Sampling the Mesh Leaf Bags
Mesh leaf bags should be first checked 2 weeks after they are placed within the stream. The second sampling should occur 4 weeks after they are placed into the stream, at which time they should be emptied and removed. To check the bags you will need a fine-mesh dipnet, a 5-gallon bucket, a sorting tray, and several alcohol filled vials. You should begin the sampling at the downstream end of the site. Record the habitat that the mesh bag is in and the amount of the bag within the water, as indicated on the data sheet. Carefully remove the large rocks on top of the first mesh leaf bag, looking for larval and adult salamanders that may be underneath. If you see any salamanders, capture them with your dipnet and move them to your sorting tray with 1cm (~1/2”) of stream water. Be sure to keep track of any larval or adult salamanders that you observe but escape your capture!
Next, carefully and quickly move the mesh bag into your dipnet and shake it for 10 seconds to remove any salamanders within the bag. Place the bag into the 5-gallon bucket containing enough stream water to cover the bag. Remove any captured salamander larvae or adults from the dipnet to the sorting tray. Returning to the mesh leaf bag, shake it in the bucket of water for an additional 10 seconds. Remove the bag and filter the water through your dipnet. Move any captured salamander larvae or adults from the dipnet to the sorting tray.
Identification of adult salamanders captured should not be difficult. Refer to Pfingsten and Downs (1989), Petranka (1998), or Conant and Collins (1991) for help in identifying adult salamanders. Record the species and number of each adult salamander captured on the data sheet. If a camera is available, photographs of adult specimens are very valuable. Return the captured adult salamanders to the stream.
Next, examine the larval salamanders in the sorting tray. Carefully compare all of the larvae you have captured to determine if you have more than one species. It is not necessary for you to identify the larvae caught as a particular species. Instead, you should use the “morpho-species” concept to merely identify different species. For a complete description of the morpho-species concept, click here.
When you have determined the number of morpho-species you have captured, place one representative individual of each type into separate vials of alcohol for preservation. Each jar should already contain a tag identifying the specimen as “Species A,” Species B,” etc. Clearly write the date (including year) on the top of the vial with a permanent marker. On your data sheet, write each morpho-species identification and the number of each captured in mesh bag #1. Release the remaining larvae back into the stream.
Return the mesh leaf bag into the water. If the bag moved from its original location, or if the water level in the stream has changed considerably in the past 2 weeks, you may reposition the bag as needed. DO NOT MOVE THE BAG FOR ANY OTHER REASON! Moving the bag simply because it did not capture any larvae or because another area “looks better” will violate the assumptions being used to analyze the data you are collecting.
Moving on to mesh bag #2, repeat the same process of shaking and rinsing the mesh bag. As before, identify, record, and release any adult salamanders captured. Examine the larvae captured and determine if they are of a different morpho-species than those captured in mesh bag #1. If they appear to be the same there is no need to preserve another voucher specimen. Instead, record the number of each type captured in the appropriate column in the row labeled “2.” If there appears to be a different species, or you are unsure, preserve one representative specimen in a vial of alcohol, assign it a morpho-species identification, and record the number of individuals captured of that type.
Repeat this process until you have checked all 12 mesh leaf bags. During the second sampling period (4 weeks after placing the mesh bags into the stream) you will follow the same procedure, except that you will remove all of the material from within the bag and remove the bag from the stream.
Timing of Sampling
The best time to sample for Ohio’s stream-dwelling salamanders has not yet been definitively determined. The larval period for many species is multiple years, so sample timing may not be important for monitoring those species. Four of the stream-dwelling salamanders have larval periods of less than 1 year, however: Stream-side Salamander; Northern Dusky Salamander; Mountain Dusky Salamander; and Long-tailed Salamander. In order to adequately survey all of the species that may be present at your site, it is recommended that the mesh leaf bags be placed into the stream in mid to late April. This will allow for 2 sampling periods to be conducted prior to June when these three species will be completing metamorphosis.
Next section: Morpho-species concept