\u201cOur findings show that forest elephants preferentially consume ebony fruits and play a crucial role in seed dispersal,\u201d said Thomas Smith, one of the study\u2019s authors and a founder and director of CBI.<\/p>\n
This relationship is so close-knit that when poaching lowers elephant populations or removes them from forests altogether, ebony trees also dwindle. Deblauwe and his team documented a 68% drop in ebony saplings in areas lacking its key disperser. The sprouting and growth of new ebony trees virtually collapsed.<\/p>\n
Ebony trees are already vulnerable, as the trees are felled for timber and forests leveled to make way for expanding human populations. This smooth, hard, black wood is also highly sought after for musical instruments and other high-end products.<\/p>\n This study \u201cdoes such a thorough job of linking this sort of mechanistic relationship with really clearly demonstrable data of declines of ebony with elephant declines, said elephant ecologist Stephen Blake at Saint Louis University, U.S., who was not involved in the research. \u201cNobody\u2019s quite nailed that before.\u201d<\/p>\n The findings \u201cunderscore the broader consequences of forest elephant declines for many other rainforest trees that rely on large vertebrates for seed dispersal,\u201d Smith said. It adds to a growing body of research showing that up to 90% of tree species have evolved relationships with animals to reproduce and spread.<\/p>\n As gardeners of the forest, elephants change the structure and composition of forests by trampling, bulldozing and digging up plants and trees. They favor slow-growing trees that have high wood density. The higher the density, the more carbon trees store, thereby increasing the carbon stocks of forests. As seed dispersers, elephants carry seeds of dense, slow-growing trees \u2014 like ebony \u2014 far, far away, over longer distances than any other animal.<\/p>\n \u201cElephants are an intrinsic, incredibly important part of the ecosystem,\u201d Blake said, and their decline in recent years is worrying for the future of rainforests. \u201cTheir ecosystem processes are vanishing with them,\u201d he said, adding that \u201dthe loss of gardeners from the garden means that the weeds take over.\u201d<\/p>\n During the 19th century, forest elephants occupied the entire Congo Basin, but today, they are a critically endangered species with populations restricted to fragmented forest patches. In just a decade, from 2002-11, about 62% have vanished, and their range has shrunk by nearly 30%. Today, forest elephants overlap with only one-third of the ebony tree\u2019s historical range.<\/p>\n For their study, the researchers sampled ebony trees in four unlogged forest patches in and around the Dja Faunal Reserve, a protected area in Cameroon. Two sites within the protected area had elephants \u2014 and low levels of poaching. The other two sites were outside the reserve, where poaching has nearly extirpated most animals, including elephants.<\/p>\n At each site, the team collected data on the diameter of ebony trees (to determine age), spatial and genetic distribution of saplings, and conducted experiments on how well seeds germinated with and without elephants and their protective dung.<\/p>\n The study correlated declines in elephant numbers with fewer young ebony trees. In areas where elephants were present, almost half of all ebony trees were young saplings, compared with just 15.1% in areas without the pachyderms. Seed \u201cimmigration\u201d \u2014 the distance seeds dispersed from the mother tree \u2014 was five times higher in areas where hunting pressure was low, compared with areas where poaching was rampant.<\/p>\n Genetic diversity and survival of ebony trees were also affected in the absence of elephants. Since these gentle giants deposit the seeds far away from the parent tree, it reduces the chances of saplings clumping close to each other, competing for sunlight under the crown of their mother tree and spreads ebony genes widely.<\/p>\n Low genetic diversity makes trees less resilient to environmental changes, including diseases and impacts of climate change. Though primates and other animals also disperse ebony seeds, the authors say they fall short of filling the elephants\u2019 role.<\/p>\n The team proved that elephant dung played a key role in helping ebony seeds survive and grow. The dung protects seeds from being chewed up and destroyed by rodents such as Emin\u2019s pouched rats (Cricetomys emini) and herbivores like yellow-backed duikers (Cephalophus silvicultor). The study found that naked seeds were 8.5 times more likely to be devoured than those encased within elephant dung. This loss due to predation, the researchers say, explains why ebony declines when elephant numbers decrease.<\/p>\n Seeds that drop to the forest floor within fruits also had low sprouting success: They rot before germinating. So it\u2019s vital for elephants and other fruit-eating (but seed-sparing) animals, to chew up the pulp and excrete the seeds.<\/p>\n Deblauwe said the findings highlight the indirect benefit of conserving charismatic species like elephants that attract substantial funding. \u201cHere we show that when you protect elephants, you are also protecting trees that are important for both the ecosystem and people over the long, long-term.\u201d<\/p>\n Ebony \u2014 the first wood to be commercially exploited from Africa that remains economically valuable \u2014 is so slow-growing that it takes more than a century to mature. Therefore, this tree can also act as an indicator of elephant numbers in the past, Deblauwe said. Ebony\u2019s decline today is the result of elephant declines a few decades ago. \u201cIn 100 years, maybe we\u2019ll discover the true damage that has been done to the forest today.\u201d<\/p>\n The study underscores the interwoven nature of ecosystems and the long-term consequences of eliminating members of these communities. In this case, losing elephants impacts the diversity of rainforests, not just ebony. It also reiterates the need to stop elephant poaching \u2014 and build wildlife corridors between protected areas for elephants to move and disperse seeds so the forests remain biodiverse and resilient.<\/p>\n \u201cWe are really on the precipice of extinction of forest elephants and the extinction of those ecological processes that regenerate forests,\u201d Smith said. \u201cThis is kind of code red. \u2026 We need to really act now to preserve forest elephants.\u201d<\/p>\n African forest elephant feeding on ebony fruits in the rainforest of Lob\u00e9k\u00e9 National Park, Cameroon. Video courtesy of Vincent Deblauwe, IITA, CBI, UCLA.<\/p>\n Deblauwe, V., Luskin, M.S., Assola, S.D., Hardy, O.J\u2026.Jansen, S., (2025). Declines of ebony and ivory are inextricably linked in an African rainforest. Science Advances, 11(35), doi:10.1126\/sciadv<\/p>\n Caughlin, T. T., Ferguson, J. M., Lichstein, J. W., Zuidema, P. A., Bunyavejchewin, S., & Levey, D. J. (2014). Loss of animal seed dispersal increases extinction risk in a tropical tree species due to pervasive negative density dependence across life stages. Proceedings of the Royal Society B Biological Sciences, 282(1798), 20142095. doi:10.1098\/rspb.2014.2095<\/p>\n Berzaghi, F., Bretagnolle, F., Durand-Bessart, C., & Blake, S. (2023). Megaherbivores modify forest structure and increase carbon stocks through multiple pathways. Proceedings of the National Academy of Sciences, 120(5). doi:10.1073\/pnas.2201832120<\/p>\nElephants: Landscape architects of the forest<\/h2>\n
Ivory and ebony, once lived in perfect harmony<\/h2>\n
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