Plant species composition and richness in abandoned agricultural terraces vs. natural soils on Lanzarote (Canary Islands)

Abstract

Farmland abandonment constitutes a major land use change, with its importance acknowledged today due to the implications it has for biodiversity and cultural values. The present paper analyzes the vegetation of several groups of abandoned agricultural terraces on the island of Lanzarote. Species composition, species richness and vegetation cover were examined and the terraces were compared to non-terraced soils (uncultivated, natural-soil control plots) in similar environmental conditions.The number and diversity of species were found to be significantly higher in the terraced plots than in the control plots. Of the total species identified (41), five did not appear in the abandoned terraces, while sixteen were not present in the control plots. In addition, vegetation cover was significantly greater in the abandoned terrace fields than in the control plots. Canonical Correspondence Analysis (CCA) did not throw up differences in species composition between the abandoned terraces and control plots, while only a small number of environmental variables (mean temperature, annual precipitation, and sand percentage) proved significant in accounting for species distribution. Despite the absence of differences in species composition, we were able to create a gradient of preferences from abandoned fields to the control plots. Species behave individually in accordance with these environmental requirements.