Rising global temperatures have been linked to several critical climate issues, such as an increase in extreme weather events and melting Arctic ice sheets. But a new study has flagged higher temperatures as a direct threat to the gharial population in India.
What’s happening?
According to a team of researchers from the Wildlife Institute of India, increased ambient and nest temperatures are heavily influencing the sex of gharial hatchlings. Warmer climate conditions have led to more female gharials than males, which is affecting the sustainability of the critically endangered species.
Gharials, also known as fish-eating crocodiles, are notable for their distinctively long, narrow snouts. Primarily found in freshwater river systems of India and Nepal, they are well adapted for catching fish, their main food source. However, habitat loss caused by pollution and human activities has drastically reduced their numbers, leading to their critically endangered status.
Gharial eggs are reliant on stable and favorable growing conditions to ensure healthy hatchlings. Incubation temperatures can determine how the eggs develop and how likely they are to survive. With a heavily skewed ratio of female gharial hatchlings, the species may face struggles with breeding, further harming its already dwindling population.
Why is a healthy gharial population important?
Surya Sharma, a project scientist at the Wildlife Institute of India and co-author of the study, spoke to Mongabay about the team’s research. “Our study was prompted by growing concerns from field observations suggesting a female-biased sex ratio in gharials,” Sharma said.
“Since crocodilians, including gharials, have temperature-dependent sex determination, we suspected that rising ambient and nest temperatures, likely driven by climate change and habitat alterations, might be altering hatchling sex ratios and shifting population dynamics,” Sharma added.
As predators and scavengers, gharials can play a vital role in maintaining healthy river ecosystems. Their presence indicates a stable food chain by regulating fish populations, contributing to the overall biodiversity. Without a sufficient number of gharials patrolling waterways, the entire ecosystem may face increasing difficulties.
“A heat wave during the thermosensitive period could push nest temperatures past the tipping point, leading to nest failure or severely skewed sex ratios,” added Sharma. As noted by the Climate Change Knowledge Portal, mean temperatures have steadily increased throughout India since 1901, aligning with the overall warming trend throughout the planet over the same time frame.
What’s being done about rising global temperatures?
In an effort to address rising global temperatures, there has been an increased focus on reducing emissions, adapting to climate impacts, and promoting international cooperation. This includes initiatives such as the Paris Agreement that aim to promote actions such as reducing energy consumption and adopting sustainable practices.
Species such as the gharial are now dependent on the human population to enact change to ensure their survival. “By mapping the relationship between ambient conditions and nest-specific temperatures, conservationists can identify which nests are most vulnerable and target interventions accordingly,” explained Sharma.
“This kind of predictive planning will be vital as we prepare for future climate scenarios and extreme weather events,” Sharma said.
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