Rewilding Flashcards
(28 cards)
What is the definition of Rewilding?
“Rewilding is a restoration approach that aims to promote self-regulating complex
ecosystems by restoring non-human ecological processes while reducing human control
and pressures. Rewilding is forward-looking in that it aims to enhance functionality for
biodiversity, accepting and indeed promoting the dynamic nature of ecosystems, rather
than fixating on static composition or structure.”
What is another definition of rewilding?
”Rewilding is the process of rebuilding, following major human disturbance, a natural ecosystem
by restoring natural processes and the complete or near complete food web at all trophic levels
as a self-sustaining and resilient ecosystem with biota that would have been present had the
disturbance not occurred.”
In the lecture, 4 different type of rewilding approaches were listed. What were they?
- Rewilding
- Pleistocene rewilding
- Passive rewilding
- Translocation rewilding
What does rewilding aim at?
rebuilding natural ecosystems, after major human disturbance, by restoring:
- natural processes and the
- complete or near complete food web at all trophic levels
- as a self-sustaining and resilient ecosystem with biota that would have been present had the disturbance not occurred
It accepts the dynamic nature of ecosystems, rather than fixating on static composition or structure
It has open-ended goals in comparison to many other conservation efforts aiming at sustaining a specific species etc.
What does pleistocene rewilding aim at?
Restoring some of the evolutionary and ecological potential that was lost 13,000 years ago. By introducing relatives or functional equivalents of extinct taxa (such as re-introducing the wooly mammoth)
What doew passive rewilding aim at?
Management of ecological succession with the goal of restoring natural ecosystem processes and reducing human control of landscapes
What does translocation rewilding aim at?
It seeks to restore missing or dysfunctional ecological processes and ecosystem function via a process of species reintroduction
How does rewilding try to achieve its aim?
It tries to achieve this by
restoring/ reintroducing
- trophic interactions/ ecosystem processes
- restoring habitats and/ or trophic interactions
- by reintroducing species or functionally similar species to upkeep the processes
often by reintroducing large herbivores or top predators, as the lack/ loss of these has had cascading effects - minimizing human impact, after necessary amount of restoration is done
What is good about rewilding?
- it tries to restore the functioning of ecosystems by natural processes and interactions which is likely to make the ecosystems resilient to changes
- expected to be low cost after initial restoration and reintroduction activities, as to be left alone to evolve as a functional ecosystem
What is challenging with rewilding?
- decide/ define what is the previous state of nature that rewilding aims to bring back, the baseline
- determine the causes for the losses and to ensure they will not happen again, for the reintroduced biota to be able to restore the processes and interactions
- reintroduction of large mammals (herbivores or predators) which may cause conflict with human/ may be difficult to be accepted
Describe the major ecosystem functions in a landscape that is changed by the (re)introduction of megaherbivores
In a lecture the topic of bringing back mammoths was discussed and four of the ecological functions previously provided by them was as follows;
1. Large migrating groups of mammoths moved nutrients (pooping, on feet?), which changed landscape wide patterns of productivity
2. They caused a decreased snow pack on the ground, which caused reductions in ground temperatures.
3. Trampling caused leaf litter decay and soil compaction that then changed decomposition and nutrient cycling.
4. They crushed delicate vegetation such as mosses and made place for more palatable vegetation like grass and herbs.
What is the focus of trophic rewilding?
With trophic rewilding the focus is on restoring trophic complexity mediated by wild, large-bodied animals. Abundant large herbivores would impact vegetation by grazing, trampling and defecating, thus changing the plant coverage (keeping areas non-forested), soil conditions, nutrient cycling, seed dispersal and microhabitats.
With the trophic rewilding approach, why would it be beneficial to bring the woolly mammoth alive and reintroduce it?
- The idea of bringing the woolly mammoth back is to restore the ecological functions the mammoth used to do. The ecological functions are based on mammoth’s large role in the ecosystem by being a very large herbivore. They grazed a lot, keeping areas open, and they travelled long distances, by which they both modified the soil conditions and decomposition by trampling and moving of nutrients.
For trophic rewilding it would be good to have a diverse fauna, to do the above functions in different ways. Thus reintroducing only the woolly mammoth does not serve that idea fully.
What happened to large herbivores and what did their absence cause?
Many large herbivores, including the woolly mammoth, went extinct due to hunting and climate change, and the lack of these herbivores has likely led to a drastic decrease in naturally open areas, and thus caused declines in species dependent on these habitats.
What are some questions that needs to be answered before rewilding can take place?
- What is the aim of the restoration? and how is it defined? (e.g. turn habitat into pristine conditions, what are those? how are they defined?)
- What was the initial cause for the degradation/population decline/malfunctioning and can that be corrected?
- How much money and effort is needed? is it worth it?
What are the 10 guiding principles of rewilding?
- Rewilding utilizes wildlife to restore trophic interactions. Successful rewilding results in a self
sustaining ecosystem - Rewilding employs landscape-scale planning that considers core areas, connectivity, and co
existence - Rewilding focuses on the recovery of ecological processes, interactions, and conditions based on reference ecosystems
- Rewilding recognizes that ecosystems are dynamic and constantly changing
- Rewilding should anticipate the effects of climate change and where possible act as a tool to
mitigate impacts - Rewilding requires local engagement and support
- Rewilding is informed by science, traditional ecological knowledge (TEK), and other local knowledge
- Rewilding is adaptive and dependent on monitoring and feedback.
- Rewilding recognizes the intrinsic value of all species and ecosystems
10.Rewilding requires a paradigm shift in the coexistence of humans and nature
Introducing species is a difficult matter, because it may lead to the need of introducing even more species.
In Mauritius, ecosystem functions were lost due to species loss - What happened and how was it solved?
Anthropogenic extinctions of native species and introduction of non-native species changed the trophic interations, and how the community functioned
When frugivore community composition changed, it affected seed dispersal of native plants. Because the new introduced frugivorous birds were too small to disperse the largest seeds, and many of the new introductions for the plant was with seed predators instead.
To solve this, they introduced another non-native species that could replace the ecosystem functions of big-seed disperal. They introduced a sea tortoise species
In Australia, the introduction of ungulates (sv. hovdjur) created a new issue which had to be solved with more non-native species introductions. What happened?
Historically there were no ungulates (sv. hovdjur) in Australia, only marsupials. With anthropogenic settlement ungulates were brought to the island.
Nearly 500 native species of dung beetles were adapted to marsupial droppings. Which are very different from ungulate droppings.
The droppings from the introduced ungulates could therefore not be taken care of by the native dung beetles. So the dung was left on the soil surface, locking up organic matter, smothering the pasture, polluting water ways and serving as a habitat for flies and parasites.
Exotic dung beetles that could handle ungulate dung were introduced, and now act as important biocontrol preventing flies and parasites from causing harm to cattle.
What is the history of Pleistocene megafaunal extinctions and human hunting? Give an example of how this happened for the wooly mammoth.
50.000 years ago, over 150 genera of megafauna existed. 10.000 years ago at least 97 of those genera were gone.
The reason for this was human hunting coupled with climate change.
Climate change reduced suitable geographical range by 90% for wooly mammoths –> this caused a massive decrease in population size –> causing them to be more vulnerable to increasing hunting pressure from human populations
What is de-extinction?
It is the process of using new developments in ancient DNA sequencing and genetic engineering to resurrect species that once were extinct.
It is so far not possible to produce exact replicas of the extinct species.
What is functional extinction? and what is 2 ways it can happen?
It refers to a situation where a species still has living individuals, but its population has declined to such a low number or is so severely impacted that it no longer fulfills its ecological role or function within its ecosystem. Or looses its population viability.
Loss of ecological role/function:
Ecological role (pollinator, predator) is lost –> causes cascading effect throughout the food web/ecosystem (e.g. flower dependant on pollinator decreases or prey-population increases due to lack of predation pressure)
Reduced population viability:
Lack of reproductive success (can’t find a mate or individuals are past reproductive age)
Reduced genetic diversity (due to small /isolated populations)
Habitat fragmentation (interactions and reproduction is not possible)
What is the imperative difference between functional extinction and true extinction? Why is true extinction hard to determine?
Functional extinction implies there are still living individuals remaining, but the remaining individuals cannot perform its functional role.
- Funtional extinction happens before true extinction and can go on for years or decades.
True extinction refers to the death of every last individual, the species is completely gone from the planet.
- it is hard to determine because you can’t definitively prove something doesn’t exist. No matter how extensive searches are, there’s always a theoretical possibility that a few individuals are hiding in an unexplored area, have adapted to a new habitat, or simply eluded detection.
In which 5 areas can there be potential problems with rewilding?
- Biological diversity
- Biocontrol/invasions
- Economy
- Societal conflicts
- Ecosystem services
What problems does rewilding face in area 1 (biological diversity)? And what are some solutions to those problems?
Problems:
- Unexpected cascading effects
- Uncertain re-wiring of ecological communities after rewilding under global change
- Local extinctions of native/protected species after re-introductions
Solutions:
- More research on species community changes after translocation, on a variety of taxa/environments
- Conservation efforts focused on protection of biodiversity, and reduction of main threats to ecosystem presistence (IAS, land use, overhunting, climate change)
