The broad scale impact of climate change on planning aerial wildlife surveys with drone-based thermal cameras

Abstract

Helicopters used for aerial wildlife surveys are expensive, dangerous and time consuming. Drones and thermal infrared cameras can detect wildlife, though the ability to detect individuals is dependent on weather conditions. While we have a good understanding of local weather conditions, we do not have a broad-scale assessment of ambient temperature to plan drone wildlife surveys. Climate change will affect our ability to conduct thermal surveys in the future. Our objective was to determine optimal annual and daily time periods to conduct surveys. We present a case study in Texas, (United States of America [USA]) where we acquired and compared average monthly temperature data from 1990 to 2019, hourly temperature data from 2010 to 2019 and projected monthly temperature data from 2021 to 2040 to identify areas where surveys would detect a commonly studied ungulate (white-tailed deer [Odocoileus virginianus]) during sunny or cloudy conditions. Mean temperatures increased when comparing the 1990–2019 to 2010–2019 periods. Mean temperatures above the maximum ambient temperature in which white-tailed deer can be detected increased in 72, 10, 10, and 24 of the 254 Texas counties in June, July, August, and September, respectively. Future climate projections indicate that temperatures above the maximum ambient temperature in which white-tailed deer can be detected will increase in 32, 12, 15, and 47 counties in June, July, August, and September, respectively when comparing 2010–2019 with 2021–2040. This analysis can assist planning, and scheduling thermal drone wildlife surveys across the year and combined with daily data can be efficient to plan drone flights.

The first use of a photogrammetry drone to estimate population abundance and predict age structure of threatened Sumatran elephants

“…Obtaining accurate calculations using conventional survey methods in tropical rainforests is challenging due to the need for well-trained field workers and long survey durations to cover large areas with challenging terrain. Detecting animals in tropical rainforests can be difficult due to weather conditions, dense and hard-to-reach canopies, and the visual camouflage of various species 42 , 43 . It is crucial to develop a method that can improve the accuracy, precision, and bias reduction in Sumatran elephant surveys.…”

Evaluation of drone surveys for ungulates in southwestern rangelands

“…The preliminary flights indicated optimal thermal contrast occurred during cooler, early morning hours. Thus, surveys were largely limited to mornings after sunrise with temperatures <27°C (Camacho et al 2023).…”

Spatiotemporal Variations of Production–Living–Ecological Space under Various, Changing Climate and Land Use Scenarios in the Upper Reaches of Hanjiang River Basin, China

“…The two models, UKES and MIR2, were selected based on the ranking of the total scores. Therefore, with multi-model ensemble mean approaches [61,62], the average value of the two models was obtained as the prediction data in the future climate scenarios.…”