Technique developed in Kenya offers a refined way to map tree cover



File 20170908 25859 9cthdc.jpg?ixlib=rb 1.1
Each year satellite images and maps show patterns linked to land use/cover change.
Flickr/NASA

Michael Marshall, World Agroforestry Centre (ICRAF)

Scientists at the World Agroforestry Centre in Nairobi, Kenya, recently pioneered a new approach which uses satellite images and maps to show patterns linked to land use and cover change on a yearly basis. Though the technique was developed in Kenya, it can be used regionally and potentially across the world.

“Land use and cover change” are terms used by scientists to define changes to the earth’s surface. This can be due to natural causes or because of the way in which land is put to use by people. Land use refers to what’s being done on it, for example mechanised farming, while land cover refers to what is physically on the land, for example what crops are being grown.

What’s important about the new approach is that the maps consist of an array of both physical and human geographic data to explain changes. It can also be used in combination with large-scale climate models, for example to understand how changes in vegetation in East Africa might be affecting climate in other regions of Africa.

In Kenya’s case, the system mapped changes in agriculture and natural vegetation with information from over a 30-year period. Using a series of aerial photographic surveys – which could be used to distinguish specific crops or natural vegetation – and freely-available spatial data such as rainfall, and population density, interpreters were able to classify Kenya’s land use and cover change. They were then able to construct maps of this change on a yearly basis without extensive and costly field visits typically used when mapping change.

Understanding land use and cover change is important because they both affect how land responds to the environment. Many of the changes are human-induced – for example the way that people use the land can lead to habitat loss, increase the stress of life that the land supports, affect greenhouse gas emissions and storage, modify runoff and ground water storage, or alter the climate.

Deforestation, perhaps the most well-known type of land use and cover change, comes about primarily from agriculture and logging. It has an impact on the world’s climate because trees store huge amounts of carbon that would otherwise be in the air trapping heat. The absence of trees therefore contributes to global warming.

Deforestation also affects people locally, particularly in the global south. Forests help regulate rainfall and water storage, and the help maintain a high level of biodiversity.

Much of the global north has seen an increase in tree cover in recent years. But much of the global south continues to show declines due to population growth, weak institutions and other social and ecological factors.

Mapping deforestation

To understand the drivers as well as the effects of deforestation, geographers use various tools that map the extent and density of tree cover. These include aerial photos, satellite images and other spatial data through time.

The World Agroforestry Centre’s approach takes this a number of steps further. It also uses demographic data, such as population density, which is often bypassed by scientists when mapping change.

The new approach suggests that physical drivers, like rainfall, may not be as important as previously thought.

Finally, the new technique provides a way forward for scientists interested in understanding what drives land use and cover change. It allows them to look at how this process interacts with processes like climate change over large areas and long periods of time.

From a scientific perspective, this helps us better to understand the environment and how humans may be modifying it. This in turn will help those designing land management strategies.

Kenyan case

Our research in Kenya shows that the most important predictor of land use and cover change was population density. Kenya is part of the East African Horn region. Like many other countries in Africa, its population is growing rapidly and is largely devoted to rain-fed subsistence agriculture and pastoralism.

Population growth occurred more rapidly in fertile areas, so the conversion of natural vegetation to agriculture was much higher. In less fertile areas, population growth was much slower, so the conversion was less.

Kenyan farmers and pastoralists are largely unable to acquire new land and are instead forced to intensify their practices on subdivided land.

We were able to detect that as the number of people per square kilometre increased, the amount of natural vegetation declined, because it was being replaced by farm or grazing land.

Climate predictors, such as rainfall and air temperature, were also correlated with the conversion of natural vegetation to agriculture, but less so compared to population density.

The ConversationAs seen in the Kenya case, the growing demand for food in Africa must be met with effective land tenure reform. By mapping changes in our environment continuously over long time periods, farmers and policymakers can understand underlying mechanisms and explore opportunities for reform.

Michael Marshall, Climate Change Scientist, World Agroforestry Centre (ICRAF)

This article was originally published on The Conversation. Read the original article.

Australia: Indigenous Language Map


The link below is to an article that reports on the recently developed ‘Indigenous Language Map,’ which is a crucial tool in preserving Aboriginal culture and languages in Australia.

For more visit:
http://www.australiangeographic.com.au/journal/mapping-aboriginal-language.htm

Good News for Visitors to Uluru


303 There are always pros and cons when it comes to such issues as to whether or not people should be allowed to climb Uluru in the Northern Territory, Australia. To continue to allow visitors to climb the monolith is to go against the wishes of the traditional owners of the site (local aborigines), as well as to continue to impact on the local environs of the Uluru area.

Having said that however, the Uluru site is a site of major significance in Australia and to visitors the world over. If the site is looked after responsibly visitors should be able to climb the rock for many years to come with limited impact to the site.

Currently some 100 000 people climb the rock each year, though a number get no further than ‘chicken rock.’

Visitors will be able to continue to climb Uluru until such time as numbers dwindle significantly (to fewer than 20% of visitors climbing the rock), until such time as the climb is no longer the main reason for a visit to the rock or until a number of new visitor experiences (yet to be developed/thought out) are in place.

NEW SOUTH WALES NATIONAL PARKS UNDER THREAT???


The New South Wales government is now considering some level of development in the national parks of New South Wales. Just what level of development that may be is yet to be made clear. It is understood that the development may include accommodation projects, various commercial enterprises and guided bush walks.

Tourism Minster Jodi McKay, a former news reader with NBN television, is waiting on a report from a government commissioned taskforce looking into ways that tourism can be increased in the state’s national parks.

The planned tourism development of national parks is a major step away from the ‘wilderness’ goals of recent times and represents a threat to the wilderness values of national parks and world heritage listed areas.

However, a certain level of development may be appropriate, given the serious deterioration of many of the amenities and signage within New South Wales national parks. Many access routes are also seriously degraded following years of poor management.

Perhaps a quality New South Wales national parks and reserves web site could be developed, with the current web site being quite dated and not particularly useful for visitors to the national parks of New South Wales. Quality information on the attractions and access to each national park would greatly improve the tourist potential of New South Wales national parks.

If quality visitor brochures/leaflets on such things as camping facilities, access routes, walking trails and park attractions could be developed and made available via PDF documents on the web site, potential visitors could plan their trips and this would certainly increase visitor numbers to the national parks.

Quality content and relevant up-to-date information on each national park, as well as well maintained access routes and facilities would encourage far more people to visit the national parks and give visitors a memorable experience.

BELOW: Footage of the Warrumbungle National Park in NSW.