Floristic diversity changes substantially depending on the type of land management. We evaluated the impact of a continuous (CG) and rotational (RG) grazing system on the dynamics of plant diversity and community composition in a heather-gorse understory after a two and six-year pause from horse grazing. Previously grazed sites had higher total and rare species richness and diversity than ungrazed (UN), regardless the type of grazing system. The positive impact of previous grazing on species richness was higher in CG and continued after six years in both grazing systems. Seven species of high conservation interest in heathlands were present in the studied areas. Most of them were associated to CG management and none was exclusively in RG. The reduction of the shrub component by previous horse grazing led to a decrease of gorse dominance, thus potentially reducing fire risk and increasing plant diversity. The extent of the positive effect of horse grazing controlling excessive accumulation of combustible material and favoring species richness differed when relative abundance of species, and not solely the number of species, was taken into account (Simpson’s dominance increased and Pielou’s evenness decreased after six years). Overall, the effects of previous rotational and continuous grazing on plant diversity in an Atlantic heather-gorse dominated plant community were still apparent 2 or 6 years after grazing interruption, although declined after the six-year grazing interlude. Rotational management revealed a slight advantage upon the control of gorse biomass long term, and assisted to maintain the relative abundance of species more evenly over time. The alpha and beta diversity indices confirmed that plant diversity similarity between rotational and continuous management increased after six years.

植物多样性在很大程度上取决于土地管理的类型。我们评估了连续（CG）和旋转（RG）放牧系统对马放牧停顿了两年和六年后希瑟·金斯林下植物动态和群落组成的影响。不论放牧系统的类型如何，以前放牧的地点的总物种和稀有物种的丰富度和多样性要高于未放牧的地区。先前放牧对物种丰富度的积极影响在CG中更高，并且在两个放牧系统中都持续了六年。在被研究的地区中有7种在荒地上具有高度保护意义的物种。他们中的大多数与CG管理相关，没有一个人仅在RG。先前放牧对灌木成分的减少导致金雀花优势的减少，因此有可能降低火灾风险并增加植物多样性。当考虑相对物种的丰富度，而不仅仅是物种数量时，放牧对可燃物质过度积累和有利于物种丰富性的积极影响程度有所不同（六年后，辛普森的优势度增加，皮鲁的均匀度降低） 。总体而言，放牧中断后第2或6年，以前轮作和连续放牧对大西洋希瑟-戈斯主导的植物群落中植物多样性的影响仍然明显，尽管在连续6年的放牧间隔后有所减弱。轮作管理在长期控制金雀花生物量方面显示出一点优势，并有助于随着时间的推移更均匀地保持物种的相对丰度。