LECTURE 30 : Conservation Flashcards
extinction crisis
IUCN Red List of Threatening species : the gold standard to show the species of different conservation status, extinct endangered etc
28000 species are threatened
background rates in regards to extinction
The rate at which species naturally disappear over a very long time is called the “background rate” of extinction.
michael Soule
foudning pioneer of conservation biology:
requires skills in not only of biolgy, but also humanities, politics, mathematics, jounarlism, philosophy
–> all these areas should work together
aims of conservation biology
- To describe problems and understand processes
- To predict impacts of threats
- To develop solutions: undo the ‘human footprint’
- Ultimately: stop more species / communities /
ecological processes going extinct
Evil Quartet
Jared Diamond’s “Evil Quartet”
of extinction forces
* Alien species
* Over-hunting
* Habitat loss
* Co-extinction
HIPPO
Edward O. Wilson’s “HIPPO” of extinction forces
Acronym based on:
* Habitat destruction
* Invasive species
* Pollution
* Human over-Population
* Over-harvesting
Human over-population is the key difference, and underpins everything else
How is invasion colonising new environments
Deliberate introductions
* Acclimatisation societies (comfort /familiarity= Sometimes, people want to have plants or animals in their new homes that they were used to in their old homes. For example, someone who moves to a new country might miss the types of plants or animals they had back home. Acclimatization Societies try to make them feel more at home by introducing those familiar species to the new environment.)
* Ornamentals/Agricultural/Domestics
* Biological control
Human traffic
* Trade routes [can accidentally carry species with them, like seeds stuck to their shoes or animals in cargo.]
* Ease of global travel
* Poor quarantine
Native invaders
* Success rates for invaders?
The “tens” rule
The “Tens” Rule:
1 in 10 of the plant and animal species brought into a region will escape to appear in the wild
–> 1 in 10 of those escaped species will become naturalised [successfully integrated into the new environment; it’s thriving and reproducing in a way that allows it to maintain a stable population/ adapted well to the local conditions and are considered part of the natural biodiversity of that area.]
–> 1 in 10 of these will become invasive [start spreading aggressively, potentially causing harm to the local ecosystem by outcompeting native species.]
predictiosn for invasice species
Invasive species tend to have characteristics that :
*maximize or enable high reproduction
* enable great ecological dispersal
* enable species to be greatly ecologically flexible [they can adapt to a wide range of environmental conditions. This adaptability allows them to thrive in diverse ecosystems and outcompete native species that may be more specialized.]
* compared to traits of pioneer species in succession
overhunting
Humans over-exploiting wildlife
see them As potential competitors:
see them As food/resources:
* overfishing when fish stocks are depleted due to excessive fishing activities –> Fisheries management is crucial to prevent the collapse of marine ecosystems and to ensure sustainable harvesting
* Overseas as bushmeat, wild meat –> overhunting of certain species
* Overexploitation risks higher in data-deficient systems [areas where information about the population sizes and ecological roles of species is deficient]
Habitat loss and extinction debt
Habitat destruction is the major cause of species extinctions
Island biogeographic theory suggests that:
* reducing habitat area to 10% of its
former extent will eventually cause
about 50% of species dependent
on natural habitat to disappear
- but, these predictions are not
always matched by observations …
[ME : while the theory predicts that when you shrink a habitat a lot, you’d expect many species to disappear, in reality, it doesn’t always happen exactly that way and maybe even when habitats are reduced a lot, not all the species vanish. It can be a bit more complex in real life, and there are other factors at play.
–> In ecology, “extinction debt” is a bit like that credit card bill. It refers to species that are still alive today, but they’re in habitats that have been damaged or reduced. Even though they’re alive now, they might be in trouble because their homes have been changed or destroyed. So, it’s like they have a “debt” or a problem they’ll face in the future. they will still go extinct in the future later on]
Co-extinction
Critical ecosystem functions lost when species are lost
Co-extinction happens when one species goes extinct because it relies on another species that has also gone extinct. It’s like a chain reaction. If one species disappears, it can cause another species that depends on it to disappear as well.
This means that some species in an ecosystem have really important jobs, like helping plants grow, spreading seeds, or pollinating flowers. When these species are lost, it can mess up how the whole ecosystem works.
includes parasites and their hosts
solutions : models
- Models of population dynamics are useful to predict impacts and to identify management options
* Population Viability Analysis
–> Most effective at comparing management options/ it helps identify the most suitable strategies for maintaining or improving population health.
* Minimum viable population (MVP) size : smallest population size that can ensure the long-term survival of a species
* Data hungry process, but very helpful and effective to understand this threshold / It helps determine the minimum population size required to prevent the negative effects of inbreeding, genetic drift, and environmental stochasticity.
Solutions : legislation
- Legislation
NSW Scientific Committee
* List species, populations, communities
- Provides for Recovery Plans
* Identify critical habitat
* List threatening processes
- Threat Abatement Plans [strategies to reduce or eliminate the harmful things (threats) that can hurt the environment.]
Solutions : evidence based
Smart ecological solutions
Evidence-based (evidence-informed)
Addressing causal factors rather than patterns
Integrated Pest management Interrelationships between pests means we can’t
just control one or others will benefit: need good
ecological understanding
Restoration Ecology and Rewilding
Restoration def
“Ecological restoration is the process of
repairing damage caused by humans to the
diversity and dynamics of indigenous
ecosystems”
Restoration goals
- Restoring ecosystems to some pre-impact or reference state (can be problematic as we have seen)
- Enhancing habitat quality
- Restoring ecosystem functions via reintroductions
bauxite mining : restoration
digging big holes in the ground, and remove the bauxite found in the holes.
the goal is to make the land healthy again
–> want to recreate a natural environment, like a forest. –> all the animals and plants that used to live there to come back over time.
Does ecological resotration actually work?
Does ecological restoration work?
* Examining remnants, pastures and restored areas
(3-5 and 8-10 years old) [They’re doing this by looking at different places, some that were restored a few years ago and some that were never damaged.]
* especially focusing on a place called the Cumberland Plain Woodland.
studying bugs and other small creatures in these areas. They’re checking things like who helps in pollinating plants, spreading seeds, and eating pests. They’re also looking at how well these bugs are doing their jobs in the restored areas compared to the undamaged ones.
why the cumberland plain woodland for area to study restoration
It’s considered an “endangered ecological community” under the laws of New South Wales (NSW) = it’s at risk of disappearing.
has lost a lot of its original area.
Less than 5% of it remains, and that’s not much.
Location: It’s part of the green belt around Sydney, which is a big city in Australia. This woodland is like a natural oasis in an urban area.
Iconic and Unique: It’s an important and iconic landscape, meaning it’s a special and well-known place.
Special Species: There are plants and animals in this woodland that can only be found here, and some of them are at risk of disappearing forever.
Threats: There are many dangers to this woodland, like clearing for agriculture (making way for farms), urban development (building cities), and pollution.
effects of revegetation
Structural Attributes: the new plants that grow back may have less variety in their flowers.
Seed Dispersal by Ants function returned quickly: it doesn’t really depend on which types of plants are there, but more on the specific groups of ants that do this job.
Insect Pollination: When new plants grow, they might not be pollinated by the same types of insects as before. But the new insects still do a similar job, just in a slightly different way.
Beetle Assemblages: support “field of dreams” hypothesis where if you build it (in this case, if you plant new vegetation), the beetles will come. In other words, new plants can bring back different types of beetles to the area.
