Supporting conservation work for the endangered Mongolian saiga antelope

The SIBELIUs project is all about helping the herding communities in Mongolia, but Zuzanna Skorniewska, an intern student working with eOsphere over the summer has shown that the pasture information being derived as a part of the project can also help support conservation work for endangered animal species.

The saiga antelope is listed as critically endangered on the IUCN Red List and since the early 1990s over 95% of the saiga population has disappeared. Saiga live in a limited number of regions in Kazakhstan and Russia, while the Mongolia saiga sub-species is now reduced to inhabiting a few small regions in western Mongolia. Saiga are under pressure from several perspectives. A key problem in Mongolia is competition with the herding community for access to pasture. The number of livestock in Mongolia has risen by a factor four since 1990, so pasture is increasingly under pressure and if the spring and summer rains are late or if there is a drought, then the pasture can be badly affected, leading to saigas becoming malnourished as they enter the harsh Mongolian winter. In recent years saiga have also been subject to diseases that have had a dramatic impact on their numbers. Between 2016 and 2017 the Mongolian Saiga population was been reduced by over 50 percent because of “goat plague” outbreak and according to the latest 2018 data, there are approximately 3,800 saiga left in Mongolia. Poaching can also be a problem for saiga. They are hunted for their translucent amber horn, which is sold for Chinese traditional medicine.

Saiga tatarica (2)The saiga antelope is listed as Critically Endangered on the IUCN Red List. Since the early 1990s over 95% of the saiga population has been lost. All saiga photographs are copyright WWF-Mongolia.

The World Wide Fund for Nature (WWF) in Mongolia have been working to re-establish saiga numbers, to help make them resilient to further shocks from disease and drought. WWF have identified 13 regions which are potentially suitable for reintroducing saiga populations. These 13 regions are all situated where saiga used to live in the past when their numbers were greater. These are several factors which need to be considered when looking to reintroduce saiga. One of these factors is the quality and stability of the pasture in the potential reintroduction regions and this is the topic where Zuzanna has been able to help provide useful information for WWF.

saiga-habitat-and-reintroduction-map
Light green areas show the regions where the Mongolian saiga antelope is currently living. The dark green areas indicate the regions being evaluated to asses their suitability for saiga reintroduction.

The SIBELIUs project, in collaboration with NAMEM, is monitoring pasture levels and pasture trends across Mongolia. At the heart of the SIBELIUs system is the Mongolian Data Cube, which is an efficient method for storing large time series of satellite data and useful products derived from satellite data, including pasture maps.

The Data Cube has allowed Zuzanna to extract information about pasture levels for the existing saiga habitat and for each of the proposed reintroduction sites, for a period of 10 years from 2009 to 2018. The bar charts below show the median pasture biomass, measured in kilograms per hectare, for each of the regions (existing habitat and proposed reintroduction sites) for the month of June for the ten years between 2009 and 2018. We started working with the June data, because this is a critical month in terms of pasture establishing itself, however the Data Cube structure allows us to interrogate any time periods that we wish.

pasture surface density annotated
Median of pasture values (kg per hectare) for June between 2009-2018. Each red horizontal line shows the average of these values for that region over the 10-year period.

There are many factors to be considered when reintroducing saiga, however, based solely on the pasture information here, it is possibly to identify the regions which appear to show the best promise. The bar charts show that the best Reintroduction regions are those numbered: 1, 6, 8 and 9. The Reintroduction regions 6 and 9 would provide the most additional total pasture, 117.29 and 154.15 Million kg respectively, because they are relatively large regions as well having relatively good average pasture levels.

It is also interesting to note, that all of the 5 existing saiga sites have average pasture densities of less than 100 kg/ha, for the month of June, with regions 3 and 5, being particularly low, which helps confirm that other factors are at play as well as just pasture conditions. For example, saiga antelope are well known for being very shy, so they tend to avoid regions close to human habitation, or near roads or tracks.

Gantulga Bayandonoi, from WWF-Mongolia has provided input and feedback throughout the duration of Zuzanna’s project. After reviewing the outcomes from this project, he told the SIBELIUs team “Thank you very much for the help. I see the result to be one of the crucial factor for choosing a reintroduction site. Summer biomass is very important for the Saiga. … Such a result you guys produced will help us to assess the rapid pasture changes within and between years which can decide a long term survival of the saiga population at sites.”

Another key issue for WWF is understanding the composition of land cover in the different regions. This is because sometimes inedible plant species, such as shrubs, can appear in satellite imagery as if it were edible pasture. A potential next step, currently being explored, will be for the botanists at WWF to examine the colour (RGB) images from the Sentinel-2 satellites to see if they can discriminate between different vegetative land cover types, based on clues such as the texture of the terrain as seen in the imagery.

Zuzanna Skorniewska
Zuzanna Skorniewska studies physics at the University of Southampton and has just finished her second year. Her studentship with eOsphere was organised by the South of England Physics Network (SepNET), which administers approximately 80 studentships per year, allowing for physics students the opportunity to gain valuable work experience.

 

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