Managing Problem Wildlife - Midterm Flashcards
Describe the negative impacts that wildlife can have on forest resources (provide example).
Herbivores can cause damage to all stages of forest regeneration on both free growing plantations and planted or seeded sites.
ex. beavers and mountain beavers, rodents eating conifer seeds
Describe the negative impacts that wildlife can have on food crops (provide example).
Rodents damage the crop themselves, by both eating and the plants themselves and/or the seeds.
Also cause damage to storage facilities holding crop harvest which may cause public health problems and lead to starvation in developing countries
ex. mouse plague in Australia eating seed
Describe the negative impacts that wildlife can have on endangered species (provide example).
Problem wildlife can put added pressure on endangered species by increasing competition, and potentially spreading disease. Species can prey on these vulnerable species.
ex. black rat invaded Lord Howe Island and within 10 years, 40% of island land bird species were eradicated
How does a population increase from first colonizing a site to finally reaching carrying capacity?
Depending on certain factors (competition, predation, and disease) the population will grow at a rapid or slow rate.
What is carrying capacity (K)?
Species population being limited by environmental factors (food, water, shelter, etc.). Once the population reaches capacity on these environmental factors, numbers will begin to drop until resources rebound.
Logistic growth vs. Irruptive growth
Logistic growth: slow ans gradual growth until it reaches carrying capacity, then levels out. requires favourable conditions
Irruptive growth: slow start to rapid growth, until past carrying capacity, then a crash in population, then irruptive growth again. Fluctuating patterns of peaks and crashes.
Explain phase 1, 2 and 3 of logistical growth.
Phase 1 - population introduction
Phase 2 - population growth
Phase 3 - carrying capacity
What prevents a population from growing continuously?
- Available resources (food, water, shelter, mates)
- Carrying capacity
What are the characteristics of a “r” strategist? Provide an example of a r-selected species.
- HIGH reproduction rate
- YOUNGER sexual maturity
- Can sustain higher levels of mortality
- Not competitive
- Direct energy into reproduction
- Eg. voles, rats, mice
What are the characteristics of a “k” strategist? Provide an example of a k-selected species.
- LOW reproduction rate
- OLDER sexual maturity
- Can sustain lower levels of mortality
- Very competitive
- Direct energy into protection
- Eg. deer, bear, cougar
What habitats are “r” strategists adapted for?
- Early to mid successional stage habitats
What habitats are “k” strategists adapted for?
- Late successional stage habitats
Management needed for logistic growth
- Control measures must be sustained over the life of the crop, goods, or structures being protected
Management needed for irruptive growth
- Focus on prediction and monitoring of outbreaks, then tactical use of appropriate control measures may prevent plague
Approaches to managing damage caused by small mammals (state 3).
- Diversionary foods
- Behavioural (how to make the site unfavourable)
- Manipulation (less quality food, use of fences, enhance competition)
Why are toxicants not an appropriate management approach? (state 4 reasons)
- Small mammals are RESILIENT to depopulation
- Hazard to NON- TARGET species
- BAIT may not be accepted
- Increased RESISTANCE to BAIT formulations
Describe resiliency to depopulation.
- Resiliency to depopulation: The ability for a population to absorb change and persist. Individuals may be coming from a different site, so destroying the particular population of concern will not work
Describe recovery ratios.
- Recovery ratios: Number of animals colonizing removal grid at a time
What characteristics make a habitat appealing? (state 4)
- Water: abundance and accessibility
- Food: abundance of good quality
- Shelter: avoid predation (random search, pursuit, refuge)
- Space: little competition
How can a manager reduce attractiveness of food to a pest species?
- Plant undesirable species
- Physical barriers
- Reduce fertilization
- Resistant seedlings
How does addition of complexity to simple habitats help reduce a pest species?
- Could attract competing species which might effect pest numbers
Why is it important to know habitat associations of pest species?
- To avoid creating optimal habitat for pest species
Is burning beneficial for small mammal pest control?
- Burning tends to be beneficial for some species, and less beneficial to others.
Why would diversionary food help reduce damage bioenergetically?
- Animals will prioritize the best and easiest way to get good quality food
Advantages of diversionary food (state 5).
- Can be useful for SEVERAL widely diverse SPECIES
- Rarely has adverse effects
- Favorably perceived by the PUBLIC
- Safe, no hazard to humans
- Eliminates need for lethal control
Disadvantages of diversionary food (state 5).
- Cost can be high (cost benefit ratio needs to be assessed)
- Lure crops utilize land
- May result in increased target population by increasing reproduction and survival
- May attract more individuals
- Target species may become overly dependant
Why is the quality of diversionary food important?
- Food needs to be more palatable than food being protected
- Food needs to be similar or lower nutrients to prevent increased survival and reproduction
