How global warming and climate change will affect sloths? 

How global warming and climate change will affect sloths?

Dr. Cliffe’s research from 2018 determining the metabolic rate of three-fingered sloths was utilized by a team of researchers based in Brazil, working to conserve sloths in the Amazon and Atlantic Forests of Brazil. Dr. Cliffe’s data was modeled against climate change predictions, and data from different ecologists quantifying and predicting current and future land cover and land use in the Amazon and Atlantic Forests were also used.

This paper is truly an amalgamation of many different people and organizations’ work used to draw hypotheses and conclusions about the future of wild sloths.

sloth drinking water
Are sloths drinking more water due to global warming?  / Photo: Suzi Eszterhas

 

The vulnerability to climate change

The paper, Integrating climate, ecophysiology, and forest cover to estimate the vulnerability of sloths to climate change is a great example of how to draw predictions from data without taking raw data out of context.

When all data is compiled together to give a broad, well-informed view of the situation, more reliable and accurate results can be produced. For example, only taking climate change into account, the conditions in some areas would become climatically suitable for the Maned Sloth to live in. What this data modeling doesn’t tell you is that with the rate of land use change occurring, those areas are likely to be deforested, and therefore uninhabitable for the Maned Sloth despite appropriate climate conditions.

 

maned sloth brazil
Maned Sooth (Bradypus torquatus) at Reserva Sapiranga

 

The research also shows how modeling the metabolic rate and behavior of the average mammal against climate change data gives entirely different results than using data specific to sloths. Sloths are extremely specific animals – they are poikilotherms, exclusively arboreal, and record-breakingly slow movers.

However, while multiple variables are modeled in this study, there are still many factors not taken into account which can result in variation of the given results. The inclusion of every possible variable into a model is currently too complex to produce readable results.

 

The results:

The results of this study are represented by the predicted net gain or loss of livable habitat for each species. Despite having similar lifestyles, each species produced different results.

Brown-throated sloths (B. variegatus) – Amazon rainforest

Photo: Suzi Eszterhas

These sloths produced the most promising results by a large margin. Taking global warming and changes in land use into account, a 174% habitat net gain is predicted. It is important to note that this species of sloth is considered to be the most populous and widely distributed of the three sloths considered in this study.

Pale-throated sloths (B. tridactylus) – Amazon rainforest

Pale-throated sloth Bradypus tridactylus. Sloth Island, Guyana. Photo: Suzi Eszterhas

These sloths produced the most concerning results of the three species. A 65% net loss of habitat is predicted. Despite encouraging predictions in a reduction of deforestation of the Amazon, climate change is predicted to cause these areas to become uninhabitable for sloths due to decreased rainfall. However, these animals are still considered ‘least concern’ by IUCN.

Maned sloths (B. torquatus)  – Atlantic forest

maned sloth brazil
Photo: Cecilia Pamich

 

A 7% net loss of habitat is predicted for this species. The Atlantic forest which the Maned sloth inhabits has already lost over 70% of its trees, so while this is the smallest margin found in the study, it is a detrimental loss for the habitat and species living within it. Loss of habitat is the main reason the maned sloth was given ‘Vulnerable’ status by IUCN, and this study has determined that the maned sloth is the most affected by climate change in comparison to the brown-throated sloth and the yellow-throated sloth.

 

Reforestation and forest conservation against global warming

The study predicts that adequate reforestation occurring on the outskirts of their current regions will likely result in a greater distribution of these animals, especially in the case of the maned sloths in the Atlantic Forest of Brazil as the climatic conditions will be favorable due to Global warming. Currently, the Atlantic Forest has been reduced to less than 30% of its original size, therefore reforestation is predicted to be the most effective conservation strategy for this area.

 

maned sloth distribuition
Maned Sloth Distribuition / Image: Instituto Tamandua

 

While the Amazon Rainforest still holds over 80% of its trees, it’s predicted that climate change will transform this damp, neotropical climate into a much drier and sparser habitat, which is entirely unsuitable for sloths, as well as many other rainforest species.

The research clarifies that the dispersal rate (the rate at which sloth populations are able to inhabit previously uninhabited areas) is overestimated, due to sloths’ low reproductive rates.

This study helps to determine whether reforestation and conservation of already standing forests are the best courses of action in order to conserve these already vulnerable sloths – they are!

 

-Amelia Symeou

Ecology Coordinator