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How Tsavo’s geology saved its animals

Geology describes the scientific study of the Earth, and although, as a science, it is more about rocks than “rock’n’roll,” it remains extremely important. The geology of an environment forms the literal foundation of ecosystems and significantly impacts the vegetation and animals that inhabit it.

In Tsavo, not only has the geology shaped the soil and, therefore, the vegetation, but specific geological formations found within the Tsavo Conservation Area also support a significant proportion of life.

In this article, we will explore some of Tsavo Conservation Area’s more interesting geological features and delve into how they consistently provide for Tsavo’s animals and how they may have saved them altogether.

Mudanda Rock

If you have been lucky enough to visit Tsavo East National Park, there is a strong chance you have seen the well-known Mudanda Rock. This impressive geological formation forms a natural rocky amphitheatre to view the best of Tsavo’s wildlife.

The rock itself is a Precambrian basement rock between 570 and 4550 million years old. Basement rock is typically very old, hard, and found deep underground. Essentially, these rocks are the foundational layer upon which younger rocks and sediments are deposited over millions of years.

The Mudanda basement rock, however, has been exposed through a combination of tectonic activity pushing it to the surface and erosion gradually unveiling it.

Now, this huge geological feature is the perfect place for tourists to perch and have a picnic. As water flows off the rock’s large surface, collecting at its base, it also becomes a crucial place for many animals to come and drink, particularly during the dry season.

Mzima Springs

Another well-renowned geological feature of Tsavo is Mzima Springs. This unique sequence of streams and pools, filled with crystal-clear water, is a popular tourist attraction. Visitors are able to clearly see Africa’s aquatic species, such as crocodiles and hippos, within Mzima’s clear waters.

SEPTEMBER 2023 Tsavo Trust Monthly Report
Hippos within the crystal clear waters of Mzima Springs

Mzima Springs also provides a lifeline for Tsavo’s animals, particularly in the dry season, providing a constant water source in an often dry environment. The springs flow for only two kilometres before they are forced underground again by a solidified lava flow; however, along the springs’ banks, there is an abundance of life. Fruiting trees, including dates, figs, and waterberries, attract vervet monkeys and birds. Meanwhile, the fish that swim within the clear waters sustain crocodiles and cormorants.

Interestingly, this upwelling of clear water is actually part of a larger geological system that starts 50 kilometres away in the volcanic Chyulu Hills.

How the Chyulu Hills Clean Water

The Chyulu Hills are a mountain range comprising a 100-kilometer volcanic field. The substrate is made up of volcanic rock and ash. The hills are relatively young for mountain ranges, with volcanic activity starting only 1.5 million years ago. The area is still considered volcanically active, with two eruptions occurring in 1856.

As the soil of Chyulu is volcanic, water is unable to stay on its surface. Instead, water percolates through the porous soil, undergoing a natural filtration and purification process as it flows underground.

Remarkably, the water can remain subterranean for up to 25 years, gradually journeying southward before resurfacing as the pristine waters of Mzima Springs, where many animals of Tsavo West rely on it as a water source.

If you would like to learn more about Mzima Springs and how hippos help sustain life there, follow this link to read a previous article.

The Red Elephants of Tsavo

The elephants of Tsavo are a distinctive and easily recognizable population, largely due to their red skin. This red colour does not come from any genetic differences but from constant dust bathing in Tsavo’s red soil.

The soil of Tsavo is known as ferralsol, typically very old, highly weathered soil often found in undulating topography of tropical climates.

Ferralsols are known for their poor fertility, which contributes to Tsavo’s sparse vegetation, but they also have a very high iron oxide content, which is red in colour.

Big tusker
A big tusker elephant with the distinctive red colouring as a result of high iron oxide content in Tsavo’ soils.

Elephants deliberately spray this iron-rich laterite soil on their bodies, which helps protect them from sun exposure and parasites and contributes to their general skin care.

The soils of Tsavo have a huge impact on the animals living there today and could also be the reason that Tsavo, as a protected area, exists at all.

How Soils Saved Tsavo

The Tsavo Conservation Area is an exemplary wildlife management area known worldwide. As Kenya’s largest wildlife protection area, Tsavo’s successes significantly impact the nation’s wildlife conservation.

However, it wasn’t always like this. Though the Tsavo area is now well-known for its biodiversity and the relatively large numbers of megafauna it hosts, it was chosen as a wildlife reserve back in 1949 not because of what it boasted but because of what it lacked.

The poor fertility of the soils, combined with a harsh climate, made Tsavo unsuitable for farming, and it was therefore designated as a wildlife protection area.

Today, this vast expanse of government-protected land is home to incredible biodiversity: from big cats to hyraxes, elephants to kudus, and from the fringe-eyed oryx to the critically endangered hirola.

Tsavo’s geology has played a pivotal role in preserving its rich and diverse wildlife. Interestingly, it was the very harshness and infertility of Tsavo’s soils that initially protected it from agricultural development, allowing it to be designated as a wildlife reserve. This serendipitous preservation has made Tsavo a sanctuary for countless species, showcasing how geology not only supports life but also safeguards it. Thus, the geology of Tsavo has not merely shaped its landscape but has indeed saved its animals, ensuring the survival and thriving of this extraordinary conservation area.

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