The world’s most famous tropical forests found on lowlands, like those of the Amazon or Borneo, are celebrated for their ability to store carbon. The Amazon rainforest itself holds up to twenty years’ worth of fossil fuel carbon emissions in its trees and soil.

While tropical forests can also be found on tropical mountains such as Mount Kinabalu in Borneo, these have long been assumed to store much less carbon. On mountains, temperature decreases with increasing elevation, negatively affecting tree growth. Also, common mountain features such as thick fog, wind and steep slopes tend to constrain tree height.

If trees are smaller, and grow slower, then mountain forests should contain less carbon sequestered from the atmosphere through growth processes: a hypothesis which has been reflected in studies of tropical mountains in the Andes and southeast Asia.

But our research, recently published in Nature, shows that tropical mountain forests in Africa actually store as much carbon per hectare as those found in African lowlands – a finding specific to the continent.

This is because, although African tropical mountain forests have fewer trees (about 450 per hectare compared to 600 in other continents) than their lowland counterparts, they have a greater abundance of large trees (over 70 cm in diameter), whose increased mass means they hold on to more carbon.

We wondered if this unusual finding was thanks to elephant populations resident in many African tropical mountain regions, who eat and destroy smaller tree stems – creating room for others to grow larger – and also transport nutrients which are limited in mountain soils.

But we didn’t find significant differences in tree height between forests with and without elephants, although unfortunately our data only showed us if elephants were present in a given area and not how many were around. Other explanations could include the low frequency of tropical cyclones or active volcanoes in Africa, making it less likely for trees to be destroyed before they grow tall.

Carbon storage

A group of 101 researchers working at different institutions across Africa, Europe, North America, Asia and New Zealand measured 72,336 trees with trunks of over 10cm diameter on 44 mountains in 12 countries within the African continent. For each tree we recorded trunk diameter, species and height.

We used an equation to estimate the carbon stored in these forests, since actually cutting, drying and weighing trees – technically the most accurate method for analysing carbon capture – would rather undermine our aim to mitigate climate change.

We then calculated how much tropical mountain forest had been lost in the African continent over the past 20 years, using data from satellites. We estimated that 0.8 million hectares had been lost, mostly in DRC, Uganda and Ethiopia.

Unexpectedly, given the steep terrains which make logging operations or large-scale farming challenging, we found that in many African countries deforestation rates were higher in the mountains than the lowlands.

So if these mountain forests store more carbon than expected, we are releasing more carbon dioxide into the atmosphere than previously assumed. In fact, the 0.8 million hectares of mountain forest destroyed since 2001 has emitted more than 450 million tonnes of carbon dioxide into the planet’s atmosphere, accelerating global warming.

Biodiversity loss

African tropical mountain forests are not only carbon-rich: they are also rich in biodiversity. Among their huge trees live elephants, mountain gorillas, chimpanzees, and numerous species of birds, amphibians and snakes found nowhere else in the world. Continued deforestation will push many of these creatures further towards extinction.

These forests also act as “water towers” (like giant water tanks), irrigating agricultural land and supplying numerous vital river systems including the Congo and the Nile. This makes them crucial for local and regional crop growth, hydropower systems providing renewable energy, and inland fisheries supporting nutritious diets and livelihoods for local communities.

Mountain forests often collect water droplets from fog in a process known as “occult precipitation”. This makes local landscapes much more humid than if the forests were not present. Destroying these forests is therefore not only terrible for our global climate, but also for regional weather and biodiversity, since many species require the specific conditions created by this humidity to thrive.

But our study also provides some hope. If these forests store more carbon than previously assumed, it could allow us to increase the economic benefits awarded to developing countries who successfully decrease deforestation, meaning greater incentives for forest conservation – and better futures for those who call the mountain forests home.

Aida Cuní Sanchez, honorary fellow, University of York; Martin Sullivan, Lecturer in Statistical Ecology, Manchester Metropolitan University, and Phil Platts, Research Fellow, University of York

This article is republished from The Conversation under a Creative Commons license. Read the original article.
Featured photo by Hamsavani Raja Komaraim/Scopio

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The logging concessions would impact one of Africa’s great biodiversity hotspots. Ebo Forest is the habitat of a possible new subspecies of gorilla, as well as a culturally unique population of chimpanzees: the 700 chimpanzees appear to be the only ones in the world that have mastered both cracking nuts using stones and wooden hammers, as well as fishing for termites using long sticks. In other regions, chimpanzees use only one or the other of these techniques.

Over 40 communities in the region have been living in harmony within and around the forest for generations. The forest has ancestral and spiritual significance as a site for traditional rituals, and contains the gravesites of revered community elders. The local people were not consulted or even informed of the government’s intentions, and their rights to their ancestral land were ignored. If realized, the logging concessions would cost local communities their livelihoods and cultural heritage and make them increasingly vulnerable to new emerging diseases.

In its petition, which is addressed to the President of the Republic of Cameroon, Paul Biya, Rainforest Rescue calls on the Cameroonian government to:

• revoke the logging concessions
• protect Ebo forest and fulfill the promise to declare it a national park and
• respect the local population’s traditional rights and the principles of free, prior informed consent (FPIC) and involve them in any future land use planning process.

Rainforest Rescue co-chair Marianne Klute: “If realized, the logging concessions would cause immense social injustice and impact regional ecosystems as well as the climate. Logging opens the door for the wholesale destruction of the environment, as poachers, settlers, and land grabbers pour into the newly opened areas. We need the Cameroonian government to realize its responsibility for this unique and irreplaceable natural treasure.”

 

View this post on Instagram

 

Cameroon’s #EboForest is home to gorillas, tool-wielding Chimpanzees, Forest Elephants, Presuss’ Red colobus, Drills and many other rare and endangered species. It is one half of the Yabassi #KeyBiodiversityArea, making it a site of global importance to the planet’s overall health. It is also the ancestral land of more than 40 communities that surround it. In a letter to the Cameroonian government, scientists from @global_wildlife_conservation, San Diego Zoo Global Conservation Research Institute, @kewgardens and IUCN Primate Specialist Group, asked the government to suspend plans to create 2 long-term logging concessions in Ebo Forest. They asked that the government develop an inclusive land-use plan with the local communities who would be most affected by logging. Let’s #ProtectEboForest.

A post shared by Leonardo DiCaprio (@leonardodicaprio) on May 5, 2020 at 10:53am PDT

UPDATE

Good news!
Cameroon’s President Paul Biya has ordered the cancellation of logging concessions in the Ebo Forest. A choice for conservation and an example for the world. The rare ebo gorilla and other endangered species can still call this forest home.
Via Regina Fonjia Leke (Broadcast Journalist at Canal 2 International TV)

To view the petition, please visit: https://www.rainforest-rescue.org/petitions/1221/no-to-logging-in-cameroons-ebo-forest

Photo: Francesco Ungaro

The post Help prevent logging and save rare gorillas in Cameroon’s Ebo Forest appeared first on African Conservation Foundation.

Children in every corner of the globe can identify an elephant in a wildlife lineup. They are as recognizable as any basic shape and as endearing as any household pet. Yet the same cannot be said for the hundreds of tropical flora and fauna that are liable to disappear should forest elephant populations continue to crash.

“[Elephants] have a disproportionately large impact on their ecosystem and the organisms living in it,” says John R. Poulsen, assistant professor of tropical ecology at Duke University’s Nicholas School of the Environment. “If people are aware of the potential result of losing elephants […] perhaps they can transfer that understanding to less well known species.”

Poulsen and his colleagues recently published a study in Conservation Biology examining how the loss of forest elephants would impact the rest of their natural habitat. After diligently reviewing dozens of papers on Afrotropical flora and fauna, they predict that the loss of forest elephants will reshape the ecological processes at work in their environment. Species composition will change, in addition to the size and abundance of large tree species — and, by extension, the ability of these ecosystems to store carbon dioxide.

“[The] killing of elephants for their ivory is not only depriving the world of one of its most charismatic species, but might also be making the Earth less inhabitable for humans,” Poulsen says.

A Tale of Two Species

Although many people are familiar with elephant conservation, few know that the African elephant is not one, but two distinct species: forest (Loxodonta cyclotis) and savanna (Loxodonta Africana). The two are different in their anatomy, reproduction, even their social structures.

When most people think of Africa’s elephants they are actually picturing savanna elephants: those that live out in the open, in places like the Serengeti, and are therefore easier to study. Forest elephants are comparatively smaller and weave their way through vibrant Afrotropical forests, such as in the Congo, forging elephant-wide paths as they do so. Scientists looking at genetic markers estimate the two species split between 2 million and 6.5 million years ago; humans and chimpanzees, by comparison, diverged between 5 million and 7 million years ago.

Despite such differences, the International Union for Conservation of Nature (IUCN) does not currently recognize forest and savanna elephants as distinct species. Both fall under the title of African elephant.

“The two-species question is pretty much accepted by the taxonomists but has yet to be officialized by IUCN,” says Fiona Maisels, surveys and monitoring adviser at the Wildlife Conservation Society (WCS) in Gabon.

Scientists generally define species as a group of organisms that can successfully mate and produce fertile offspring. The primary holdup in the case of the African elephant is that forest and savanna elephants can interbreed and produce fertile offspring, and occasionally have. However, this is also the case with wolves and coyotes, which are universally considered distinct species. And many bacteria and plants reproduce without mating at all, which provides further confusion.

But, according to Poulsen, treating the two African elephant species as one has had dire implications for their respective conservation. When forest and savanna elephants are bundled together as “African elephants,” it inflates the true population of each species.

“With a larger population, the conservation status of the ‘African elephant’ can be listed as ‘Vulnerable,’” Poulsen says, “which allows some [southern] African countries the possibility of trading ivory.”

If the IUCN recognized forest and savanna elephants as distinct, both species would be considered “endangered,” likely necessitating stricter rules for trading ivory.

According to Poulsen, the current unified conservation assessment is a barrier to the protection of forest elephants in particular. In Central Africa, 62 percent of forest elephants were lost between 2002 and 2011, primarily due to poaching. However, as they are considered the same species as the savanna elephant, the IUCN recorded a smaller overall loss in the “African elephant” population. A study in 2013 by Maisels found that current forest elephant populations are only at 10 percent of their potential size.

We are losing these elephants without knowing much of what their extinction might mean for Afrotropical forests, for Central Africa, and even for global climate.

“The problem is that elephant populations are doing poorly in most places and allowing the sale of ivory has traditionally grown the demand, rather than saturating it, leading to killing across the entire range of both species,” Poulsen says.

Big Feet, Big Footprint

Forest elephants are ecosystem engineers, meaning their various behaviors heavily alter their habitat.

Their size matters. Although smaller than their savanna counterparts, forest elephants are still just that: elephants. Simply by walking around, they can shape their environment. By moving in herds, their impact is multiplied. By stomping saplings, peeling bark, breaking limbs, clipping branches and trampling vegetation, forest elephants generate trail systems that can stretch tens of kilometers.

All of that elephant activity shapes the forest canopy. Poulsen and his colleagues say that, although destructive, the elephants clear the understory of the forest, allowing large trees to spread their roots and grow to their greatest heights. Without this service, greater competition for light and soil could slow tree growth and reduce trees’ potential size.

Elephants are also the largest fruit-eating animals on the planet, and they aren’t picky about their food. They consume more than 500 plant species in Central Africa. Plants that produce fruit often rely on animals to disperse their seeds far and wide. Since elephants are so large, they can eat and carry seeds that are too big, hard or fibrous for other, smaller animals. Forest elephants, and forest elephants alone, disperse the seeds of at least 43 plant species in Central Africa.

By doing so, they also boost the odds that the seeds will take root. The digestive tract of elephants improves the germination time and growth rates of seedlings that pass through it.

Additionally, the wide swaths of forest floor that elephants open up provide ample space for new seedlings to settle.

Dung is another important contribution from forest elephants. Although poop may seem an unlikely gift, it is a critical ingredient for lush forests. Besides light and water, the most important thing for forest health is nutrients. As elephants chew, swallow, digest and excrete, they unlock and redistribute nutrients like sodium and nitrogen that would otherwise stay put. And when they excavate termite mounds and salt licks, they unearth rare nutrients like potassium, calcium, magnesium and sodium, which would have been previously inaccessible to the rest of the forest. Elephants in the forest unlock and redistribute the building blocks of life, broadly dispersing ingredients both rare and critical throughout the forest.

“I have walked through forests with healthy elephant populations and forests that have been elephant-free for decades. There is a stark difference,” Poulsen says. “Elephant-free forests can have a thick understory and middle story with lots of herbaceous vegetation and thorny vines, visibility is limited and it is difficult to walk through. Forests with elephants can look like a park with good visibility and well-worn trails to walk along.”

Making Molehills of Mountains

The great footprint of the forest elephant doesn’t tread on just Central African forests. Tropical forests are an integral component of global carbon storage. The larger the tree, the more carbon it sequesters over its lifetime.

“While there is a big focus on stopping deforestation, we speculate that the loss of elephants might also affect the ability of forests to store carbon,” Poulsen says.

Because forest elephants are key to the growth and survival of large trees, the loss of elephants means less carbon sequestration by Africa’s forests — and a warmer planet, according to the paper.

To conserve both African elephant species — and every plant, animal and fungus that relies on the ecosystem services they provide — the demand for ivory must end. Poulsen is adamant that the two species must be listed as distinct in order to have the proper restrictions in place for the ivory trade.

Poulsen says the U.S. public can help by expressing concern for elephant conservation to their congresspersons. Although Central Africa may seem distant, the U.S. Fish and Wildlife Service (USFWS), as well as other federal agencies, delegate a portion of funding to international conservation in the African tropics. Poulsen also encourages speaking out against allowing tusks and elephant body parts to be imported into the United States and elsewhere.

This spring, the Trump Administration allowed elephant parts to be imported via the USFWS on a case-by-case basis.

“The only way to stop the ivory trade and the killing of elephants,” Poulsen says, “is to shut down all trade of ivory, everywhere.”

Citations

Poulsen J.R., Rosin C, Meier A, Mills E, Nuñez C. L., et al. (2018) Ecological consequences of forest elephant declines for Afrotropical forests. Conservation Biology 32 (3). DOI: 10.1111/cobi.13035

Maisels F, Strindberg S, Blake S, Wittemyer G, Hart J, et al. (2013) Devastating Decline of Forest Elephants in Central Africa. PLOS ONE 8(3): e59469. https://doi.org/10.1371/journal.pone.0059469

https://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_41

https://news.mongabay.com/2013/03/62-of-all-africas-forest-elephants-killed-in-10-years-warning-graphic-images/

Article published by Maria Salazar in Mongabay

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