Drivers of vegetation change in grasslands of the Sheffield region, northern England, between 1965 and 2012/13

Carly J. Stevens,Tobias Ceulemans,J. Philip Grime,Simon M. Smart,Susan Jarvis,John G. Hodgson

doi:10.1111/avsc.12206

Abstract

AbstractQuestionsHow has vegetation species diversity and species composition changed between 1965 and 2012/13 in acidic and calcareous grasslands? What has driven this change in vegetation?LocationA 2400‐km2 area around Sheffield, northern England.MethodsIn 1965 a survey was conducted to describe grassland vegetation of the Sheffield region. We repeated this survey in 2012/13, revisiting acidic and calcareous grassland sites (455 quadrats). Climate, N and sulphur deposition, cattle and sheep stocking rates, soil pH, altitude, aspect and slope were considered to be potential drivers of variation in vegetation. We analysed temporal changes in vegetation and examined relationships with spatial and temporal variation in driver variables.ResultsBoth acidic and calcareous grasslands showed clear changes in species composition between the two time periods. In acidic grasslands there was no significant change in richness but there were declines in diversity. There were significant increases in Ellenberg N. Nitrogen deposition and grazing were identified as potential drivers of spatial and temporal patterns but it was not possible to discriminate the respective impacts of potential drivers. In calcareous grasslands there were declines in species richness, diversity and appropriate diversity indices. Climate and soil pH were identified as potential drivers of spatial and temporal patterns.ConclusionsDespite only small site losses compared to other surveys in the UK, especially within the national park, both calcareous and acidic grasslands showed very clear changes in species composition. In acidic grasslands, high abundance of Pteridium aquilinum was a particular problem and had increased considerably between the two survey periods. Atmospheric N deposition and grazing were identified as drivers of species diversity. A number of calcareous grasslands showed signs of reduced management intensity leading to scrub invasion.

Highlights

Over the past 50 yr, humans have changed ecosystems more rapidly and extensively than in any comparable period of human history (Mace et al 2005)
Despite only small site losses compared to other surveys in the UK, especially within the national park, both calcareous and acidic grasslands showed very clear changes in species composition
Atmospheric N deposition and grazing were identified as drivers of species diversity

Summary

Introduction

Over the past 50 yr, humans have changed ecosystems more rapidly and extensively than in any comparable period of human history (Mace et al 2005). Semi-natural grasslands make up 37% of UK land area (Carey et al 2008) but have declined considerably in their extent during the last century. Enclosed semi-natural grasslands declined by 97% in England and Wales between 1930 and 1984 (Fuller 1987). The UK Countryside Survey (CS) identified a significant decrease in the area of calcareous and acidic grasslands between 1990 and 1998, no change was observed between 1998 and 2007 (Carey et al 2008). The UK National Ecosystem Assessment (NEA) (2011) identifies

Results

Discussion

Conclusion