From stationary to directional transition: a case study in Doñana

Description

Context: Doñana's landscape is a mosaic of different types of transitions at different spatial and temporal scales. Among them, stationary transitions are relatively stable over time, while directional transitions involve the unidirectional movement of boundaries. The fiftieth anniversary of the Doñana National Park (SW Spain) provided a framework to test the transformation of a biotic transition from stationary to directional. Objectives: This study aimed to examine landscape changes along a stationary groundwater-dependent transition, the processes responsible for them, and the consequences for the biotic transition. Methods: Through detailed photointerpretation, nine land use/land cover categories were mapped at four dates (1971, 1984, 2002, 2019) on a ca. 2 square km plot, and then changes analysed at three levels (interval, category, and transition) using Intensity Analysis. Potential causes including precipitation, groundwater levels, local management and changes in the surroundings were examined to understand the changes. Results: Juniper woodland, spontaneous pines and mixed shrub categories showed the greatest gains and were most active. In the third interval (2002–19) largest transitions from pond-grassland to several terrestrial categories and the dead of heathlands indicate the encroachment of xeric communities into hygrophytic ones. Observed changes seem to be due to succession, forestry management and extrinsic drivers such groundwater overexploitation in the surroundings of the protected area. Conclusions: The long-term study of this stationary transition shows the weakening of the factors that controlled its establishment, the loss of its constituent habitats due to groundwater withdrawal, and its conversion into a directional transition.

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