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Lookup NU author(s): Dr Magdalena SmigajORCiD, Dr Rachel GaultonORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Hedgerows are an abundant and ecologically important feature of many rural areas. Their biodiversity value depends on composition, structure and availability of food resources, which can be significantly impacted by poor management. However, information about hedgerow condition is very limited due to field surveys being costly and labour-intensive. Unmanned Aerial Vehicles (UAVs) equipped with miniaturised cameras could prove a more cost-effective and time-efficient hedgerow surveying solution whilst preserving a high level of detail unattainable with airborne or satellite sensors. This study explored whether UAV remote sensing is a viable alternative for performing hedgerow condition surveys at local scale, focusing on hedgerow structure and flowering abundance. We acquired UAV Red, Green, and Blue (RGB) and multispectral nadir and oblique imagery of structurally different hedgerows and used them to generate 3D point clouds and models with SfM workflow. Height thresholding allowed extraction of hedgerow extents, with RMSE of height and width ranging from 0.11 to 0.23 m. RGB flower classification showed poor relationship with ground measurements (R2 = 0.31-0.42) due to confusion with woody material of hedgerows. Inclusion of a near-infrared channel in multispectral imagery significantly improved the relationship (R2 = 0.68-0.75, RMSE = 10%). Our study shows UAV remote sensing has high potential for performing detailed surveys of hedgerows, providing better characterisation of structural variations and distribution of flowers than traditional ground surveys due to larger coverage. More comprehensive understanding of hedgerow, or other vegetated buffer strips, conditions offered by UAV surveys can enable better informed decisions on habitat management and biodiversity conservation in rural areas. Acquisitions over larger areas, potentially integrated with satellite remote sensing, can allow assessment of hedgerow connectivity over farm to landscape scales, contributing to better understanding of the hedgerow network and its role as a wildlife corridor.
Author(s): Smigaj M, Gaulton R
Publication type: Article
Publication status: Published
Journal: Remote Sensing in Ecology and Conservation
Year: 2021
Volume: 7
Issue: 3
Pages: 521-533
Print publication date: 01/09/2021
Online publication date: 07/05/2021
Acceptance date: 17/03/2021
Date deposited: 09/05/2021
ISSN (electronic): 2056-3485
Publisher: Wiley-Blackwell Publishing Ltd
URL: https://doi.org/10.1002/rse2.208
DOI: 10.1002/rse2.208
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