As you may know, amphibian monitoring is challenging because of the elusive ways of amphibians. Occupancy modeling is designed to deal with this problem. It takes into account the probability that a surveyor will see these camoflauged species when it is there; this is called detection probability.
To achieve this, we survey each catchment two or more times each season, and see how often surveyors detect each species. In general, the more surveys at a catchment, the better estimates of detection probability, which makes for better occupancy estimates. Data can then be used to look at trends in occupancy over time.
The number of independent surveys per visit to a catchment varies with the method used.
In addition to this more intensive amphibian monitoring protocol, we also encourage anyone to submit random observations (sight or sound) of amphibians.
MONITORING: DUAL-OBSERVER METHOD
This is the easiest way to get two independent surveys for each visit to a catchment. If at all possible, we encourage surveyors to visit the catchment twice during the breeding season, which will produce four independent surveys.
Both team members start at the base of the site, or at one side, and walk in different directions, zig-zagging through the meadow or shorelines. When you meet at the opposite end, team members pause for 10 minutes, check water and air temperatures and fill out data sheets. Then, team members switch sides and zig-zag back to the starting point. Then, move on to the next site in your catchment and repeat.
MONITORING: TEAM METHOD
This is ideal for groups of three or more who would like to survey a catchment. Work together as a team to survey all sites in a catchment. This method produces one independent survey per visit (unless you have a lot of people and can re-survey the catchment in the same day or split into 2 teams that work independently). We encourage groups using the team method to visit each catchment two times during the breeding season.
This method starts with all team members along the base of the site, or on one side, and move forward together as one front staying within their imaginary column until everyone reaches the other side. Then, team members pause for 10 minutes, check water and air temperatures and fill out data sheets. Finally, everyone switches spots and repeats the process to get back to the starting point. Move on to the next site in your catchment and repeat.
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Watch this introductory video on why and how we survey catchments, including how it varies with pair or team methods.
A detailed explanation of our study design is available here.