How much of Madagascar's forest have we really lost?

There has been much recent debate over the extent to which Madagascar forest cover has disappeared over time. Some estimate that around 80 to 90% of the forest cover is gone (1), while others argue that the number is actually smaller, although still significant (2).

Research Summary

Until recently, it was widely accepted that Madagascar has lost 90% of its forest cover. We now understand that this claim is most likely over-exaggerated, as it is heavily based on unreliable 18th century research. Imaging technology and modern botanical research has helped to produce more accurate estimates that Madagascar has actually lost 50% or less of its original forest cover. Additionally, the 90% claim is harmful to the reputation and wellbeing of rural Malagasy people.

Indris in Anjanaharibe Sud Special Reserve By Lynne Venart

According to McConnell and Kull (2014), it is difficult to measure the net loss of forest cover due to the messy process of integrating conflicting and problematic historical data, satellite imagery, and air photos.

It’s important to note that the 90% loss of forest cover estimate is based on flimsy, biased, and poorly obtained data from 18th century scientific reports (2).

McConnell and Kull (2014) suggest a way to calculate a more accurate estimate of the change over time of the island’s forest cover in order to correct exaggerated and problematic claims about deforestation. By taking into consideration the sociological and historical context of past research, they propose a method for more accurately synthesizing information related to the following two key components for determining the level of deforestation in Madagascar:

Historical accounts of forest cover compared to more recently published data
The development of newer and more precise technologies for measuring the land

What We Know about Madagascar’s Historical Landscapes

At first glance, the literature seems to suggest that we don’t know what Madagascar’s original landscapes really looked like historically or pre-historically. Some colonial research claims the entire island was completely covered in forest (3), while others argue that the grasslands and other non-forest biomes actually existed before human presence on the island (4).

En Route to Anjanaharibe Sud By Lynne Venart

However, there is now quite a bit of empirical evidence to support the latter claim, that Madagascar was originally made up of several different biomes even before humans inhabited the island (4,5).

It is also most likely true that many colonial accounts of the geography of Madagascar are biased and were designed to paint the indigenous Malagasy people in a negative light (2). Additionally, much of this colonial ‘research’ was based on casual observations of the land rather than extensive and accurate mapping (3,6).

Therefore, the island was most likely not 100% forested to begin with (2).

Determining How Much of Madagascar’s Forest has Disappeared

We know that Madagascar has lost some amount of forest cover (7,8,9), but how can we quantify this loss?

To put it simply, it’s complicated. According to McConnell and Kull (2014), this calculation is rather involved and requires a “careful, evidence-based [approach]” that integrates modern and historical imaging technology with botanical data. This analysis cannot rely entirely on outdated colonial claims.

So what is the actual estimate?

“…as much as half – but perhaps much less – of the most easily identified ‘primary’ forest types changed to other land covers during the latter half of the twentieth century (2).”

Thanks to recent research, we also know that between 1995 and 2011, 11% of forest cover on Madagascar has decreased (10).

What is so bad about the claim that ‘90%’ of the forest has been lost?

The exaggerated claim that Madagascar has lost 90% of its forest can be problematic. Its inaccuracy undermines genuine scientific efforts and causes problems for Malagasy people. It has fueled conservation policies that often disparage rural people, silence their voices, and restrict their ability to access resources (2).

“The discourse paints Madagascar first and foremost as a hot spot of biological diversity, environmental degradation, and conservation action. It often relies on a narrative whose roots go directly back to the work of Perrier de la Bâthie and Humbert in the 1920s and 1930s. The story, as they framed it, begins with the original island-wide forest, and then blames the agricultural practices of Malagasy farmers as the primary cause of deforestation, together with colonial logging (2).”

Sources

About the Author

Katie Hallsten is a primate cognition researcher and MSc student at the University of St. Andrews where she studies planning behavior and physical cognition in chimpanzees, orangutans, and macaque monkeys.

She is dedicated to conserving the world’s most endangered primates and hopes to inspire others to do the same.

How much of Madagascar’s forest have we really lost?

Research Summary

Historical accounts of forest cover compared to more recently published data

The development of newer and more precise technologies for measuring the land