中文摘要：

公路被认为是促进入侵植物扩散的主要通道之一。为了揭示公路与植物入侵的关系，我们在云南省北热带和南亚热带地区选择13条公路，按照公路性质、修建年代以及干扰历史将公路分为高、中、低3个干扰水平，研究了7种主要入侵植物在公路两侧的扩散格局，以及环境因素（干扰、光照、坡向、气候带）对扩散格局的影响。结果表明：紫茎泽兰（Eupatorium adenophorum）、飞机草（E.odoratum）、胜红蓟（Ageratumconyzoides）和肿柄菊（Tithonia diversifolia）的密度以及紫茎泽兰的频度沿公路扩散格局呈明显的单峰变化，峰值一般都出现在4m以内。高干扰公路两侧，紫茎泽兰、飞机草、胜红蓟、肿柄菊与金腰箭（Synedrella nodiflora）的密度以及紫茎泽兰、飞机草、胜红蓟、肿柄菊的频度均明显高于中、低干扰公路，说明高干扰公路比中、低干扰公路更有利于促进植物入侵。高光水平下紫茎泽兰、飞机草、胜红蓟的密度以及紫茎泽兰、胜红蓟和金腰箭的频度明显大于中、低光水平，说明高光水平显著促进公路两侧的这4种入侵植物向远距离扩散。紫茎泽兰、胜红蓟与金腰箭的密度在阳坡显著高于阴坡。紫茎泽兰与肿柄菊主要出现在南亚热带，而飞机草与金腰箭主要出现在北热带，胜红蓟与赛葵（Malvastrum coromandelianum）在两种气候带中均有出现。羽芒菊（Tridax procumbens）在公路两侧出现的频率与密度均很低，无统计学意义。因此，公路两侧的生境应作为防治外来植物入侵的重点，提高公路两侧本地植被郁闭度将有利于控制紫茎泽兰等外来植物的进一步扩散。

英文摘要：

Roads serve multiple functions that enhance exotic species invasion. In this paper, we examined the roles of disturbance, light availability, slope aspect, and climate in explaining density and frequency of exotic invasive plants. We analyzed the effect of main environmental factors along 13 roads with different levels of anthropological disturbances （heavy, moderate, and light） in the north tropical and south subtropical mountainous zones in Yunnan Province. The results demonstrated that density of four species, Eupatorium adenophorum, E. odoratum, Ageratum conyzoides and Tithonia diversifoli, and frequency ofE. adenophorum were significantly associated with distance from roads. The curves of these four alien plants all presented a single-peak pattern, and their maximum abundance occurred within 4 m of roads. These four alien plants invaded native plant communities from primary colonization points along road margins. Density of E. adenophorum, E. odoratum, A. eonyzoides, T. diversifoli and Synedrella nodiflora and frequency of E. adenophorum, E. odoratum, A. conyzoides and T. diversifoli tended to be significantly higher along highly disturbed roads than moderately and lightly disturbed roads, indicating that plant communities adjacent to highly disturbed roads might be more prone to invasion. Density of E. adenophorum, E. odoratum and A. conyzoides and frequency of E. adenophorum, A. conyzoides and S. nodiflora were significantly higher in areas with high light level than those that had medium or low light levels. E. adenophorum, E. odoratum and A. conyzoides might obviously invade farther in habitats along roads that had high light level. Density ofE. adenophorum, A. conyzoides and S. nodiflora were significantly higher on warm aspects than on cool aspects. E. adenophorum and T. diversifoli were mainly distributed in the south subtropical mountainous zones, while E. odoratum and S. nodiflora were mainly in the north tropical mountainous zones. A. conyzoides and Malvastrum coromandelianum were distributed i