Species everywhere are on the move
Every year we get more evidence that the climate is changing, in the ocean and on land. Reports of heat records, marine heatwaves, declining rainfall and drying landscapes, shifting ocean currents, and intensifying bushfire seasons are becoming commonplace.
Australia’s unique species of plants and animals are already feeling this shift and are showing signs of an ‘adapt, move or die’ response.
In the ocean off eastern Australia at least 70 fish species, sea snails and octopus have already moved much further south. Ocean warming has facilitated the invasion of the long-spined sea urchin and the accompanying loss of giant kelp in the waters off Tasmania.
In 2011, a marine heatwave off the west coast of Australia meant many species were found further south, and an important algal species called Scytothalia dorycarpa, was eliminated from more than 100 km of coast at the northern edge of its range.
On land, the changing distribution of tree species in the Australian Alps, bird distributions across northern and eastern Australia, and the movement upslope of the little known ringtail possum in the Wet Tropics are all signs of changes in the local climate.
Changes in the timing of life-cycle events such as migration and breeding in birds, and population declines in koalas, wetland birds and platypus are a result of heat stress and droughts. Some species have already shifted their geographical ranges and smaller average body sizes have been noted in some bird species. Mass die-off events during days of extreme heat have been recorded in flying foxes and the Roe’s Abalone in Western Australia. In reptiles, a change in the offspring sex ratio has also been linked to increasing temperatures.
In February, scientists from across the spectrum of biological and human sciences, who are working on understanding, predicting and responding to the movement of species in response to climate change, came together in Hobart for the inaugural international conference, Species on the Move.
New research presented showed that prior studies have underestimated the proportion of species impacted by climate change.
Camille Parmesan from the University of Plymouth indicated that every major group studied – including trees, herbs, butterflies, birds, mammals, amphibians, corals, other invertebrates, fish, marine mammals and plankton – showed signs of being affected by recent climatic changes.
She said that approximately half of species studied have shifted their ranges poleward by between 50km – 1600km, or up to 400m upward in elevation. Around two-thirds of species studied have shifted towards earlier spring breeding, migration, or blooming.
Conference Keynote Speaker from the Zoological Society of Lindon, Dr Nathalie Pettorelli said “there’s no question that around the world today, biodiversity is under pressure from a host of causes and most can be put down to human impact from things like climate change, landscape changes and pollution”.
Species on the Move provided an integrated perspective on how climate change is impacting human health and disease, food security, biodiversity of the ocean, our forests, rivers, valleys and mountain tops, as well as the research that will mitigate against some of these changes.
For example CSIRO scientists, working with the Australian Fisheries Management Authority, showed how mapping the ocean habitat of southern Bluefin tuna is a step to preconditioning decision makers to cope with novel climatic conditions and the changed distributions of this species.
Other highlights from the conference included work presented by the US National Oceanic and Atmospheric Administration Marine Fisheries Service and Oceans and Fisheries Canada who are using a rapid assessment scheme to estimate each commercial fisheries species’ overall vulnerability to climate-related changes. The framework for this study emerged from leading work by Australian researchers at IMAS and CSIRO for application to fisheries in south-east Australia.
While serious challenges abound, science offers a range of solutions to minimise the impacts of climate change, by understanding, predicting and responding to species that are on the move.
Recorded keynotes and other selected talks are viewable at speciesonthemove.com