which methods do not use a probability of detection can be m

which methods do not use a probability of detection? (can be more than one answer)

a. census
b. fixed-area plot
c. variable area plot
d. double observer
e. double sampling

I know census is one and I know observer isn\'t one

Solution

(e).Double sampling method is used for the availability not for the probability of detection.Along with the census method which is not used for detection.

Detection probability is modeled as a function of individual covariates. An intercept (0) and a slope (1) parameter are estimated to model the detection process.

A necessary condition for the DS method to provide an unbiased estimate of the total population is that the intensive method yields an unbiased estimate of the total number of birds in units surveyed.

In this we have taken the example of birds for better explanation:-

If some birds present in the survey unit are not detected with the intensive method, the population will be underestimated. The magnitude of the underestimation is directly related to the proportion of the birds detected with the intensive method. If only 90% of the birds in intensively surveyed units are observed, population estimates will on average be 90% of the actual population. Thus, for studies where population size is of primary importance, the DS method will provide reliable estimates only if the intensive method provides an unbiased estimate of all birds present in units surveyed. However, as long as the proportion of birds detected with the intensive method remains constant over time, the DS method will provide an unbiased estimate of population trend.

With the DS method, a population estimate cannot be calculated if no birds are observed with the rapid method in units surveyed with both the rapid and intensive methods or if no birds are observed with the intensive method. In our simulations, these circumstances were most likely to happen with the HC population and a survey proportion of 25% because the HC population contained many survey units with no birds. In field studies, no detections of birds in intensively surveyed units also could happen if the species occurs at low densities throughout the study area. Species present at low densities present challenges for all estimation methods, but for highly clustered populations, a stratified sampling approach can minimize the potential of not observing any birds in the intensive units in the study.