Plant diversity and community composition in managed humid coastal dune slacks in NW England.

Margaret A Connor,Megan Quail,Stephanie Tarvin,Sven Peter Batke,Yajuan Zhu

doi:10.1371/journal.pone.0256215

Abstract

Humid coastal dune slacks are an endangered habitat in Northwestern Europe. In the UK, dune slacks are currently classified as being in ‘unfavourable’ condition, with projected decrease in England of up to 30% by 2036. Studies in mainland Europe suggest that regional factors (e.g. slack area, age, and isolation) are more important than local factors (e.g. soil, pH, soil nutrient and water status) in driving successional vegetation processes in coastal slacks. However, this has never been tested for the UK, where approximately 14% of European slacks occur. We used previously established survey protocols to test whether regional factors are more important than local factors in UK coastal slacks, along the Sefton Coast in NW England. We found that slack area and slack age were more important than local factors in driving plant community composition and species richness. We also showed that higher levels of management, such as active grazing and invasive shrub and tree removal, are effective in increasing soil moisture levels in slacks. Our results suggest that similar successional processes are likely to be important in slacks in the NW of England, compared to mainland Europe.

Highlights

Humid dune slacks are low-lying wetland coastal habitats that are subjected to large seasonal shifts in the water table
Using the same methodology employed by Bossuyt, Honnay [14], we investigated and compared for the first time, whether similar local and regional factors are important in driving plant community and diversity differences in coastal dune slacks on the Sefton Coast in NW England—a Special Area of Conservation (SAC) and a Site of Special Scientific Interest (SSSI)
Species richness was positively associated with an increase in slack area and negatively with maximum soil moisture and percentage of bare ground (Table 1)

Summary

Introduction

Humid dune slacks are low-lying wetland coastal habitats that are subjected to large seasonal shifts in the water table. Many slacks in the UK are currently classified as ‘unfavourable’, due to land development, drainage and under-grazing [3]. Many rare and endemic species that are often associated with coastal slacks are becoming more threatened [4]. Key local factors that are believed to determine changes in plant community composition and succession in dune slacks include biomass accumulation over time [5,6,7], seed bank age [8, 9], soil moisture, pH and hydrological changes [6, 10, 11] and management intensity such as cutting and grazing [12]. It has been shown that soil accumulation and scrub

Methods

Results

Conclusion