旅游及城市化影响下的避暑山庄植被及其生态规划研究

避暑山庄是现存我国最大的皇家园林。由于种种原因，避暑山庄植被从建庄至今，发生了很大的变化，原始植被破坏殆尽，仅留下少数古树，现状植被多为五十年代大搞绿化时所植，植物配冤出现了与这一历史名园不相协调的矛盾;近几十年来旅游及城市的发展对避暑山庄植被有一定的冲击，要求有相应的对策。 我有从生态学的观点出发，首先对避暑山庄的历史及现状植被进行了研究，然后研究了旅游与城市化对避暑山庄植被的影响，最后，对避暑山庄不同游览区的生境优劣(土壤肥力及小气侯因子)及环境污染(S、Pb)的现状进行了观测与分析。根据上述研究，我们进进了避暑山庄植被生态规划。结果如下: 1、避暑山庄盛期的主要植被是以油松、栎类为主的针(阔)叶林或混交林，尚有以白榆、国槐、旱柳、元宝械等组成的混合林等10个植物群落。 2、避暑山庄现状植被可划分为14个植物群落，以油松群落面积最大。 3、旅游及城市化对避暑山庄植被的影响，主要表现在对土壤的影响及对植被的直接影响，主要方式有机械破坏及造成的环境污染的危害等，这些影响与避暑山庄古松死亡(26.5棵/年)有很大关系。 4、山庄各游览区环境污染的大小顺序是:宫殿区>湖洲区>平原区>山峦区。其中避暑山庄S污染严重是北京北京植物园的2.1倍。 5、避暑山庄各游览区生境优劣:山峦区优予胡洲区，湖洲区优于平原区，平原区优于宫殿区;在山峦区，沟谷优于阴坡，阴坡优于阳坡。 6、避暑山庄湖水出现了富营养化污染，总N及总P含量超过国家标准3倍多。 7、基于上述分析，提出了以旅游为主的避暑山庄植被生态规划原则，根据这一原则，规划出11个植物群落。 8、共编绘了1:10000的避署山庄历史、现状及规划植被图3幅。

旅游相关活动对九寨沟核心景区植物多样性与结构的影响

日益增强的旅游活动干扰正成为九寨沟世界自然遗产的有效保护与持续管理不可回避的挑战，已成为当前区域生态保护与经济发展的焦点问题之一。阐明相关旅游的干扰活动对核心景区植物物种组成、多样性与结构的影响是九寨沟有效保护与持续管理的必要前提和基础，然而至今少有研究。选择九寨沟与旅游活动相关的九个景点、公路建设地段以及退耕地还林地，详细调查了林下植被结构、物种组成与多样性，比较了相关旅游活动干扰与基本未受干扰地段的差异。目的是阐明九寨沟核心景区旅游干扰条件下植物多样性与群落结构及其特点，揭示旅游干扰与植被结构和生物多样的相互关系，评估九寨沟旅游管理的有效性，探索减免旅游干扰影响的对策与措施。初步结论如下。 1.旅游活动引起九寨沟核心景区植物组成和群落结构特征改变显著。栈道及公路附近许多耐荫喜湿的敏感种局部消失，而早熟禾、车前草、委陵菜等耐干旱、耐践踏、繁殖能力强的植物种群扩大；外来物种频繁出现并已少量侵入干扰相对较轻的林分深处；林下群落以草本植物为优势，灌木与苔藓植物的频度、盖度、高度以及灌木密度均有所下降。可见，大量的游人活动和景区公路建设已对九寨沟丰富的乡土植物构成极大威胁，导致其生物多样性降低。而九寨沟农耕地退耕有利于九寨沟生态环境和生物多样性保护，正逐步向稳定群落演替。 2．干扰强度的差异导致九寨沟植物所受影响的程度不同。栈道附近植物受影响的程度与游人活动频率有关，活动频率高的地段干扰强度大，对植物的影响程度重，反之植物所受的影响较轻。强度干扰地段，耐荫喜湿的物种少见，伴生植物优势地位突出，生物多样性明显降低，植物群落结构特征改变也极为显著；干扰较轻的地段，伴生物种少量出现，植物群落结构变化不明显，生物多样性略为降低，部分地区结构参数值和多样性指数有所升高。公路修建是一种强度干扰，它导致附近植物种类极为单一，草本优势种异常突出，多数植物生活力低下、生长更新能力差。 3.不同植物类群受干扰影响的程度不同。草本及苔藓植物的种类组成和多样性指数受干扰影响较大，灌木和苔藓植物的结构受干扰影响较大，苔藓植物对干扰影响最为敏感。 综合分析表明，九寨沟核心景区的管理虽然比较规范，但目前核心区热点景点段的管理仍然不够，旅游活动驱动了林下植被退化明显、物种组成显著变化、生物多样性衰退、非乡土喜光耐旱种群扩大。导致九寨沟核心区旅游活动与生物多样性保护目标尖锐冲突，进一步约束旅游活动带来的干扰，强化管理，开展林下植被恢复与非乡土喜光耐旱种群调控是九寨沟自然遗产地保护一项紧迫任务。 The increasing tourism disturbance is an unavoidable challenge to effective conservation and sustained tourist management of Jiuzhaigou Nature Reserve. It has become one of the focal problems of regional ecological protect and economic development. It is important to clarify effects of tourism disturbance on plant species composition, diversity and community structure in kernel spot for effective conservation and sustained tourist management in Jiuzhaigou, China. However, there were little studies about this yet. The study investigated the vegetation structure, species composition and diversity at nine sight spot, road area and four abandoned farmlands connecting with tourism, and compared the differences between disturbed area and undisturbed area. The purpose of the this study is clarifying the plant diversity and community structure and characteristics of the disturbed area in kernel spot of Jiuzhaigou, discovering the relation between vegetation structure and biodiversity, evaluating the effect of tourist management and exploring the measure decreasing tourist disturbance. Our results are following: 1. Tourism disturbance caused a significant change in species composition and structure of plant communities in kernel Spot of Jiuzhaigou. In the vicinity of plank and road, some native shade-tolerant or hygrophilous plants had disappeared, accompanying with the population expansion of some xerophilous and disturbance-resisting species such as Poa sp. Plantago depressa, Potentiila multicaulis and some exotic and synanthropic species. Herbs were domaint species, while frequency coverage and height of shrubs and bryophytes, and shrub density decreased. In indicated that tourist activities and build of road had adversely affected on native plant species, and led to decline in biodiversity of Jiuzhaigou Nature Reserve. Abandoned farmlands maybe conduced to entironment and biodiversity conservation. 2. Nearby the plank, influency variable of tourism disturbance on plant was alosely and positively correlated with disturbance intensity. There was companion plant species and lacked shape-loving species in heavy disturbed areas, which caused decrease in biodiversity and significant change in community structure in these places. On the contrary, in the slightly disturbed areas, some companion speices displayed and biodiversity decreased slightly, but no significant change in community structure in these areas. The biuld of road is a heavy disturbance form, which led to increase of herb species and to decrease in vitality and regeneration capacity. 3. The intensity of tourism disturbance on plant depended on plant groups. Tourism interference significantly influenced species composition and diversity index of herb and bryophyte; it also significantly influenced community structure; the bryophyte was more sensitive to tourism disturbance. Our result indicated that the management in kernel spot of Jiuzhaigou is relatively reasonable, but not adequate. Tourism speed the degradation of the vegetation under woodland, the change of the species composition, the decreaing of the biodiversity and the expanding of the exotic sunloving plant populations. The contradiction between tourism and conserving biodiversity is increasing, so enforcing management, regenerating the vegetation under woodland and adjusting the exotic sunloving arid-tolerent plant populations is a pressing work to protect the Jiuzhaigou natural legacy.