Background
The Falkland Islands (52°S, 59°W), 12,000km2 in area, have the highest proportion of land cover of peat in any of the UK overseas territories. They have a cool (2.2°C–9.4°C), temperate oceanic climate. Rainfall varies between 400–800mm and is lowest in spring. The islands were partially glaciated and acid, organic soils have formed mainly because of low temperatures and the impervious clay-rich subsoil creating conditions which favour waterlogging. Histosols and histic soils, upland peat, lowland peat or tussac (coastal) peat cover a large portion of the land surface. In many areas these are shallow, prone to drying out and have low rewetting potential. The Falklands store an estimated 1000 Mt of Soil Organic Carbon (SOC).
The TEFRA Project
The EU- funded TEFRA project (Terrestrial Ecosystems of the Falklands – a Climate Change Risk Assessment) has identified priority impacts: increased soil moisture deficits and erosion; changes in plant pests, diseases + invasive plants; changes in the ranges of native plants; habitat disturbance by extreme events – wildfire occurrence; changes in soil carbon content.
The project (due to be completed next year) has provided basic information on the peatlands of the Falklands which will be of huge help to land managers and others working to control erosion, restore eroded peatlands and conserve soil carbon stocks in the face of predicted temperature increases and potential rainfall pattern changes.
From the project, Rodney Burton has developed a much-improved soil map of the Falklands (see below). This is based largely on surface drift geology and some very limited previous local surveys. Rodney delivered some soil survey training in the islands last May and it is hoped this will eventually lead to a more refined peatland distribution map and an improved estimate of the soil organic carbon stock of the Falklands.
Peatlands at High risk of erosion include shallow peat soils where there is already evidence of and therefore high risk of further erosion from decreased soil moisture, storminess and fire; Medium risk – sloping areas and areas in danger of flooding and increased run-off; and Low risk – wet peat areas and mineral soils.
Agriculture is confined to extensive sheep farming in large enclosures (89% > c. 2000 ha). Traditionally, large tracts of the native Cortaderia dominant grasslands have been burnt in spring to rejuvenate the grasslands. Pasture improvement through reseeding and fertilising was practiced only on a very small scale. Recently the development of pastures with improved grasses and legumes coupled with rotational grazing has received much greater priority than previously. Climate change predictions have indicated a steady temperature rise resulting in an unfavourable precipitation-evapotranspiration balance and there are concerns that this may contribute to the instability of the peatlands. Now and in the future, agricultural management practices such as burning are likely to be critically reviewed in light of the key role they will play in ecosystem services delivery and climate change mitigation in the islands. Fire is a particular risk to Falklands peatlands and a paper to highlight this (The Use of Fire on the Peatlands of the Falkland Islands) was presented by Jim McAdam, Rodney Burton and Rebecca Upson at the recent 5th International Conference on the Effects of Fire on Soil Properties.
In the paper, recent climate change predictions were aligned with an overview of the practice of burning the pastures in spring to highlight concerns of the effect of fire on biodiversity and the carbon storage potential of the shallow, extensive peatlands of the Falklands.
Find out more about work on the ground
Local work on peatland restoration is being carried out by Falklands Conservation.
Jim McAdam and Rodney Burton
