Satellites help conserve Egypt's wildlife
A Sinai agama - this lizard is part of the unique fauna of the Sinai Desert in Egypt
17 March 2008 by Tim Newbold
Tim Newbold describes an ingenious way of predicting what wildlife will be found, before a place has even been visited.
Many people imagine Egypt to be a country of barren, lifeless deserts and bustling cities. In reality, its wildlife is distinctive and surprisingly diverse. The Western Desert, one of the most biologically exciting but inaccessible regions in Egypt, spans a staggering 700 thousand square kilometres - an expanse that would comfortably fit Great Britain eight times over. Not surprisingly, it's a daunting task for ecologists to record the biodiversity of such an enormous habitat.
A solution may come from new modelling techniques. Tom Reader and I have been working with Samy Zalat and Francis Gilbert who are co-ordinating an Egypt-based conservation project called BioMAP. For nearly three years Samy and Francis have been collecting recorded sightings of Egyptian plants and animals from museums, books and papers. Their database currently stands at half a million records and is still growing. Using the latest computer modelling techniques, we have turned these sightings into maps that show how suitable different parts of Egypt are for each species.
A BioMAP of Egypt using satellite data. The map shows predicted numbers of butterfly species found in different parts of Egypt. Red indicates hotspots for butterflies.
We created the maps by comparing the species records with satellite maps of environmental conditions. Satellites can detect all sorts of radiation from visible light to infra-red, which gives us an enormous amount of information. With these images, we can generate environmental maps showing climatic conditions such as temperature and rainfall, the topography of the land, altitude, and even the types of plant growing and the productivity of the habitat.
Using all this information, we built up a picture of the typical conditions in which the animals and plants live. So for an un-sampled area, we can simply look at its environmental conditions and match it to the species we know thrive in the same conditions elsewhere. By over laying the different species maps, we can then identify those areas that are particularly rich in biodiversity.
However, life isn't quite so simple. Climate and habitat are not the only factors that determine whether a species is found in a certain place. Many animals live quite happily side by side but others compete with each other. For example, there are several species of gerbil living in the same sorts of conditions in Egypt, but they are spatially separated, we think due to competition over resources. The predictions may also overestimate the area in which a species lives because animals and plants cannot get to all suitable places.
One major barrier is the river Nile. Our predictions tell us that slender-horned gazelles could live in locations on both sides of the Nile, but in reality they are found only to the west of the river. Some animals are also limited by the distance that they can travel. For example, the Sinai baton blue butterfly - the smallest butterfly in the world - lives in a tiny area of the Egyptian Sinai Desert and rarely moves more than a hundred metres in its lifetime; an inhabitable area 16km away could be impossible to reach.
Satellites for conservation
To test the model's accuracy, we visited a number of places and recorded butterfly and reptile species living there to see if they matched our predictions of what we thought we would find. So far, the models seem to be getting it right most of the time.
We have also applied the predictions to test whether Egypt's newly designated national parks, which cover 12 percent of the country, have been situated in the right places for biodiversity. Encouragingly, the preliminary results based on analysis of butterfly diversity suggest that they have, although looking at butterflies alone is not sufficient to give us the complete picture.
Another important use for this research is in trying to predict the effect that climate change will have on wildlife. A few years ago, a research group from the University of York made the headlines when they estimated, using similar techniques, that as many as half of the world's species could become extinct as a result of climate change. In the later stages of our project, we will use our maps to investigate what might happen with climate change in Egypt.
The Convention on Biological Diversity, signed by 168 countries, aims to reduce the rate of biodiversity loss significantly by 2010. To meet these targets, people need to know where species are found. We don't have sufficient time or resources to visit every place on Earth to find out what lives there. Using computer models and satellite imagery is a quick, and we think, an effective alternative. As with all models that try to describe real-life situations, they can always be improved by adding more of the complexities that ecologists know happen in nature. Nevertheless, models like these are a very powerful tool for conservation.
Egypt wildlife facts
- Napoleon's occupation of Egypt (1798-1801) resulted in a comprehensive description of the country's natural history - recorded in the Description De L'Egypte. A team of scholars accompanied Napoleon's expedition and described many species, including the hippopotamus, for the first time.
- Egypt has one of the longest and most continuous histories of people interfering with habitats in the world (humans first settled in Egypt more than 12,000 years ago). As a result, much of its native flora and fauna has been lost. In the past, Egypt was home to lions and hippopotami which have now disappeared. There were also sightings of cheetahs and leopards as late as the end of the last century. Papyrus was saved from extinction at the last minute.
- Egypt is home to the smallest butterfly in the world, the Sinai baton blue, which is found only in the high mountains of the Sinai Desert.
- Wadi Al-Hitan, or whale valley, now part of the Western Desert, was once the Tethys seabed. As a result, it is now home to an impressive collection of whale fossils that document an important link in the evolution of whales today.
Professor Samy Zalat is a behavioural ecologist at Egypt's Suez Canal University. Behavioural ecologists Dr Francis Gilbert and Dr Tom Reader and PhD student Tim Newbold are all from the University of Nottingham. Tim previously volunteered for the BioMAP project.