By Nathalie Pettorelli, Zoological Society of London, Institute of Zoology (www.zsl.org/science), London; Kamran Safi, Department of Migration and Immuno-Ecology, Max Planck Institute for Ornithology (www.orn.mpg.de), Seewiesen, Germany, and University of Konstanz (www.uni-konstanz.de), Konstanz, Germany; and Woody Turner, NASA Earth Science Division (http://science.nasa.gov/earth-science), Washington, D.C.
Fifty years ago, the world's imagination was captured by the space race and the prospect that, one day, humans would walk on the moon and plan a mission to Mars. As the decades passed, however, scientific and political attention slowly shifted to making sure Earth continues to be a hospitable place for future generations to prosper.
Indeed, human activities are threatening to breach planetary boundaries through climate change, changes in land use, the release of nitrogen and phosphorus into the environment, freshwater extraction and diversion, ocean acidification and ozone depletion. Moreover, with one in every 10,000 species estimated to be lost per year, the current rapid rate of biodiversity loss is of particular concern given the mounting evidence linking biodiversity levels, essential ecosystem services and human well-being.
Conservation biology has been tasked with coordinating research and monitoring efforts to revert the current biodiversity crisis. Rooted in ecology, the discipline traditionally sought relevant information from ground-based methodologies. On the other hand, the roots of environmental remote sensing lie in the geography and engineering disciplines.
Merging the Disciplines
Interestingly, biodiversity and environment are concepts that have a large degree of overlap, as several features that describe an environment are components of biodiversity. Abiotic environmental conditions (e.g., climatic conditions, road and building distributions, and sea surface temperature) are key drivers of changes in biological diversity, making it relevant for ecologists and conservation biologists to monitor such features.
Moreover, conservation biology and geography are disciplines that have partially converging aims. For example, environmental geography is a branch of the discipline that examines the relationships among human beings and the natural world. Such knowledge is key to developing effective conservation strategies. Given the level of common interests, much potential exists for interdisciplinary work between remote sensing and ecology to trigger innovative approaches and new research directions in both disciplines.
A Road Paved with Challenges
Pressing challenges affecting our home planet at a global scale emphasize the need for space-based Earth observations. For decades, such observations have provided an increasingly powerful understanding of weather and climate, along with other geophysical phenomena.
Similarly, there's little doubt that satellite remote sensing can make a difference in biodiversity monitoring and conservation. This potential is best achieved when effective collaborations among experts in remote sensing and biodiversity monitoring and conservation are developed. However, such collaborative work is rare.
One reason arises from the lack of a shared interdisciplinary space to facilitate collaboration among communities. With remote sensing generally located in social sciences or engineering departments and ecology falling under life sciences, students and staff from each community are spatially segregated within academia, reducing potential interactions. Likewise, few conferences and peer-reviewed journals reach both communities equally.
Another issue lies in the different resolutions at which the two communities typically work. Remote sensing experts are used to dealing with large areas, with spatial resolutions typically ranging from tens of meters to several kilometers and temporal resolutions between daily and decadal. Ecologists, on the other hand, often deal with relatively smaller areas at spatial resolutions of a few meters and temporal resolutions that tend to be either daily or annual. This lack of common reference frames can hamper collaborative work.
In addition, data and algorithm accessibility might be preventing more collaboration between the remote sensing and ecology communities. Access to many remote sensing products isn't free, and only a small fraction of ecological data ever collected is readily discoverable and accessible, much less usable. There are also several logistical and technical challenges associated with storing, sharing, manipulating and analyzing datasets of common interest to both communities.
Bridging the Gaps
A higher level of interdisciplinary work among remote sensing experts and ecologists has the potential to help us tackle many environmental challenges while creating numerous opportunities to advance both disciplines. To reach this potential, better and stronger communication channels are needed for these communities to start developing a better coordinated, more effective research agenda.
Scientific platforms enabling information transfer and networking opportunities, such as the Group on Earth Observations Biodiversity Observation Network (https://www.earthobservations.org/geobon.shtml) or the group on Remote Sensing for Biodiversity within the Committee on Earth Observation Satellites (http://www.remote-sensing-biodiversity.org/ceos), need to continue and expand. In addition, user-friendly, intuitive and centralized data and algorithm portals need to be developed to further enhance communication and promote joint use of different types of tools and data products.
Training opportunities that help set common references across communities are still rare, hampering the emergence of a new generation of scientists who can carry out integrated, multidisciplinary approaches. To address this shortcoming, the biodiversity and remote sensing communities should seek to develop joint undergraduate and postgraduate programs. Moreover, they should seek to increase access to free tools, both in terms of open-source software development and increased training opportunities that focus on using these free tools. In addition, perhaps it's time for a new society and associated journals specifically dedicated to bridging gaps in training, terminology and understanding.
Better ways of linking in-situ ground- or water-based efforts with remote sensing initiatives are crucial to overcoming the challenge of scale currently separating the communities. These may include increased efforts to share more widely existing biodiversity data via Web interfaces (Movebank, Smithsonian Wild, Map of Life, etc.) or developing ways to recognize and reward those making their data available (e.g., by citing authors or dataset creators in scientific journals). Developing citizen science approaches to collect environmental reference information and biodiversity data simultaneously also has the potential to ease the integration of coarser-scale remotely sensed data of environmental parameters with countless fine-scale in-situ observations of biodiversity elements.
Satellite remote sensing can tell us much about the condition of biodiversity and the potential for conservation interventions across multiple spatial and temporal scales. Good work is taking place, but much more is required given the current pace of change in environments around the world. Integration and collaboration across disciplinary lines are the keys to a brighter future for both communities and the planet they share.
Editor's Note: This column is an adapted excerpt from Satellite Remote Sensing, Biodiversity Research, and Conservation of the Future, which was published in Philosophical Transactions, Royal Society Publishing (http://dx.doi.org/10.1098/rstb.2013.0190).