DOI: 10.5061/dryad.8gtht76jx
title: Data from: The contribution of successional grasslands to the conservation of semi-natural grasslands species – A landscape perspective

description: 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.
description: The methods are described in detail in Schmid et al.
 (2017)  For the variables S1-S4 in the environmental
 data file, see Löfgren et al. (in revision: Journal of Vegetation
 Science).
description: <strong>Descriptions to the data
 files</strong> Species_list.csv: Species names
 and the abbreviations used in Schmid et al. (2017) and Löfgren et al. (in
 revision: Journal of
 Vegetation Science). Nomenclature follows Mossberg, B.,
 & Stenberg, L. (2010). Den nya nordiska floran. Stockholm, Sweden:
 Wahlström & Widstrand. VegData_smallplots.csv:
 Plant species frequency data in 220 (0.4m*0.4m) plots (used in Schmid et
 al. 2017) VegData_largeplots.csv: Plant species
 presence/absence data in 220 (2m*2m) plots (used in Löfgren et al. in
 revision: Journal of
 Vegetation Science)
 VegData_frequencies40sp_largeplots.csv: Plant species frequency
 data in 160 (2m*2m) plots for the 40 most common species (used in Schmid
 et al. 2017) Specialists.csv: List of plant species
 typical for dry, grazed grasslands (used in Schmid et al. 2017)
 EnvData.csv: Details for the environmenal variables are described
 in the enclosed metadata-file ("EnvData_metadata.csv")