Located in Tanzania, with a height of almost 6,000 metres, Mount Kilimanjaro is Africa’s tallest mountain. Over the years, there’s been extensive urbanisation and development at the base of the mountain, which could change what lives on the mountain.

Satellite images show that, between 1976 and 2000, there have been dramatic changes to the strips of land between Mount Kilimanjaro and Mount Meru, which is located less than 100km to the east. Areas that originally had dense natural vegetation were forced to make room for intensive agriculture and residential development to accommodate a growing population.

Nowadays, Mount Kilimanjaro is almost completely surrounded by developed areas that include wheat farms, commercial sugar cane plantations and rice paddies. There are also smallholder farms all around and growing, built-up settlements.

This means the mountain’s ecosystem is at risk of turning into an “ecological island”, entirely surrounded by cultivation and development. When natural habitats are isolated in this way, species are less able to migrate, leading to less genetic variation and diversity.

Less genetic variation makes ecosystems more vulnerable during environmental changes. Diversity increases the ability to adapt. For instance, if there’s a warming event some plants or animals might not survive and others might.

We carried out a study to uncover what the long‐term effects of this land‐cover change could be on biodiversity. Specifically, we wanted to know how important natural vegetation bridges are.

We did this by studying a group of insects called Orthoptera – commonly known as grasshoppers, crickets and bush crickets. These serve as an early warning system because they are adapted to a very special microclimate. This means they’re affected by even small changes in environmental conditions and this is immediately reflected in which species are living in a certain community in a certain habitat. Any changes to grasshoppers can signal far-reaching effects for other animal groups, which are often difficult to study.

Grasshoppers can also easily be collected and identified.

We found that – because of the distribution of different species – Orthoptera used vegetation between Mount Meru and Mount Kilimanjaro as natural bridges. These bridges allowed species in the area to develop to their current diversity levels.

If bridges of vegetation between the mountains weaken or vanish altogether, it is not just the mobility of these insects that is affected. Larger animals such as antelope, small mammals, snakes, or chameleons are at an even higher risk of becoming isolated and thus going extinct in the foreseeable future. They need genetic exchange and large habitats.