Factors controlling seed predation by rodents and non-native Sus scrofa in Araucaria araucana forests: potential effects on seedling establishment
Factors controlling seed predation by rodents and non-native Sus scrofa in Araucaria araucana forests: potential effects on seedling establishment
复制标题
控制南洋杉森林中啮齿动物和非本地野猪捕食种子的因素：对幼苗建立的潜在影响
DOI：
10.1007/s10530-009-9474-8
复制
发表时间：
2010
影响因子：
2.9
通讯作者：
T. Kitzberger
中科院分区：
文献类型：
--
作者：
Javier D Sanguinetti;T. Kitzberger
传播后的种子捕食会严重限制植物的补充，但其最终影响可能会受到环境因素和食粮动物行会组成的调节。在这里，我们分析了非本地野猪和本地啮齿动物对肥大针叶树南洋杉种子存活和幼苗建立的相对影响。在种子产量显着波动的时期内，在拉宁国家公园（阿根廷）的 11 棵孤立的树木的不同微地点和距离测量了捕食、种子存活和幼苗生长。野猪在 13 天内消耗了 10% 至 30% 的可用种子，比啮齿动物少三倍。野猪的捕食主要受森林冠层组成的影响，而微环境条件对两种捕食者都有影响，在茂密的植被下，啮齿类动物的慢性捕食程度很高，而在植被贫乏的微环境中，野猪的捕食程度中等（但年际变化）。啮齿类动物的捕食在空间上聚集在微型场所尺度上，特别是在无桅杆年份；而野猪的捕食在空间结构上则更为粗糙，并且受到桅杆的影响较小。排除野猪显着增加了存活种子的数量，导致中间生产年的幼苗建立率更高，但在丰收年却没有影响。在树水平上，幼苗的建立与捕食呈负相关；而在林分水平上，球果产量占幼苗建立变异的大部分。目前的野猪种群可能不会影响种群规模的幼苗建立，这可能是由于南洋杉肥育策略将其影响降至最低。然而，如果野猪数量继续增加，其影响可能从单树规模转向林分规模，威胁南洋杉森林的再生。
Post-dispersal seed predation can severely limit plant recruitment, but its ultimate impact could be modulated by environmental factors and by the composition of the granivore guild. Here, we analyze the relative impact of the non-native wild boar and native rodents on seed survival and seedling establishment of the mast conifer Araucaria araucana. Predation, seed survival and seedling establishment were measured at different microsites and distances from 11 isolated trees in Lanín National Park (Argentina) over a period of marked fluctuation in seed production. Wild boar consumed between 10 and 30% of available seeds on a 13-day period, threefold less than rodents. Wild boar predation was mainly affected by forest canopy composition, while microsite conditions influenced both kind of predators, with high chronic rodent predation underneath dense vegetation and moderate (but interannually variable) wild boar predation at poorly vegetated microsites. Predation by rodents was spatially clustered at the microsite scale, particularly during non-mast years; while predation by wild boar was spatially structured at a coarser scale and less modified by masting. The exclusion of wild boar increased significantly the amount of surviving seeds, resulting in higher seedling establishment in intermediate production years, but not affecting it during the mast year. At tree level, seedling establishment was negatively correlated with predation; while at stand level, cone production accounted for most of the seedling establishment variability. The current wild boar population may not be affecting the seedling establishment at population scale, probably due to minimization of its impact by the Araucaria masting strategy. However, if wild boar population numbers continue to increase, their impact may shift from individual tree scale to stand scale, threatening Araucaria forest regeneration.