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This study aims to analyze the effects that snow cover may have on the survival of one-year-old seedlings from 15 different taxa in the Mediterranean high mountains (Sierra Nevada National Park, SE Spain) in order to have clearer criteria for the planning and management of restoration efforts in these environments. Additionally, the influence of variables that have been scarcely explored up to now is also revised. We use the survival rates of the seedlings observed from the ecological restoration trial as reference values. The survival data analyzed are based on six variables to evaluate their effects. The results confirm that the permanence of snow is a favorable factor for seedlings, independent of the plant community. Contrastingly, a specific type of foundation (stones and rocks) stands out for being clearly unfavorable, regardless of other variables. For both altitude and solar radiation, a worsening of the survival ratio has been observed as they increase. The species' geographic ranges are all shown to be unfavorable for taxa of a boreo-alpine distribution. Finally, the plant community does not have a significant influence on the survival of seedlings. These results provide novel indications to improve the results of the first stages of restoration work in the Mediterranean high mountains. They are also valuable for the management and cataloging of threatened flora, as well as having direct applications in recovery plans and protection lists.

This paper explores the dynamics of temporal evolution of the high mountain Mediterranean grasslands, (Sierra Nevada, Spain SE). The indicator used is the emission of pollen (Pollen Index, PI) with respect to two important aspects: the incidence of the snow dynamic together with other hydro-meteorological parameters, and the changes in land use, which can Influence the evolution of the grasslands throughout time. The results reveal that pollen emissions in the last 25 years have shown a slight downward trend, with large interannual fluctuations, which are a consequence of diverse environmental factors, both general and specific to the area. One of the most influential parameters on pollen concentrations is snow cover, which reinforces the importance of the presence of snow-packs as water resource outside the winter season in the High Mediterranean Mountain environments. The changes in land use experienced in the area are a driver of change, especially due to the losses experienced in the last decades in the preferred habitats for many species of grasses. It can be concluded that the vulnerability of these ecosystems will be affected by an increase in winter temperatures and/or a decrease in rainfall (climate change) and an increase in the intensity of anthropogenic activities on land use. In this context, the PI is shown as a useful indicator of global change given its sensitivity to both anthropic and hydro-meteorological changes. In addition, it has a wide range of spatial detection and discrimination capacity by altitudinal dimensions., (Copyright © 2018 Elsevier B.V. All rights reserved.)