Vegetation and landscape dynamics under natural and anthropogenic forcing on the Azores Islands: A 700-year pollen record from the São Miguel Island. (1st March 2017)

• Record Type: Journal Article
• Authors: Rull, Valentí; Lara, Arantza; Rubio-Inglés, María Jesús; Giralt, Santiago; Gonçalves, Vítor; Raposeiro, Pedro; Hernández, Armand; Sánchez-López, Guiomar; Vázquez-Loureiro, David; Bao, Roberto; Masqué, Pere; Sáez, Alberto
• Is Part Of: Quaternary science reviews. Volume 159(2017)
• Page Start: 155
• Page End: 168
• Publication Date: 2017-03-01
• Subjects: Palynology -- Palaeoecology -- Palaeoclimates -- Last millennium -- Azores -- Early settlement; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2017.01.021
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: The Azores archipelago has provided significant clues to the ecological, biogeographic and evolutionary knowledge of oceanic islands. Palaeoecological records are comparatively scarce, but they can provide relevant information on these subjects. We report the palynological reconstruction of the vegetation and landscape dynamics of the São Miguel Island before and after human settlement using the sediments of Lake Azul. The landscape was dominated by dense laurisilvas of Juniperus brevifolia and Morella faya from ca. 1280 CE to the official European establishment (1449 CE). After this date, the original forests were replaced by a complex of Erica azorica/Myrsine africana forests/shrublands and grassy meadows, which remained until ca. 1800 CE. Extractive forestry, cereal cultivation (rye, maize, wheat) and animal husbandry progressed until another extensive deforestation (ca. 1774 CE), followed by the large-scale introduction (1845 CE) of the exotic forest species Cryptomeria japonica and Pinus pinaster, which shaped the present-day landscape. Fire was a significant driver in these vegetation changes. The lake levels experienced a progressive rise during the time interval studied, reaching a maximum by ca. 1778–1852 CE, followed by a hydrological decline likely due to a combination of climatic and anthropogenic drivers. Our pollen record suggests that São Miguel were already settled by humans by ca. 1287 CE, approximately one century and a half prior to the official historically documented occupation of the archipelago. The results of this study are compared with the few palynological records available from other Azores islands (Pico and Flores). Highlights: The original Azorean laurisilvas were removed after the official human settlement (1449 CE). Current vegetation established after a second deforestation (1774 CE) and the introduction of exotic trees. Modern landscapes are almost totally anthropogenic, climatic shifts have been less influential. Lake levels increased until a maximum (1778–1852 CE) and then decreased to present-day values. The island was likely colonized by humans a century and a half before the official settlement.