Data from: Pioneer habitats drive high plant beta diversity and conservation value of mineral extraction sites

Mineral extraction sites have been shown to serve as secondary habitats
and provide suitable conditions for a wide range of plant species. The
areas created by extraction are characterized by a high degree of
disturbance, nutrient depletion, and low competition. Here, we compare
plant communities across a wide range of sites and substrate classes, to
assess drivers of plant biodiversity and provide practical insights for
restoration that can be applied by extraction companies. We studied alpha-
and beta-diversity of plant species in 12 German mineral extraction sites
for building materials (gravel, gypsum, limestone, sand). We assessed
plant diversity, abundance, and abiotic and structural parameters on 124
plots. We found only minor variation in species richness between plots,
whereas species composition differed substantially. Species richness
increased with soil pH while it decreased with proportion of open soil.
The local contribution to beta diversity (LCBD) of sites was particularly
high on open and acidic plots. The acidic and older plots harboured the
highest proportion of endangered species. The floristic composition was
significantly influenced by age, herb-layer height, open soil, and pH;
however, site and substrate accounted for a substantially greater
proportion of the total variance in community composition. Our
findings highlight the significance of open pioneer habitats in driving
plant beta diversity of extraction sites for building materials. Nutrient
depletion and site heterogeneity facilitate the colonization by a wide
range of generalist and specialized plant species through natural
succession. Given the excellent nutrient-poor starting conditions, mineral
extraction sites should therefore be prioritized for the development and
restoration of low-productive open habitats, such as grass- and
heathlands, while common recultivation measures, in particular soil
amelioration and afforestation, should be avoided. The persistence of open
pioneer habitats can be promoted by deliberate mechanical disturbances or
grazing to slow down succession on abandoned patches. Addressing
shortcomings in long-term management and advancing the development of
post-extraction habitats for conservation purposes is crucial and could
make a substantial contribution to the protection of plant diversity at
both local and regional scales.