How are grassland ecosystem functions impacted by flood or drought and how do they recover following single or multiple extreme stress events?
Abstract
Improved grasslands make up an important part of UK agriculture and in addition to providing forage for livestock, grasslands provide additional ecosystem services including carbon storage, pollution attenuation and the regulation of water quantity and quality. In the context of global climate change the most recent IPCC report predicts greater uncertainty in weather patterns and an increased incidence of extreme weather events, such as heat waves, drought and heavy rains and storms. Subsequently, new areas of grassland are likely to be exposed to such stresses which may include multiple successive extreme events, for example a spring flood followed by summer drought. Better information on how these systems respond to extreme and multiple events and their ability to recover is vital to safeguard the UK's agricultural sector. Despite the large risks posed, our understanding of how extreme events will impact on plant and soil functioning and the downstream benefits/impacts remains poor. To address this gap we established a plot-scale field trial on an improved lowland sheep grazed pasture. The trial design consists of 16 field plots 3 m by 3 m subjected to four treatment regimes with four replicates as follows; (i) control, (ii) spring flood, (iii) summer drought, (iv) spring flood & summer drought. Each treatment regime was imposed for 8 weeks and the following recovery is being monitored over a year. The spring flood was initiated in April 2016 and the summer drought was initiated in July 2016 allowing a 4 week recovery period between the two stresses in treatment (iv). During the 8 weeks of each stress event and during the subsequent recovery period, plant and soil indicators of ecosystem function were measured. These include plant biomass, sward composition and forage quality, soil physical, chemical and biological indicators, greenhouse gas emissions and soil water chemistry. We will present the results to date and discuss the implications for agriculture.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMGC53D1323D
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCESDE: 0439 Ecosystems;
- structure and dynamics;
- BIOGEOSCIENCESDE: 1622 Earth system modeling;
- GLOBAL CHANGEDE: 1630 Impacts of global change;
- GLOBAL CHANGE