Sensors have found a wide range of applications in industry, research, healthcare, and several other fields. However, there has been a focus on using sensors in conservation efforts in recent years.
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Why Conservation Matters
There is an increasing awareness of human activity's effect on the environment and biodiversity. Numerous species enter the endangered list every year, and habitats are being destroyed at an alarming rate. Worse still, species have become extinct as a direct or indirect consequence of human activity, some of which have not even been discovered. Biodiversity is incredibly vital for ecological stability, and without significant mitigation efforts, its fate will worsen.
Monitoring the environmental impact of human society is therefore paramount. Conservation efforts are vital to limit the dangers posed by pollution, illegal poaching, mining, illegal logging, climate change, the expansion of urban areas into vulnerable habitats, and many other risks.
Sensor technologies are increasingly utilized in these efforts.
Overview of Sensors Used in Conservation Efforts
To tackle such a huge issue requires technological advances that are fit for purpose. The field of sensors provides many technical solutions making it well-suited to the efforts of conservationists. Sensors can be classified as either contact, non-contact or remote. Conservation efforts have made use of the latter in particular.
Passive and active remote sensors are used in conservation. Passive sensors detect visible light that has been reflected by a feature or has been absorbed and re-emitted as infrared radiation. Typically, this is in bands of wavelengths that are detected by multiple components in the sensor. Landsat 8, a series of satellites launched in 2013, is fitted with two passive sensors that detect light in the visible and long and short-wavelength infrared spectra.
Getting a Bird’s-Eye View of Biodiversity With Landsat
Video Credit: NASA Goddard/YouTube.com
Active sensors emit radiation. This radiation is directed at the target and is reflected toward the sensor where the data is then recorded. Common examples of active sensors are RADAR, SONAR, and LiDAR. LiDAR works by directing extremely fast pulses of light at an object, and how long the light takes to travel back to the sensor determines the three-dimensional shape of the target. With this, complex, accurate 3D images can be constructed.
Sensors used in conservation efforts are typically mounted on airplanes, satellites, and drones/UAVs. Other applications of sensors in conservation include their use in camera traps.
How Can Sensors Aid Conservation Efforts?
Conservation efforts are increasingly making use of remote sensors for several applications. Remote sensors can help monitor species distribution, improve researchers' understanding of the movements of animal populations, and monitor and evaluate current conservation projects. They are also used in efforts that monitor the effects of climate change on ecosystems, inform how protected area networks should be configured, and facilitate governance, resource management, and regulatory compliance.
In recent years, numerous studies in the field of conservation have made use of sensors to capture crucial data that has informed efforts to protect species and monitor ecosystems. Data from orbiting satellites have been used since the 1970s to understand ecological changes and inform conservation strategies.
One of the most successful examples of using remote sensing data for conservation efforts was a project that created a habitat suitability model to protect chimpanzees. Landsat data was used in this vital study. Some other examples of conservation efforts using sensors are listed below.
Using Infrared Sensors in Camera Traps to Study Animals
Passive infrared (PIR) sensors are commonly used in camera traps for conservation studies. They detect infrared radiation emitted by objects and contain parts, including a lens and sensor. When an animal passes the camera trap, an electrical current is generated by the pyroelectric elements in the sensor. The camera trap is triggered if this electrical current exceeds a certain threshold.
A paper published in 2016 in the journal Remote Sensing in Ecology and Conservation sought to clarify the language and description of these vital pieces of equipment. By doing so, they ensured that flawed data in studies using PIR triggered camera traps would be lessened.
Passive infrared sensor triggered camera traps are increasingly being used in wildlife research as they can detect the body heat given off by animals, which is typically much higher than the surrounding environment. By providing clear, unambiguous, and consistent technology descriptions, operators will not make false inferences from the data gathered.
Field work with camera traps!
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Using Unmanned Aircraft-Mounted Sensors to Improve Animal Monitoring
As human populations grow, so do their urban areas and associated infrastructure. Improved monitoring of animal populations, especially in areas such as airports, is vital to protect species groups. In recent years, small unmanned aircraft systems (sUAS) have been used to carry out this task because they are easy to operate, can be customized, can access places that are difficult to navigate, and do not disturb animal populations.
In a recent study, an automated system mounted on an sUAS with visible spectrum cameras was used to capture over a thousand images of four cattle, horse, Canada Geese, and white-tailed deer species. Data gathered by the equipment was processed using a deep learning neural network. Results indicated high levels of overall accuracy, showing promise for classifying large datasets of diverse species with sUAS-mounted sensor-based systems.
Monitoring Invasive Plant Species with a Hypersectional Spectrometer
Invasive plant species can pose a huge danger to ecosystems. Reliable distribution maps are vital to monitor their growth. Traditionally, field surveys have been the method of choice for conservationists. However, a paper published in 2017 demonstrated an alternative method using remote sensing data. Using this technique improves the coverage of large areas, aiding conservation efforts to protect native species.
Hypersectional remote sensing data was used in combination with field data to construct a distribution map of Campylopus introflexus, an invasive species of bryophyte. The study was carried out on the island of Sylt, which is located in Northern Germany. Using the data gathered by the equipment, distribution was mapped with an overall accuracy of 75%.
To protect endangered animal populations and vulnerable ecosystems, effective conservation strategies must be deployed. As the need for more accurate data for conservation efforts accelerates, both active and passive remote sensors will doubtless become one of the critical technologies in the field.
See this Interview: Continuing NASA's Earth Observation Legacy with Landsat 9
References and Further Reading
Feagan, S., (2018) Remote Sensing in Conservation. [online] Working Abroad. Available at: https://www.workingabroad.com/blog/remote-sensing-in-conservation/#
Skrowronek. D., et al. (2017) Mapping an invasive bryophyte species using hyperspectral remote sensing data Biological Invasions 19 pp. 239-254 Available at: https://link.springer.com/article/10.1007/s10530-016-1276-1
Zhou, M., et al. (2021) Improving Animal Monitoring Using Small Unmanned Aircraft Systems (sUAS) and Deep Learning Networks Sensors 21:17 page 5697. Available at: https://www.mdpi.com/1424-8220/21/17/5697/htm
Welbourne, D.J .,et al. (2016) How do passive infrared triggered camera traps operate and why does it matter? Breaking down common misperceptions Remote Sensing in Ecology and Conservation 2:2 pp. 77-83. Available at: https://zslpublications.onlinelibrary.wiley.com/doi/10.1002/rse2.20