Tropical Christmas Island Red Crabs Impacted by Climate Change

What do land-dwelling Christmas Island crabs have to do with climate change? It turns out these creatures may face some serious complications in the future. Erratic rainfall could be detrimental to animals that migrate with the dry-wet seasonal cycle that breaks up the tropical year.

Each year, Christmas Island red crabs journey from their earthen burrows to the shores of the Indian Ocean. There, they engage in weeks of mating and egg-laying. When the November rains hit, millions of these crabs travel toward the sea. Yet a lack of rain can delay or entirely cancel this meticulous process, which could have serious repercussions for the species.

In order to better understand how changing weather conditions could impact these crabs, the researchers examined migrations data for 36 years that fell between 1919 and 1939, and 1976 to 2011. They predicted the egg-release date for each year and compared the later figures to actual rainfall measurements from 1973 to 2011.

"Potentially there's been a perspective bias in how migratory species are studied, and this particular species represents two perspectives that have not been well documented--species that are migrating because they have to breed in a certain area, and species that are migrating in response to rainfall," said Allison Shaw, one of the researchers, in a news release. "Targeting those two types of migration patterns that have so far been understudied is really what we're hoping to accomplish with this paper, and to encourage more studies in those areas."

In fact, the researchers found that erratic rainfall could be detrimental to animals that migrate with the dry-wet seasonal cycle that breaks up the tropical year. If fluctuations in rainfall become more extreme and frequent with climate change, then scores of animals could be in trouble. For example, the wildebeests and gazelles of Africa could also be impacted by erratic rainfall.

The findings reveal a little bit more about how weather patterns can drastically impact migration patterns. Climate change could potentially be devastating for species that rely on yearly trips for breeding. That said, more research needs to be conducted on this phenomenon as conditions continue to shift and change.

The findings are published in the journal Global Change Biology.