Background and Aims: Temperate forests suffer continuous deforestation and other anthropogenic disturbances. Additionally, some types of forest management, such as secondary vegetation removal ("chaponeo"), can be another disturbance that negatively affects the values of some environmental variables important for seed germination. Light, soil temperature and moisture characterize microsites and determine germination percentages. These variables are also affected by slope orientation and vegetation structure. The aim of this study was to characterize microsites for Symphoricarpos microphyllus seed germination in a temperate forest, its response to light qualities in germination cameras, and seed viability during two years.Methods: Twenty-four microsites that differed according to their position in north/south (N/S) facing slopes, and by the presence/absence of secondary vegetation (“chaponeo”) due to forest management (U-undisturbed/P-perturbed) were characterized for light, soil temperature, moisture, pH and nitrogen. We also studied germination under different light qualities (white light, red light, far red light -FRL-, darkness) in germination cameras and seed viability for two years.Key results: All microsites were different in light, temperature and soil moisture. Microsites with the highest germination percentages were those US (undisturbed south) and UN (undisturbed north), where higher soil moisture and lower temperatures were registered, favoring embryo growth of seeds, since they possess morphophysiological dormancy. In cameras, germination percentages were the highest in FRL (32%). Seeds of S. microphyllus can remain viable for two years (60%).Conclusions: We do not recommend secondary vegetation removal because it affects variables of soil moisture (decreasing it) and temperature (increasing it) in microsites. This negatively influences this species germination, which needs a filtering of light and an alternation of high-low temperatures for dormancy breaking. These findings are important if we consider that the populations of this species are reducing due to overexploitation.

Fire causes a reduction of plant cover due to the death of several structures, especially of those that are not isolated from high temperatures; such as seeds and fruits. After a disturbance the availability of diaspores is crucial for the recovery of the community. This work studied the composition and abundance of the seed rain in the xerophytic shrubland of the Pedregal de San Ángel Ecological Reserve, located at the Universidad Nacional Autónoma de México campus in Mexico City, which was affected by a surface fire. In order to understand the role of diaspores in the natural regeneration of a burned site, seed traps were placed on 2 sites, one affected by the fire and the other in an unburned location. During 1 year the dispersed seeds and fruits were collected and identified. Results showed that species richness, life forms, and dispersal syndromes were different between sites. The highest abundance and richness values were observed in the burned site. This work offers basic data on the availability of species as diaspores, information which is useful for potential restoration strategies especially in those areas under constant anthropogenic disturbances.

Biotic and abiotic heterogeneity in spatial and temporal scales were characterized for two areas of the xerophytic shrubland of the “Pedregal de San Ángel” (REPSA) ecological reserve. Nine floristic groups were identified and they showed a differential distribution of the plant species that inhabit this community. Each one of the groups was named according to the key species, therefore they were considered as determinants in the communities physiognomy. Through the use of multivariate analysis (TWINSPAN and CANOCO) we observed that species composition in the groups is modified in spatial and temporal scales. This study suggests that variation of some abiotic factors such as soil depth and slope influences differentially the systems heterogeneity. Temporal heterogeneity was evident since there was a different floristic composition in this area during the dry and the rainy season.