Quantitative estimates of past vegetation cover are needed both regionally so human-landscape interactions can be better understood, and globally to evaluate the effects of changing vegetation cover on the climate system. Models reducing the bias in the pollen representation of vegetation cover have been developed in the temperate regions of the northern hemisphere, while experience applying them in other parts of the world is limited. The Araucaria forest-grassland mosaic of southern Brazil is an area where open and forested plant communities exist naturally and have changed their cover over time due to changing climate and human activities. Therefore, this area is of particular interest for such studies. Modern pollen and vegetation comparisons were carried out in two protected areas: Vila Velha State Park in Paraná state and Aparados da Serra National Park in Rio Grande do Sul. Vegetation mapping and analysis focused on Araucaria angustifolia as the characteristic tree of this vegetation type. In the Araucaria forest-grassland mosaic open vegetation and woodland change at a scale of hundreds of metres. These changes are difficult to capture based on pollen proportions in surface samples. While the abundance of Poaceae pollen is not a good indicator of locally open conditions, several pollen taxa can be used as indicators of the local vegetation cover. Pollen vegetation ratios (R-values) compare well between the two study regions, indicating that pollen production of individual species within the large plant families of Poaceae and Asteraceae are similar within the overall region. Araucaria angustifolia pollen is underrepresented with regards to its vegetation cover, while Poaceae are among the highest pollen producers in the region. Diverse woodland species other than A. angustifolia were grouped as one forest taxon and as the species composition of woodlands differed between the two study areas, so did the estimated pollen productivity of this group. It would be rewarding in future investigations to estimate pollen productivity for groups of trees with the same pollen dispersal syndrome. The application of pollen dispersal models designed for closed canopy in the protected areas was challenging. Further model development is required to deal with pollen released at different levels in semi-open vegetation types.

既需要在区域范围内对过去的植被覆盖度进行定量估计，以便可以更好地理解人与景观之间的相互作用，还需要在全球范围内评估植被覆盖度变化对气候系统的影响。在北半球的温带地区，已经开发出了减少植被覆盖的花粉表现形式偏差的模型，而在世界其他地区应用这些模型的经验却很有限。在南洋杉巴西南部的森林-草原马赛克是一个自然开放的森林植物群落的地区，由于气候和人类活动的变化，植被的覆盖面也随着时间的推移而发生了变化。因此，该领域对于此类研究特别感兴趣。在两个保护区进行了现代花粉和植被的比较：巴拉那州的维拉维拉州立公园和南里奥格兰德州的阿帕拉多斯达塞拉国家公园。植被定位和分析的重点是南洋杉（Araucaria angustifolia）作为这种植被类型的特征树。在南洋杉森林-草地马赛克开阔的植被和林地变化了数百米。这些变化很难根据表面样品中的花粉比例来捕获。虽然禾本科花粉的丰度并不是当地开放条件的良好指标，但可以将几种花粉类群用作当地植被覆盖的指标。两个研究区域之间的花粉植被比率（R值）比较好，表明在禾本科和菊科的大型植物科中单个物种的花粉生产在整个区域内是相似的。就其植被覆盖而言，南洋杉花粉的代表性不足，而禾本科则是该地区最高的花粉生产者之一。除A. angustifolia以外的其他林地物种被划分为一个森林分类单元，并且两个研究区域之间林地的物种组成有所不同，因此该组的估计花粉生产率也有所不同。在未来的调查中，估计具有相同花粉散布综合征的树木的花粉生产力将是有益的。为保护区中的封闭树冠设计的花粉散布模型的应用具有挑战性。需要进一步的模型开发来处理半开放植被类型中不同水平释放的花粉。