In subtropical grasslands, characterized by the coexistence of species with different physiology, for example C3 and C4 grasses, studies on the reproductive patterns of plants at the community level are scarce. Most available studies are limited to plant-pollinator interactions, and do not include grasses, even though knowledge on phenology of this species group is highly relevant, e.g., for grazing management or ecological restoration. In this study, we monthly evaluated flowering and fruiting in Brazilian subtropical grasslands under different grazing intensities (high, moderate, low, very low, ungrazed) over one year. To estimate the effect of the seasonal variation on the phenology of functional groups (C3 grass, C4 grass, monocots, dicots, shrubs) we used circular statistics. The highest flowering activity occurred in October and November, while fruiting peaked in March and April. Shrubs had the highest number of flowers and fruits, and C4 grasses contributed the largest number of fruiting species. The flowering peak of most functional groups occurred in October, except for C4 grasses and shrubs that peaked in February and November, respectively. Fruiting of C3 grasses peaked in December, C4 grasses and shrubs were most abundant in April and dicots, and monocots peaked in October. Grazing treatments differed considerably in flowering and fruiting patterns for all species groups. Monocots and dicots herbs showed high flowering activity under intense grazing. C3 grasses presented highest peaks in moderate and low grazing intensities, while C4 grasses peaked in very low grazing, and shrubs showed the highest peaks in ungrazed plots. Flowering and fruiting occurred throughout the year in our study system, with clear variation among functional groups in response to climatic and management patterns. Our results can guide seed collection in the field or vegetation cutting for hay transfer, and thus should lead to improvements in the ecological restoration of subtropical grasslands.

中文翻译：

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放牧对南巴西亚热带草原开花结果物候的影响

亚热带草原以不同生理物种共存为特征，例如C3和C4草，对群落水平植物繁殖模式的研究很少。大多数可用的研究仅限于植物与传粉媒介的相互作用，并且不包括禾本科植物，尽管该物种组物候学的知识与放牧管理或生态恢复等高度相关。在这项研究中，我们每月评估一年内不同放牧强度（高、中、低、极低、未放牧）下巴西亚热带草原的开花和结果。为了估计季节变化对功能类群（C3 草、C4 草、单子叶植物、双子叶植物、灌木）物候的影响，我们使用了循环统计。花期最高的月份是 10 月和 11 月，而果期的高峰期是 3 月和 4 月。灌木的花和果数最多，C4草的果数最多。除C4草类和灌木分别在2月和11月开花外，大多数功能类群的开花高峰发生在10月。 C3草类的结果高峰在12月，C4草类和灌木在4月最为丰富，双子叶植物和单子叶植物的结果高峰在10月。放牧处理对所有物种组的开花和结果模式有很大差异。单子叶植物和双子叶草本植物在强烈放牧下表现出高开花活性。 C3草在中等和低放牧强度下呈现最高峰值，而C4草在极低放牧强度下呈现最高峰值，灌木在未放牧地块中呈现最高峰值。在我们的研究系统中，开花和结果全年都会发生，不同功能组之间因气候和管理模式而存在明显差异。我们的结果可以指导田间的种子收集或用于干草转移的植被切割，从而改善亚热带草原的生态恢复。