Sensors have found a wide range of uses in industry, research, healthcare and many other areas. In recent years, however, a focus has been placed on the use of sensors in conservation efforts.
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Why conservation is important
Awareness of the effects of human activity on the environment and biodiversity is growing. Numerous species appear on the endangered list each year, and habitats are being destroyed at an alarming rate. Worse, species became extinct as a direct or indirect result of human activity, some of which have not even been discovered. Biodiversity is incredibly important to ecological stability, and without significant mitigation measures, its fate will worsen.
Monitoring the environmental impact of human society is therefore of paramount importance. Conservation efforts are vital to limit the dangers of pollution, illegal poaching, mining, illegal logging, climate change, the expansion of urban areas into endangered habitats, and many other risks.
Sensor technologies are increasingly being used.
Overview of the sensors used in nature conservation
Appropriate technological advances are required to address such a large problem. The field of sensors offers many technical solutions and is therefore well suited for the efforts of conservationists. Sensors can be classified as contact, non-contact, or remote sensors. Conservation efforts in particular have made use of the latter.
Passive and active remote sensors are used in conservation. Passive sensors detect visible light that has been reflected or absorbed by a feature and re-emitted as infrared radiation. Typically this is the case in wavelength bands that are detected by several components in the sensor. Landsat 8, a satellite series launched in 2013, is equipped with two passive sensors that detect light in the visible and long-wave and short-wave infrared spectrum.
With Landsat. view biodiversity from a bird’s eye view
Video Credit: NASA Goddard / YouTube.com
Active sensors emit radiation. This radiation is directed towards the target and reflected back to 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 return to the sensor determines the three-dimensional shape of the target. This allows complex, accurate 3D images to be constructed.
Sensors used in conservation efforts are typically attached to airplanes, satellites, and drones / UAVs. Other uses of sensors in conservation include their use in camera traps.
How can sensors support conservation efforts?
Conservation efforts are increasingly using remote sensors for various applications. Remote sensors can help monitor species distribution, improve researchers’ understanding of animal population movements, and monitor and evaluate ongoing conservation projects. They are also used in efforts to monitor the effects of climate change on ecosystems, provide information on how to configure networks of protected areas, and facilitate governance, resource management and regulatory compliance.
In recent years, numerous conservation studies have used sensors to collect critical data in efforts to protect species and monitor ecosystems. Orbiting satellite data has been used since the 1970s to understand ecological changes and support 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 important study. Some other examples of conservation efforts using sensors are listed below.
Use of infrared sensors in camera traps to examine animals
Passive infrared sensors (PIR) are often used in camera traps for conservation studies. They detect infrared radiation emitted by objects and contain parts including a lens and a sensor. When an animal passes the camera trap, an electric current is generated by the pyroelectric elements in the sensor. The camera trap is triggered when this electrical current exceeds a certain threshold value.
An article published in the magazine in 2016 Remote sensing in ecology and nature conservation tries to clarify the language and description of these vital pieces of equipment. In this way, they ensured that erroneous data in studies with PIR-triggered camera traps would be reduced.
In wildlife research, camera traps triggered by passive infrared sensors are increasingly being used, as they can detect the body heat given off by animals, which is typically much higher than that of the environment. By providing clear, unambiguous and consistent technology descriptions, operators will not draw false conclusions from the data collected.
Field work with camera traps!
Video Credit: Universiteit Leiden / YouTube.com
Use of unmanned airborne sensors to improve animal surveillance
As the human population grows, so do its urban areas and associated infrastructure. Improved monitoring of animal populations, especially in areas such as airports, is critical to protecting groups of species. In recent years, small unmanned aerial vehicle systems (sUAS) have been used for this task because they are easy to use, can be customized, can reach hard-to-navigate locations, and do not disrupt animal populations.
In a recent study, an automated system mounted on a sUAS with visible spectrum cameras was used to take over a thousand images of four cattle, horses, Canada geese and white-tailed deer. The data collected by the devices was processed using a deep learning neural network. The results showed a high level of overall accuracy, which is promising for classifying large data sets of various types using sUAS-mounted sensor-based systems.
Monitoring invasive plant species with a hypersectional spectrometer
Invasive plant species can pose a major threat to ecosystems. Reliable distribution maps are essential to monitor their growth. Field surveys have traditionally been the method of choice for conservationists. However, a paper published in 2017 showed an alternative method using remote sensing data. Using this technique improves coverage of large areas and aids conservation efforts to protect native species.
Hypersectional remote sensing data were used in combination with field data to produce a distribution map of. to create Campylopus introflexus, an invasive type of moss. The study was carried out on the north German island of Sylt. Using the data collected from the devices, the distribution was mapped to an overall accuracy of 75%.
Effective conservation strategies must be used to protect endangered animal populations and ecosystems. As the need for more accurate data for conservation efforts grows, both active and passive remote sensors will undoubtedly become one of the critical technologies in the field.
Check out this interview: Continuing NASA’s Earth Observation Legacy with Landsat 9
References and further reading
Feagan, S., (2018) Remote sensing in nature conservation. [online] To work abroad. Available at: https://www.workingabroad.com/blog/remote-sensing-in-conservation/#
Skrowronek. D., et al. (2017) Mapping an invasive moss species with hyperspectral remote sensing data Biological invasions 19 p. 239-254 Available at: https://link.springer.com/article/10.1007/s10530-016-1276-1
Zhou, M., et al. (2021) Improving animal surveillance with small unmanned aircraft systems (sUAS) and deep learning networks Sensors 21:17 page 5697. Available from: https://www.mdpi.com/1424-8220/21/17/5697/htm
Welbourne, DJ ., et al. (2016) How do passive infrared camera traps work and why is it important? Breaking up of frequent false perceptions Remote sensing in ecology and nature conservation 2: 2 pp. 77-83. Available at: https://zslpublications.onlinelibrary.wiley.com/doi/10.1002/rse2.20