By Patrick Yang ‘20

Average annual temperatures worldwide have reached an approximate 1°C increase since 1880 – a shift hardly noticeable to humans, but a harbinger of biodiversity loss in plants and animals, especially in warmer regions. Past models have predicted 0% to >50% species loss due to future climate change. However, the extent of biodiversity loss is much harder to ascertain because of the variety of responses a species may have, including local extinction. Local extinction can be interpreted as simply migration, but it also means that these species cannot adapt to a warmer climate and must migrate in order to survive. As global temperatures continue to rise, there will be less suitable migration destinations and local extinction may escalate to global extinction.

In a new study, Dr. John Wiens of the University of Arizona investigated the current extent of local biodiversity loss. He performed a meta-analysis on 27 studies that recorded the migration shift of 976 plant and animal species. These studies spanned an average of approximately 50 years and observed species that lived in the warmest edge of their climate range. Many geographic regions, including North and South America, Asia, and Europe, were represented in the analysis; an equal amount of studies observing tropical and temperate regions were also included. Warm-edge contraction, or the migration of an entire species to a higher elevation and colder environment, was considered criteria for climate-based local extinction.

Warm-edge contraction, or local extinction, occurred in 47.1% of the surveyed species. Local extinction occurred significantly more in tropical animals than temperate animals – 52.4% of surveyed tropical species fell to local extinction, compared to 38.8% of surveyed temperate species. Animals also had more incidents of local extinction than plants – 50% of surveyed animal species fell to local extinction, compared to 39% of surveyed plant species. With climate increase projected to increase from 1 to 4°C by the end of the century, these current local extinctions have grim implications for the extent of future biodiversity loss.

References:

1. J. Wiens, Climate-related local extinctions are already widespread among plant and animal species. Public Library of Science (2016). doi: 10.1371/journal.pbio.2001104.
2. Image retrieved from: https://www.flickr.com/photos/49399018@N00/4686421824.