Q 21-30 Flashcards
Outline some of the key threats impacting Australia’s small marsupials with examples
what is a marsupial?
- a mammal that raises newborn inside a pouch
- eg - tassie devils, kangaroos, wallabies, possums
Disease: Devil facial tumour disease & chlamydiosis
- variety of diseases that have a major impact on population numbers
- tassie devils are an example of this with devil facial tumour disease which has declined the population by 50%, and now considered endangered
- parasitic cancer that spreads through biting behaviours when fighting/mating
- Koalas are another example with a bacteria called chlamdyiosis.
- causes respiratory, urinary and reproductive issues, but also can go unnoticed with little clinical signs
- severe cases = death, again affecting population
Habitat loss: koala
- habitat loss has a major effect on population numbers as it causes animals to become vulnerable
- koala’s have a specific diet of eucalyptus trees = no trees = have to migrate = danger of disease spread, more time on ground (hit by cars, dog attacks, etc)
Invasive/introduced species
- Northern quolls population numbers have dropped due to introduced species
- including cane toads (mistaking them for native frogs), feral cats, feral foxes
- also more competition for food/water sources
climate change
- warmer temps can have an effect on behavioural/psychological traits
- can lead to less water/food being available due to heat
human impact
- deforestation = habitat loss
- again causing animals to migrate which can cause future problems
Outline and illustrate the key considerations when planning and implementing a reintroduction project.
what is a reintroduction project?
- purposely releasing a species into the wild where they are able to adapt and survive well in the area
- the goal is to release this species where theyre self sufficient and provide some type of benefit to the ecosystem = boosting biodiversity
Example
- Introducing Western quolls back into the Flinders Rangers to control rabbit populations and again boost biodiversity in that area
Key considerations
- Have a purpose: think about what this project will achieve (good/bad), what will they bring, potentially could go bad in what way?
- Have a clear plan: long process of planning with risk assessments, laying out all possibilities, having a goal, reviewing all stages of process to ensure safety of species
- permission/approval: have to get approval/permission from the right people first. this is why having a plan to present is important as people will have concerns
- sourcing individuals & considering welfare: taking them from habitat to another, therefore need to ensure providing them with livable conditions (correct food sources, climates, places to burrow/hide, predator to prey numbers) & also need to minimise stress as much as possible during the sourcing stage (may need to be transported across states)
- genetics/disease: ensure the species sourced are genetically healthy and no disease, obvs need to be able to reproduce. introducing a disease into the new habitat could cause an imbalance and major issues within the ecosystem. ways to minimise risks and surveillance and quarantine periods. also consider what disease may be present in the ecosystem you’re introducing them to.
- release style - hard/soft: depending on species, there’ll be a preferred release style.
- monitoring the release: how will the species be monitored to ensure they’re safe and it was a successful reintroduction project? through collars and GPS tracking?
Discuss the conservation and management issues of Koalas in South Australia
“koalas are now considered threatened species due to a decline in population numbers, due to a number of threats such as disease, habitat loss and climate change.
Habitat loss:
- habitat loss due to human impact (clearing of land)
- specific diet of eucaplytpus trees = rely on them as major food source
- also their home and shelter
- habitat loss causes them to migrate and seek food/shelter elsewhere = more ground movement = more risk to traumatic injuries (car accidents, dog attacks) & spread of disease (lots in one area)
climate change:
- seeking for more water again leading to migrating
- bushfires = loss of trees = home, injuries, food source, etc
Disease: Chlamydiosis
- Bacteria, also known as chlamydia, spread through reproductive/social behaviours
- causes severe clinical disease causing respiratory, urinary, reproductive problems, but also can show very little clinical signs
- death in worse cases
Disease: Mange
- skin infection caused by parasitic mite
- signs include scratching, redness, hairloss
- limited treatment, can be hospitalised/given antibiotics, euthanasia
Conservation/management:
- specialist hospitals which aim to rehabilitate and release when well
- committed volunteers to help
- research being done to better understand diseases
List the main threats to reptile and amphibian conservation in Australia and overseas
“the status of reptiles and amphibians are continuously changing, with an increase of threatened and endangered species. This is due to a number of threats such as habitat loss, climate change, introduced species and disease.”
Habitat loss:
- Biggest factor due to human movements/clearing of land
- for reptiles: taking away their habitats, they’re exposed, less places to hide/bask safely
- for amphibians: this human movement and clearance is causing contamination of water
- overall restricts normal behaviours for both
Climate change:
- reptiles require sunlight and have a bask in the sun in order to be able to function. warmer temps than usual tho causes reptiles to be heated above their optimal temp, meaning they aren’t functioning like normal and are seeking shade a lot more (when you consider clearance of land too = more difficult)
- specific e.g of turtles, is that warmer climates cause more turtle eggs to be males, causing imbalances within ecosystems
- not just about behaviour then
- Amphibians have less water availability = more exposed to predators and ruins their habitat quality
- they also struggle to regulate their body temp on warmer than usual days
Invasive/Introduced species:
- imbalance of predator to prey numbers, therefore there’s a decline of population numbers
- they have more competition for resources, e.g food, water, shelter
- Invasive fish are a major factor
Disease/pathogens:
- major impact on both in terms of population numbers
- Ranavirus affects both amphibians and reptiles, considered global threat. affects at all life stages, causing gradual organ failure, leading to death.
- Amphibians: a parasitic fungi that opposed a major threat to them and ended up causing major population declines and extinction in some cases. Some amphibian species were asymptomatic, therefore were just carriers of the disease
What are the pinniped species found in SA and how did the populations of two of those species evolve through the last 200 years?
What are found in SA:
- Pinniped = seals
- 3 species found in SA: Aus fur seal, Long nose fur seal & Aus sea lion, focusing on just the last two for this Q
How their populations were effected in 1800s:
- all seal species in 1800s in Aus were exposed to hunting acitivties which were not regulated
- before these activities started, there was little research done therefore weren’t aware of what original population numbers were like
- this lead to a huge drop in populations
- only just saw recovery in these species/populations in 1970, as they were announced a threatened species.
Long Nose Fur Seal populations today:
- researching/monitoring populations easy due to sychronised, annual breeding seasons
- researches use the mark-recapture technique with pups at the end of breeding seasons to get an average number
- over the last 20-30 yrs, there’s been a 5% increase of pups every breeding season
- their populations are slowly getting there with increasing numbers, showing great signs for the future
Australia Sea Lion populations today:
- Australian sea lions have very different breeding seasons compared to Long nose fur seals, making it difficult to research population numbers
- they breed every 18 months, and breeding seasons can last up to 4 to 8 months depending on the individuals, meaning its happening at all different times
- hard to perform surveys and have accurate results
- from what we do know, currently Australian sea lions are only 1/10th of what the long nose fur seal populations are (waaay less)
- there’s been a 24% decline in populations the last 10 years
- listed as threatened species, through research plans are being put in place to help restore numbers
How did the Australian pinniped population evolve over the last 100 years, which mitigation and management strategies were put in place?
- 3 species found in Aus are: Australian fur seal, long nose fur seal & Australian sea lion
- were exposed to hunting practices in 1800s which were unregulated therefore populations dropped
Long Nose Fur Seal populations today:
- researching/monitoring populations easy due to sychronised, annual breeding seasons
- researches use the mark-recapture technique with pups at the end of breeding seasons to get an average number
- over the last 20-30 yrs, there’s been a 5% increase of pups every breeding season
- their populations are slowly getting there with increasing numbers, showing great signs for the future
Australia Sea Lion populations today:
- Australian sea lions have very different breeding seasons compared to Long nose fur seals, making it difficult to research population numbers
- they breed every 18 months, and breeding seasons can last up to 4 to 8 months depending on the individuals, meaning its happening at all different times
- hard to perform surveys and have accurate results
- from what we do know, currently Australian sea lions are only 1/10th of what the long nose fur seal populations are (waaay less)
- there’s been a 24% decline in populations the last 10 years
- listed as threatened species, through research plans are being put in place to help restore numbers
what threats are they facing?
- disease
- climate change
- pollution/oil spills
- fisheries bycatch interactions = mainly what im focusing on
mitigation/management strategies:
- gillnets are the most prevalent material found to effect seals = hundreds found caught in these nets every year
- when caught in this material, prevents them from being able to do normal things, and in worse cases can lead to drowning
- to help prevent the damage these gillnets are causing, the Government started a program in 2010 (Australian Sea Lion program 2010-2012)
- involved setting up cameras on boats to show interactions fishermen had with sea lions (closely regulating them)
- closures surrounding breeding sites to allow seals to exhibit natural behaviours and not be disturbed
- some fishing practices are better suggested to prevent injuries to seals
- consequences put in place if breaching laws/bad interactions with pinnipeds
Why and how were western quolls reintroduced into the Flinders Ranges.
WHY?
- Rabbits were a massive pest = eating everything = ruining biodiversity
- Western quoll was introduced to control rabbit populations & mice
- whole ecosystem approach = control populations and boost biodiversity plants & animals
HOW:
- built a plan and purpose and then had to seek permission/approval/funding
- started in 2014 after recieving approval
- Quolls were sourced in WA through catching/trapping = transported to SA (more and more throughout 2015/2016 were also caught/transported)
- Once arrived in SA, popped in slow release pens (preferred style) and females were released first
- they were collared before release so they could be tracked (where they are, what they’re doing, are they alive) & also camera traps were used
- after 2014 first releases, were successfully controlling rabbit populations and also began breeding, also boosting their own populations
HURDLES:
- feral cats were a predator of the western quoll (sure it was considered but not to the extent of how often it was happening)
- it was a chain = feral cat kills quoll = young either killed too or have no mother, eventually die
- controlled through poisoning = baited the quolls (doesn’t affect them) = feral cats hunt down quoll = kills cats
- at one quolls expense but saves dozens of others
CONCLUSION
- overall a very successful example of a reintroduction project
Describe what are the key planning activities that need to occur in the lead up to a reintroduction and expand one of these activities with an example.
what is a reintroduction project?
- purposely releasing a species into the wild where they are able to adapt and survive well in the area
- the goal is to release this species where theyre self sufficient and provide some type of benefit to the ecosystem = boosting biodiversity
Key considerations
- Have a purpose: think about what this project will achieve (good/bad), what will they bring, potentially could go bad in what way?
- Have a clear plan: long process of planning with risk assessments, laying out all possibilities, having a goal, reviewing all stages of process to ensure safety of species
- permission/approval: have to get approval/permission from the right people first. this is why having a plan to present is important as people will have concerns
- sourcing individuals & considering welfare: taking them from habitat to another, therefore need to ensure providing them with livable conditions (correct food sources, climates, places to burrow/hide, predator to prey numbers) & also need to minimise stress as much as possible during the sourcing stage (may need to be transported across states)
- genetics/disease: ensure the species sourced are genetically healthy and no disease, obvs need to be able to reproduce. introducing a disease into the new habitat could cause an imbalance and major issues within the ecosystem. ways to minimise risks and surveillance and quarantine periods. also consider what disease may be present in the ecosystem you’re introducing them to.
- release style - hard/soft: depending on species, there’ll be a preferred release style.
- monitoring the release: how will the species be monitored to ensure they’re safe and it was a successful reintroduction project? through collars and GPS tracking?
EXAMPLE:
An example of a reintroduction project was reintroducing quolls into the flinders rangers. This was a whole ecosystem approach, as the main goal of this reintroduction was for the quoll to act as a predator to rabbits, which would restore are native plants that were being ruined by them. This reintroduction project therefore had a clear purpose and plan in place with the appropriate permission and approval. The quolls were sourced from WA and transported to SA where a soft release pen was used. The quolls were managed through trapping techniques, while also using camera traps, collars and radiotracking. A downfall in this project was feral cats, however the solution was to use poisoning as a control method. Overall the reintroduction project was a success.
What is rewilding? Give an example of the challenges and benefits linked to rewilding
What is it?
- a planned reintroduction of either a plant species or animal species into a habitat where it has disappeared
- restores ecosystems and boosts biodiversity
- supper important as us humans heavily rely on the services our wildlife supplies: pollination, insect control, breakdowns of waste products
- rewilding approach relies on nature taking care of itself, letting nature do its thing with little human input
Benefits linked to rewilding:
- can effectively control pests using predation technique - controlling populations, preventing overgrazing, preventing disease being spread, preventing competition between native/introduced species = Western quoll & flinders rangers
- introducing/rewilding insectivores to minimise their numbers and therefore damage they cause e.g native birds/frogs
- benefitting soil quality by rewilding/introducing ‘soil engineers’ such as native rodents or reptiles
- Improve seed disperal and boost plant species biodiversity by rewilding/introducing ‘gardeners’ such as native rodents or birds
- pollinators rewilding to help native plant species survive and again boost biodiversity - e.g bats
Risks/challenges:
- there is risk of rewilding going wrong or not as planned. can create further problems within that ecosystem, lead to population decline or disease being spread
- always the risk of introducing a disease along with the animal being introduced, can cause imbalance to ecosystem
- Management costs that come along with rewilding, all the research/planning costs, sourcing costs, monitoring costs
- have to be careful with introducing insectivores as they can cause issues such as crop damage, have to navigate/know whats nearby and if it can cause issues for them
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Which diseases are affecting Koalas?
“Unfortunately in recent years koalas numbers have been declining, and are now considered endangered species. A range of threats are causing this, such as habitat loss and climate change, but disease is considered a major threat too. Diseases that affect koalas includes chlamydiosis, retrovirus, mange and oxalate nephrosis”
Chlamydiosis
- very common bacteria, also known as chlamydia that causes a range of clinical disease
- ocular: conjunctivitis
- Respiratory
- Urinary: kidney/bladder infections = reproduction: can cause infertility
- some show no clinical signs
- transmits through sexual behaviours (direct contact) or faecal-oral transmission
- research still taking place to understand the disease, but treatment includes veterinary treatment (fluid therapy, euthanasia), culling (saves other populations) and vaccinations being trialled
Mange
- skin infection caused by parasitic mite
- clinical signs: scratching, redness/thickening skin, hair loss
- treatment very limited: veterinary treatment (antibiotics, fluid therapy, euthanasia)
Retrovirus
- works by a virus entering the genome of host cells
- spreads two ways: can be passed from mother to offspring (endogenously) or exogenously, which can be from things such as fighting behaviours
- majorly effects the immune system, making koalas very susceptible to cancers evolving
- no treatment currently, undertaking research
Oxalate nephrosis
- kidney disease
- clinical signs: increased thirst, eating less leading to weight loss
- treatment in less severe cases is hospitalisation and fluid therapy, euthanasia in severe cases, upon necropsies can see crystalloids of calcium oxalate in the kidney
