Ecological Indicators (May 2021)
Land-use history affects vascular plant composition of calcareous grasslands – Does it affect cryptogam composition, too?
Abstract
Land-use history and habitat age are considered highly important regarding the species composition and conservation value of, e.g., grasslands and forests. Ancient sites, i.e., sites with a continuous habitat history, are thought to be richer in rare, threatened, and more specialised species than recent sites. However, species composition is also affected by abiotic and ecological factors such as soil and climate parameters, and further analyses are needed to determine whether history or other factors are more important. In previous studies carried out at two study areas in the German Jurassic mountains, land-use history was identified as the main factor shaping vascular plant composition of ancient vs. recent grassland sites. Ancient was defined that there was a continuous grazing history since at least 200 years, while recent grasslands have developed from arable fields considerably after this time. Many species such as arable weeds and crop species, being residuals of the former land-use type, were found in the recent grasslands. In the present study, we assessed the terricolous cryptogam vegetation (bryophytes, lichens, macromycetes) of the same ancient and recent sites regarding species composition, occurrence of endangered species, and the applicability of the indicator species concept and Ellenberg indicator values. Although land-use history was the strongest explaining factor regarding vascular plant vegetation in previous studies, cryptogam vegetation did not reflect this signal. Species numbers and Ellenberg indicator values were quite similar in ancient and recent grasslands but we could, nevertheless, identify indicator species for both grassland types, with Rhytidium rugosum, Cladonia furcata ssp. subrangiformis and Hygrocybe persistens as strongest indicators of ancient grasslands, and Rhytidiadelphus squarrosus as strongest indicator of recent grasslands. When we compared the results for vascular plant and cryptogam vegetation we found that land-use history seems to have much less influence on the composition of the cryptogam vegetation in grasslands, given a certain time of recreation and succession. This is very likely due to an enhanced dispersability of cryptogam propagules. We found rare and endangered cryptogam species in ancient and recent sites; therefore, species maintenance measures can be worthwile in both grassland types.
