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In the context of the landscape and history of the southern Peruvian Andean territory, a phytosociological approach to the vegetation linked to human activity is presented. To obtain a comprehensive study, we focused the study on different elements of the Andean landscape, including plant communities: crop terraces with Brassica rapaand Medicago hispidacommunities, irrigation channels with Mimulus glabratusand Polypogon interruptuscommunities, roads with Alternanthera pungensand Lepidium bipinnatifidumcommunities, overgrazed areas with Bouteloua simplex, Michrochloa indicaand Cyperus andinus, farmyards, dumps and wall bases of villages with ruderal communities with Malva parvifloraand Urocarpidium peruvianum, and wall fissures with Parietaria debilisand Cheilanthes pruinatacommunities.The study area is especially the Colca canyon in the Arequipa Department (southern Peru), where traditional agriculture is practiced and where we lifted 144 plots following the Braun-Blanquet methodology, adding 853 plots from other authors. In total, 997 plots and 426 species were considered. To interpret the variability and vertical continuum of the associations, we have used the concepts of basal community (BC), derived community (DC), and altitudinal form were used.Field and bibliographic tables were synthetized, and as a result of column comparisons, we have concluded with a diversity of 41 Andean associations and communities described for areas of human impact distributed in different climatic belts.From a syntaxonomical point of view, 10 new associations are described: Nassello pubiflorae-Stipetum mucronatae –supra- and orotropical communities associated with the crops of southern Peru where the soil has been turned using the Roman plough –, Chlorido virgatae-Pennisetetum villosi –thermo- and mesotropical communities on abandoned fields, wastelands and road margins in the Bolivian Andes –, Mimulo glabratiPolypogonetum interrupti –streams and irrigation ditch vegetation with running waters –, Monnino ramosae-Boutelouetum simplicis – pioneer annual vegetation on sandy soils of the supratropical belt of southern Peru –, Hypseocharito bilobatae-Boutelouetum simplicis –pioneer annual vegetation on clayey soils of the supra- and low orotropical belts of southern Peru –, Pectocaryo lateriflorae-Boutelouetum simplicis –pioneer annual vegetation on clayey soils of the mesotropical belt of southern Peru –, Evolvulo arizoniciMuhlenbergietum peruvianae –pioneer annual vegetation on clayey soils of the supratropical belt of the eastern cordillera of Bolivia –, Urtico flabellatae-Urocarpidetum peruviani –nitrophilous meso- and supratropical vegetation on disturbed soils of dumps, street margins and wall bases of the houses of the villages of central and southern Peru –, Oxalido petrophilae-Cheilanthetum pruinatae –supratropical association in the fissures of the andesitic rocks and walls of the villages of southern Peru – and Cheilanthetum arequipensis –fissure vegetation of the andesitic rocks of the mesotropical belt of southern Peru. For all these associations, we have commented on their variability with sub-associations, derived communities, basal communities, altitudinal forms and geo-vicarious associations. To connect the vegetation linked to the crops on soils turned by the Roman plough in the supra- and orotropical belt, we have created the new alliance Hordeion mutici (while vegetation on soils turned by the Inca plough –“taclla”- belongs to the Calandrinion ciliatae) and the Calandrinietalia ciliatae order. The vegetation of irrigation ditches in the tropical Andes belongs to the new alliance Mimulion glabrati, and the hygronitrophilous ones to Rumicion cuneifolii and the Polygono hydropiperoidis-Rumicetalia cuneifolii. Pioneer annual vegetation of the Occidental Peruvian Andes belongs to the Monnino pterocarpae-Cyperion andinae, and for the meso- and supratropical rock vegetation we have described the Woodsio montevidensis-Cheilanthion pruinatae.Moreover, all vegetation types of the Colca canyon linked to human activity have been compared with other tropical Andean localities with similar ecological conditions, especially from central Peru, Bolivia and Ecuador, and also with extra-tropical conditions from Chile and Argentina.

The effects of different agricultural regimes on the mosaic of plant communities and the dynamics of the landscape are analysed: smallholdings in Alto Alenteio (Portugal) and latifundia in Extremadura (Spain). The Spanish area is located in the Sierra de Guadalupe, in Villuercas. The Portuguese area is located in Serra de S. Mamede, in Alto Alenteio. These two areas selected have identical geology, similar climatic conditions and the same type of climax vegetation (Arbuto unedonis-Querceto pyrenaicae sigmetum, Sanguisorbo agrimonioidis-Querceto suberis sigmetum, and Pyro bourgeanaeQuerceto rotundifoliae sigmetum), but different replacement communities can be observed. The differences have been studied in all types of vegetation, including forests, pastures, crops, roads, trails, irrigation ditches, streets and walls of some villages, and hydrophilous plant communities. Beyond the classical associations, fragmentary vegetation types are also considered (basal communities, derived communities). The mosaic of vegetation types was sampled by SIGMA relevés (15 in Extremadura and 15 in Alto Alenteio, of 1 km2 each one). As a result, "dehesas" are more frequent in Spain than in Portugal, where forests have been cleared for agriculture. Rockrose shrubs (Cistus ladanifer), and heaths (Erica sp.), indicate burnt areas. Generally, Extremadura shows well conserved pastures suitable for livestock grazing (Poo bulbosae-Trifolietum subterranei, Pulicario-Agrostietum pourretii, Gaudinio-Agrostietum castellanae), while in Portugal, subnitrophilous fallow land communities are more variable, due to the more intensive and less mechanised use of soil (Chrysanthemo-Chamaemeletum fuscati, Rumici angiocarpi-Coleostephetum myconis). Roadside communities are clearly linked to their history and influenced by the contact communities. Communities linked to settlements are more diversified in Portugal than in Spain, because stony walls around fortresses and in Jewish quarters (Parietarietum judaicae, Anogrammo-Umbilicetum rupestris), and medieval paved streets with their respective plant communities (Gymnostiletum stoloniferae, Euphorbio-Oxalidetum corniculatae), have been conserved. Riverside vegetation complexes also differ in Spain and Portugal, as a result of different relief features and hydrological conditions. In Extremadura there are wide plains disturbed by the flooding of rivers, with the association Pyro bourgeanae-Securinegetum tinctoriae ("tamujares"); in Portugal, riversides are more abrupt, thus alder (Scrophulario-Alnetum glutinosae) and willow groves (Viti-Salicetum atrocinereae) are more frequent.