Horizontal viewsheds of large herbivores as a function of woodland structure

• Published in: Ecology and evolution Vol. 13; no. 11; pp. e10699 - n/a
• Main Authors: Gresham, Amy, Healey, John R., Eichhorn, Markus P., Barton, Owain, Smith, Andrew R., Shannon, Graeme
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01-11-2023; John Wiley and Sons Inc; Wiley
• Subjects: Activity patterns; Applied Ecology; Behavioural Ecology; Cameras; Community Ecology; Conservation; Dama dama; Deer; Density; Foraging behavior; Forests; Habitats; Height; Herbivores; Lasers; Leaf area; Leaf area index; LiDAR; National parks; Predation; Risk perception; Scanners; Sensory Ecology; Stems; Structure-function relationships; Summer; terrestrial laser scanning; Understory; ungulates; Vegetation; viewsheds; wildlife management; Winter; Woodlands; Woody plants; Zoology; United Kingdom > UK; Wales; terrestrial laser scanning; wildlife management; viewsheds; ungulates; LiDAR; risk perception
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.10699

There is great potential for the use of terrestrial laser scanning (TLS) to quantify aspects of habitat structure in the study of animal ecology and behaviour. Viewsheds—the area visible from a given position—influence an animal's perception of risk and ability to respond to potential danger. The management and conservation of large herbivores and their habitats can benefit greatly from understanding how vegetation structure shapes viewsheds and influences animal activity patterns and foraging behaviour. This study aimed to identify how woodland understory structure influenced horizontal viewsheds at deer eye height. Mobile TLS was used in August 2020 to quantify horizontal visibility—in the form of Viewshed Coefficients (VC)—and understory leaf area index (LAI) of 71 circular sample plots (15‐m radius) across 10 woodland sites in North Wales (UK) where fallow deer (Dama dama) are present. The plots were also surveyed in summer for woody plant size structure, stem density and bramble (Rubus fruticosus agg.). Eight plots were re‐scanned twice in winter to compare seasonal VC values and assess scan consistency. Sample plots with higher densities of small stems had significantly reduced VC 1 m from the ground. Other stem size classes, mean percentage bramble cover and understory LAI did not significantly affect VC. There was no difference in VC between summer and winter scans, or between repeated winter scans. The density of small stems influenced viewsheds at deer eye height and may alter behavioural responses to perceived risk. This study demonstrates how TLS technology can be applied to address questions in large herbivore ecology and conservation.
Viewsheds (the area visible from a given location) can affect animal responses to danger. This study used mobile terrestrial laser scanning (TLS) to reveal that higher densities of small tree stems reduce viewsheds for deer in woodland environments. We discuss potential implications for deer management and demonstrate how mobile TLS can be applied to study the influence of habitat structure on animal behaviour and ecology.