperature along altitudes plays a decisive role in Taiwan. For forest ecosystems, various temporal trends in diversity have been observed during succession, including increases, decreases, and one or more peaks with passing time (e.g. Auclair & Goff, 1971Auclair, A. N. & Goff, F. G. 1971. Diversity relations of upland forests in the western Great Lakes area. The American Naturalist 105: 499–528. http://dx.doi.org/10.1086/282742; Peet, 1978Peet, R. K. 1978. Forest vegetation of the Colorado Front Range: patterns of species diversity. Vegetatio 37: 65–78. http://dx.doi.org/10.1007/BF00121025; Halpern & Spies, 1995Halpern, C. B. & Spies, T. A. 1995. Plant species diversity in natural and managed forests of the Pacific Northwest. Ecological Applications 5: 913–934. http://dx.doi.org/10.2307/2269343; Turner et al., 1997Turner, I. M., Wong, Y. K., Chew, P. T. & Ibrahim A. B. 1997. Tree species richness in primary and old secondary tropical forest in Singapore. Biodiversity and Conservation 6: 537–543. http://dx.doi.org/10.1023/A:1018381111842). Relationships between diversity and succession are complex and should be seen as system-specific. Secondary forests under varying degrees of human disturbance, such as coppice woods or those growing on abandoned farmland, exhibit a range of stages of plant succession in the EBLF zones of both the Yunnan and Taiwan areas. The peak in diversity in the stands at the middle successional stage of each study site in Yunnan and Taiwan (Fig. 11A, B) reflects the persistence of species with varying attributes, including fast growth, slow growth, light demands, limited or greater shade-tolerance, contributing to significantly higher species diversities as compared with the early successional stage. In general, as a forest develops, diversity in the late stage tends to decrease with the disappearance of short-lived light-demanding pioneer species (e.g. Pinus, Alnus Mill., Populus L., Carpinus L., Acacia Mill., Mallotus Lour., and Diospyros L.); however, in both Yunnan and Taiwan the differences in species diversity between the middle and late successional stages are not significant, which reflects the recruitment of shade-tolerant evergreen trees (e.g. Cyclobalanopsis, Castanopsis, Machilus, Ficus L., Manglietia, and Michelia) into the overstory.

Figure 11. (A), changes in species diversity with site moisture and successional time in the EBLFs of Yunnan; (B), changes in species diversity with altitude and successional time in the EBLFs of Taiwan. Data source: Tang et al. (2013Tang, C. Q., Chiou, C.-R., Lin, C.-T. et al. 2013. Plant diversity patterns in subtropical evergreen broad-leaved forests of Yunnan and Taiwan. Ecological Research 28: 81–92. http://dx.doi.org/10.1007/s11284-012-1002-0). [View full size] [Descargar tamaño completo]

This brief comparison clearly shows the effects of moisture, altitude, and disturbance/succession on plant species diversity patterns in the two EBLF ecosystems of Yunnan and Taiwan.

ACKNOWLEDGEMENTSTop

I sincerely thank Dr. J. López-Pujol who invited me to synthesize the available work on the subtropical evergreen broad-leaved forests of China.

REFERENCESTop