# How to calculate the abundance of a formula population? ### How to calculate the abundance of a formula population?

The estimate ofplenty is equal to the quantity of marked individuals divided by the proportion of marked individuals.

### How to calculate the population size?

L’effective total is the number of values ​​within the statistical series. There are 2 methods for calculate the workforce total: Count all the values ​​of the series one by one. Add the workforce of each value.

### What is the main interest of the capture-mark-recapture method?

This method proves most useful when it is difficult to individually count all the individuals in a population and that it is therefore necessary to resort to a statistical estimate. It also makes it possible to obtain other demographic parameters such as birth rate, death rate or the survival rate.

### What is the difference between abundance and dominance?

L’plenty : is the total number of individuals of each species in the total sample. The dominance : the area occupied (using the cover) by a species in a stand, per unit area.

### How to calculate recapture sample size?

If it is assumed that the proportion of marked individuals is identical in the recapture sample and in the total population, the number of the latter is obtained by calculating a fourth proportional.

### What is the capture-mark-recapture method?

The capture-mark-recapture method is often used to estimate the number of individuals in an active and concealed population, such as trout in a lake or voles in a field. Indeed, it is difficult with this type of population to delimit a sampling unit and to count the number of individuals present.

### How to calculate the number of marked individuals during recapture?

According to the Lincoln-Peterson method, the number of individuals marked during recapture is equal to the number of individuals marked after the first capture, i.e.: Example of the Lincoln-Petersen principle for the capture-mark-recapture method

### How to calculate the probability of capture?

The capture probability must be the same for each individual: this probability must be the same for the same capture opportunity but also between the first and second opportunity. The marking must be recognizable, tenable in the long term and must not alter the probability of survival of the species: