Supporting Chimpanzee Conservation from Space

Gombe National Park, Tanzania. Acquired by Sentinel-2 in December 2016. Image courtesy of ESA.

Being able to visualise the changing face of the planet over time is one of the greatest strengths of satellite remote sensing. Our previous blog showed how Dubai’s coastline has evolved over a decade, and last week NASA described interesting work they’re doing on monitoring habitat loss for chimpanzees in conjunction with the Jane Goodall Institute.

Jane Goodall has spent over fifty years working to protect and conserve chimpanzees from the Gombe National Park in Tanzania, and formed the Jane Goodall Institute in 1977. The Institute works with local communities to provide sustainable conservation programmes.

A hundred years ago more than one million chimpanzees lived in Africa, today the World Wildlife Fund estimate the population may only be around 150,000 to 250,000. The decline is stark. For example, the Ivory Coast populations have declined by 90% within the last twenty years.

One of the key factors contributing to this decline is habitat loss, mostly through deforestation; although other factors such as hunting, disease and illegal capture also contributed.

Forests cover around 31% of the planet, and deforestation occurs when trees are removed and the land has another use instead of being a forest. In chimpanzee habitats, the deforestation is mostly due to logging, mining and drilling for oil. This change in land use can be monitored from space using remote sensing. Satellites produce regular images which can be used to monitor changes in the natural environment, in turn giving valuable information to conservation charities and other organisations.

In 2000 Lilian Pintea, from the Jane Goodall Institute, was shown Landsat images comparing the area around the Gombe National Park in 1972 and 1999. The latter image showed huge deforestation outside the park’s boundary. The Institute have continued to use Landsat imagery to monitor what is happening around the National Park. In 2009 they began a citizen science project with local communities giving them smartphones to report their observations. Combining these with ongoing satellite data from NASA has helped develop and implement local plans for land use and protection of the forests. Further visualisation of this work can be found here. The image at the top was acquired Sentinel-2 in December 2016 and shows the Gombe National Park, although it is under a little haze.

The satellite data supplied by NASA comes from the Landsat missions, which currently have an archive of almost forty-five years of satellite data, which is freely available to anyone. We also used Landsat for data in our Dubai animation last week. Landsat captures optical data, which means it operates in a similar manner to the human eye – although the instruments also have infrared capabilities. However, one drawback of optical instruments is that they cannot see through clouds. Therefore, whilst Landsat is great for monitoring land use when there are clear skies, it can be combined with synthetic aperture radar (SAR), from the microwave spectrum, as it can see through both clouds and smoke. This combination enables land use and land change to monitored anywhere in the world. Using the freely available Landsat and Sentinel-1 SAR data you could monitor what is happening to the forests in your neighbourhoods.

Satellite data is powerful tool for monitoring changes in the environment, and with the archive of data available offers a unique opportunity to see what has happened over the last four decades.

Islands of Sand

Animation showing the creation of islands in Dubai between 2001 & 2009 using Landsat images. Data courtesy of NASA.

This week we’re focusing on the development of Dubai’s land-coast interface between July 2001 and October 2009, looking specifically at the creation of the Palm islands and the World Archipelago. Dubai is the most populous city in the United Arab Emirates, home to 2.7 million people as of January 2017. In a place where Dubai police vehicles include a Lamborghini and a Ferrari, and where it’s possible to buy gold bars from vending machines perhaps it’s not surprising to see the creation of extravagant islands.

Palm Islands & The World Archipelago

In the animation at the top of the blog, the development of the Palm Islands and The World Archipelago are clearly visible. The first island created was Palm Jumeirah, the smallest of the three planned palm islands, and can be seen just off centre on the animation. It consists of a tree trunk, a crown with seventeen fronds and a surrounding crescent, and is approximately 25 square kilometres in size. Construction began in 2001 and was completed in 2006. The workers used GPS signals to determine the correct place to deposit sand to create the palm effect.

Built in tandem were the Palm Jebel Ali and The World Archipelago. Construction began in 2002 and was expected to be completed in 2015, however work stopped in 2008 due to the financial crisis. Work has remained suspended on Palm Jebel Ali, but development on the World may be about to start. The World has three hundred islands reclaimed from the sea, but most of them are bare sand. In the last twelve months there have been rumours that ‘The Heart of Europe’ project and floating seahorses around St Petersburg island could be developed in the near future.

It is also possible to see the preliminary creation of Palm Deira at the top of the animation. 300 million cubic metres of sand were used to form the initial reclamation. However, between 2009 and 2016 there has been no further development.

Images of Dubai in 2001, left, and 2009 taken by Landsat 7. Data courtesy of NASA.

It is also worth noting the significant urban sprawl between the first and last images. Dubai’s population increased by 95%, from 910,336 to 1,770,978, during the period we’re looking at and whilst the growth of Dubai is obvious, it is particularly visible southeast of the Palm Jumeirah development.

Creating the Time Series Animation

The animation was created using the first (blue) visible band of the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) instrument. In May 2003, the scan line corrector – used to compensate for forward motion of the spacecraft, ensuring scan lines are parallel – failed. Consequently, the instrument images in a zigzag fashion; some data is captured twice, whilst some is not captured at all. As a result, 22 % of data in Landsat 7 images post May 2003 are missing. To compensate for this we’ve used a Geospatial Data Abstraction Library (GDAL) tool to fill “no data” regions by interpolating from nearby valid pixels. The results, whilst not perfect, are nearly indistinguishable at this resolution.

Impacts of the Islands

The development of these islands has not been without its criticism as it has impacted the local ecology. The dredging of sand has increased the turbidity of the seawater, with sediment transport evident in the animation, which has damaged coral reefs. In addition, water around parts of the islands can remain almost stationary for weeks, increasing the risk of algal blooms. Whilst fish have returned to these waters, they are not the same species as were there before.

Viewed from space, both the speed and scale of the development is mesmerising. It is no surprise that tourism is a vitally important part of the local economy, attracting more than 13 million visitors in 2014. With the limitations of available land in Dubai, developments are sure to start again.

 

Blog produced by Tom Jones on work placement with Pixalytics Ltd.