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Property-Based Monitoring for Dragonflies and Damselflies (Odonata). Bob DuBois Ecological Inventory & Monitoring Bureau of Endangered Resources Dept. of Natural Resources Superior, WI. Why Bother With Odonates? Because people care about them!.
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Property-Based Monitoring for Dragonflies and Damselflies (Odonata) Bob DuBois Ecological Inventory & Monitoring Bureau of Endangered Resources Dept. of Natural Resources Superior, WI
Why Bother With Odonates? Because people care about them! • First, a group of animals captures people’s attention. • Next, field guides and books become available. • Then over time, the pool of people grows who are competent in identification of and knowledge about the group • Odonates are starting to enter this more mature phase of public awareness
Decide on what the objectives will be, what life stages to sample, and who will do the collecting and make the identifications
But you need to know just a little about Odonata life history… An aquatic larva transforms to a terrestrial adult
New adult Dragonhunter emerging from its exuvia Shed larval exoskeleton is called an “exuvia”
Now called a “teneral” Same individual 20 minutes later
Considerations for Sampling Adults • Are present for several weeks to several months depending on species • Warning – they could have flown from elsewhere! • Should be seen mating or ovipositing • Some species are rarely seen as adults • Easiest life stage to identify • May be challenging to sample
Lyre-tipped spreadwings laying eggs into a plant stem
Considerations for Sampling Larvae • Are present for the longest time frame • Indicate a breeding site with certainty • May be very time-consuming to collect • Are the most difficult life stage to identify • Need special equipment and knowledge to identify • May be part-grown and unidentifiable • Current keys to larvae stink
Empire Bog Douglas Co., WI
Ebony boghaunter Williamsonia fletcheri larva
Empire Bog Douglas Co., WI
Considerations for Sampling Exuviae • Are present for the shortest time frame • Indicate a breeding site with certainty • Are often easy (time efficient) to collect • Are difficult to identify as are larvae, except that they are full grown • Least collecting impact ecologically
Searching for exuviae in a sheltered area where they will often persist for a longer time
Ophiogomphus exuviae found at least a month post-emergence
Monitoring recommendations if the goal is a comprehensive species list for a property • Visit a site at least 4 times during flight season (mid-May through September) • Sample adults and exuviae each visit • Larval sampling may help (esp. rivers) • Look for evidence of adult breeding • Choose nice weather days to sample • Sample all habitat types on the property • Bring along a competent odonatist
Identification Helps • Field guides (user-friendly; minimal equipment needed) • Keys (harder to learn to use; more equipment needed) • Internet discussion groups and websites (show your photos; ask questions) • Regional experts (show photos; ask questions; send specimens)
Add the data to the Wisconsin Odonata Survey (WOS) Website http://WIatri.net/inventory/odonata Or Google “Wisconsin Odonata Survey”