Gorongosa 2024-FULL-FINAL - Flipbook - Page 70
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GORONGOSA SP ECIAL
Suddenly, he falls quiet.
A low rumble means a lion
is nearby.
their colors. But as he has grown in his studies, his love
has deepened: “Now it’s not only about the singing but
their biology and behavior.”
The Gorongosa Savanna Ecology Experiment is
intended as a long-term study and a research playground that allows Gorongosa students to contribute to a detailed understanding of savanna function.
The experimental area consists of 10 blocks, each with
six plots: three that are open to large mammal herbivores and three that are fenced off. (The open ones
are very much within a lion’s range.) Of those six, two
are burned early in the season, two are burned late in
the season, and two aren’t burned at all—allowing scientists to understand how the effects of fire and large
mammals interact.
Similar experiments exist in Kenya and in South
Africa at Kruger National Park, but they aren’t designed
to test the effects of fire regimes and the presence of
large mammal herbivores in a fully crossed experiment,
Massad says. Another aspect of the project in Gorongosa that sets it apart is that it is looking at biodiversity
comprehensively, because students are studying multiple species. “Because of these little projects within
the big project,” Massad says, “we’re able to understand
not just how these factors influence the big mammals—
which are usually what people care about—but also all
the smaller and more biodiverse taxa as well.”
After one year of the experimental data has been
analyzed, Massad is excited to see differences in the
results from the plots. Researchers who take part in the
project have found that in plots that are burned, there
is more grass biomass—which is good for large foraging
and grazing mammals. On the other hand, the plots that
are open to herbivores have limited grasses—a result
that is “not a surprise but it’s neat to see that happening
within a year, and it’s also cool that it’s matching results
from other parts of Africa,” Massad says.
Another finding is that both fire and herbivores
limit the abundance and regeneration of shrubs—data
that support similar conclusions in other parts of
Africa. A big remaining question in savannas is how
the balance of trees and grass is maintained. “How
is it that it’s not just grasses that dominate or just
trees?” Massad says. “Fire and large herbivores have
different effects on grasses versus woody vegetation,
and this experiment allows us to understand their
interaction, which is likely to become stronger over
time. In the future, we expect to see effects on tree
growth as well.”
Much of the human management of savannas is
done through fire—burning allows for more grass
to grow, which is good for tourist areas that want to
attract antelope and other photogenic species sought
after by tourists. But the experiment in Gorongosa has
shown that fire has different effects on different species. While early-season fire was beneficial to small
mammals, it led to a decrease in the abundance of
amphibians. Massad says there are very limited studies
about the effects of fire or large mammals on other animal taxa; in particular, there are few, if any, studies testing burn regimes on biodiversity outside of Gorongosa,
making the results notable.
“By focusing just on using fire as a management tool
for large mammals, people might not necessarily be
promoting biodiversity holistically across savannas,”
Massad says, “even though you might be giving tourists what they want to see, which is a good view of large
grazing animals.”
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