MoorLIFE 2020: using UAVs to monitor vegetation

Reservoir ;andscape

Monitoring conservation using aerial imagery

We use unmanned aerial vehicles (UAVs) to monitor and analyse the impact of conservation works across vast, open moorlands to give us a picture of our works at a landscape scale.

How we use unmanned aerial vehicles

We still use traditional surveying methods to monitor vegetation, water flows, water table and peat depth; the UAV adds another tool to the monitoring toolbox. UAVs allow us to monitor at a bigger scale. For example, a traditional monitoring site is 0.01 square kilometres in size and contains 10 quadrats for monitoring vegetation. With a UAV we can collect data across an area of 0.5 square kilometres in one flight. The aerial imagery collected can be analysed to produce maps showing the type and extent of vegetation and land cover.

We are particularly interested in monitoring blanket bogs that have become dominated by single species such as cotton grass, purple moor grass and heather, as well as areas that were previously dominated by bare peat. We have chosen areas that feature these characteristics to monitor; these have become our field ‘laboratories’. The first year of flying the UAV (2018) was to collect baseline data to measure the effects of successive conservation works against.

Each ‘lab’ has been ‘flown’ three times to collect three different types of images: true colour, multi-spectral (different vegetation types appear on computer as different colours), and thermal images which indicate the wetness of the moors.

The images were ‘stitched together’ and geo-referenced using ground control targets with special software, so that we know exactly which photo is which bit of moorland. This is helped by the fact that our GPS is accurate to 2cm. We plan to compare future changes against the vegetation cover data.

In one such experiment, we are planting 11 different species of sphagnum, with their precise locations input to ‘train’ the computer software to recognise the different species.

The use of UAVs is subject to safety rules, which are underpinned by UK law. Our team members need all the correct permissions in place before they can fly, including from the Civil Aviation Authority (CAA), Natural England, and individual landowners and tenants. They also have to follow the ‘Drone Code’, launched by the CAA last year, ensuring they abide by rules such as staying below 120m (400ft) in altitude and keeping a safe distance from people and property.

UAV

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