Ecological Effects


Ian Redmond, Geographical 

Date Published

$150 million. That is the estimated black market value of the 105 tonne-stockpile of confiscated ivory that Kenya torched at the end of April this year

Some people question the wisdom of a developing country destroying rather than selling such a resource, but Kenya’s stance is that wildlife tourism brings many times the putative value of these tusks and that their real value is zero unless attached to a living elephant.

Moreover, history shows that the sale of contraband wildlife products stimulates the very market that drives the poaching, costing far more in salaries and equipment for anti-poacher patrols as well as causing the tragic loss of rangers’ lives. There is, however, another largely unsung value to wild animals that transcends the potential earnings from tourism or the sale of their teeth, horns, fur or feathers – the role each individual plays in its ecosystem. Elephants provide a striking example.

Let us estimate the ecological effect of the loss of the 8,000 elephants whose tusks were cremated by Kenya. An elephant eats about four per cent of its body weight in vegetation each day, much of which passes through undigested. This means every adult elephant produces roughly one tonne of dung – aka first-class organic manure – every week, enriching the soils of the forests and savannahs in 50 countries (there are 37 elephant range states in Africa and 13 in Asia). The Kenyan ivory pyre represents about 8,000 tonnes less fertiliser being spread per week.

Not only is elephant dung packed with nutrients; after a mammoth meal of fruit or seed pods, it is studded with seeds. Elephants disperse more seeds of more species of trees, lianas and other plants, over longer distances than any other animal. Such is their beneficial role in forest-savannah landscapes, they have been dubbed ‘super-keystone species’ and ‘mega-gardeners of the forest’.

Their size is important, because while trees with small seeds can be dispersed by fruit-eating birds and primates, those with big seeds need big animals to be able to swallow them. Some species, such as the African rainforest tree Balanites wilsoniana, are solely dependent upon elephants for the next generation (as, therefore, are any insects that feed on its leaves or bark, and to a lesser extent any birds, bats and reptiles that feed on those insects).

“Tropical forests are essential to our efforts to stabilise the climate, and the health of the forest depends on the seed-dispersing animals”

Gorillas are second only to elephants for seed dispersal in the ten African countries where they live. Orang-utans and forest-dwelling rhinos play a similar role in South and Southeast Asian forests, along with Asian elephants, just as tapirs, spider monkeys and uakaris do in South and Central America. Such ecological inter-dependencies are seen as interesting to academics and naturalists, but they should be noted by economists too because breaking those links will have serious economic consequences, especially in the context of climate change.

Carbon accounting is the relatively new discipline that underscores our efforts to reduce greenhouse gas emissions, and the carbon stored in forests is an important part of the global equation. Not all trees store the same amount of carbon, however. Botanists report a curious correlation between seed size and wood density: tree species with large seeds have denser wood, which therefore stores more carbon per unit volume than lighter woods. The amount of carbon per unit area of forest is an important consideration in deciding which forests should be conserved and which might be cleared for agriculture, flooded by dams or divided by roads and railways. But the impact of infrastructural development on seed dispersing mammals and birds is seldom taken into account. This must change.

Ever since the UN climate talks in Bali, Indonesia, in 2007, the role of forests in sequestering and storing carbon has been recognised by the climate negotiators, resulting in their inclusion in the historic Paris Climate Agreement last December. The text of that agreement does refer to the importance of biodiversity and ‘ecosystem integrity’ but almost as an extra benefit rather than being essential to climate stability.

Despite the growing interest in some UN agencies in the concept of ‘payment for ecosystem services’ and the publication of the influential TEEB (The Economics of Ecosystems and Biodiversity) report no-one has yet drilled down into the ‘ecosystem accounts’ to estimate the economic importance of keystone species such as apes and elephants. Arguments for their conservation seem to focus on how much DNA apes share with us and how it would be sad for our children to grow up in a world without elephants – which it would, of course. But these are anthropocentric arguments and I am seeking a more biocentric appraisal of their importance. Tropical forests are essential to our efforts to stabilise the climate, and the health of the forest depends on the seed-dispersing animals. Thus, it is essential that excessive hunting be controlled and that some of the carbon finance being directed towards forests be used to protect elephants, primates and other #GardenersoftheForest.

Ian Redmond OBE is a tropical field biologist and conservationist, and is a founder of Ape Alliance. Find out more by virtually visiting these habitats via or by downloading the ApeAppVR from