Module 1: Imperiled Species

Question 1

4 major threats driving population declines today

Answer 1

Habitat loss
Overharvest
Climate Change
Invasive Species

Question 2

Define Population

Answer 2

Group of individuals of same species inhabiting the same area

Question 3

Define Population Size

Answer 3

The total number of individuals in a population

Question 4

Define Population Density

Answer 4

The number of individuals in a population per unit area

Question 5

Describe the different types of Population Distribution

Answer 5

If the population is random, clumped or uniform

Question 6

Define Population Trend

Answer 6

The change in population size over time

Question 7

What information is needed to list a species as endangered?

Answer 7

Population size, population trend and long-term population viability

Question 8

What do sample units need?

Answer 8

To be randomly placed, replicated and stratified

Question 9

Why is randomization important?

Answer 9

so that you don’t put the sample units in a place to get the result you want

Question 10

Why is replication important?

Answer 10

when you use multiple samples, you get a more accurate picture of the population. Just one might show biased picture of the pop.

Question 11

Why is stratification imporatant?

Answer 11

You make sure that your estimate reflects the full range of conditions and densities in the area of interest

Question 12

Steps to Listing Imperiled Species in Canada

Answer 12

1) COSEWIC: independent group makes status report
2) Status report reviewed by COSEWIC’s species specialist groups make recommendation to larger COSEWIC Committee
3) COSEWIC makes a recommendation to Fed gov
4) Fed gov holds consultations with affected stakeholders
5) Fed government makes the final decision whether species is listed under Species at Risk Act.

Question 13

Define a deterministic model

Answer 13

a model which doesn’t account for random events

Question 14

Define stochastic model

Answer 14

a model that accounts for random events

Question 15

Define a model with discrete time steps

Answer 15

each time-step is modeled separately

Question 16

Define continuous time in a model

Answer 16

uses rates of change rather than breaking it up in to separate timesteps

Question 17

What are some difficulties in estimating population size?

Answer 17

Not knowing if you’ve counted an animal already
Not knowing if size is representative of the long term
Access to study area
Observation errors - making errors in measuring or sampling design
Process error - errors in assuming what the population trends are due to.

Question 18

Define an observation error

Answer 18

mistakes due to errors in measurement or sampling design

Question 19

Define a process error

Answer 19

mistake due to assumptions about what the population size or trend is due to.

Question 20

Key assumption of exponential growth

Answer 20

growth isn’t limited

Question 21

Describe logistic growth model

Answer 21

assumes carrying capacity (K) that pop can’t exceed. growth slows as it nears K.

Question 22

Describe interference in competitition

Answer 22

type of direct competition. could physically interfere with the activities of other individuals, for example if they have a home range for foraging that overlaps with another individual’s home range

Question 23

Describe exploitative competition

Answer 23

when an individual uses up a resource so that others can’t use that resource anymore

Question 24

Describe apparent competition

Answer 24

when a predator hunts two species, predator abundance will stay high if one of the prey species pops is high, even if the other is low, putting the more scarce species under more stress