Last-century vegetation dynamics in a highland Pyrenean national park and implications for conservation

Abstract

Ecological records from before and after the creation of natural parks are valuable for informing conservation and restoration actions. Such records are often unavailable, but high-resolution paleoecological studies may provide useful information. This paper presents a sub-decadal paleoecological reconstruction of vegetation and landscape in a national park in the Pyrenean highlands, established in the 1950s. The park lands were traditionally been used for small-scale cultivation, extensive grazing, forest exploitation and, since 1910, hydroelectricity generation following the damming of numerous glacial lakes. A significant finding is that present-like forests, with negligible changes in composition, have dominated the landscape during the study period. Major vegetation changes involved shifts in forest cover, influenced by both climatic and anthropic factors. Interestingly, the creation of the park in 1955 and the initial restrictions on forest exploitation in 1975 did not significantly affect vegetation cover or composition. Forest expansion did not occur significantly until the 1980s when the park was enlarged, and forest exploitation was further restricted. This expansion peaked in the mid-1990s coinciding with a warming trend and a decrease in fire incidence, before declining due to warmer and drier climates. This decline in forest cover occurred concurrently with the ongoing global forest dieback phenomenon and may be exacerbated by the predicted global warming in this century, which could also increase fire incidence due to the accumulation of dead wood. Under current conservation measures, the main threats are global warming, fire and, on a more local scale, the massification of tourism. Expanding the park and implementing forest restoration actions on degraded terrains surrounding the park could only be beneficial.