Tigers and elephants: two good news for species conservation

In the flow of depressing news on the state of biodiversity, when something works we have to pay attention: for this reason we are pleased to report two small success stories in the conservation of species, which concern two large mammals with very different habits and geographies, but which both link their survival to the forests.

The first news concerns an investigation conducted with camera traps (photographic stations connected to motion sensors used to document very rare and elusive animals) within the Leuser ecosystem, one of the largest and most uncontaminated areas of tropical rainforest in Southeast Asia: a green expanse between the provinces of Aceh and North Sumatra (Indonesia), extremely precious for animal and plant biodiversity.

The survey documented the presence in the area of ​​more than double the number of Sumatran tigers (Panthera tigris sumatrae) than those found elsewhere on the island of Sumatra. A good sign of the health status of this population.

Thanks to a collaboration between the indigenous Gayo population, who knows these forests like the back of their hands, the conservation organization Hutan Harimau and other research bodies, 60 camera traps have been installed in a little-studied part of the ecosystem. They photographed 17 Sumatran tigers in a 90-day window in 2023, and 18 in the same period in 2024: in the same period of time, previous searches had only identified 7 tigers on average. The new issue goes far beyond expectations.

As the study, published on Frontiers in Conservation Sciencetoday the majority of tigers are found in India where in recent years there have been several advances in conservation. Much more critical is the state of the populations of tiger subspecies present in the rainforests of Southeast Asia, on which less reliable data is available.

Sumatran tigers are predators at the top of the food chain that require a large abundance of prey: having found them in higher numbers than expected means that these forests are rich in other animals, such as the sambar deer that the tigers feed on.

The doubling of tiger specimens encountered by camera traps also means that the monthly ranger patrols organized in the forest by NGOs to dissuade smugglers are working, even if more could be done: according to the IUCN list (drafted by the International Union for Conservation of Nature) there are currently between 441 and 679 total specimens of Sumatran tigers, and in recent years, Southeast Asia has already completely lost its tigers from the countries of Vietnam, Cambodia and Laos.

The second piece of news concerns African forest elephants (Loxodonta cyclotis) present in the forests of central Africa (in states such as the Republic of the Congo, Gabon, the Democratic Republic of the Congo, the Central African Republic). These mammals, smaller than savannah elephants, are considered ecosystem engineers, due to their ability to eliminate smaller trees from forests and make larger ones thrive, and because they promote seed dispersal. Only since 2021 has their conservation status been assessed separately from that of savannah elephants (Loxodonta Africana).

Well, a new assessment of the number of forest elephants based on DNA samples taken from their excrement has made it possible to more accurately define the total size of their population, now estimated at 135,690 individuals.

This is a number 16% higher than data published in 2016, even though the pachyderm remains at critical risk of extinction, due to poaching and the fragmentation of its habitat. As IUCN experts point out, «the updated numbers of African forest elephants should not be interpreted as population growth, but rather as the result of improved survey coverage made possible by DNA-based methods. These techniques significantly reduced uncertainty in detection estimates and allowed us to evaluate previously inaccessible areas.”