The key facts

  • 40 elephant carcass sites studied, remains aged 8 to 2814 days (about 7.7 years)
  • Ammonium in soil near remains is on average 31 times higher than control values; nitrogen compounds at fresh remains up to ~3000 times
  • Impalas and buffaloes grazed near remains about three times more often; the effect persisted for more than seven years

International study of the impact of elephant remains on the ecosystem

As Naked Science reports, the study was conducted by an international team led by University of California, Santa Barbara scientist Deron Burkpyle. The work was published in the journal Proceedings of the National Academy of Sciences. The authors examined how long an elephant's influence on the ecosystem persists after its death: while alive, elephants alter the appearance of the savanna by eating large amounts of vegetation, breaking branches and sometimes felling trees.

Methodology: 40 sites, soil analysis, DNA and camera traps

The scientists surveyed 40 elephant carcass sites. The age of the remains ranged from 8 to 2814 days — almost 7.7 years. At each site, soil and plants were analyzed at 0.5 and 2.5 meters from the remains; the results were compared with control plots 15 meters away. In addition, microorganism DNA was studied, and animal feeding was tracked using camera traps.

Dramatic change in soil chemistry

The greatest changes were recorded in the chemical composition of the soil. Near the remains, ammonium content was on average 31 times higher than at control sites, nitrates seven times, and phosphorus three times. At some fresh remains, the amount of nitrogen compounds in the soil exceeded the normal level by almost 3000 times; this is explained by the influx of a large volume of organic matter during the decomposition of a multi-ton carcass.

Toxicity and reduced diversity

An excess of nutrients is not always beneficial to plants: too high a concentration of ammonium can be toxic to them, so around fresh remains the conditions for growth turned out to be unfavorable. Plant diversity near the remains was noticeably lower than at control sites — this difference persisted even at remains aged 7.7 years. The diversity of soil bacteria and fungi also decreased, while the activity of microorganisms decomposing organic matter remained high for one to two years.

More nutritious grass and animal visits

The grass that did grow in such places turned out to be more nutritious: the nitrogen content in its leaves was on average 1.5 times higher than at control sites — and this was observed even at old remains. According to camera trap data, impalas and buffaloes grazed near elephant remains about three times more often than at control plots, and this activity continued for more than seven years after the elephant's death.