## 5 Discussion
### Mid-Holocene Vegetation History and Neolithic Landscape Transformation in the Western Mediterranean
#### 5.3.1 Site Formation Processes and Environmental Evolution  
The analysis of pollen and non-pollen palynomorphs in archaeological profiles gives a picture of environmental evolution within the site and in the nearby surroundings. In addition, the pollen content of different archaeological layers and structures provides significant information to reconstruct site formation processes and, in combination with geomorphological studies, enables the identification of depositional and post-depositional events in archaeological contexts. In La Draga, the lake marl offers an insight into the landscape prior to the Neolithic occupation, showing that there was a dense oak forest (_Quercus_ deciduous), presence of pines and fir in the surrounding mountains (_Pinus_ and _Abies_), and riparian forests at local scale (Figure 6). Once Neolithic communities settled at La Draga (Phase I, Figure 6) evident vegetation shifts occur: a fall in _Quercus_ deciduous, the overrepresentation of herbs, the expansion of hygrophilous plants indicating open spaces at local scale, and a slight expansion of pines. The contact layer (first 2 cm) between lake marl and archaeological sediments in Sector A is noteworthy, as the evidence of human impact is already detected, suggesting that in this emerged sector, the lake marl was exposed (confirmed by high valuesof soil erosion indicating sub-aerial or terrestrial environments) and used as the occupation surface where humans carried out their activities (clearly evidenced, for example, in the presence of Cerealia-t pollen, Figure 6). In Phase II (Sector B-D) and in Sector A structures, the signal of landscape transformation is accentuated, showing both lower values of _Quercus_ deciduous and high values of Cerealia-t. In Sector B-D, the occurrence of high values of coprophilous spores in both phases contrast with their absence in the analysed profiles in Sector A and their rare occurrence in the spatial analysis [49; 93]. Once the settlement was abandoned, a peaty layer formed and riparian forests expanded (mainly _Alnus_ spp.) colonizing the open spaces previously dominated by hygrophilous plants during the Neolithic occupation (Figure 6). This expansion of alder carr environments on the shores of Lake Banyoles is consistent with data from SB2 sequence, where _Alnus_ expanded from 5.5 kyr cal BP onwards (Figure 5) [38]. The importance of site formation processes and taphonomic issues in the interpretation of pollen records is shown in this study by the DCA in spatial analysis in both Sector A and Sector B-D (Figure 7) at La Draga. In both cases, the first Axis is explained by taphonomic processes. In Sector A, there is a contrast between layers (mainly UE2002) in the northern part, characterized by a high mineral content (determined by loss on ignition [49], low organic matter, and high values of pollen and spores resistant to erosion (_Pinus_, _Abies_, _Pteridium_, _Ophioglossum_-t); and, in the south, sediments characterized by high CaCO\({}_{3}\) content and high values of local-growing plants in edaphic soils, such as Asteraceae liquidiforae and _Typha-Sparganium_. Thus, while the first sediments were deposited through soil erosion episodes, the second indicate clear signs of edaphisation and authigenic deposition. In Sector B-D, there is an east-west gradient, showing a wet environment with accumulation of algae and hygrophilous vegetation to the east, and various fungal indicators of sub-aerial conditions to the west. The comparative analysis of the pollen and NPP record in Sectors A and B-D was able to characterise the depositional environment of this new sector as well as demonstrate the important capacity of some non-pollen palynomorphs to define local environments. While the pollen record indicates similarities between Sectors A and B-D (Figure 6), NPP show a clear difference between the two sectors. Greater richness, ubiquity and abundance of fungi were documented in the waterlogged Sector B-D.