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|HOW are you going to measure it?|
In this section you will contemplate the arrangement of the details of a monitoring program. Here you will choose the counting technique, determine the number of sites you will need to sample, and choose an analytical approach. This will be your most difficult task. You will have to confront the inherent variability of your populations, the many types of measurement errors that are a part of every monitoring technique and approach, and the bias, risks, and nuances associated with interpreting the resulting program.
Before you begin considering which technique or approach to use in your monitoring program it is important to understand the difference between monitoring approaches that use population indices and those that use population estimates to track changes.
All monitoring programs, whether they are estimating or indexing population sizes, use counts of some kind. For each species or group of species, several counting techniques exist. Each of those counting techniques can be modified by changing plot size, sampling time, the equipment used, and altering existing protocols. Such modifications both help adapt these general techniques to local situations and can limit the usefulness of the data, when done inappropriately. On our counting techniques page we present a basic description of the technique, estimate of the type and amount of resources necessary to conduct the counts, outline the biases known to be present within the technique, list the equipment needed, cite the pros and cons, present a bibliography, some of the appropriate analytical approaches, and links to specific protocols and programs that use the technique. We also provide a space for you to comment on your own experiences with the technique, and to read others' comments.
One of the problems that loom the largest when starting a monitoring program is determining how many samples you will need to adequately monitor a population. If you put in too few samples, you will not have sufficient data to detect anything but the largest of population changes. If you put in too many, you will be spending money that probably could be used better elsewhere.
Review by a Statistician
Finally, no matter what guidance anyone gives, this web site included, it is always worthwhile to have a second opinion. We strongly suggest that you take the results of your worksheets and have a statistician review them. They will likely have some additional suggestions or detect flaws in your reasoning. It is far better to detect sampling problems at the start of a monitoring program rather than when analyzing the results. Remember, you can never go back and collect new data.
Next step: On to the worksheets.
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