In Defence of Satellite Data: The Perfect Companion to Ground-Based Research

Post provided by Dr Nathalie Pettorelli

Nathalie is an Institute Research Fellow at the Zoological Society of London. She heads the Environmental Monitoring and Conservation Modelling (EMCM) team and her main research involves assessing and predicting the impacts of global environmental change on biodiversity and ecosystem services. Nathalie was one of the presenters at the UK half of the Methods in Ecology and Evolution 5th Anniversary Symposium in April. You can watch her talk, ‘Harnessing the Potential of Satellite Remote Research’ here.

If there is one question I hear over and over again, it’s this: “why, oh why, do you use satellite data instead of ground-based data in your research?” People seem to think that I believe satellite data are better than ground-based data. Do I not value fieldwork? Do I not trust ground-based data? My answer to all of this is: you’ll never catch me preaching that satellite remote sensing can solve the entire data collection gap in ecological monitoring.

I use satellite data because a lot of my work happens at relatively large spatial and temporal scales, targets regions where ground-based data are simply unavailable or extremely difficult to gather and relies on being able to access data that have been collected in a systematic and scalable manner.

Yes, satellite-based techniques can address spatial and temporal domains inaccessible to traditional, on-the-ground, approaches, but I am the first to acknowledge that satellite remote sensing cannot match the accuracy, precision and thematic richness of in-situ measurement and monitoring.

©Clare Duncan

The New Generation of Ecologists in Action: Clare Duncan conducting field measurements in the Philippines to be combined with satellite remote sensing information to monitor ecosystem services delivery. ©Clare Duncan

In spite of this, data collected on the ground are currently difficult to use for mapping and predicting regional or global changes in the spatio-temporal distribution of biodiversity (a problem for those of us trying to tackle these kinds of issues). Ground-based data can also be expensive and tend to come from a single annual time period. This makes it difficult to gather information on temporal changes and phenology. Continue reading