Some fern species are among the world’s worst weeds, but little is known about the establishment of alien ferns in relatively conserved ecosystems. Exotic species may outperform native ones during germination and facilitate invasion into new environments. Macrothelypteris torresiana is an Asian fern species that was introduced and spread throughout multiple areas of tropical America. We tested the hypothesis that germination of the exotic fern will be higher at high resource levels and will have wider ecological amplitude compared to native fern species in a cloud forest in central Mexico. Spore germination was evaluated through a gradient of water potential (0 to − 1.0 MPa), photon flux density (0 to 200 µmol m⁻² s⁻¹), and light quality (0 to 7.2 red:far-red ratio) in the laboratory, whereas plant relative frequency was determinate in the forest to describe the distribution of the ferns under the light environment. Comparing to three native ferns (sun-loving Hypolepis blepharochlaena and shade-loving Blechnum wardiae and Polystichum ordinatum), M. torresiana was more tolerant to water deficit, germinated better under low photon flux but responded similarly to light quality gradient, and occurred over a far wider range of field light conditions. Our results support the hypothesis that the germination requirements of the invasive fern species are less specific and thus facilitate the colonization of sites with diverse light conditions and water availability.

一些蕨类物种是世界上最严重的杂草之一，但对于在相对保守的生态系统中建立外来蕨类植物知之甚少。外来物种在发芽过程中的表现可能优于本地物种，并有利于入侵新环境。香（Macrothelypteris torresiana）是一种亚洲蕨类物种，已被引入并传播到热带美洲的多个地区。我们测试了以下假设：与墨西哥中部云雾森林中的本地蕨类物种相比，高资源水平下外来蕨类植物的发芽会更高，并且生态幅度更大。通过水势（0至-1.0 MPa），光子通量密度（0至200 µmol m ^-2 s ^-1）的梯度来评估孢子萌发），以及实验室的光照质量（0：7.2的红色：远红比率），而在森林中确定植物的相对频率来描述蕨类植物在光照环境下的分布。比较三种天然蕨类植物（阳光灿烂的Hypolepis blepharochlaena和喜阴，乌毛wardiae和蕨ordinatum），M. torresiana对水分缺乏具有更强的耐受性，在低光子通量下发芽更好，但对光质量梯度的响应相似，并且发生在更广范围的野外光照条件下。我们的结果支持以下假设，即入侵性蕨类植物的萌发要求不那么具体，因此有利于在各种光照条件和水利用条件下定殖。