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Data from: The contribution of successional grasslands to the conservation of semi-natural grasslands species – A landscape perspective

Schmid, Barbara C.1; Löfgren, Oskar1; Sykes, Martin T.1; Poschlod, Peter2; Hall, Karin1; Prentice, Honor C.1

Published Dec 18, 2019 on Dryad. https://doi.org/10.5061/dryad.8gtht76jx

Data files

Dec 18, 2019 version files 257.17 KB

Abstract

These data have been used in the following works:

Schmid, B. C., Poschlod, P., & Prentice, H. C. (2017). The contribution of successional grasslands to the conservation of semi-natural grasslands species – A landscape perspective. Biological Conservation, 206, 112-119. doi:10.1016/j.biocon.2016.12.002

Oskar Löfgren, Karin Hall, Barbara C. Schmid, Honor C. Prentice. (in revision: Journal of Vegetation Science). Grasslands ancient and modern: soil nutrients, habitat age and their relation to Ellenberg N

 

Abstract (Schmid et al. 2017)

Many species that are typical of calcareous, semi-natural grasslands (“typical grassland species”) are declining in Europe as a result of habitat-loss and -fragmentation. Whereas populations of these species are expected to be largest in old semi-natural grasslands, these species may also occur in successional grasslands on previously arable fields. We used a space-for-time approach to analyse changes in the frequencies of typical grassland species, and changes in soil properties, over a 280-year arable-to-grassland succession within a Swedish landscape. Our study revealed that a number of typical grassland species had higher frequencies in mid-successional (50–279 years) than in old (≥280 years) grasslands. Mid-successional grasslands also contained many of the typical grassland species that were present in old grasslands, but at lower frequencies, and had soil conditions similar to those of old grasslands. Early-successional (5–14 and 15–49 years) grasslands contained few typical grassland species. In highly fragmented landscapes, mid-successional grasslands provide additional habitat for many typical grassland species, and can function as temporary refugia (“substitute habitat”) for these species until old grasslands are “restored”. The overall population sizes of some typical grassland species and red-listed species are likely to be substantially increased by the presence of mid-successional grasslands within the landscape. Our study suggests that, rather than focussing solely on old grassland fragments, conservation strategies for typical grassland species should adopt a dynamic, landscape-based perspective that recognizes the role of successional grasslands. Ensuring a continuous development of mid-successional grasslands is expected to be beneficial for populations of many typical grassland species.

 

Abstract (Löfgren et al. in revision: Journal of Vegetation Science) 

Questions. To what extent does the long-term process of grassland succession reflect changes in nutrient availability or other effects of grassland history? Plant communities in ancient, semi-natural pastures include many species associated with nutrient-poor soils. However, semi-natural pasture communities can also develop on previously arable sites – as nutrient levels decline over time. In Europe, Ellenberg N-values represent species’ overall nutrient preferences, and are often used as a proxy for soil-nutrient availability. But how well do N-values actually reflect species’ relationships with measured nutrient concentrations during grassland succession?

Location. A successional series of grazed, previously arable to ancient, grasslands on the Baltic island of Öland, Sweden.

Methods. We collected data on community composition and soil nutrient (phosphorus, ammonium, nitrate) concentrations. We used Bayesian joint community modelling to parametrize species’ relationships with nutrients and grassland age, and quantified the relative contributions of the variables. Species responses were then compared with Ellenberg N-values.

Results. Phosphorus was the best explanatory variable for most species. However, species occurrences were not simply explained by gradients in particular nutrients, but by combinations of different nutrients and grassland age. There was overall agreement between N-values and species’ nutrient responses – although the occurrences of species with identical N-values may be explained by different nutrients. Species with high and low N-values represent more reliable nutrient-indicators than intermediate-N species, but their occurrences also reflect other factors that, as with nutrients, depend on the grassland age.

Conclusions. Our results confirm that Ellenberg N provides a robust indication of the overall nutrient preferences of individual grassland species. However, in grassland sites developing on previously arable land – where nutrient availability is strongly associated with habitat age – N-values may represent an integrated response not only to nutrients but also to other historical processes that drive grassland community assembly.