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Nature Conservation from Space – Researchers develop new methods for monitoring protected areas

Prof. Dr. Ariane Walz. Photo: Karla Fritze.
Photo :
Prof. Dr. Ariane Walz. Photo: Karla Fritze.

Earth is being increasingly observed, measured, and photographed. Satellites orbiting our planet at altitudes of hundreds to a thousand kilometers are continuously collecting detailed data on the earth’s surface, humidity, temperature, and vegetation density. The EU project ECOPOTENTIAL aims to utilize progressively higher quality remote data to improve monitoring and management of protected areas in Europe – from the Wadden Sea to the Sierra Nevada. 

The Negev desert in Israel is an inhospitable place – only specialized plants and animals can survive here – and yet, it is of major ecological importance. Large swaths of it are protected in the Har HaNegev nature reserve, which is the habitat of rare species such as the Arabian leopard, the ibex, the wild donkey, and the edmi gazelle. Researchers at the University of Potsdam examine the desert with satellite imagery and computer models.

The barren ecosystem is one of 23 mostly European protected areas being studied by hundreds of researchers from 47 institutions in the EU’s H2020 project ECOPOTENTIAL. Its central objective is to improve the management of protected areas with the help of remote sensing data. The project comprises marine and alpine habitats, forests, deserts, steppes, and coasts. Areas being researched include ecosystems as diverse as the Wadden Sea, the Bavarian Forest, and the Sierra Nevada. 

Remote sensing data provide a host of detailed information 

The researchers are interested in the status quo of the protected areas but also want to monitor their development over time. How much damage does a fire cause? How has the stock of trees developed over the past decade? Which coastal stretches are being affected by algal bloom? Can trends be identified? Remote sensing data may provide answers to all of these questions – for large areas and in increasingly higher resolution. Five new European satellites have been launched since 2014 as part of the Sentinel programme. Outfitted with high-resolution spectral sensors and radar, these satellites are monitoring the earth’s surface, atmosphere, and oceans. The remote sensing data they generate have become universally accessible over the past years, much available online almost in real time, for instance as part of the Copernicus European earth observation program. Also older data have been freely accessible, such as the archives of the LANDSAT missions’ historical satellite imagery since 2008. The sensors capture pictures in a wide range of spectra, partly far beyond what the human eye can see – for instance in the infrared range. But there’s a catch: “They are of no use to most people,” explains junior professor Ariane Walz, who chairs the Potsdam research team. Before conclusions can be drawn from them, such as how the vegetation in a protected area is changing, the data need to be converted and interpreted. This requires numerous intermediate steps, adaptations, a great deal of care, and sometimes computer models. 

These data have a huge potential for the management of protected areas. “They are very well suited for monitoring. You can see what is changing, how quickly, and whether this is in line with conservation goals,” Walz explains. In the Italian Gran Paradiso national park, for instance, remote sensing data may help us to understand an urgent problem: The ibex population there is plagued by high death rates among their young for unknown reasons. Evaluating satellite imagery offered a possible clue: “The images allow for the protein content of the grass to be estimated,” Walz explains. The composition of species on the alpine pastures has shifted as a result – to the detriment of those animals no longer able to consume the necessary amount of nutrients. 

Potsdam team researches vegetation in the Negev desert

This example shows the kind of detailed analyses that are now possible. The researchers are particularly interested in combining remote sensing data with those that have been collected on the ground over the years and decades: Which species and how many of each live in an area? How much biomass grows on one square meter of alpine grassland? How have ecological communities developed recently? The results from years of fieldwork have turned out to be crucial for satellite data, because they help researchers to interpret them even more precisely. The researchers are also planning to establish the information value of the LANDSAT missions’ remote sensing data that have been collected since the 1980s, allowing for meaningful time series to be made. 

The Potsdam research focuses on the Negev desert in Israel. Using computer models, the team around Walz simulates how the vegetation there may develop over time thanks to remote sensing data that depicts the composition of the vegetation on the earth’s surface. Israeli research partners are also analyzing how settlement structures change, since the area is also used by settlers and Bedouins for winegrowing and ranching, which can strain the sensitive dry-zone vegetation.

In their models, the researchers pay particular attention to the effects of extreme events like heavy rainfall or long dry spells on the habitat, since these are expected to occur more often in the future due to climate change. The model, which is validated with current remote sensing data, will enable researchers to estimate plant growth in the Negev desert for the coming decades under various scenarios – and design protective measures. 

Researchers and nature conservation authorities cooperate closely

It seems certain that the Negev desert climate will change and its plant community along with it. “We expect longer dry periods and precipitation, often in the form of heavy rainfall that runs off the surface,” Walz describes the possible development. Which species will benefit or be displaced as a result of it, though, is not yet clear. Grass is currently the dominant vegetation, interspersed with some adapted shrubs and bushes. The simulations indicate that the area might become overgrown with bushes – a development managers of the protected area want to avoid. When grass disappears, soil erodes faster, which in turn starves pastures and wild animals alike.

In many of the protected areas in this project, researchers are closely cooperating with rangers and nature conservation authorities. In the end, they hope to be able to analyze and use remote sensing data on their own, with the instruments and tools provided to them by the researchers. Looking at the data will be a faster and more convenient way for them to get important information – and insight into areas that are very difficult or impossible to access. Teaching programs, advanced training, and workshops will ensure this knowledge transfer has a long-term impact. If the project reaches its objectives, ECOPOTENTIAL will make a major contribution to opening up the potential of the data for everyday practical use. 

For a very long time, high-resolution remote sensing data were just an instrument for scientists. The effort it took to process them was too great for them to offer insight to everyone. This has completely changed. “If there was a forest fire yesterday, I can see today what area has been affected,” Walz explains. But the researcher is also aware of the limits of the method: “Whether the vegetation looks especially vital because of the blossoming mistletoes or the sprouting birches is not discernible from space.” But even though data from space cannot replace field monitoring, they can strongly support it and fill in large gaps.

The Researcher

Junior Prof. Dr. Ariane Walz studied geography, geology, physics, and social sciences at the University of Würzburg and the University of Wales (UK). Since 2012, she has been Junior Professor of Landscape Management at the University of Potsdam.
Universität Potsdam
Institut für Erd- und Umweltwissenschaften
Karl-Liebknecht-Str. 24–25
14476 Potsdam
Email: ariane.walzuni-potsdamde

The Project

ECOPOTENTIAL is a Horizon 2020 project that analyzes ecosystems and their functions using remote sensing data.
Funding: European Union, Grant Agreement No. 641762
Duration: 2015–2019
Participants: 47 European scientific institutions 
Leadership: National Research Council of Italy (CNR)

This research is linked to the research initiative NEXUS: Earth Surface Dynamics, which clusters approaches from various scientific disciplines in the Berlin-Brandenburg area within the overarching theme of Earth surface dynamics. The University of Potsdam, along with its partnering institutions the Helmholtz-Centre Potsdam - German Research Centre for Geosciences (GFZ), the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) and partners from the Potsdam Institute for Climate Impact Research (PIK), the Museum für Naturkunde - Leibniz Institute for Evolution and Biodiversity Science (MfN) and the Technische Universität Berlin (TUB) therefore combines the outstanding expertise from geo-, bio-, climate and data sciences.  

Text: Heike Kampe
Translation: Monika Wilke
Online published by: Marieke Bäumer
Contact us: onlineredaktionuni-potsdamde

Read this and other articles on research at the University of Potsdam in our research magazine Portal Wissen.