Jens-Christian Svenning: the world today is divided into regions of ongoing megafauna attrition and megafauna rebounce in other parts of the world
Jacquelyn Gill: really impressive combination of paleo specialists with contemporary ecologists
Chris Johnson: in the modern world we are always being surprised by sudden changes. The paleo world is full of dramatic shocks. If we want to understand how rapidly the world can change we can look at the past.
Mauro Galetti: in Brazil most researchers work in a abiotic world view
Yadvinder Malhi: what is the most important ecosystem effect of megafaunal extinction?
Jacquelyn Gill: Cascading effects on small mammal communities and invertebrates. Impacts on aquatic systems,
Mathias: co-extinction (e.g. dung beetles and mites, giant scavenger birds) and competitive release of other species
Chris Johnson: in Australia the biggest effect was the loss of predators, and resulting increase in abundance of mesopredators. The effect was disastrous for Australia’s ecosystems. Predators are important.
Frans Vera: many herbivores are still considered destructive elements of the ecosystem because we do not understand what is natural. We cull them to homeopathic densities
Sandra Diaz: the megafaunal extinction is yesterday in evolutionary time. With climate change we learn that evolution can be past. Have the megafaunal extinctions affected plant evolution?
Jens-Christian Svenning: we see microevolutionary responses but there are constraints in range of response.
Jens-Christian Svenning: pre-extinction carnivore guilds were hyper diverse, and there is really no modern analogue
Andrew Balmford: in marine ecosystems the megafaunal loss is happening in recent times.Any lessons between the terrestrial and marine worlds?
Jim Estes: something crystallised for him today. When we talking about rewilding today it really is about bringing back carnivores. Now he realised that they were very different systems with big herbivores sitting up on the top. The Pleistocene was a very different system and a very different food web.
John Terborgh. What trophic downgrading means is successive loss of trophic levels. In African forests the herbivore biomass is more than an order of magnitude than it is in South America, In the contemporary world the predators are able to take any of the herbivores and control their populations,
Large animals move nutrients laterally and subsidise poor habitats, but they also hugely accelerate the mobilisation of plant biomass. The recycling greatly short-circuited nutrient cycling. In a post-megafaunal world this is left to detritivores and is much smaller.
Adrian Lister: we heard several examples today of environmental change following megafaunal loss. In these cases one is need of a null, e.g. run a vegetation model responding to climate change
Abby Swann: the models are not up to that yet. The relevant processes aren’t written in.
David Nogoue-Bravo: how far are we are from understanding consequences of shifts in fauna?
Elizabeth Jeffers: we can do that now, even if not very reliable for decision-making at this stage.
Jim Estes: can the oceans be an interesting comparison to terrestrial systems? There are important differences: there has been almost no megafaunal extinction in the ocean (Steller’s sea cow and Caribbean seal). Ocoan trophic structure is very different - the autotrophs turn over so quickly. The ocean sciences community are so focussed on physical forcing that they really consider what what role animals play. The coastal sees may be a useful comparison system.
Blaire Van Valkenburgh: there are lessons to be learnt from marine ecosystems in terms of rebounding effects, importance of redundancy, hysteresis.
Jim Estes: there is still the possibility of megafaunal rebound in the oceans.
Frans Vera: we have a lot of theories and models that should be tested in reality. He has seen that 80% of young die anyway without predation. Let’s practically test the effects.
Rodolfo Dirzo: Janzen’s concept of the living dead. Species lingering on but functionally extinct.
Jacquelyn Gill: we actually do a lot about about the behaviour of extinct creatures
David Nogues-Bravo: what are the possible negative consequences of rewilding?
Jacquelyn Gill: driving species extinctions caused novel ecosystems, reintroducing them will also cause novel ecosystems
Jens-Christian Svenning: it would be easy to undo megafauna introductions if we needed to
Chris Doughty: Human-wildlife conflict is a major issue
Jacquelyn Gill: really impressive combination of paleo specialists with contemporary ecologists
Chris Johnson: in the modern world we are always being surprised by sudden changes. The paleo world is full of dramatic shocks. If we want to understand how rapidly the world can change we can look at the past.
Mauro Galetti: in Brazil most researchers work in a abiotic world view
Yadvinder Malhi: what is the most important ecosystem effect of megafaunal extinction?
Jacquelyn Gill: Cascading effects on small mammal communities and invertebrates. Impacts on aquatic systems,
Mathias: co-extinction (e.g. dung beetles and mites, giant scavenger birds) and competitive release of other species
Chris Johnson: in Australia the biggest effect was the loss of predators, and resulting increase in abundance of mesopredators. The effect was disastrous for Australia’s ecosystems. Predators are important.
Frans Vera: many herbivores are still considered destructive elements of the ecosystem because we do not understand what is natural. We cull them to homeopathic densities
Sandra Diaz: the megafaunal extinction is yesterday in evolutionary time. With climate change we learn that evolution can be past. Have the megafaunal extinctions affected plant evolution?
Jens-Christian Svenning: we see microevolutionary responses but there are constraints in range of response.
Jens-Christian Svenning: pre-extinction carnivore guilds were hyper diverse, and there is really no modern analogue
Andrew Balmford: in marine ecosystems the megafaunal loss is happening in recent times.Any lessons between the terrestrial and marine worlds?
Jim Estes: something crystallised for him today. When we talking about rewilding today it really is about bringing back carnivores. Now he realised that they were very different systems with big herbivores sitting up on the top. The Pleistocene was a very different system and a very different food web.
John Terborgh. What trophic downgrading means is successive loss of trophic levels. In African forests the herbivore biomass is more than an order of magnitude than it is in South America, In the contemporary world the predators are able to take any of the herbivores and control their populations,
Large animals move nutrients laterally and subsidise poor habitats, but they also hugely accelerate the mobilisation of plant biomass. The recycling greatly short-circuited nutrient cycling. In a post-megafaunal world this is left to detritivores and is much smaller.
Adrian Lister: we heard several examples today of environmental change following megafaunal loss. In these cases one is need of a null, e.g. run a vegetation model responding to climate change
Abby Swann: the models are not up to that yet. The relevant processes aren’t written in.
David Nogoue-Bravo: how far are we are from understanding consequences of shifts in fauna?
Elizabeth Jeffers: we can do that now, even if not very reliable for decision-making at this stage.
Jim Estes: can the oceans be an interesting comparison to terrestrial systems? There are important differences: there has been almost no megafaunal extinction in the ocean (Steller’s sea cow and Caribbean seal). Ocoan trophic structure is very different - the autotrophs turn over so quickly. The ocean sciences community are so focussed on physical forcing that they really consider what what role animals play. The coastal sees may be a useful comparison system.
Blaire Van Valkenburgh: there are lessons to be learnt from marine ecosystems in terms of rebounding effects, importance of redundancy, hysteresis.
Jim Estes: there is still the possibility of megafaunal rebound in the oceans.
Frans Vera: we have a lot of theories and models that should be tested in reality. He has seen that 80% of young die anyway without predation. Let’s practically test the effects.
Rodolfo Dirzo: Janzen’s concept of the living dead. Species lingering on but functionally extinct.
Jacquelyn Gill: we actually do a lot about about the behaviour of extinct creatures
David Nogues-Bravo: what are the possible negative consequences of rewilding?
Jacquelyn Gill: driving species extinctions caused novel ecosystems, reintroducing them will also cause novel ecosystems
Jens-Christian Svenning: it would be easy to undo megafauna introductions if we needed to
Chris Doughty: Human-wildlife conflict is a major issue