盜獵威脅仍在 兩非洲象獨立物種雙雙落入瀕危等級

Poaching for ivory and loss of habitat over the past five decades have taken a grim toll on African elephants. The African forest elephant, Loxodonta cyclotis, is now listed as Critically Endangered and the African savanna elephant, Loxodonta africana, is listed as Endangered on the authoritative Red List of Threatened Species compiled by the International Union for the Conservation of Nature, IUCN.

Before today’s update, African elephants were treated as a single species, listed as Vulnerable to extinction. This is the first time the two species have been assessed separately for the IUCN Red List, after the emergence of new genetic evidence.

The 2016 IUCN African Elephant Status Report provides the most recent reliable estimate of the continental population of the two species combined, at around 415,000 elephants.

The IUCN Red List now covers 134,425 species of which 37,480 are threatened with extinction.

Two Separate African Elephant Species Emerge

The decision to treat African forest and savanna elephants as two separate species is the result of the consensus that has emerged among experts following new research into the genetics of elephant populations. There is also a third species, the Asian elephant, which is not covered in this assessment.

Forest elephants occur in the tropical forests of Central Africa and in a range of habitats in West Africa. They rarely overlap with the range of the savanna elephant, which prefers open country and is found in a variety of habitats in Sub-Saharan Africa including grasslands and deserts.

Long considered to be a subspecies of the African elephant, the African forest elephant is now believed by many scientists to be a species separate from the African savanna or bush elephant. They are smaller than the better-known savanna elephant, have tusks that are straight and point downward, unlike the savanna elephants’ curved tusks.

The forest elephant, which has a more restricted natural distribution, is thought to occupy only a quarter of its historic range today, with the largest remaining populations found in Gabon and the Republic of the Congo.

Forest elephants have the slowest reproductive rate of the three elephant species, according to the Kenya-based nonprofit African Wildlife Foundation. “The sexually mature age of these elephants is not until 23 and then the average gestation period is about two years. In this case, any population decline caused by poaching, bushmeat trade, logging operations, and natural resource extraction is more devastating. If poaching was stopped today, then scientists say it would take 81 years to reverse the 62 percent decline experienced in the last decade.”

Dr. Jon Paul Rodríguez, who chairs the IUCN Species Survival Commission, said, “These two Red List assessments reflect the outcome of the IUCN SSC African Elephant Specialist Group taking a bold, collaborative, evidence-based decision to assess the African elephant as two separate species for the first time and understanding the implications and consequences of this shift.”

“The outcome is robust assessments that provide users with the options to focus conservation efforts appropriately for the Critically Endangered forest elephant and the Endangered savanna elephant,” he said.

“For these assessments, a team of six assessors used data from as far back as the 1960s and a fully data-driven modeling approach to consolidate the decades-long efforts of many survey teams for the first time,” said Dr. Kathleen Gobush, lead assessor of the African elephants and member of the IUCN Species Survival Commission African Elephant Specialist Group.

“The results quantify the dramatic extent of the decline of these ecologically important animals. With persistent demand for ivory and escalating human pressures on Africa’s wildlands, concern for Africa’s elephants is high, and the need to creatively conserve and wisely manage these animals and their habitats is more acute than ever,” Dr. Gobush said.

“The Forest Elephant and the Savannah Elephant are already listed as two separate species on Appendix II of the Convention on Migratory Species,” said Amy Fraenkel, executive secretary of the Convention on the Conservation of Migratory Species of Wild Animals. “We welcome IUCN’s recognition of two distinct African elephant species and hope that it will lead to greater conservation actions for both species. In particular, the Forest Elephant has suffered drastic declines over the past few decades.”

The latest assessments reveal a broad decline in African elephant numbers across the continent. The number of African forest elephants fell by more than 86 percent over a period of 31 years, while the population of African savanna elephants decreased by at least 60 percent over the last 50 years, according to the assessments.

Both species have declined since 2008 due to an increase in poaching, which peaked in 2011 but continues to threaten elephant populations. The ongoing conversion of their habitats to agricultural and other land uses is another threat.

Dr. Dave Balfour, an assessor of the African elephants and member of the IUCN Species Survival Commission African Elephant Specialist Group, said, “While the results of the assessment place the continental population of savanna elephants in the Endangered category, it is important to keep in mind that at a site level, some subpopulations are thriving. For this reason, considerable caution and local knowledge are required when translating these results into policy.”

These latest assessments do show the impact of successful conservation efforts despite the overall declining trend of both African elephant species. Anti-poaching measures on the ground, together with more supportive legislation and land use planning which seeks to foster human-wildlife coexistence, have been key to successful elephant conservation, the IUCN says.

As a result, some forest elephants have stabilized in well-managed conservation areas in Gabon and the Republic of the Congo.

Savanna elephant numbers have also been stable or growing for decades especially in the Kavango-Zambezi Transfrontier Conservation Area, which harbors the largest subpopulation of this species on the continent.