BACKGROUND There is much debate concerning which ecological constraints are the most limiting factors to seedling recruitment in disturbed communities. We provide the first comparison between selective herbivory and plant competition effects among two post-mined forest ecosystems (primary succession) and one post-fire woodland ecosystem (secondary succession). Animal exclosure assessments of nine common species across eight sites were performed for comparison within three locations separated by up to 200 km. Additionally, we asked whether pre-browsed plants differed in nutrient content between or within species in the separate systems. RESULTS Among the nine common species, seven of these were affected by mammal herbivory while five shared a similar vulnerability to predation regardless of system. One species was limited by competition (planting density). There was a strong linear correlation between herbivore selectivity (% browsed) and impact (biomass loss) on the fertilized minesites, but not post-fire sites. Phosphorus and potassium were higher for most species in the post-mined system. Principal components analyses revealed that nutrients in shortest supply may be the most likely components of selection within each system. Among all locations, species with highest levels of phosphorus, ADF and leaf water content were often favoured, while high tannins and nitrogen content were generally selected against. CONCLUSION Herbivory, rather than seedling competition, was the limiting factor for plant performance among post-fire and post-mined reclamation areas. The post-fire seedlings were smaller and more water and nutrient limited, nevertheless browsing prevalence was equivalent at all locations with nearly all seedlings predated. Kangaroo density in the post-fire community declined from the beginning of the experiment, while numbers in the post-mined revegetation increased fourfold within one year. Differences in water and nutrient availability may explain why herbivores are more likely to be attracted to post-mined communities.

中文翻译：

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哺乳动物食草和植物间距对火灾和采矿后幼苗补充的相对影响。


背景技术关于哪些生态约束是受干扰群落中幼苗补充的最大限制因素存在很多争论。我们首次比较了两个采矿后森林生态系统（初级演替）和一个火灾后林地生态系统（次级演替）之间的选择性食草和植物竞争效应。对八个地点的九种常见物种进行了动物排除评估，以在相距 200 公里的三个地点进行比较。此外，我们询问预先浏览的植物在不同系统中的物种之间或物种内部的营养成分是否存在差异。结果 在九种常见物种中，其中七种受到哺乳动物草食性的影响，而五种无论系统如何，都具有相似的捕食脆弱性。一种物种受到竞争（种植密度）的限制。草食动物的选择性（浏览百分比）和对施肥矿区的影响（生物量损失）之间存在很强的线性相关性，但对火后地点则不然。开采后系统中大多数物种的磷和钾含量较高。主成分分析表明，供应最短的营养物质可能是每个系统中最有可能进行选择的成分。在所有地点中，磷、ADF 和叶片含水量最高的物种通常受到青睐，而单宁和氮含量高的物种通常不被选择。结论 草食性，而不是幼苗竞争，是火灾后和采矿后复垦地区植物性能的限制因素。火灾后的幼苗较小，水和养分也更有限，但所有地点的啃食率是相同的，几乎所有幼苗都被抢食了。 从实验一开始，火灾后社区的袋鼠密度就下降了，而采矿后重新植被的袋鼠数量在一年内增加了四倍。水和养分供应的差异可以解释为什么食草动物更有可能被采矿后的社区所吸引。