D

Question 1

Deep percolation

Answer 1

Water draining through soil to underlying permeable rock.

Question 2

Delayed density dependence

Answer 2

The survival, fecundity or migration rates of individuals in one generation are dependent on the density of individuals in the previous generation. An important factor underlying large cycles of predator prey populations.

Question 3

Denitrification

Answer 3

Process where nitrates are reduced to gaseous nitrogen or oxides of nitrogen.

Question 4

Density dependence

Answer 4

Variables, such as fecundity, survival or migration, that change with density and thus influence pop dynamics. Density dependence is required for population regulation.

Question 5

Density independent

Answer 5

Refers to models of population change in which parameters such as survival or fecundity are assumed to not change with density. Eg they are independent of density.

Question 6

Dependent variable

Answer 6

A variable that changes in response to an independent variable.

Question 7

Diazotrophs

Answer 7

Microorganisms that fix nitrogen.

Question 8

Diffusion

Answer 8

Mixing or spreading, usually by unresolved processes.

Question 9

Diffusivity

Answer 9

The rate of diffusive mixing.

Question 10

Discrete logistic equation

Answer 10

Represents a simple math model of regulated pop dynamics. Regulation is achieved by incorporating density dependence into equations.

Question 11

Diurnal average

Answer 11

Average over one day, 24 h period.

Question 12

DON

Answer 12

Dissolved organic nitrogen found in soils, such as amino acids.

Question 13

Dynamic global vegetation model DGVM

Answer 13

A computer model of global vegetation, including dynamic (disequilibrium) effects such as establishment and succession.