Due to human activities, elephant habitat has decreased by approximately 67% since 1700, resulting in fragmented populations.

Despite their distinctive stature and long association with humans, Asian elephants are one of the most endangered large mammals. Thought to number between 45,000 and 50,000 individuals worldwide, they are endangered throughout Asia due to human activities such as deforestation, mining, dam construction and road construction, which Many ecosystems have been destroyed.

My colleagues and I wanted to find out when human actions began fragmenting wildlife habitats and populations to the degree we are seeing today. We quantified these impacts by taking into account the needs of the species.

in Recently published studyIn this book, we examine the centuries-old history of Asian landscapes that were once suitable habitats for elephants and were often managed by local communities before colonial times. In our view, understanding this history and restoring some of these relationships may be the key to living with elephants and other large wild animals in the future.

How have humans affected wildlife?

It is not easy to measure human impacts on wildlife across a region as large and diverse as Asia and more than a century ago. Historical data for many species is sparse. Museums, for example, only contain specimens collected from certain locations.

Many animals also have very specific environmental requirements, and there is often insufficient data on these features at a good scale from long ago. For example, species may prefer certain microclimates or plant species that only occur at certain altitudes.

For nearly two decades I was studying Asian elephants. As a species, these animals are amazingly adaptable: they can live in seasonally dry forests, grasslands, or denser rainforests. If we can match the habitat requirements of elephants with data sets that show how these habitats have changed over time, we know we can understand how changes in land use have affected elephants and other wildlife in these environments.

Identification of elephant ecosystems

the home scale sizes Asian elephants can range anywhere from a few hundred square miles to a few thousand. But since we couldn’t know exactly where elephants were centuries ago, we had to model the odds based on where they are today.

By identifying ecological features that correspond to the sites where wild elephants live now, we can discern where they were likely to live in the past. In principle, this should represent the “good” habitat.

Many scientists today use this type of model to determine the climatic requirements of specific species and to predict how suitable areas for these species will change under future climate change scenarios. We applied the same reasoning retrospectively, using land use and land cover types rather than climate change projections.

We got this information from Land Use Harmonization (LUH2) Dataset released by a research group at the University of Maryland. The group defined historical land-use categories by type, beginning in the year 850 — long before states as we know them today emerged, with fewer large population centers — and extending through 2015.

My co-authors and I compiled records for the first time of where Asian elephants were seen in the recent past. Our study was limited to 13 countries that still contain wild elephants today: Bangladesh, Bhutan, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Sri Lanka, Thailand, and Vietnam.

We excluded areas where elephant populations are vulnerable Collide with people, such as intensively cultivated landscapes and plantations, in order to avoid these areas being classified as “good” habitat for elephants. We included areas of lighter human impact, such as selectively felled forests, because they actually contain great food for elephants.

Next, we used a machine learning algorithm to identify the types of land use and land cover present at our remaining sites. This allowed us to determine where elephants might have lived as of the year 2000. By applying our model to earlier and later years, we were able to create maps of areas with suitable habitat for elephants and see how those areas have changed over the centuries.

Dramatic declines

land use patterns It changed dramatically on every continent Starting with the Industrial Revolution in the eighteenth century and extending through the colonial era to the mid-twentieth century. Asia was no exception.

For most areas, we found that suitable habitat for the elephant made a steep dive around this time. We estimate that from 1700 through 2015 the total amount of suitable habitat decreased by 64%. More than 1.2 million square miles (3 million square kilometers) of land has been converted for farms, industry, and urban development. In terms of potential elephant habitat, most of the change occurred in India and China, each of which saw a transformation in more than 80% of these landscapes.

In other areas of Southeast Asia — such as a large elephant habitat hotspot in central Thailand, which was never colonized — habitat loss occurred more recently, in the mid-20th century. This timing corresponds to the simultaneous recording with the so-called Green Revolutionthat introduced industrial agriculture to many parts of the world.

Can the past be the key to the future?

Looking back at land use change over centuries shows us how human actions have dramatically reduced the habitat of Asian elephants. The losses we measured far exceed estimates.”Catastrophic human influences on the so-called wilderness forests in recent decades.

Our analysis shows that if you were an elephant in the 1700s, you might have been able to access 40% of the available habitats in Asia without any problem, because it was a large, contiguous area with many ecosystems in which you could live. This enabled gene flow between many groups of elephants. But by 2015, human activities had fragmented the total area suitable for elephants so significantly that the largest patch of good habitat accounts for less than 7% of it.

Sri Lanka and Peninsular Malaysia have a disproportionately high proportion of wild elephant populations in Asia, compared to the available elephant habitat area. Thailand and Myanmar have smaller populations in relation to the area. Interestingly, the latter are countries known to have large numbers of captive or semi-captive elephants.

Less than half of the areas containing wild elephants today have suitable habitat for them. The resulting elephant use of increasingly human-dominated landscapes is leading to harmful confrontations For both elephants and people.

However, this long view of history reminds us that protected areas alone are not the answer, simply because they are It can’t be big enough To support elephant groups. Indeed, human societies have These landscapes were formed thousands of years ago.

Today there is an urgent challenge to strike a balance between the requirements of living, human subsistence and the needs of wildlife. Recovery traditional forms of land administration And local agency These landscapes can be an essential part of protecting and restoring ecosystems that serve both people and wildlife in the future.

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