Rainfall disruption by the warming climate brings more drought and more flooding to Kenya’s Maasai Mara National Reserve and the Serengeti, where the largest terrestrial migration of Wildebeest, Gazelle, and Zebra has so damaged the ecosystem that the herds lose the pastures that have kept them alive for over two and a half million years according to the fossil record.
Once upon a time, an estimated two million animals migrated from North to South from Tanzania's Serengeti National Park into the Maasai Mara in Kenya, over 1,865 miles. There used to be four wildebeest migrations in Kenya, but now there is only one with an estimated population of a couple of hundred thousand animals. The decline in population of over sixty percent since 1977.
Human populations have exploded across the Earth, but there is not enough land in a fragile ecosystem for both. Fences go up; cattle feed on the same grasslands as the herds, and residents shoot migrating animals as competition for resources increases.
From Context:
East Africa is one of the most vulnerable regions to climate change, with countries such as Kenya, Ethiopia and Somalia regularly experiencing unpredictable weather, from long dry spells to torrential rains and floods.
The region is currently experiencing the driest conditions recorded since 1981, following the failure of four consecutive rainy seasons. That has left 26 million people in the three countries on the brink of extreme hunger, according to the World Food Programme.
In the Maasai Mara reserve, the increased dry spells are also stoking conflict between humans and predators.
"When there is drought, the herbivores move into areas looking for pasture and water and they are followed by lions, who then attack cattle," said Kasaine Sankan, senior programme researcher at the Mara Predator Conservation Programme.
"Community members then seek revenge by killing lions in order to save their livestock."
Sankan said dry periods also meant that Maasai cattle herders were encroaching into the reserve - leaving less grazing land for herbivores like the wildebeest.
From Anthropocene Magazine on how animals help the carbon cycle.
When it comes to nature-based climate solutions, plants get all the love. It’s easy to envisage the carbon locked up in a mighty redwood or a forest of sea kelp. But now many scientists are also getting excited by the role that animals can play in sequestering carbon, through their diet and behavior, the way they cycle nutrients, and even how they die. This evolving science is called animating the carbon cycle. In 2019, the International Monetary Fund estimated that each great whale is worth well over $2 million in terms of the carbon it will sequester during its life. The science of such calculations is far from settled however, and even if it were, should we be valuing our planet’s other inhabitants according to how well they can clean up humanity’s carbon mess?
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On grasslands. At a larger scale, heavy grazers such as elephants and wildebeest can strip shrubs and small trees from the African savannah—and that’s not a bad thing. In 2009, researchers at the Imperial College in the UK calculated that grazers not only reduce combustible biomass, reducing the risk of wildfires, but also produce dung that returns nutrients and carbon to the soil.
Why the future of Africa’s forests and savannas is under threat
Tropical Africa has two distinct features – rain forests which are dominated by trees and savannas which are dominated by grasses. Both depend on rainfall quantity and seasonality. Seasonality measures how constant the distribution of rainfall over the course of a year is – in other words how long the dry season is.
Forests located close to the Equator receive lots of rainfall constantly over the year, while savannas receive less rainfall and only during the wet season.
Forests and savannas are expected to be strongly affected in the coming decades by changing rainfall patterns, including increased dry periods and decreasing annual rainfall. These changes are already being felt. In some areas of Burkina Faso desertification is increasing, while in Chad rainfall is increasing. These changes are being linked to climate change across the world.
Forests and savannas are expected to be affected greatly by these changes because they depend heavily on rainfall quantity and seasonality.