A team of scientists led by a researcher from the University of California San Diego (UCSD) has discovered that over the past three centuries, the Asian elephant’s natural habitat has shrunk by a staggering 3 million square kilometers.
To better understand this dramatic decline, the experts developed new insights from a unique data set that models land-use change over 13 centuries. They discovered that habitats suitable for Asian elephants have been cut by nearly two-thirds within the past 300 years.
At their peak, these elephants thrived in grasslands and rainforests that spanned the breadth of Asia. However, the study, published in the journal Scientific Reports, estimates that more than 64 percent of historic suitable elephant habitat across Asia has been lost due to land-use practices, particularly during the colonial era. Timber extraction, farming, and agriculture reduced the average habitat patch size by over 80%, from 99,000 to 16,000 square kilometers.
According to the research, the remaining elephant populations today may not have adequate habitat areas. In 1700, 100 percent of the area within 100 kilometers of the current elephant range was considered suitable habitat, but by 2015, this proportion had declined to less than 50 percent. This sets up a high potential for conflicts with people living in those areas as elephant populations alter their behavior and adjust to more human-dominated spaces.
De Silva, an assistant professor in the School of Biological Sciences’ Department of Ecology, Behavior and Evolution, and founder of the nonprofit Trunks & Leaves, highlights the dramatic transformation in land use during the 1600s and 1700s, which has consequences that persist even to this day. Researchers from across the globe, including Smithsonian’s National Zoo and Conservation Biology Institute, University of Nottingham Malaysia, Frankfurt Zoological Society, Vietnam National University of Forestry, Wild Earth Allies, Zoological Society of London, and Colby College, also contributed to the study.
Study co-author Professor Philip Nyhus of Colby College noted that the research has implications for understanding the history of elephant landscapes in Asia and their potential future. He also highlighted the collaborative and multi-institutional nature of the research.
While the study’s immediate focus is on Asian elephants, the results can be used to assess land-use practices and develop conservation strategies for all of the area’s inhabitants. Professor De Silva explains that they are using elephants as indicators to examine the impact of land-use change on diverse ecosystems over a longer time scale.
Historical records of the impact of human actions and climate change on wildlife have been scarce, making long-term assessments difficult. The new study is based on information from the Land-Use Harmonization (LUH) data set, produced by researchers at the University of Maryland. This data set provides historical reconstructions of various types of land uses, including forests, crops, pastures, and others, reaching back to the ninth century.
The authors argue that much more work is needed to understand the possible changes facing these habitats in the future. They caution that attempts at habitat restoration need to be guided under a reckoning of social and environmental justice for historically marginalized communities.
“Exploring the relationship between past land management practices and the distributions of elephant ecosystems would be a useful direction for future studies from the perspectives of both ecological and social policy,” they note in the report.
Asian elephants (Elephas maximus) are one of the largest land mammals on the planet, second only to their African counterparts. They are a fascinating and intelligent species with a rich cultural history in many Asian countries. Their historic range once spanned the entire Asian continent, from the borders of Persia to the coastlines of China, and from the Himalayan foothills down to the southernmost tip of the Asian continent. However, due to habitat loss, poaching, and human-elephant conflict, their current range is much more restricted, primarily found in India, Sri Lanka, and parts of Southeast Asia.
Asian elephants have several distinctive features. They are smaller than African elephants, with males typically reaching a shoulder height of up to 3.5 meters, compared to the 4 meters of African elephant males. Asian elephants also have smaller, rounded ears and a more arched back. Another distinctive feature is their trunk or proboscis, a remarkable organ with over 40,000 muscles that serve as an arm-like appendage used for feeding, drinking, communication, and even as a sensory organ.
One of the most significant distinctions between Asian and African elephants is that only some male Asian elephants have tusks, while female Asian elephants do not. This is in contrast to African elephants where both males and females can have tusks. In Asian elephants, the tuskless males are known as ‘makhnas’. The possession of tusks has unfortunately made Asian elephants a target for illegal ivory poaching.
Asian elephants are a keystone species, meaning they play a crucial role in maintaining the biodiversity of the ecosystems they inhabit. They are known as “ecosystem engineers” because of their ability to modify their habitat in ways that benefit other species. For example, by uprooting trees and trampling vegetation, they create clearings that enable new plant growth and provide smaller creatures with access to food and paths through dense vegetation.
These elephants are highly social animals, usually found in closely knit matriarchal groups consisting of related females and their offspring. Male elephants, on the other hand, typically lead solitary lives or form small bachelor groups, and only join female groups during the breeding season.
Sadly, Asian elephants are classified as ‘Endangered’ by the International Union for Conservation of Nature (IUCN). Their population has declined by at least 50% over the last three generations, primarily due to habitat loss and fragmentation, human-elephant conflict, and poaching for their ivory, meat, and hides.
Conservation efforts for Asian elephants include anti-poaching initiatives, maintaining and restoring their habitats, establishing wildlife corridors to connect fragmented habitats, and resolving human-elephant conflicts in a way that is sustainable for both elephants and people.