Wallabies living near humans breed later in the season, potentially missing valuable resources that could mean the difference between life and death for their growing offspring.

New research published last month in Proceedings B that found that light pollution in Australia is putting the tammar wallaby (Macropus eugenii) out of sync with the seasons. Robert and colleagues from La Trobe University in Melbourne studied wallaby breeding near urban areas and in natural bush, and found that human light pollution prevents the marsupials from responding to light cues that normally signal the start of the breeding season. Wallabies living near humans had lower levels of melatonin, a hormone linked to the sleep-wake cycle, and gave birth on average 27 days later than wallabies in wild conditions. The authors say that this may lead to a mismatch between the birth of young wallabies and food availability.

These “phenological mismatches” are a concern for the survival of animal populations worldwide, as climate change and human activities disrupt and disentangle natural signals of seasonal changes. We’ve known about them for a while know, but the more we look the more we find – birds out of sync with their insect prey, insects out of sync with the plants they feed on, plants out of sync with the seasons. If the natural world can’t track the changes human impose on them, our ecosystems may begin to crumble before us. And in some cases, the cracks are already starting to appear.

Want to Know More?

• Robert et al (2015) Artificial light at night desynchronizes strictly seasonal reproduction in a wild mammal Proceedings B