Vegetation change over a period of 46 years in a Mediterranean mountain massif (Penyagolosa, Spain)

Abstract

[EN] Questions The Mediterranean mountain massifs are biodiversity hotspots threatened by climate change and land use transformations, among other factors. Did vegetation composition and alpha- and beta-diversities change in mid- and high-elevation Mediterranean ecosystems over the last 46 years? Can these changes be explained by climate change or land use? Location Medium and high altitudes of the Penyagolosa Massif, Castellon, Eastern Spain. Methods In 2014, we resurveyed 92 vegetation plots sampled in 1968, belonging to nine plant communities distributed on basic and acid soils. We performed estimates of alpha- and beta-diversity, multidimensional ordination of species composition, ecological characterisation of species and non-parametric tests to identify vegetation change over time. Results We observed different patterns of vegetation change depending on the plant community; an increase in alpha-diversity, especially in high-altitude habitats, and a homogenisation of species composition among plant communities. Seral communities and forests increased particularly in locations on basic soils that used to be occupied by pastures and communities of degraded successional stages. Higher Ellenberg indicator values of temperature and light, and loss of temperate taxa, which are usually rare in the region, were found in the climax forest of high altitudes and some acidophilous communities. However, altitudinal shifts of species distributions were detected only in 14% of plant species, both upwards and downwards. An increase of nitrophily at medium altitudes was also observed. Conclusions The results suggested that land use change related with abandonment of agro-sylvo-pastoral systems was the major driving force of vegetation dynamics in most of the seral plant communities, while thermophilisation was more evident in the high-altitude climax forest.