Interactions among animals and plants are key to understanding seed dispersal, plant regeneration and plant community patterns. These interactions can be dynamic, with changes of species and functional roles across space and time. Despite fluctuations in species abundances and resources over time being the rule in natural communities, most studies approach plant–frugivore interactions as temporally static. We documented changes in bird and ant species in interactions with plants producing carbohydrate- (Miconia rubiginosa) or lipid-rich diaspores (Xylopia aromatica) comparing two fruiting seasons 15 years apart in a savanna in southeastern Brazil. We tested if abundance and body size of dispersal vectors (birds and ants) affected the frequency of interactions and the quantitative effectiveness of seed dispersal (QTC). Rich bird (26 species) and ant (18 genera) assemblages interacted with the diaspores. A core of bird and ant taxa was temporally consistent, and responsible for most seed removal across the two years for both plants. Temporal transience was more common for sporadic partners of interactions, and for species with similar functional roles. Abundance and body size of birds affected the interspecific contributions to QTC. Large-bodied birds dispersed large quantities of seeds of our relatively small-seeded plants, even if their visits were sporadic. For ants, variations in temperature and rainfall across time seems more important in driving variations in the contributions to QTC. The combined effect of birds and ants in the same system helps to stabilize the temporal fluctuations in the amount of seeds dispersed. However, ants alone are unlikely to replace the functional roles of vertebrate dispersers. Even though species in the assemblage change either their quantitative contribution to seed dispersal or their presence or absence in the interaction network, species persisting in interaction over time are the most important quantitative partners for plants.

中文翻译：

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新热带稀树草原中鸟类、蚂蚁和植物之间相互作用的时间一致性

动植物之间的相互作用是了解种子传播、植物再生和植物群落模式的关键。这些相互作用可以是动态的，随着时间和空间的物种和功能角色的变化。尽管随着时间的推移物种丰度和资源的波动是自然群落的规律，但大多数研究将植物-食果动物的相互作用视为时间上的静态。我们记录了鸟类和蚂蚁物种在与产生碳水化合物（Miconia rubiginosa）或富含脂质的水铝石（Xylopiaaromatica) 比较巴西东南部热带稀树草原上相隔 15 年的两个结果季。我们测试了传播媒介（鸟类和蚂蚁）的丰度和体型是否影响相互作用的频率和种子传播（QTC）的定量有效性。丰富的鸟类（26 种）和蚂蚁（18 属）组合与水铝石相互作用。鸟类和蚂蚁类群的核心在时间上是一致的，并且是这两种植物两年内大部分种子去除的原因。对于零星的相互作用伙伴和具有相似功能角色的物种来说，时间短暂性更为常见。鸟类的丰度和体型影响了对 QTC 的种间贡献。体型较大的鸟类会散布我们种子相对较小的植物的大量种子，即使它们的访问是零星的。对于蚂蚁，温度和降雨量随时间的变化似乎对推动 QTC 贡献的变化更为重要。同一系统中鸟类和蚂蚁的综合作用有助于稳定散播种子量的时间波动。然而，单靠蚂蚁不太可能取代脊椎动物分散器的功能作用。尽管组合中的物种改变了它们对种子传播的数量贡献或它们在相互作用网络中的存在或不存在，但随着时间的推移持续相互作用的物种是植物最重要的数量伙伴。蚂蚁本身不太可能取代脊椎动物分散器的功能作用。尽管组合中的物种改变了它们对种子传播的数量贡献或它们在相互作用网络中的存在或不存在，但随着时间的推移持续相互作用的物种是植物最重要的数量伙伴。蚂蚁本身不太可能取代脊椎动物分散器的功能作用。尽管组合中的物种改变了它们对种子传播的数量贡献或它们在相互作用网络中的存在或不存在，但随着时间的推移持续相互作用的物种是植物最重要的数量伙伴。