Species’ ranges changing in a warming world
The world has warmed over the past 50 years and is likely to continue to do so over the coming century. This poses problems for life on land and in the ocean, since most species have a defined range of temperatures within which they can live.
When temperatures exceed the upper limit for a particular species in a particular location, that species can no longer live there. Likewise, places can become newly habitable when temperatures become warmer than a species’ lower limit.
As climate change unfolds over the next century, plants and animals will need to adapt or shift locations to track their ideal climate.
Identifying locations of at-risk species
We worked with an international team of researchers to develop global maps showing how fast and in which direction local temperatures have shifted over the past 50 years. From these climate pathways, we can identify vulnerable environments and the species within them that may be threatened by a changing climate.
Over the past few decades many fish and invertebrate species living in the southern hemisphere have already shifted towards cooler regions. In the waters off south-eastern Australia, range shifts have been observed in around 30 per cent of coastal fish species. On land, species have started to seek relief from warmer conditions by moving closer to the coast, to higher elevations, to shaded hill aspects or further from the equator.
Environmental and economic consequences
Species migration can have important consequences for local biodiversity. For example, warming waters and a strengthening of the East Australian Current have mobilised the long-spined sea urchin (Centrostephanus rodgersii), previously only found as far south as southern NSW, to invade the eastern Tasmania coast. This has resulted in the decline of giant kelp forests with knock-on effects for commercially-fished rock lobsters.
Focusing conservation efforts
Knowing where vulnerable areas occur can help focus conservation efforts and information management decisions.
Areas of slow temperature shifts may be better suited to protecting endemic species or long-lived structural species (such as those forming forests or coral reefs). Areas exposed to significant pressures from climate change may need help to enable climate-driven migration. For species unable to move, assisted movement to new more acceptable places may be needed. For example, active translocation of species, given due care to potential negative ecological and production consequences.
This research provides conservation managers and decision makers a simpler way to look at the effects of climate change on biodiversity, and gives them another tool with which to make informed decisions on how to best manage these changes.