## 6 Discussion
### Landscape and Human Impact  
2.1 The Case of PNAESM: Contribution of Phytoliths to Landscape Reconstruction, Contrasting with Other Proxies  
The comparative study of phytoliths and other vegetal remains from the Neolithic occupation at Cova del Sardo between 7300 and 6300 cal BP has proved to be an extremely useful tool for the reconstruction of the social practices of the first Neolithic communities who occupied the high mountain valleys in the central axial Pyrenees. The study of the test pit at Forcall de Sant Esperit (AS2), 530 m from Cova del Sardo and at a similar altitude (1771 m asl) has revealed two phenomena. First, that the human occupation of the valley took place two or three centuries before the use of the rock shelter, as the first anthropized palaeosoil documented in the valley bottom has been dated between 7243 and 6882 cal BP, whereas the first reiterated use of the rock shelter is dated between 6776 and 4319 cal BP. However, the site had been occupied briefly at an earlier time, between 7513 and 7326 cal BP [28].  
Second, the comparative study of phytoliths, macro-and micro-charcoal, pollen, organic and chemical matter in the area outside the site indicates an early intense modification of the forest in the valley bottom, formed by mountain pine (_Pinus mugo uncinata_) and birch (_Betula pendula_), through the iterated use of burning in the Early Neolithic, between 7300 and 6300 cal BP. The archaeobotanical and palaeoenvironmental results are compatible with the maintenance of woodland with clearings, suitable for forestry and livestock use, while maintaining the vegetation cover. This type of non-arable anthropic Neolithic landscape has been determined with a similar methodological approach in the middle Rhone valley, in the montane altitude zone [97].  
The scarcity of domestic cereals or other cultivated species in the carpological and palynological record [31] does not completely rule out the creation of cropland in the area of the Sant Nicolau valley. However, the analyses of phytoliths from the interior of Cova del Sardo and its outer terrace, and from Forcall de Sant Esperit, have not revealed significant evidence of crops in the area of study.  
It therefore seems likely that the model of forest management applied by the first agropastoral communities in the Sant Nicolau valley in the Early Neolithic (7300-6300 cal BC) involved the deliberate transformation of the vegetation around the inhabited areas, through the iterated use of fire and the introduction of small flocks of domestic animals in the surroundings of the rock shelters. The local cultivation of crops has not been demonstrated, only their sporadic consumption in Cova del Sardo. The environmental conditions in the valley, at least in the shady humid areas, would not have been optimal for cereals, although the occasional consumption of barley (_Hordeum vulgare_ L. var. _nudum_) has been documented [21]. These were probably grown in another part of the valley or nearby area, because the tools discarded by the occupants of Cova del Sardo had also been used for harvesting [98]. This dynamic of the management of medium and high mountain territories would not correspond to any kind of specialization in animal husbandry by the Pyrenean Neolithic communities [99]. Instead, a dynamic of seasonal altitudinal mobility might have been established, with the occupation of the higher areas in summer and autumn. The smaller shelters and sites in high mountain areas, like Cova del Sardo, would not have been occupied all year, unlike other larger sites at medium altitudes [99; 100].