The level of CO2 in the atmosphere will increase if elephants go extinct. Why will this happen?
Elephants are among the few megaherbivores that survive today. Forest elephants shape their environment by dispersing seeds and by acting as bulldozers, feeding on around 100 different species of fruits, trampling bushes and felling trees. In this post, we already told you how elephants and frogs are related thanks to these activities.
The ecological impact of these activities therefore affects tree populations and carbon levels in the forest , which has significant implications for climate and conservation policies.
In a study conducted by Saint Louis University and published in Nature Geoscience , Central African forest elephant populations have been found to stimulate the growth of slow-growing trees. These trees have a high density of wood and therefore sequester more carbon from CO2 from the atmosphere.
How do they influence CO2?
These pachyderms prefer to feed on fast-growing species, which causes high levels of mortality and damage to these species compared to slow-growing, high-density wood species.
The collapse of their populations could cause an increase in the abundance of fast-growing species at the expense of slow-growing species that are better able to fix CO2 from the atmosphere.
Study author Stephen Blake, a professor of biology at Saint Louis University, spent 17 years in Central Africa working on elephant conservation. In addition, it collected data on the structure and composition of species in the Nouabalé-Ndoki forest in northern Congo.
What would happen to the composition of the forest over time without the presence of elephants?
To answer this question, they developed a mathematical model that assumed that elephants graze certain species at different rates. When they are in open spaces they prefer fast-growing plants, so that as they feed and graze, they cause damage, breaking trees or shrubs.
The model calculated feeding and breaking rates along with elephant mortality rates to see their effect on certain woody plants.
“From this point on, when we look at the number of elephants in a forest and observe the composition of the forests over time, we find that the proportion of trees with high-density wood is higher in forests with elephants,” he said. Blake.
The simulation found that slow-growing plant species survive better when pachyderms are present . These species are not consumed by them and, over time, the forest becomes dominated by these slow-growing species. Wood (lignin) has a carbon backbone, which means that it has a large number of carbon molecules that come from atmospheric CO2.
Slow-growing, high-density wood species contain more carbon molecules per unit volume than fast-growing, low-density wood species. As elephants “thin” the forest, they increase the number of slow-growing species. Trees and forests are capable of storing more carbon ”.
The reduction in the density of forest feet due to the presence of these animals leads to changes in the competition for light, water and the space between the trees. These changes favor the appearance of fewer and larger trees with a higher density of wood. This change in the structure of the African rainforest and in the composition of species increases the long-term balance of aboveground biomass.
The extinction of this species would lead to a 7% decrease in aerial biomass in the tropical forests of central Africa. These modeled results are confirmed by field inventory data, according to the study.
The authors speculate that the presence of forest elephants may have shaped the structure of the African rainforests, which probably plays an important role in differentiating the Amazon rainforests.
The need to protect them
These findings suggest far-reaching ecological consequences. The loss of this species will seriously reduce the capacity of the remaining forest to sequester carbon. Trees and plants use CO2 during photosynthesis, removing it from the atmosphere. For this reason, plants are useful to combat global warming and serve to store carbon emissions.
Without forest elephants, less carbon dioxide will be removed from the atmosphere. In monetary terms, forest elephants represent a carbon storage service of $ 43 billion.
“The sad reality is that humanity is doing everything possible to rid the planet of elephants as quickly as possible,” said Blake. ‘Forest elephants are rapidly declining and facing extinction. From a climate perspective, all their positive effects on carbon and their myriad other ecological roles as gardeners and foresters will be lost. ‘
The study authors note that forest elephant conservation could reverse this loss. The biggest threats to this species are habitat loss and poaching for the highly prized pink ivory of its tusks.
‘Elephants are an iconic species. People love elephants – we spend millions each year on stuffed animals, they are zoo favorites, and who didn’t cry during Dumbo? And yet we are bringing them closer to extinction every day. On the one hand, admire them, empathize and be horrified when they are murdered, and on the other hand we are not prepared to do anything serious about it. The consequences can be serious for everyone. We need to change our ways.