The influence of grazing on soil seed bank (SSB) characteristics determines the management of rangelands in different climates. Here we studied the responses of SSBs to livestock grazing in three regions with different climates – arid, semiarid and subhumid – in northern Iran. In each region 30 pairwise SSB samples were collected on 1 m² plots, 15 in intensely grazed areas and 15 in ungrazed areas. The total SSB densities, their diversity and species richness and the densities of functional groups were compared between the grazed and ungrazed plots and between the climatic regions. Both climate and grazing as well as their interaction affected SSB characteristics. Although the results of the non-metric multidimensional scaling (NMDS) showed noticeable differences in SSB species composition between grazed and ungrazed plots in all three regions, the magnitude of the grazing effect on the SSB was different between climatic regions. In total, 119 species germinated from the soil samples: 33 species in semiarid, 39 species in arid and 61 species in subhumid samples. The highest total SSB density, diversity (Shannon index) and richness were found in subhumid climate with an average of 138.90 seeds/m², H = 2.27 and 17.83 species/sample, respectively. In ungrazed areas the average SSB density was 26.60 seeds/m², 46.06 seeds/m² and 195.90 seeds/m² in arid, semiarid and subhumid climate, respectively. In grazed areas the corresponding figures were 12.40 seeds/m², 7.00 seeds/m² and 110.40 seeds/m². Averages of SSB diversity in ungrazed areas were 1.24, 1.60 and 2.42 in arid, semiarid and subhumid climates, respectively, as compared to 1.27, 0.97 and 2.20 in grazed areas. The averages SSB richness in ungrazed areas were 5.21 species/sample, 7.54 species/sample and 21.25 species/sample in arid, semiarid and subhumid climate, respectively, whereas in grazed areas 4.00 species/sample, 2.86 species/sample and 16.15 species/sample were found on average. Overall, intensive grazing was linked to lower SSB characteristics in all three climatic regions, but the size of the effect differed between the climatic regions. Thus, we concluded that the impact of grazing on SSB density, diversity and richness is climate-dependent. Hence, the climatic conditions have to be considered when evaluating the effects of grazing on soil seed banks.

放牧对土壤种子库（SSB）特征的影响决定了不同气候下牧场的管理。在这里，我们研究了伊朗北部三个不同气候（干旱、半干旱和半湿润）地区的SSBs对牲畜放牧的反应。^{在每个区域中，在 1 m 2 的地块}上收集了 30 个成对的 SSB 样本，其中 15 个在密集放牧区域，15 个在未放牧区域。比较了放牧地和未放牧地以及不同气候区之间的SSB总密度、多样性和物种丰富度以及功能群密度。气候和放牧及其相互作用都会影响SSB特征。尽管非度量多维尺度（NMDS）的结果显示所有三个地区放牧和未放牧地块的SSB物种组成存在显着差异，但放牧对SSB影响的大小在不同气候区域是不同的。土壤样品中总共发芽了 119 种植物：半干旱地区 33 种，干旱地区 39 种，半湿润地区 61 种。半湿润气候中的SSB总密度、多样性（香农指数）和丰富度最高，平均分别为138.90粒种子/m ²、 H = 2.27和17.83种/样本。在未放牧地区，干旱、半干旱和半湿润气候下的平均SSB密度分别为26.60粒/m ²、46.06粒/m ²和195.90粒/m ²。在放牧区，相应数字为12.40 粒种子/m ²、7.00 粒种子/m ²和110.40 粒种子/m ²。在干旱、半干旱和半湿润气候下，未放牧地区的SSB多样性平均值分别为1.24、1.60和2.42，而放牧地区的SSB多样性平均值分别为1.27、0.97和2.20。在干旱、半干旱和半湿润气候下，未放牧地区的SSB平均丰富度分别为5.21种/样本、7.54种/样本和21.25种/样本，而放牧地区的平均SSB丰富度分别为4.00种/样本、2.86种/样本和16.15种/样本。平均被发现。总体而言，集约化放牧与所有三个气候区的较低SSB特征有关，但影响的大小在不同气候区之间有所不同。因此，我们得出的结论是，放牧对SSB密度、多样性和丰富度的影响取决于气候。因此，在评估放牧对土壤种子库的影响时必须考虑气候条件。