Long-lasting Imprint of Former Glassworks on Vegetation Pattern in an Extremely Species-rich Grassland: A Battle of Species Pools on Mesic Soils

Nineteenth-century land use shapes the current occurrence of some plant species, but weakly affects the richness and total composition of Central European grasslands

Context

Historical land use is thought to have influenced plant community diversity, composition and function through the local persistence of taxa that reflect ecological conditions of the past.

Objectives

We tested for the effects of historical land use on contemporary plant species richness, composition, and ecological preferences in the grassland vegetation of Central Europe.

Methods

We analyzed 6975 vegetation plots sampled between 1946 and 2021 in dry, mesic, and wet grasslands in the borderland between Austria, the Czech Republic, and Slovakia. Using 1819-1853 military maps, we assigned each plot to a historical land-use category (arable land, forest, grassland, settlement, permanent crop, and water body). We modeled the response of species richness, composition, and plant ecological preferences to the historical land use including contemporary covariates.

Results

Nineteenth-century land use explained little overall variation in species richness and composition, whereas more variation was explained by contemporary environmental conditions. However, we found that ecological preferences of some species were associated with specific historical land uses. Specifically, species more frequently occurring in historically forested grasslands showed lower light and disturbance frequency indicator values, while those associated with former settlements displayed higher disturbance severity indicator values.

Conclusions

We conclude that signatures of specific land-use conversions, including the restoration of grasslands in human-impacted areas, may still be detectable in grasslands even 200 years into the future. However, while local historical land use influences the occurrence of some species based on their ecological preferences, these effects do not significantly influence community species richness and total composition.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10980-024-02016-6.

Habitat extremity and conservation management stabilise endangered calcareous fens in a changing world

Calcareous fens represent an endangered type of peatlands, acting as refugia for stress-tolerant species in the currently changing landscapes. The resurveys across many regions have reported their recent disappearance or deterioration despite both the extreme habitat conditions (carbonate richness, presence of calcareous tufa, nutrient limitation, high water level) and conservation management. To test the stability of their biotic communities in different environmental and management configurations, we repeatedly sampled molluscs (terrestrial and aquatic), vascular plants, and bryophytes at 30 calcareous fens in the Inner Western Carpathians (Slovakia, Poland) after 13-17 years of warm summers and land-use changes. We found a small yet statistically significant effect of sampling period (old versus new survey) on the species composition of all three groups of organisms when the effect of various positions of sites along ecological gradients was controlled for. The compositional changes, interpreted with the help of Ellenberg Indicator Values, suggest an incipient succession towards grasslands and shrublands, driven by decreasing soil moisture and increasing nutrient availability. Although the number of habitat specialists did not change, the number of matrix-derived vascular plant and bryophyte species significantly increased, with six ubiquitous species of productive habitats being significantly more represented currently, while the richness of aquatic molluscs significantly decreased. Fens in which potentially strongly competitive plant species were less stressed because of less intense management and lower habitat extremity were more prone to such succession. There was no single factor that could predict the magnitude of composition changes; instead, tested factors were found to act synergistically. Conservation management was predominantly important for bryophytes, while extreme habitat conditions were predominantly important for terrestrial snails. We suggested a way how nature conservancy authorities can prioritise the management needs by applying an abiotic indicator system, with less environmentally extreme fens requiring more intense conservation management.