Photonic Monitoring of Atmospheric and Aquatic Fauna

Flying insects are of utmost importance in ecology and for human living conditions. Certain species serve as indispensable pollinators to ensure the availability of food stuffs, while others are dangerous vectors for spreading deadly diseases, such as malaria. Agricultural pests reduce the yield of crops, and their abatement through pesticides cause many additional problems. Birds and bats are frequently carriers of diseases, which, especially for long-distance migrants, cause serious consequences. Clearly, there is high motivation to be able to effectively identify and quantify flying fauna. Here, the emerging field of optics and laser-based monitoring of flying fauna is reviewed with an emphasis on remote sensing based on pulsed and contineous wave (CW) lidar systems, and how they complement existing radar techniques. Furthermore, ground-truth laboratory studies are covered. Wing-beat and overtone spectra as well as reflectance, depolarization and fluorescence properties are studied. The aquatic environment is for many reasons less accessible for optical studies, but is clearly also of great importance. Phytoplankton constitute the start of the aquatic food chain, followed by zooplankton and a long chain of higher animals, including fish, an important part of the human food supply. Finally, how optical monitoring can complement sonar and sampling techniques is discussed.