Q 11-20 Flashcards
Describe pest bird management in agricultural areas, discuss aims, strategies and challenges.
why are they a pest?
- damage to crops, destroy nearby ecosystems, carry disease
- major loss of income to farmers
- the damage they cause can be variable: depends on how many birds present, seasons, growing stages of crops
what needs to be considered?
- the types of species as they all cause different types of damage
- behaviour of species, what are they attracted to most
- what height is the crop sitting at - they prefer to be up higher
(all the questioning and planning helps build a management plan and come up with best solution to protect crops)
methods of control
- population reduction: can be done through trapping (slow/labour), shooting (doesn’t always scare them) or baiting/poisoning (can lead to off target-kills, welfare problems, public not impressed)
- fruit block/habitat management: involves changing your farm (habitat) to attract bird elsewhere. can include providing birds with an alternative food source (requires planning, understanding birds) which trains birds to feed elsewhere (ideally grow crops before other ones grow)
- scarring: usually loud noises, but can cause stress = more energy output = more damage to crops as eating more. have to understand what sounds will scare them, typically something that sounds like a predator
- exclusion fencing: costly/labour intensive
- do nothing: requires a careful assessment of the damage, the species, can be risky as gets worse before its better
stay vigilant
Why are goats considered as a pest species and how is their population being controlled in Australia?
why are they a pest?
- agricultural damage & environmental damage: eat anything/everything, massive competitor for food leaving nothing for native species, cause soil erosion due to overgrazing, damage to plant species (less diversity), damage fencing to eat crops = loss income to farmers, carry disease
why numbers increase?
- little to no predators: large birds/foxes only take kids, therefore no predators for adults
- also put in exclusion fencing, which means they’re away from dingoes & can also rapidly breed in those areas
- in dry climates in Aus there’s little disease/parasites that infect them
control methods:
note how often controlling populations is performed depends on market pricing at the time, e.g when worth more then more controlling will be done
- judas technique: catching one goat, putting tracker on and release back to others, then feral goats in company will be shot. great to control populations, welfare issues for Judas tho as stressful
- mustering using dogs/horses/motorbikes, etc. gathered into large herds to kill
- trapping/exclusion fencing
- shooting (on land or helicopter)
all these methods are done in conjunction
Why are cane toads (Rhinella marina) considered a pest species and how is their population being controlled in Australia?
- Arrived 1930’s: clear example of an introduced species gone wrong
- released as a biological control to control another pest but are now considered one themselves
- tough/hardy little toads that can live in so many different environments/climates, now found across AUS
why are they a pest?
- firstly reproduce super fast, lay so many eggs that hatch fast, produce a lot of offspring, therefore population numbers are so high
- eat anything! crops = damage to farmers, plant species = less diversity, small native species = less biodiversity, insects = ruining ecosystems - also just compete with others for food in general
- poisonous at all life stages, even an egg, major threat to predators that are native species we want to protect. strong enough to kill anything that ingests them
- transmit disease e.g salmonella (zoonotic)
control:
- both the public and professionals can humanely kill cane toads, under very strict law (sentient beings)
- SOP has been released on how to properly identify a cane toad/how to humanely kill them
- most humane method of control is to trap/catch cane toad, then freeze them (time consuming)
- collecting eggs and disposing of them properly = wont hatch (gets mixed up with other frog species, have to be sure)
- chemical spray that sedates then causes death minutes later
- stun and decapitate
- exposure to carbon dioxide
Why are rabbits considered as a pest species in Australia and how is their population being controlled in Australia?
- Originally introduced to Aus for hunting activities
- due to fast reproduction rates, 50 yrs later were found everywhere = pest
- very adaptive, live in any climate
why considered a pest?
- again: reproduce very fast, produce a lot of offspring
- eat/graze on so much: including crops which is a major loss of income for farmers. also competitor for food for native species then & loss of plant diversity too
- attract predators (feral cats/foxes) which then also hunt on native species in that area
- digging causes soil erosion therefore making that land fairly useless
control:
- exclusion fencing: can reduce population numbers if kept in an area with high amount of predators, not preferred option tho as $$
- trapping: used in conjunction with these following methods:
- baiting: must be done correctly so don’t kill off-target animals, must understand how many rabbits present in area, what attracts them
- destroying habitats: this essentially means the rabbits are exposed, have nowhere to raise young, vulnerable but has to be done with lots of planning/done correctly
- gassing when present in burrows
- shooting: humane/quick if done correctly
Why are cats considered as a pest species in Australia and how is their population being controlled in Australia?
Background
- originally released to control rabbit populations
Why a pest?
- threaten the survival of hundreds of native species from birds to medium sized mammals, including the Western Quoll = loss of biodiversity
- carriers of disease to native species, livestock and humans’
Management problems
- ambush predators = only hunt/stalk live prey whereas other animals its easier to set up baits for example
control:
- trapping: cage or leg hold, to lure them in can use a cat call machine (mimics cat sounds) or chemical lures (through smell). has to be approved as can cause unnecessary suffering in the case of a leg hold trap.
- exclusion fencing: can be bad as trapping lots in small area leads to spread of disease, and great climbers so have to plan and choose correct fencing
- spotlight shooting: have to hold permit, humane if done correctly, can keep track
- aerial baiting: great for large, hard to get to, heavily populated areas. precise delivery of baits with great coverage by using GPS and planning in advance. again, ambush predators, so baiting doesnt always work. can also lead to off-track kills too
What seasonal factors influence mouse infestation levels and impacts in Australian grain crops? Which control measures are effective?
- data shows mouse plagues have become more common over the last 30 yrs = more damage to crops = loss of income
- through research/monitoring, we’ve been able to figure out why/when its worse
seasonal factors:
- high autumn rain: increases the infestation the following autumn
- high rainfall in growing season = more crops available
- high grain yields = again more available feed
- rainfall at the end of growing seasons
how do they predict a plague?
- predictions surrounding weather (e.g high rainfall)
- regional monitoring (is there mice nearby at other farms)
- identifying problem paddocks (what grains they prefer, past issues)
assessing plagues
- counting holes/tracks
- spotlight counting
- using bait cards
control measures - 2 options:
1. managing population numbers: baiting after laying out seeds
2. instead of focusing on managing populations, manage the damage caused instead
- effective weed control
- managing stubble as the mice feed on this
- laying out seeds early & leave stubble so they can feed on that instead
- increase the depth of how the seeds are planted so less accessible
How has reduced tillage affected mouse infestation in Australian grain crops? Which control measures are effective?
Background
- Research has shown mouse plagues have become worse over the last 30 yrs due causing crop damage = loss of income
- apart of why theyve become worse is due to changed farming practices, such as reducing tillage
- tillage is the preparation of soil to prepare for seeding
- it essentially means that the mice actually have easier/more access to feed = more mice
- more feed = more energy = better reproductive output = more mice
- creates a damaging cycle of more mice = more damaged crops
- also means the seeds a buried at a more shallow level = easier for mice
how do they predict a plague?
- predictions surrounding weather (e.g high rainfall)
- regional monitoring (is there mice nearby at other farms)
- identifying problem paddocks (what grains they prefer, past issues)
assessing plagues
- counting holes/tracks
- spotlight counting
- using bait cards
control measures - 2 options:
1. managing population numbers: baiting after laying out seeds
2. instead of focusing on managing populations, manage the damage caused instead
- effective weed control
- managing stubble as the mice feed on this
- laying out seeds early & leave stubble so they can feed on that instead
- increase the depth of how the seeds are planted so less accessible
Are dingoes a pest species or an iconic animal?
background on dingoes:
- pack animals with one dominant male/female
- pack sizes depend on how much food/prey is available
why considered a pest:
- cause economical and environmental problems
- sheep industry: cause major loss of income to farmers as they damage fencing and kill sheep: many have actually gone out of buisness due to this
- hunt down calves as well = loss $
- hunt down feral goats: although considered a pest, worth a bit in the markets but when killed by a dingoe that worth is lost
- spread disease e.g distemper, rabies
- public safety: not too many recordings but a few at camping sites
iconic animal:
- actually do some good for us and our native species
- regulate numbers of invasive/pest species: for e.g feral goats, rabbits
- by hunting down feral cats/foxes, actually doing us a favour by controlling their population numbers and protecting native species
unfortunately due to pest label, control methods include shooting, baiting, exclusion fencing, electric fencing
My final decision: depends what side of the fence you sit on
- as a farmer, absolutely a pest as loss of $
- someone who manages wildlife and works towards protecting species may see them as an iconic species (provide ecological balance)
Give at least one example of how genetic techniques have been used to save endangered species
- so many wildlife conservation projects set up to help threatened/endangered species, where a variety of genetic techniques are used
- wildlife parks and zoos have captive breeding programs which refers to research/planning and working to help improve reproduction rates of these species
- helps to of course increase chance of offspring but can choose strongest genes
- two types of captive breeding programs
1. natural recruitment
2. assisted reproductive technologies
gamete collection and cryopreservation
- collection of sperm (electroejaculation or artificial vagina) or oocytes. cryopreservation then refers to storing these samples at a low temp
artificial insemination
- sperm is collected (electroejaculation/artificial vagina), stored then injected into uterus
- e.g is in 1980 with the giant panda
in vitro fertilisation (IVF)
- eggs are retrieved from female then fertilised with sperm.
- this is more of an intrusive process
advantages:
- increasing reproductive output of individuals
- selective of what genes are chosen
- relatively untintrusive and safe for the animals
Describe the advantages and disadvantages of Assisted Reproductive Technology in threatened species management
What is ART?
- Assisted reproductive technology refers to any fertility treatment involving handling sperm, eggs or embryo’s
- Examples of ART includes gamete collection & cryopreservation, Artificial insemination and in vitro fertilisation (IVF)
- bit of a gap due to financial costs and human resources, but helpful tool in helping boost population numbers for threatened/endangered species
Advantages:
- increasing reproductive input: guranteeing there’ll be offspring, helping increase population numbers
- can breed individuals that wouldn’t usually be able to due to barriers
- selective of what genes are chosen (strongest vs weak)
- can use sick/recently dead animals to save those genes
- screening for pathogens and overall health = healthy, strong offspring
- depending on type of ART chosen, relatively safe and unintrusive for the animal with amazing results
Disadvantages
- can be invasive and painful depending on ART chosen for e.g IVF & don’t want to be causing stress on low populated animals
- requires lots of $$, high tech equipment, trained individuals which can be hard esp for zoo’s who already struggle financially
- if not performed properly, can cause significant problems in individuals but also birth defects in offspring
- success rates can be invariable and low depending on options - can cause therefore unnecessary stress
