Since the Qinling-Huaihe line was delimited as the boundary between north and south China in 1958, discussions on the local position of the line, criteria for dividing temperature zones, the line's environmental effect, among others, are ongoing. The National Basic Resources Investigation Program "Integrated Scientific Investigation of the North-South Transitional Zone" launched in 2017, introduced the concept of north-south transitional zone (Qinling-Daba Mountains) and planned to explore the north-south dividing line from the perspective of transitional zone, so as to strengthen and make some breakthroughs in the study of the north-south division. The Qinling-Daba Mountains are the main body of China's north-south transitional zone, with multi-dimensional zonal structures and high degree of environmental complexity, biological diversity, and climatic sensitivity. The following 10 scientific issues need to be dealt with in the years to come: 1) The relationship between the north-south dividing line and the north-south transitional zone; 2) improvement of criteria for identifying subtropical and warm-temperate zones; 3) integral north-south series and variation of vegetation and soil types; 4) relationship between global warming and spatial change of key bioclimatic criteria; 5) decomposition and integration of multi-dimensional zonal structures in the Qinling-Daba Mountains; 6) pattern and mechanism of biological diversity and endemics; 7) the corridor effect of the Qinling-Daba Mountains; 8) regional environmental effect of the Qinling-Daba Mountains and implications for the national ecological security; 9) significance and position of the Qinling-Daba Mountains for the history and development of China; and 10) significance of the geographic structure of Western Qinling Mountains for the origin of the Chinese civilization. These key issues are not only the results of previous research, but also the starting point for further exploration and study in the future. They are intended to inspire and encourage an in-depth study of China's north-south dividing line or transitional zone, and to provide new perspectives and framework for the exploration of physio-geographic theories, biodiversity, and ecological security, and even the birthplace of the earliest Chinese civilization.

秦岭-淮河一线在60 a前被科学地确定为中国南北分界线。此后中国地学科学家一直在探索分界线的具体位置和划分指标改进问题;随着数据的积累和认识的加深,还发现了一些新的科学问题。2017年启动的国家科技基础资源调查专项“中国南北过渡带综合科学考察”将秦岭-大巴山定义为中国南北过渡带的主体,拟全面系统地调查和研究其自然地理要素与资源问题,从而实现中国南北分界线研究的全面深化和突破。秦岭-大巴山具有多维地带性结构,表现出高度的过渡性、复杂性、多样性和敏感性。目前面临和需要研究的主要科学问题包括：① 南北分界线与南北过渡带的关系?② 暖温带与亚热带划分指标如何改进?③ 植被-土壤在南北方向上的渐变序列及其形成机理?④ 全球变化与地区关键生物气候指标空间变动的关系?⑤ 秦巴山地的多维地带性结构如何分解与综合?⑥ 秦巴山区生物多样性、特有性的格局与机理?⑦ 秦巴山地东西向廊道效应?⑧ 秦巴山地的区域环境效应及对国家生态安全的意义?⑨ 秦巴山地在中国历史发展中的特殊意义?⑩ 西秦岭的地理结构与华夏文明起源的关系?这些问题既是过去研究工作和认识的总结,也是未来一段时间内需要关注和研究的重点。希望这样的归纳和梳理对于中国南北过渡带和南北分界线的科学研究具有一定的启发和促进作用,为中国自然地理学理论发展、生物多样性和生态安全研究,甚至为华夏文明起源的研究提供新的视角和框架。

On account of vast territory and complex physico-geographical conditions as well aagreat human impacts, the distribution of mountain vegetation in China is very compli-cated. Yet, law of zonation still holds true. The structure and character of mountainvegetation change along two directions, i.e., from south to north and from east to west.In the eastern part of China altitudinal vegetation-belt spectrums change mainlyfrom south to north.1. Warmth-like types of altitudinal vegetation-belt spectrums being replaced bycold-resistant types with alternation of basic vertical vegetational belts from evergreenbroad-leaved forests to deciduous needle-leaved forests.2. Diminution of number of altitudinal belts and simplification of their structures.3. Lowering down of altitudes of altitudinal vegetational belts. On mountains inwestern part of subtropical zone lies the highest altitude of timberline in the world, witha maximum altitude of over 4,400 m above the sea level. It lowers down towards northby over 100 m per degree of latitude.4. Occurrence of dominant belts in vertical profiles of mountain vegetation de-pends upon the nature of horizontal zones. The dominant belts in typical geographicalzones are certainly the basic vertical vegetational belts. And in transitional zones theyoccur above the basic vertical belts.While in the arid and semi-arid western part of China, changes of altitudinal vege-tation-belt spectrums are quite different. They take place chiefly from east to west. Itis worthwhile mentioning that structures of vegetation-belt spectrums are very simpli-fied, steppes and deserts occupy the dominant position on mountains and all altitudinalvegetational belts ascend in this direction.

地球上植被的大型分布,明显地呈现地带性变化。平地上表现为水平地带性,包括纬度地带性和干燥度地带性;山地上表现为垂直(地)带性,就是所谓“三维空间”分布现象。我国地广山多,自然条件复杂,研究山地植被的分布规律不但具有理论意义,而且也富有实践意义。

China has a very vast area, complex environment and rich plant species comprising arctic, temperato and tropical types. In addition to climatic, edaphic and topographical differences in different geographical regione, the vegetation-ty-pes havo been made more complicated by certain geological factors, the glacial factor, for instance, which resulted in remaining certain amount of preglacial remnants in certain places. The anthrohic effects for more than 5,000 years have certainly caused profound changes in our natural vegetation. In general, the en- vironmental factors which affect the vegetation most are climatic, topographic, edaphic, histbric and biotic onus among which the climate is certainly the most important, but in connection wiili other features its effect is expressed differently in different regions. In China, in western part, especially in Tibetan plateau, the topographical factor becomes most prominent; in northern and eastern parts the cold tide predominates，in the coastal region the Pacific and Indian monsoons play the leading part.

我国地域广大,环境复杂,植物种类在25,000种以上,兼有寒带、温带、热带三种类型。各地区的气候、土壤、地形的差异很大,而气候、土壤、地形的不同组合和相互影响,又都根本地影响着各地区的植被群落。

This paper states the distribution of 177 species (including their varieties) of broadleaf woody evergreens on the Qin-lin Mountain, based on the viewpoint of specific phytogeographic or floral elements. It is possible to classify these species into two groups: One may be considered as that belongs to typical subtropical floral elements which are located on the southern slope of Qin-lin Mountain (Table 3); the other may be belong to the temperate ones which are found on the northern slope of the Qin-lin Mountain (Table 4). According to the distribution of above-mentioned floral elements, the northern boundary of the subtropical zone of China is located near 1000 m. above sea level on the southern slope of central part of Qin-lin Mountain, lying approximately from Latitude 33°5’, Wudu of Gansu Province, to 33°5’ North, the southern slope of the Funiu Mountain of Henan Province.

关于划分我国亚热带的北界问题,意见虽不一致,但主张以秦岭淮河一线为界者较多,然而秦岭南北宽约300公里,此线应划何处较为合适,至今意见仍有分歧。

一、前言 亚热带与暖温带的分界线,在我国是一条重要的自然界线,它的划分问题,引起了自然地理学、气候学、土壤学和地植物学等科学工作者的争论。研究这个问题不仅在理论上具有重要意义,而且它是综合自然、农业、林业等区划的依据之一。所以,亚热带与暖温带分界线的划分,能否正确地反映自然界的客观规律,是关系到运用这规律来指导生产实践的大问题。

一、前言 亚热带与暖温带的分界线,在我国是一条重要的自然界线,它的划分问题,引起了自然地理学、气候学、土壤学和地植物学等科学工作者的争论。研究这个问题不仅在理论上具有重要意义,而且它是综合自然、农业、林业等区划的依据之一。所以,亚热带与暖温带分界线的划分,能否正确地反映自然界的客观规律,是关系到运用这规律来指导生产实践的大问题。

The Qinling Mountain Range is considered as an important geo-ecological boundary between the warm temperate and the subtropical zones in eastern China, however, the specific line of the boundary has been controversial among the academic circles. Several studies based on vegetation ecology and flora geography have been done on discussing the division of this boundary, but in all of which Pteridophyta is not included. Pteridophyta is a transitional link between different flora groups in plant evolution, and thus is more sensitive to the environment that fosters it than other plant groups. It is conducive to and necessary for a better understanding of the division of the geo-ecological boundary in Qinling Mountain Range to research into the Range's Pteridophyta flora. In this paper, the composition and geographical elements of the flora of Pteridophyta were studied, and the division of the vertical Pteridophyta spectrum and the further division of the geo-ecological boundary in Qinling Mountain Range were also discussed, by applying the principles of classical florology and using quantitative ecology method as TWINSPAN and DCA into the analyses, based on comparison between the field investigation data and the relevant literatures. The results of our research have shown and revealed: 1) There are 311 species of Pteridophyta, belonging to 85 genera and 36 families in the Qinling Mountain Range; in which the dominant families are Dryopteridaceae, Athyriaceae, and Polypodiaceae, and the dominant genera Dryopteris and Polystichum; meanwhile, the main areal-types of family and genera are tropical elements, while the areal-types of species is dominated by the temperate elements. 2) The altitude of 1000 m a.s.l. at the southern piedmont of the Range should be an important ecological boundary, since the floristic composition of the Pteridophyta below this elevation showed more similar features to the subtropics, while above it the features of the composition and the vertical vegetation spectrum of the Pteridophyta are much closer to the temperate zones. 3) DCA ordination of FER (floristic element ratio) among 15 regions in northern and southern China and the both sides of Qinling Mountain Range strongly supported the hypothesis mentioned above. Based on these results, we tend to deem that the geo-ecological boundary between the subtropical and warm temperate zones lies around the altitude of 1000 m a.s.l. at the southern piedmont of the Range.

依据2007~2008年野外实地调查以及相关文献资料,运用植物区系地理学和数量生态学方法,分析了秦岭蕨类植物区系的物种组成和地理分布特征,划分了秦岭蕨类植物的垂直带谱,并以此为基础探讨了秦岭山地生态分界线的划分,得出以下主要结论:(1)秦岭共有蕨类植物36科85属311种,优势科为鳞毛蕨科、蹄盖蕨科和水龙骨科,优势属为鳞毛蕨属和耳蕨属;在科属水平上,以热带成分占优势;而种的水平则以温带成分占绝对优势。(2)根据秦岭蕨类植物南北坡垂直带谱的对比分析,南坡海拔1000m左右应该是一条重要的生态分界线。(3)南坡1000m以下蕨类植物区系组成更接近亚热带区系,而其他地带则与温带蕨类植物区系更为接近,DCA排序很好地证明了此结果。综合来看,将南坡海拔1000m作为秦岭山地亚热带与暖温带的生态分界线较为科学。

To determine the dividing index between warm temperate and subtropical zones based on the spectra of altitudinal belts, this paper collected 33 spectra of altitudinal belts in the Qinling-Daba Mountains from published literatures and then analyzed the structures and the spatial patterns from south to north, from west to east and based on exposure directions. The results show that: 1) From south to north, the basal belt gradually changes from subtropical evergreen broadleaf forest to warm temperate deciduous broadleaf forest; the spectra of altitudinal belts change from complex to simple; the dominant belt changes from montane broadleaf-conifer mixed forest and evergreen-deciduous broadleaf mixed forest to deciduous broadleaf forest. 2) From west to east, the structures of the altitudinal belt spectra show complexity in the east and west but simplicity in the middle section; the upper limits of both the evergreen-deciduous broadleaf mixed forest belt and montane deciduous broadleaf forest belt present a quadratic curve distribution pattern in the longitudinal direction. However, the upper limit of the montane broadleaf-conifer mixed forest belt exhibits a nearly linear decrease in the west-east direction. 3) Both the north and south slopes in the Qinling Mountains have the similar basal belt, whereas it varies greatly between the north and south slopes in the Daba Mountains. Comparably, dominant belts are very similar in the Qinling Mountains and the north slope of the Daba Mountains, but the south slope of the Daba Mountains has its own unique dominant belt: evergreen-deciduous broadleaf mixed forest. This implies that the Daba Mountains are more appropriate than the Qinling Mountains to act as the boundary between subtropical and warm-temperate zones in central China.

Using quantitative analysis (DCA and TWINSPAN), the vegetation and plant species diversity patterns along the elevation gradient in Mt. Niubeiliang, Qinling Mountains were studied based on 51 plots along two altitudinal transects between 1500 m and 2800 m on northern and southern slopes. Plant communities varied continuously along the elevation gradient. From low to high elevation, mountain oak forest, mountain birch forest, subalpine fir forests and subalpine shrub occurred on both slopes. Relationship between communities and topographic variables were analyzed by detrended correspondence analysis (DCA). Elevation was the primary determinant of floristic composition in Mt. Niubeiliang, and followed by exposure. In terms of species diversity, different patterns existed among total number of species, woody species richness and herbaceous species richness, and also between southern and northern slopes. The total number of species changed unimodally with elevation on the southern slope, peaking at middle elevations. No significant relationship between total number of species and elevation was detected on the northern slope. Woody species richness changed similarly on both southern and northern slopes, keeping stable at low elevations and decreasing monotonically with the increasing elevation at high elevations. In contrast, no significant pattern of herbaceous plant richness existed along the elevation gradient. β diversity was higher at lower and higher elevations than in the mid-altitudinal zone, indicating a more homogeneous habitat at middle elevation than upper and lower elevations. Human disturbance at lower elevation and the timberline ecotone at higher elevations may contribute to the increase of β diversity in these areas.

基于秦岭山脉中段牛背梁自然保护区南北坡垂直样带51个样方的调查资料，利用植被数量分析方法（TWINSPAN和DCA）对牛背梁植物群落进行了分类和排序，并分析了植物物种多样性沿海拔梯度的分布格局。结果表明，牛背梁的植被群落具有明显的海拔梯度格局，从低海拔到高海拔依次分布有： 锐齿槲栎(Quercus aliena var. acuteserrata)林，桦木(Betula spp.)林，巴山冷杉(Abies fargesii)林和亚高山灌丛。海拔梯度是牛背梁山区制约植物群落分布的主要因子，而坡向和坡度则起到次要作用。对物种多样性的分析表明，物种总数、木本植物物种多样性和草本植物物种多样性在南北坡具有不同的海拔梯度格局。物种总数在南坡呈现单峰分布格局，而在北坡分布趋势不明显; 木本植物物种多样性在南北坡具有相似的分布格局： 在低海拔沿海拔梯度变化不明显，而在高海拔则随海拔上升而急剧下降; 草本植物物种多样性在南北坡沿海拔梯度变化的规律不明显。β多样性沿海拔梯度先减少后增加，形成两端高中间低的格局，说明中海拔地区生境条件较为均一，低海拔地区的人为活动增加了生境的异质性，而高海拔地区的生态过渡特性增加了物种的更替速率以及群落的相异性。

The National Basic Resources Investigation Program "Integrated Scientific Investigation of the North-South Transitional Zone" introduced the concept of north-south transitional zone (Qinling-Daba Mountains). Variation of north-south series in vegetation of the Qinling-Daba Mountains is of great significance to reveal the transition, diversity and complexity of the regional structure of China's north-south transitional zone. Based on the survey data of plant communities, in this study, the eastern Qinling-Daba Mountains is divided into four geography units: north flank of eastern Qinling Mountains (EQMN), south flank of eastern Qinling Mountains (EQMS), north flank of eastern Daba Mountains (EBMN), south flank of eastern Daba Mountains (EBMS). The regional climate divisions on levels of plant species, plant community structure and species richness are explored. The results show that: (1) On plant species level, there are mainly north plants in EQMN, evergreen species and fewer north plants in EQMS. Then to the eastern Daba Mountains, there are mainly south plants which like wetness and heat. (2) On plant community structure level, there are 4 formations (3 northern formations, 0 southern formation, 1 widespread formation) in EQMN, 6 formations (3 northern formations, 1 southern formation, 2 widespread formations) in EQMS, 4 formations (0 northern formation, 2 southern formations, 2 widespread formations) in EBMN, 3 formations (0 northern formation, 3 southern formations, 0 widespread formation) in EBMS. In terms of the numbers and properties of formation, there is a mixture of northern and southern formations only in EQMS. On species richness level, the diversity of family, genus and species decreases with the increase of latitude, but the mixture of north and south plants occurred in the south flank of eastern Qinling Mountains. This paper studies the variation of series in vegetation, which increases the scientificity of determining north-south dividing line, and shows that the south flank of eastern Qinling Mountains is more suitable as the warm temperate-subtropical zones dividing line.

国家科技基础资源调查专项“中国南北过渡带综合科学考察”将秦岭—大巴山定义为中国南北过渡带的主体,秦巴山地植被南北变化研究,对于揭示中国南北过渡带地域结构的过渡性、多样性和复杂性具有重要意义。基于植物群落实地调查数据,本文将中国南北过渡带东段分为：东秦岭北麓（EQMN）、东秦岭南麓（EQMS）、东大巴山北麓（EBMN）和东大巴山南麓（EBMS）4个地理单元,从植物物种、群落结构和物种多样性三个层面,对区域气候分界问题进行研究。结果表明：① 植物种类层面,EQMN主要为北方植物,EQMS出现常绿树种且北方植物减少,东大巴山以喜湿喜热的南方植物为主。② 群落结构层面,EQMN群系有4个（北方群系3个,南方群系0个,广布群系1个）、EQMS有6个（北方群系3个,南方群系1个,广布群系2个）、EBMN群系有4个（北方群系0个,南方群系2个,广布群系2个）、EBMS群系3个（北方群系0个,南方群系3个,广布群系0个）,只有EQMS群系出现南北性质混合;③ 丰富度层面,随着纬度增加,科、属、种3个分类群物种多样性均减小,但南北方植物混合现象开始在EQMS出现。本文对植被变化序列的研究增加了对东秦巴山地南北分界线判断的科学性,东秦岭南麓更适合作为暖温带—北亚热带的分界线。

Qinling Mountains is not only the geographical boundary between North and South China, but also the boundary between subtropical and warm temperate zones. It plays an important role in the geo-ecological pattern of China. However, there is controversy about the specific location of this geographical boundary in academic community due to the complexity, transition and heterogeneity of the transitional zone, as well as the differences in the delimitation indicators and research purposes. To further reveal the characteristics of the North-South transitional zone and clarify the specific location of the geo-ecological boundary between North and South China, combined with SRTM topographic data, temperature and precipitation data, Pinus massoniana forest and Pinus tabulaeformis forest, which represent subtropical coniferous forests in South China and temperate coniferous forest in North China respectively, were chosen to analyze their spatial distributions in the Qinling-Daba Mountains and the climatic conditions at their boundary with the climatic indexes of annual precipitation, the coldest month (January) average temperature, the warmest month (July) average temperature and the annual average temperatures. The results show that: (1) Pinus massoniana and Pinus tabulaeformis forests and the climate indicators of their boundary can be used as one of the vegetation-climate indicators for the delimitation of subtropical and warm temperate zones. The boundary between the subtropical coniferous forest (Pinus massoniana forest) and temperate coniferous forest (Pinus tabulaeformis forest) in Qinling-Daba Mountains is located along the south slope of Funiu Mountain to the north edge of Hanzhong Basin (the south slope of Qinling Mountains) at an altitude of 1000-1200 m, where the climatic indictors are stable: the annual precipitation is about 750-1000 mm; the annual average temperature is about 12-14 ℃; the coldest monthly average temperature is 0-4 ℃; and the warmest monthly average temperature is about 22-26 ℃. (2) It could be more scientifically to delimitate the boundary of subtropical and warm temperate zones in China by comprehensively considering the vegetation-climate indicators. Additionally, the boundary between subtropical and warm temperate zones in Qinling-Daba Mountains should be a transitional zone consisting of the boundaries of coniferous forests, broad-leaved forests and shrubs between subtropical and warm temperate zones. The results provide a scientific basis for the selection of delimitation indicators of subtropical and warm temperate zones.

秦岭不仅是中国南北的地理分界线,也是中国亚热带和暖温带的气候分界线,在中国地理生态格局中占有重要的地位和作用。由于过渡带的复杂性、过渡性和异质性以及划分指标、研究目的的不同,学术界关于这一南北地理—生态分界线的具体位置一直有争论。为了进一步揭示秦巴山区过渡带的特征,明确中国南北地理—生态分界线的位置,本文选择马尾松（Pinus massoniana）林和油松（Pinus tabulaeformis）林这两类分别代表中国南方亚热带针叶林和北方温带针叶林的植被,结合研究区SRTM地形数据、气温和降水数据等,以年降水、最冷月（1月）气温、最热月（7月）气温和年均温为气候指标,详细分析了这两类植被在秦巴山区的空间分布及二者分界线处的气候条件。结果表明：① 马尾松林和油松林的分界线及相应位置的气候指标可以作为亚热带与暖温带界线划分的植被—气候指标之一。秦巴山区亚热带针叶林（马尾松林）与温带针叶林（油松林）的分界线位于伏牛山南坡至汉中盆地北缘一线（秦岭南坡）海拔1000~1200 m处;分界线处气候指标稳定：年降水750~1000 mm,年均温12~14 ℃,最冷月气温0~4 ℃,最热月气温22~26 ℃。② 通过综合的植被—气候指标来划分秦巴山区亚热带和暖温带的界线,能更科学地确定气候带分界线的位置及过渡带的特征,更全面地反映地表植被—气候格局的变化。此外,秦巴山区亚热带与暖温带的界线应该是由亚热带与暖温带针叶林分界线、阔叶林分界线、灌丛分界线等组成的一个过渡带。本文的研究结果为亚热带与暖温带划分指标的选取提供了一定的科学依据。

A plant community is an assemblage of plant populations that live in certain area, and interact with and adapt to one another in the context of long-term environmental changes. Plant communities maintain global ecosystem functions, and provide food and habitats for animals and other organisms. Plant communities also provide primary resources for human survival and development, and are therefore indispensable to human societies. China is among the countries with the most diverse plant communities in the world. However, no systematic national inventory has been conducted for Chinese plant communities. This fact obstructs exploitation and protection of China’s plant resources, and also hampers the development of the fields of Chinese ecology and geography. There is an urgent need to survey Chinese plant communities using consis-tent methods and protocols. In this paper, we review major concepts in plant community ecology, and pro-pose a framework for developing plant community inventories based on recent progress in community ecol-ogy and our own experience with long-term field surveys. Our framework provides protocols for site selec-tion and plot design, items to be measured in a plot, and measurements of functional traits of dominant spe-cies. We also review protocols for field surveys of large, long-term plots. The protocols proposed in this pa-per are expected to be a base for standardizing methodology for inventory of Chinese plant communities.

The boundary between warm temperate and subtropical zones is an important natural boundary in physical regionalization; however there is controversy about the specific location of the boundary. Because the earlier physical regionalization was mainly based on qualitative methods with expert knowledge, and the regionalization objectives and the adopted indicators were different, scholars had differences in the divisions of physical regions. Based on the idea of spatial differentiation, this paper used geodetector to quantitatively examine the impact of climate indicators on the northern boundary of subtropical zone of China, selected the important indicators with a large q value as the dominant factor and refered to the vegetation and soil data to explore the location of the subtropical northern boundary. The results show that: (1) The geodetector method can quickly and accurately screen the main climate indicators of physical regionalization, decide the precise location of the boundary, which improves the technical level of physical regionalization research and the objectivity of physical regionalization. (2) The new boundary delimitated in this paper is located at the altitude of 1000-1600 m on the south slope of the Qinling Mountains in the western part of the study area, slightly south compared to the previous boundaries (it is consistent with that of Zheng Du and Xi Chengfan in the east of Shaanxi); and it is north compared to the previous boundaries (especially in the north of eastern Henan and northern Anhui) in the eastern part of the study area. While maintaining the integrity of natural elements, the new boundary has a larger q value, indicating that it can well reflect the difference between the warm temperate zone and the northern subtropical zone, and the division results are reasonable.

暖温带与亚热带的分界线,是自然区划中一条重要的自然界线,它的划分问题曾引起诸多学科学者的争论。由于早期综合自然区划研究多以定性、专家集成方法为主,同时区划目的、使用指标等多有不同,导致不同学者所划分的自然区多存在一定的差异。本文基于空间分异性思想,使用地理探测器定量探测气候指标对中国亚热带北界的影响,选择其中q值较大的指标如日均温≥0℃天数、最冷月1月均温、年降水和湿润指数等作为主导因子并参考植被、土壤数据探讨亚热带北界界线的位置。结果表明：① 地理探测器法可以快速、准确地筛选自然区划的主要气候指标,并确定分界线的准确位置,提高了自然区划研究的技术水平和区划界线的客观性。② 使用地理探测器划分的新界线在研究区西部位于秦岭南坡1000~1600 m的位置,与以往界线相比略偏南;在研究区东部河南东部、安徽北部比以往界线略偏北。在保持自然要素完整性的同时,新界线具有更大的q值,表明新界线可以很好的反映暖温带与北亚热带2个区划带之间的差异,划分结果具有合理性。