EE Lecture 26: Density Dependence

Question 1

what four major types of population growth patterns exist

Answer 1

exponential
logistic
popn fluctuations
regual pop types

Question 2

give eqtn for exponential growth, involving lamda

Answer 2

Nt+1 = lamda Nt

Question 3

give two eqtn for exponential growth

Answer 3

Nt+1 = lamda * Nt
dN/dt = rN

Question 4

how do you know which exponential growth eqtn to use

Answer 4

depends on whether reproduction exists at discrete time periods (Nt+1 = lamda *Nt) or it is continuous dN/dt = rN

Question 5

which exponential growth eqtn do you use for continuous reproduction

Answer 5

dN/dt = rN

Question 6

which exponentia growth eqtn do you use for discrete reproduction

Answer 6

Nt+1 = lamda * Nt

Question 7

when can periods of exponential growth occur

Answer 7

limited amounts of time when condns are favorable
within the established range of a species - when good weather occurs for several years running
when species reaches a new geographic area, either by dispersing on its own, or with human assistnce

Question 8

what is the flaw in the logistic eqtn

Answer 8

for K to be constant, BR and DR would have to be too
K is a range of values - not a constant
K fluctuates around a mean

Question 9

how can you find density dependence in long term pop studies

Answer 9

if Nt+1 = λ.Nt

Then ln Nt+1 = ln λ + ln Nt =(1.0). ln Nt + ln λ

Question 10

what does a slope significantly

Answer 10

density dependence

Question 11

what is flaw of ln(Nt+1) = ln(Nt)x + ln λ

Answer 11

y and x factirs arent fully independent of eachother

Question 12

can popns persist without density dependence

Answer 12

no

Question 13

do regulating factors have to be density dependen

Answer 13

yes

Question 14

what growth do you have to investigate for exploring density dependence

Answer 14

investigate per capita growth

Question 15

d4escribe graph for per capita growth rate on y, %K popn on x

Answer 15

linearly decreasing per capita growth rate with pop size (negative correlation straight line)

Question 16

describe graph for %K on y, time on x

Answer 16

sigmoidal - logistic growth

Question 17

describe graph for rN(1-N/K) with whol pop growth rate y, %K on x

Answer 17

parabolic change in number of individuals, n shape

Question 18

what are moths a keystone species for

Answer 18

blue and great tits

Question 19

what is K

Answer 19

an additive transformation of mortality

K = -log(survival)

Question 20

what does -log(survival) equal

Answer 20

K

Question 21

how do you do K factor analysis

Answer 21

linear regression of K on log density

Question 22

where do most outbreaks of winter moth popns occur

Answer 22

regularly at higher latitudes and on heather moorland

Question 23

what are the major contributers to biological control of winter moth

Answer 23

indirect effects on pupal predation

Question 24

whyat regulates moth popn in S.UK

Answer 24

pupal predation

Question 25

when is key factor analysis more robust

Answer 25

when supported by simulation modelling

Question 26

what does constant recruitment imply about the popn

Answer 26

v strong regulation

limited spawning @ high density and massive recruitment @ low density

Question 27

discuss Icelanding cod fisheries

Answer 27

recruitment seems to be more or less constant - use stock recruitment curves along with K factor analysis