Heating Up: Tropical Species Most Vulnerable to Rising Temps

Tropical species will be most vulnerable to rising temperatures, as the discrepancy between physiological thermal limits and projected temperatures is highest in tropical regions, according to a new study.

Despite the fact that in the year 2080 ambient temperatures for the most part will be within plant and animals' tolerant ranges, indirect effects of rising temperatures may counteract that fact, putting tropical species at risk of dying off.

As described in the journal Proceedings of the Royal Society B: Biological Sciences, species become extinct, adapt or move to a different, more suitable habitat when experiencing a changing environment.

To see whether plant and animal species living in the tropics could adapt to warming temperatures, researchers of the LOEWE Biodiversity and Climate Research Centre (BiK-F) and Goethe University selected nearly 460 mammal and bird species and analyzed their tolerated temperature ranges. They accounted for geological distributions, physiological diversity and projected temperature estimates for 2080.

According to the study, 54 percent and 62 percent of the bird and mammal species, respectively, will experience temperatures above their tolerated threshold across 50 percent of their current distribution for a certain period of time.

"However... in 2080 the majority of the analyzed mammal and bird species living in the temperate zones will likely find suitable temperature conditions in a large part of their habitat," Dr. Christian Hof from BiK-F added in a statement.

But they are not off the hook. Rising temperatures may result in negative indirect effects as well. For instance, higher temperatures may bring more pathogens to tropical areas, impacting local food resources necessary for survival. Also, some species - like the Northern Treeshrew from Southeast Asia, whose tolerance is only 7.5 degrees Celsius (45 degrees Fahrenheit) - are already living at their limit.

"Bird and mammal species living in tropical regions tend to live closer to their upper temperature limits," explained lead author Imran Khaliq. "Even small increases in ambient temperatures may therefore challenge their long-term survival."