Abstract The often mass flowering of Watsonia and other geophyte species in the first year after a fire in the South African fynbos vegetation is well known, but it has rarely been quantified. Many fynbos geophytes also flower after the fynbos canopy was physically removed, but these flowering responses have also not been quantified. A study comparing the flowering response of geophytes after physical removal versus fire removal of the fynbos canopy was conducted to establish to what degree these species are fire dependant. It was also done to improve our understanding of fynbos geophyte ecology, especially towards establishing if the flowering response of these plants is due to fire related factors per se, or not. Vegetative growth, flowering response, seed set and seedling establishment of Watsonia fourcadei were recorded after two treatments, burning and physical removal of vegetation (slashing) in two veld ages (5- and 16 years). Responses of other co-occurring geophytic species to these treatments were also recorded. The number of vegetatively active W. fourcadei plants doubled and flowering percentage increased from 2.3% to 38.7% in the first year after the fire. In the second year after the fire the number of vegetatively active W. fourcadei plants was similar to those in the first year after the fire, but flowering percentage decreased to pre-fire levels. About 50% of W. fourcadei plants were dormant 5 years after the fire and > 90% were dormant in 16-year old fynbos. Flowering percentages of W. fourcadei in slashed 5-year old fynbos did not differ significantly from burned 16-year old fynbos. The flowering stimulus of W. fourcadei was thus not due to fire associated factors per se. Seed predation of W. fourcadei seed capsules decreased from 46.9% before the fire to 7.1% after the fire. Number of viable seed released increased from 15.8 seed mˉ² pre-fire to 1170.5 seed mˉ² post-fire and 233.1 seedlings mˉ² established after the fire. The 74-fold increase in seed release in the burned fynbos could not be ascribed to higher cross pollination success as about 40% of the flowers were autogamous. The number of vegetatively active geophytic species increased from 2.3 species mˉ² pre-fire to 7.9 species mˉ² post-fire in 16-year old burned fynbos and 4.0 species mˉ² in the slashed fynbos. Most (76%) of these geophytic species flowered after the fynbos was burned and 24% of the species flowered in the slashed fynbos. Only some of the geophytic species were thus dependent on fire to stimulate flowering. A repeated short cycle disturbance regime (ca. 5 years) of burning and/or slashing may result in a super-abundance of Watsonia plants that can displace smaller geophytic species. Previous hypotheses on proximate reasons for the Watsonia post-fire flowering that are rejected are: (i) greater visibility of the plants; (ii) heating of the soil and corms by fire and; (iii) increased availability of phosphorous and/or other minerals in the post-fire environment. Smoke as a factor to induce flowering in W. fourcadei growing under natural conditions is questioned.

中文翻译：

---

Watsonia Fourcadei 和其他地质植物对 South Outeniqua Sandstone Fynbos 燃烧和砍伐处理的响应

摘要 众所周知，在南非 fynbos 植被发生火灾后的第一年，Watsonia 和其他地质植物物种经常大量开花，但很少对其进行量化。许多 fynbos geophytes 在 fynbos 树冠被物理移除后也会开花，但这些开花反应也没有被量化。进行了一项研究，比较了物理去除与 fynbos 树冠的火去除后地质植物的开花反应，以确定这些物种在多大程度上依赖火。这样做也是为了提高我们对 fynbos 地球植物生态学的理解，特别是确定这些植物的开花反应是否是由于与火灾相关的因素本身。记录了两次处理后的 Watsonia Fourcadei 的营养生长、开花反应、结实和成苗情况，在两个草原年龄（5 年和 16 年）燃烧和物理清除植被（砍伐）。还记录了其他共生地球植物物种对这些处理的反应。在火灾后的第一年，营养活跃的 W.fourcadei 植物数量翻了一番，开花百分比从 2.3% 增加到 38.7%。在火灾后的第二年，营养活跃的 W.fourcadei 植物数量与火灾后的第一年相似，但开花百分比下降到火灾前的水平。大约 50% 的 W.fourcadei 植物在火灾后 5 年处于休眠状态，> 90% 在 16 岁的 fynbos 中处于休眠状态。W.fourcadei 在 5 年生花茎被砍伐后的开花百分比与 16 年生花叶被烧毁没有显着差异。W的开花刺激。因此，fourcadei 本身并不是由火灾相关因素造成的。W.fourcadei 种子胶囊的种子捕食率从火灾前的 46.9% 下降到火灾后的 7.1%。释放的活种子数从火灾前的 15.8 粒 mˉ² 增加到火灾后的 1170.5 粒 mˉ² 和火灾后建立的 233.1 苗 mˉ²。燃烧的 fynbos 中种子释放量增加 74 倍不能归因于更高的异花授粉成功，因为大约 40% 的花是自交花。植被活跃的地球植物物种数量从火灾前的 2.3 种 mˉ² 增加到火灾后 7.9 种 mˉ²，在 16 年生被烧毁的 fynbos 和 4.0 种 mˉ² 在被砍伐的 fynbos 中。大多数 (76%) 这些地球植物物种在 fynbos 被烧毁后开花，24% 的物种在被削减的 fynbos 中开花。只有一些地球植物物种因此依赖火来刺激开花。燃烧和/或砍伐的重复短周期干扰制度（约 5 年）可能会导致大量屈臣氏植物，这些植物可以取代较小的地球植物物种。先前关于被拒绝的 Watsonia 火灾后开花的近因的假设是： (i) 植物的可见度更高；(ii) 用火加热土壤和球茎；(iii) 火灾后环境中磷和/或其他矿物质的可用性增加。烟雾作为在自然条件下生长的 W.fourcadei 诱导开花的因素受到质疑。先前关于被拒绝的 Watsonia 火灾后开花的近因的假设是： (i) 植物的可见度更高；(ii) 用火加热土壤和球茎；(iii) 火灾后环境中磷和/或其他矿物质的可用性增加。烟雾作为在自然条件下生长的 W.fourcadei 诱导开花的因素受到质疑。先前关于被拒绝的 Watsonia 火灾后开花的直接原因的假设是： (i) 植物的可见度更高；(ii) 用火加热土壤和球茎；(iii) 火灾后环境中磷和/或其他矿物质的可用性增加。烟雾作为在自然条件下生长的 W.fourcadei 诱导开花的因素受到质疑。