Article Ecology May 2013 Vol.58 No.15: 17751786 doi: 10.1007/s11434-012-5657-2 Relationships between vegetation and stomata, and between vegetation and pollen surface soil in Yunnan, Southwest China SHEN HuaDong1,2, LI ChunHai1*, WAN HeWen3, TONG GuoBang4, LIU JinSong5,6 & DAN Johnson7 1 State Key Laboratory of Lake Science and Environment, Nanjng Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; 2 University of Chinese Academy of Sciences, Beijing 100049, China; 3 College of Life Sciences, Anhui University, Hefei 230039, China; 4 Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Zhengding 050803, China; 5 Mathematics and Information Science College, Hebei Normal University, Shijiazhuang 050024, China; 6 The Key Laboratory of Calculation and Application of Hebei Province, Shijiazhuang 050024, China; 7 Environmental Science, Department of Geography, University of Lethbridge, Alberta T1K 3M4, Canada Received August 26, 2012; accepted November 30, 2012; published online February 21, 2013 Surface pollen and stomata of 61 samples collected in a study area ranging from tropical seasonal rainforest to oak forest (Quer- cus spinosa) in the Yulong Snow Mountain region in Yunnan, China, are used to distinguish vegetation communities. The results show that tropical seasonal rainforest (and mountain rainforest), south subtropical evergreen broad-leaved forest, and Quercus shrub are distinguished effectively from other vegetation types by analysis of surface pollen. The south subtropical evergreen broad-leaved forest, Pinus kesiya forest and evergreen broadleaf forest are distinguished effectively from other types of vegetation by pollen analysis. However, P. yunnanensis forest is not distinguished from other vegetation types, and P. armandii, P. densata forest and temperate deciduous conifer mixed forest are not distinguished. The over-representation of Pinus pollen is the main reason that these vegetation communities are not distinguished from each other. Conifer stomata analysis is an effective tool for identifying and distinguishing different types of coniferous forest, and this method performs well even with a small number of sampling points. Yunnan, pollen, stomata, topsoil, vegetation, palynology Citation: Shen H D, Li C H, Wan H W, et al. Relationships between vegetation and stomata, and between vegetation and pollen surface soil in Yunnan, Southwest China. Chin Sci Bull, 2013, 58: 17751786, doi: 10.1007/s11434-012-5657-2 Pollen analysis provides important indicators which recon- for accurate reconstruction of palaeovegetation [3]. Howev- struct palaeovegetation [1,2]. However, such results are er, adequate and reliable fossils are often unavailable. The often inaccurate because of uncertainty related to factors other method relies on identification and quantification of affecting pollen production, dissemination, deposition, and stomata, and provides an accurate means of reconstructing identification. Therefore, other assisting means of palaeo- palaeovegetation [4]. vegetation reconstruction are needed. At present, there are In the early 1950’s, Trautmann [5] found that observa- two main auxiliary methods of reconstructing palaeovegeta- tions on conifer stomata served as a potential palaeoenvi- tion. One method is based on examination of plant fossils, ronmental analysis tool, and that some conifer stomata from which identify species, and provides important information vegetation in central Europe are morphologically distinctive. Parshall [6] found that conifer leaves could only transport a *Corresponding author (email: [email protected]) very short distance, scattering within approximately 20 m © The Author(s) 2013. This article is published with open access at Springerlink.com csb.scichina.com www.springer.com/scp 1776 Shen H D, et al. Chin Sci Bull May (2013) Vol.58 No.15 from the origin. The stomata found in closed lake sediments 1 Study area provide information on the plants which grew in the local area, serving as a substitute for observations of plant fossils Yunnan Province lies in the extreme southwest of China [7,8]. Conifer stomata observations as an important sup- (21°9′–29°15′N, 97°30′–106°12′E). Complex mountains and plement for pollen analysis have received extensive atten- valleys were formed during massive uplift and erosion dur- tion and research in Europe, North America, Siberia, and ing the end of the Tertiary and Quaternary. Elevation varies Latin America. In Europe, stomata analyses were applied to considerably, from less than 100 m on the Red River in study timberline migration [9–13]; in North America, Han- southeast Yunnan, to more than 6000 m in the northwest sen [14] first used the stomata to study vegetation changes, mountains, within the range of foothills of the Himalayas. In and further developed the identification standards of the eastern Yunnan, rivers generally flow eastward in relatively stomata, on the basis of Trautmann’s study. However, the shallow valleys, but in the west, the riversf low southward or scope of applications using stomata methodology has wid- southeastward, deeply dissecting the plateau landscape by ened. Recently, stomata analysis has been applied to re- as much as 1000 m. Altitude drops from north to south [29]. search conducted in alpine and arctic regions and Kennedy The climate of Yunnan is influenced by the interaction of evaluated Pinus stomata to distinguish mountain forest from several circulation systems, typically sub-tropical monsoon- grassland in Dominica [15]. Stomata analysis has also been al, affected by monsoons from the southwest, southeast and applied in the Yangtze River Delta and Liupangshan in northeast, and extra-tropical westerlies. The high altitude China [16,17]. strongly influences temperatures within the region. Yunnan The study of vegetation changes in the Yunnan forest ar- has a relatively mild climate, with maximum and minimum ea in China, an ecological region strongly influenced by the annual temperatures of 22.1 and 9.1°C. Average annual Asian monsoon, is important for the understanding of mon- precipitation is distinctly seasonal and varies from 800 mm soons and global climate change. Since the Quaternary, in dry valleys to 1700 mm in the southern and western areas, changes in the vertical belt of mountain forest in Northwest with 80%–90% during May to October. Yunnan may due to climate change [18–20]. Determination The topographical variety within the province has re- of the sequence and causes would be supported by accurate sulted in a rich diversity of vegetation, ranging from tropical methods of reconstruction of the vegetation community. rainforest to alpine exposed gravel, and cold desert from However, studies of surface pollen samples reveal that the Xishuangbanna in southern Yunnan to Yulong Snow Moun- accuracy of reconstruction of palaeovegetation by pollen is tain in northwestern Yunnan, within a straight-line distance limited in such areas, because of the over-representation of of more than 600 km [29]. Pinus pollen [21,22]. In addition, a wide range of gymno- Within the study area, a total of 61 surface pollen and sperms are extensively distributed in Yunnan region, vary- stomata samples were taken from Xishuangbanna in south- ing from cold temperate coniferous forest to subtropical ern Yunnan to Yulong Snow Mountain region in northwest- Pinus kesiya forest, in which conifer species are dominant. ern Yunnan (Figure 1). The main vegetation types are shown These conifers have specific significance for ecological and in Figure 1 and Table 1. palaeoecological research, if their stomata can be used as an auxiliary method to pollen analysis to reconstruct the an- cient vegetation diversity, abundance and distribution. If 2 Materials and methods validated, the method would provide a powerful means of reconstructing paleovegetation and paleoclimate. In 2005 and 2006, samples were collected from the southern The study of the relationship between current pollen ob- tropical rainforest in Xishuangbanna to the northern cold served in standard sampling to corresponding vegetation is a coniferous forest of Yulong Snow Mountain in Yunnan (Fig- very important step toward the reconstruction of palaeoveg- ure 1). The main material collected in each sample is topsoil etation [23], as a validation and calibration of the methods. and moss. At each sampling point, 4–5 samples of moss or Likewise, the study of the relationship of modern pollen topsoil were randomly selected and collected within an area stomata to corresponding vegetation can also provide im- of approximately 100 m2, then combined into one bulked portant reference relationships for reconstruction of the an- sample and tagged with the location and altitude of each cient vegetation communities. Similar research has been sampling point by GPS (Table 1). In order to study whether conducted in North America, Central Asia, and South the stomata can accurately indicate the existence of cold America [5,15,24–28]. This article reports the results of temperate coniferous vegetation communities, samples were examinations of the relationships among vegetation, pollen also collected in the forest sites where cold temperate tree and stomata, based on the study of pollen and stomata sam- species are not dominant to test the accuracy of analysis of ples from different types of vegetation in Yunnan. The pur- stomata as indicators. pose of the research is to provide evidence and data as Standard hydrofluoric (HF) methods