元江干热河谷主要环境因子(气温和降水)变化规律及蕨类植物的分布响应

为了解蕨类植物多样性及种群分布对环境因子的响应，建立元江干热河谷不同海拔气温和降水的分布模式，对蕨类植物在元江干热河谷内的自然分布进行了研究。结果表明，元江干热河谷从低海拔到高海拔，气温逐渐下降，但降水量却逐渐增加；河谷内蕨类植物多样性及种群分布呈现差异化；干热河谷内蕨类分布受气温影响不大，但与生境水分条件密切相关。元江干热河谷水热条件分布不均，生态环境破碎，气温和降水分布不均，差异化显著，促进了小生境发育。蕨类植物可以指示生态环境的完整性和连续性，某些种群可以指示和监测环境因子尤其是水因子的变化。

Variation of Major Environmental Factors (Temperature and Precipitation) in Yuanjiang Dry-hot Valley and the Response of Pteridophytes

Dry-hot valley is featured with high temperature, rapid evaporation, and poor vegetation. It is a typical representative of arid ecosystems. In order to understand the response of pteridophytes diversity and population distribution to environmental factors, the distribution patterns of temperature and precipitation at different elevations in Yuanjiang dry-hot valley were established, and the distribution of pteridophytes in dry-hot valley was studied. The results showed that the temperature in Yuanjiang dry-hot valley declined along altitude, whereas precipitation increased. The diversity and population distribution of pteridophytes in Yuanjiang dry-hot valley were strongly differentiated. The distribution of pteridophytes are not associated to temperature but closely related to water supply. Conclusively, the habitat in Yuanjiang dry-hot valley was fragmented due to heterogeneous environmental factors, which accelerates patchy vegetation. Pteridophytes were a certain kind indicator of integrative and continuous living circumstance, while some species could be potential environmental monitors especially for water condition.