Recent Advances of near Infrared Spectroscopy in Wildlife and Ecology Studies

Introduction W ildlife and ecology have been on the periphery of research applications using near infrared (NIR) spectroscopy but are gaining in popularity as more investigators become aware of the realm of possibilities that NIR spectroscopy brings to these fields of study. In the same manner that chemometrics has been at the juncture of chemistry and statistics but dominated by neither field, NIR spectroscopy lies firmly between the distant domains of chemical spectroscopy and wildlife ecology, with little overlap apart from remote sensing efforts. However, the numbers of those venturing into the abundant opportunities at the nexus of NIR spectroscopy, wildlife and ecological questions have started to increase over the past few years, and in honour of the 25 Anniversary of NIR news we would like to briefly highlight some of the new and exciting applications of NIR in these research fields. Generally speaking, wildlife and ecology questions are complex, large in scale, multi dimensional and highly variable at every level; in comparison, traditional applications of NIR spectroscopy have been in well-ordered agricultural, pharmaceutical and industrial contexts where control and uniformity in product production are the primary goals. Just as the information captured in an NIR spectrum is grounded in physical laws and chemical properties, which are not statistical problems, the extension of traditional uses of NIR spectroscopy to functionally calibrate and validate the environment and its inhabitants seems counter-intuitive. Yet, NIR spectroscopy is an ideal means by which we can examine the complexity of the natural world in terms of the types of questions that are actually asked concerning the interactions between animals and their habitats. Consider that the natural course of ecological evolution is driven by variability and complex non-linear interactions; we want to understand such systems in their natural state and how the variability drives behaviours and creates evolutionary niches. NIR spectroscopy captures a wealth of informational content to address qualitative and quantitative questions, which can lead to analysis of complex interactions between ecosystem components. Hyperspectral imaging and remote sensing have been the primary means by which natural systems have been studied on a larger scale, and many articles address such topics as ecosystem services and forest canopy chemistry, but are beyond the limited scope of this brief review. We will start here by transitioning from the agricultural applications of NIR spectroscopy into the complexity of wildlife– habitat interactions and the types of questions that get asked in this framework of research. As such, in natural systems we are often investigating connections of multiple dimensions of biodiversity that vary across taxonomic and functional elements of an ecosystem. When we examine these various elements, unusual sampling strategies may have to be considered, depending on the context and form of the material being evaluated. All of these different constituents and their interactions together form the fabric of the complex ecosystem in which we are interested, and NIR captures and generates many levels of informational content that allow us to see the different layers and the intricate connections between them.