Hello Ht. Here is a citation that might contain some useful information. Best regards, Jim Des Lauriers

Survey and monitoring methods for New Zealand lizards M Lettink & JM Monks To cite this article: M Lettink & JM Monks (2016) Survey and monitoring methods for New Zealand lizards, Journal of the Royal Society of New Zealand, 46:1, 16-28, DOI: 10.1080/03036758.2015.1108343 To link to this article: https://doi.org/10.1080/03036758.2015.1108343

For amphibians (frogs) you might want to try:

Here are the common ones

1. Active method (audio or visual encounter survey)

2. Passive method (traps, such as pit fall)

Hello,

besides the previous answers, and integrating some of them, I list some survey techniques used for amphibians and most terrestrial reptiles, inclusive of skinks, in tropical forests, but also in more general contexts.

Active methods

· Visual detection along fixed transects (not the best in tropical environments, but applicable in some context)

· Visual detection without fixed transect, freely scouting a specific area

· Acoustic encounter along fixed transects (amphibians)

· Acoustic encounter scouting a specific area (amphibians)

· Sporadical-opportunistic observations and acoustic records

Other active methods (captures):

Amphibians

· Hand-capture

· Dip-nets

Skinks

· Hand-capture

· Grabber

· Noose

The use of binoculars can be applied in some environmental contexts and cameras are often essential, as photographs of detected or captured animals are an evidence for verifying species identifications.

Obviously, a general knowledge of the potential presence of some species in the investigated area must lead to examine the zone keeping into consideration the general ecology of each taxon:

- specific forest type (e.g., zones where small areas of primary-secondary dry forest, transitional dry to moist, moist forest, human altered forest are close to each other)

- specific habitat (e.g., trees, poles, tree holes, small rivers, and waterfalls, breeding sites)

- best season

Naturally, each point should be examined regardless of the knowledge of the potential presence of some species in the investigated area (hiding places for some amphibians and skinks, poles for tadpoles, etc.).

Other similar, obvious considerations are as follows.

In all cases, the above mentioned techniques are employed in different ways based on:

- forest type

- season and/or the weather conditions

- hour of the day

(e.g., clearly, for amphibians these techniques aren’t employed in tropical dry forests, during the dry season and in full daylight).

To maximize the success of a survey, some artificial environmentscan be used, such as:

· Artificial covers (amphibians)

· Shelters (amphibians and skinks)

· Basking substrates (skinks)

If the transect techniques is used, each transect can be settled basing on the presence of one of these artificial environments.

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Passive methods (amphibians)

· Pitfall traps (eventually with drift nets)

· Funnel traps

· Bottle traps

· Artificial cover traps

· Microphones (vocalizations ;-)

· Camera-traps (very rarely)

Passive methods (skinks)

· Pit-fall traps

· Pipe-trap

· Camera-traps (very rarely)

Here again cameras are essential, as photos of captured animals are an evidence for verifying species identifications.

A general, again obvious, remark is to record the location, date, time, and micro-habitat of each record.

A conclusive short remark is as follows.

There aren’t fixed rules to plan a survey, even though sometimes it’s recommended to involve, if possible, 3 to 6 people for 3-5 days in each survey. The number of surveys and their temporal distance depending on the specificity of the study.

Last but not least, if aiming at creating an erpethological checklist of an area:

Op­portunistic records by local people

Finally, op­portunistic records of various species encountered by local people are useful to create a more exhaustive checklist of the species of an area.

General references

Bennett, D. (1999). Expedition Field Techniques - Reptiles and Amphibians. Geography Outdoors.

Heyer, W. R., M. A. Donnelly, R. W. McDiarmid, L.-A. C. Hayek, and M. S. Foster (1994). Measuring and monitoring biological diversity. Standard methods for amphibians. Smithsonian Institution Press, Washington DC.

Rödel, M.O, Ernst, R. (2004). Measuring and monitoring amphibian diver­sity in tropical forests. I. An evaluation of methods with recommen­dations for standardization. Ecotropica 10: 1–14.

Wilkinson, J. W. (2015). Amphibian Survey and Monitoring Handbook. Pelagic Publishing, Exeter.

Simply three case studies in tropical forest environments

Costa-Campos CE, Freire EMX (2019). Richness and composition of anuran assemblages from an Amazonian savanna. ZooKeys 843: 149–169. https://doi.org/10.3897/zookeys.843.33365

Mira-Mendes CB, Ruas DS, Oliveira RM, Castro IM, Dias IR, Baumgarten JE, Juncá FA, Solé M (2018). Amphibians of the Reserva Ecológica Michelin: a high diversity site in the lowland Atlantic Forest of southern Bahia, Brazil. ZooKeys 753: 1–21. https://doi.org/10.3897/zookeys.753.21438

Rödel MO, Glos J (2019). Herpetological surveys in two proposed protected areas in Liberia, West Africa. Zoosyst. Evol. 95: 15-35. https://doi.org/10.3897/zse.95.31726

I agree with the above, except that sticky traps are inhumane and would not get ethical consent in most institutions. But environmental DNA matching sounds promising too :)

I agree with Matteo Dal Zotto's excellent response and add one additional aspect to is suggestion for "Visual detection without fixed transect, freely scouting a specific area." If you are comparing several areas, these visual encounter surveys should be either time constrained or area constrained. I also agree with Andrew Pegman that sticky traps should not be used because they are inhumane plus they are indiscriminate in the species of animal they capture.