Long-term change in calcareous grassland vegetation and drivers over three time periods between 1970 and 2016

Lucy E Ridding,Patrick O Keenan,Sarah A Thacker,Robin Walls,Richard F Pywell,James M Bullock,Peter Hawes,Ulrike Dragosits,M Glória Pereira,Oliver L Pescott

doi:10.1007/s11258-020-01016-1

Lucy E Ridding, Patrick O Keenan + Show 8 more

Open Access

https://doi.org/10.1007/s11258-020-01016-1

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Journal: Plant Ecology	Publication Date: Mar 5, 2020
Citations: 18	License type: open-access

Affiliation: UK Centre for Ecology & Hydrology

Abstract

Analysis of long-term vegetation change is limited. Furthermore most studies evaluating change only examine two snapshots in time, which makes it difficult to define rates of change and accurately assess potential drivers. To assess long-term change in calcareous grassland over multiple time periods, we re-surveyed a transect study undertaken at Parsonage Down National Nature Reserve, Wiltshire, southern England in 1970 and 1990 by T. Wells. We examined differences in soil properties and species traits in each of the survey years to understand potential drivers of vegetation change, including nitrogen deposition and grazing management. There was a clear shift in species composition, combined with significant declines in species richness and diversity between 1970 and 2016, with the greater rate of change occurring between 1990 and 2016. A significant increase in soil total nitrogen was found, which was significantly associated with the decline in species diversity between 1970 and 1990. Significant changes in community-weighted mean traits were identified for plant height (increasing), specific leaf area (decreasing), grazing tolerance (decreasing) and Ellenberg N (decreasing) between 1970 and 2016. By using survey data from multiple time periods, we suggest that N deposition may have contributed towards community changes between 1970 and 1990, as indicated by the change in soil properties and the associated decline in species diversity. Vegetation change between 1990 and 2016 is likely to be largely attributable to a decline in grazing pressure, indicated by the increase in taller species and a decrease in grazing tolerance.

Highlights

Habitat degradation is one of the main drivers of biodiversity loss worldwide (Newbold et al 2015)
To reveal if changes in vegetation reflected the soil status over time, we examined the correlation between the change in each of the soil properties with both the change in species richness and diversity
The rate of species richness, diversity, indicator richness and indicator diversity change was significantly higher between 1990 and 2016, compared with between 1970 and 1990 (Table 2), which supports the generalised additive mixed models (GAMMs) results suggesting the rate of vegetation change between 1970 and 2016 was not linear

Summary

Introduction

Habitat degradation is one of the main drivers of biodiversity loss worldwide (Newbold et al 2015). Diaz et al 2013; Keith et al 2009) This static approach makes it difficult to understand trajectories of change (Renard et al 2015) or to assess potential drivers accurately. Understanding these drivers is essential for predicting future changes and adapting management to mitigate these impacts in order to conserve habitats and their species. Calcareous grassland is a classic example of a habitat that has undergone considerable destruction and degradation across Europe. Fuller (1987) estimated that 97% of seminatural grassland had been lost between 1932 and 1984 in England and Wales.

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Conclusion