12 February 2016, Hobart Tasmania
Also a summary of some key things I learnt.
Climate change impacts are happening now and managers are already responding to them
Talks today and throughout the conference have highlighted that climate-driven change in ecosystems is already under way. Today we saw a few talks showing that while many scientists debate the suitability of management actions like assisted migration, managers are already making decisions.
A series of recent fires in southern Australia is driving a state change away from ash forests explained David Bowman. This “Interval squeeze” of more frequent fires combined with slower plant growth will squeeze out some tree species and they can’t just migrate up mountains. Bowman gave an example of two rapid fires were two successional fires caused a state change, because after the second fire there are no seeds for forest recovery and the Eucalyptus species has poor seed dispersal. The third fire locked in a state change. Managers had to make a rapid decision in just a few weeks over what to do. They spread seed during the key season and have probably reversed the state shift.
Train managers to respond to short-term climate variability, to improve their skill in decision making for long-term change argued Alistair Hobday. His work on identifying seasonal tuna habitat to help avoid bycatch species, has been used in an increasingly sophisticated way over time as managers become more familiar with the model predictions (note: I have just included one pub, but I recommend contacting Hobday if you want the full story as it covers multiple papers).
The prolific tweeter David Watson spoke on linking efforts to improve landscape connectivity for conservation and ecological monitoring two large areas of ecological research that are rarely linked. ‘Connectivity conservation’ is becoming increasingly popular with stakeholders and scientists need to be providing rigorous methods for monitoring their effectiveness.
Multiple stressors and climate change
Nathalie Pettorelli answered Possingham’s challenge from day 2 that we need to study and model Change, not just Climate Change. She is using satellites to detect human impacts that may interact with climate change to drive biodiversity loss, for instance in desert ecosystems.
Tim Clark is doing exciting experimental work to look at the interactive effect of warming and fishing on coral trout mortality. I won’t say more because I think it is in prep, but a hint, he has his finger on the pulse of fish to learn how they respond to warming and fishing stress.
The right models and data are of course key when predicting the effects of multipe-stressors. Lucy Robinson is modelling the distribution of toothfish, to better understand fishing impacts. She found correcting for sampling bias in distribution modelling of toothfish makes a big difference to the predicted effect of temperature on the species.
A range shift in a lobster on the south-west coast of Africa is driving an ecosystem regime shift on rocky reefs and impacting abalone fisheries, Laura Blamey explained. But an interaction with historical overfishing is also contributing. She used models to ‘rewrite history’ (Plaganyi day 2) and found if predatory fish hadn’t been overfished, this regmie shift may not have happened.
The impacts to fisheries are interesting to me, because years ago I naively thought (and others too) the impacts of range shifts on fisheries would not be that significant. If a species moved, fisheries should be mobile enough to follow. That is not how it is playing out. In South Africa Blamey explains, expansion of lobster is creating new opportunities for small scale fisheries but having a large economic impact on the valuable abalone fishery - a different industry that can’t just switch its target species. The transition to a new ecosystem regime can be very painful for society, even if the end point looks ok.
Blamey’s work illustrates that multiple stressors, including climate change, can drive changes in the functioning of ecosytems, which is the next major theme.
Changes in the composition and function of ecosystems
At a global scale, Jorge Molinos used the velocity of climate change to predict the future redistribution of ocean biodiversity. A strength of using this simple model is that it can encompass many species, here Molinos used the aquamaps data to model almost 13 000 species. Importantly, he took a current marine ecoregionalisation and looked at change in species composition in these regions. Ecoregions won’t be the same in the future. He is working on regional testing of the models, for instance in the work presented on day one by Jan Hiddink.
Ivana Matejickova from Czech Republic is finding a native freshwater fish changes to herbivory at high temperatures. Big implications here - the ecological function of species, which we often assume is constant, changes with warming.
Climate-driven invasions can lead to the creation of novel ecosystems, the topic of Richard Hobbs’ talk. The invaders can bring new ecological interactions to an ecosystem, changing the way it functions. Research on climate invasions can learn much from invasion ecology. We don’t have a manual yet for managing novel ecosystems and species translocation, but Hobb’s talk highlights that the status-quo isn’t an option.
That’s it for today. Check out some lessons we learned by way of a conference summary from me.