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This paper presents the trampling effects on vegetation composition in three Long Term Socio-Ecological Research sites (LTSER), respectively Neajlov Catchment, Bucegi-Piatra Craiului and Braila Islands (distributed within different biogeographical regions: continental, alpine and steppic), over a period of 3 years (2007-2009). The degree of damage is related to trampling intensity. In forest ecosystems significant declines in species richness was observed two weeks after trampling, from 75 passes onward, with the exception of Neajlov Catchment site (Vadu Lat). The tolerance to different intensity of trampling (25, 75, 250 and 500 passes) depended on the proportion of growth form, the sensitivity being associate with vertical species. The analysis of vegetation composition is a simple and effective method for the assessment of his resistance to trampling and serves to development of management strategy for recreational areas concerning: the configuration of the tourist routes, sizing the pressure through the flow of visitors, number and frequency of visits.

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<p>The shallow cumulus clouds are ubiquitous in the atmosphere, populating a large part of the subtropical oceans. They may play a strong climate feedback due to their cooling effect on the Earth atmosphere. As a result, a large number of studies investigated the organization of cumulus clouds and their interaction with the climate. However, the organization of passive shallow clouds and their impact on the atmospheric convection and climate change received very limited attention. In this work, we perform a series of large eddy simulations in order to investigate how the organization and the total cloud cover depends on the relative humidity of the environment. We show that although the active cumulus clouds only show a weak correlation with the relative humidity, the passive clouds are very sensitive to it. We show thus that the cloud cover of the shallow cumuli is very sensitive to the relative humidity which could be very important in the context of the climate change. Furthermore, we formulate a conceptual picture to explain the organization of passive shallow cumulus clouds.</p>

The research of the synanthropic plant species characteristics from the urban environment offers information about their relation with the anthropic environment, on one hand, and on the other hand, they can be used as indicators of the pollution level. The research was performed in the city of Pitesti from June 2008 to may 2009, to compile an inventory of the flora, to establish the biological and ecological spectrum, the phytogeographic elements and their economic importance. The fresh above ground phytomass of the synanthropic species from 22 sample locations, was determined. The dry matter, the total nitrogen and phosphorus content, for six species of the dominant synanthropic plants, were also determined. It was identified 214 species of 38 families. The biological and ecological spectra show the high percentages of hemicryptophytes (35%), eutrophic species (54%), xeromesophilous-mesophilous species (29%) as well as eurytherm (20%) and euryacide species. The phytogeographic spectrum shows a high number of species from Eurasia (96 species). From the total number of identified species, 54% are polyploid and 27% present economic importance. It was found that the phytomass from stationaries varies between 281.7 g m-2 and 21.5 g m-2, for a number of 35 species. The highest dry matter content (64.01%) was recorded in Conyza canadensis, the highest value of N (8,200 ppm) in Lactuca serriola and the highest total P content (301.5 ppm) in Erigeron annuus. The results enable us to estimate the value of the synanthropic plants as ecologic indicators in the Pitesti area.