Question: Can grazing by goats eliminate potentially combustible plant biomass and thereby change the flammability of mediterranean vegetation? Location: Doñ ana Natural Park, SW Spain.Methods: The effect of goat grazing was evaluated, over a period of 42 mo, in 100 ha of pine forest understorey with an average density of 217 trees·ha À1 . Grazing by large herbivores was halted temporarily in the study area, with wild deer excluded from 1970, and domestic goats excluded from 2002. However, following the creation of grazing exclusion plots and sampling of the vegetation within as a control, adult female Payoya goats were introduced to the area in spring 2007. Vegetation was sampled twice yearly using the point-intercept method, and data of frequency, cover and phytovolume obtained. The study was completed with an analysis of change in the flammability of the study area (determined using data on the phytovolume and flammability of species). Changes in species richness and species diversity were determined.Results: After 42 mo, the phytovolume of the ungrazed vegetation had increased significantly by 32%, while bare soil had decreased by 5%. This gave rise to a significant increase in flammability of 25%. Within the grazed area, species phytovolume decreased significantly by 34%, leading to a significant increase in bare soil of 51%, while the flammability of the area decreased by 22%. The number of species remained constant throughout the study at 20 species. Significant differences in species diversity were observed between grazed and ungrazed areas after 42 mo of grazing (species diversity index after 42 mo of exclusion = 1.59 ± 0.17, species diversity index after 42 mo of grazing = 0.95 ± 0.13).Conclusions: Monitoring of the scrub understorey has shown the positive impact of grazing goats: the resulting decrease in the quantity of total phytovolume (easily combustible vegetation) induces changes in species diversity without lowering species richness and reduces the risk of fire.

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Dehesas are agrosilvopastoral systems characterized by a savanna-like physiognomy. Today the central problem for the continuity of the dehesas is the gradual decay of tree canopy. We have investigated the history of the vegetation and management of dehesas from the middle ages to the present day in order to know in which conditions they have persisted in the long run. The results show that the word dehesa has been used historically for private grazing lands, with no reference to any vegetation type. According with the resources used during the middle and modern times the vegetation was a mixture of grasslands, shrubs and trees. The first descriptions of the vegetation of SW Spain in the 18th century showed that open oak parklands were scarce, while oak shrublands were very common. After the privatization of the land in the 19th century large private farms called dehesas developed in SW Spain, that were devoted to livestock raising in combination with agriculture and forestry. The change in management practices favored open oak parklands over oak shrublands in the dehesas, becoming the dominant vegetation of these farms in the 20th century. Is in this moment when dehesa passed to mean open oak parklands devoted to grazing, cultivation and forestry. The effect of the change in vegetation structure and management practices on oak regeneration is discussed.

Questions: (i) How do large proportions of seeds pass through the guts of goats without damage? (ii) What is the temporal pattern of seed defecation? (iii) Does ingestion by goats enhance or depress seed germination? Location: Doñana Natural Park, SW Spain. Methods: Six female goats of similar size and age were fed with 1000 seeds of four common Mediterranean shrub species (Cistus salvifolius, Halimium halimifolium, Myrtus communis, Pistacia lentiscus), which were retrieved from the goat's dung 96 h after ingestion. The seeds retrieved were tested for germination and viability, along with seeds not eaten by the goats. Results: Less than 30% of the seeds eaten were retrieved from the dung, with significant differences between species. No seeds of P. lentiscus were retrieved. The major part of the seeds was retrieved between 48 and 72 h after ingestion in all other species. The passage through the goat gut significantly increased seed germination in C. salvifolius and H. halimifolium, and depressed it in M. communis. Viability was significantly lower in the eaten seeds of M. communis than in the uneaten ones, while there were no differences in C. salvifolius and H. halimifolium. Conclusions: Goats can potentially disperse seeds of the plants that they eat. This should be taken into account when designing management plans in order to prevent shrub invasion in undesired areas. It could also be used as a management tool for spreading populations of desireable shrub species.

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Changes in the vegetation of stabilized sand dunes of Dofiana National Park in the last four centuries have been analysed, combining ecological and historical sources of information.Quantitative vegetation data have been obtained from 5 inventories of a 15 km long transect, consisting of 34 points where nearby woody plants have been recorded. Inventories were taken in 1636, 1647, 1652, 1682 and 1859. The analysis of these data, combined with climatic and management information on the area, reveals that until 1636 a mediterranean forest dominated by Quercus suber, existed; it was used as a game preserve.