Decline of Gomphus Fraternus Fraternus (Odonata: Gomphidae) in Lake Erie

Content Provider	Semantic Scholar
Author	Catling, Paul M.
Copyright Year	2018
Abstract	Collections and literature reports indicate that Gomphus fraternus fraternus was abundant on the shoreline of Lake Erie prior to 1960, and "tens of thousands" were reported at Long Point Bay. After 1960 there were no reports from the shoreline, although there have been a number of compre­ hensive studies that have included the shoreline area and a number of Odonata specialists have also visited the Lak Erie shoreline regularly. A survey 0 . of the Lake Erie shoreline, including the Long Point Bay area in 1 d 2000, during the established peak nd late peak flight pe­ riod in southwestern Ontario, did not result in any observations. It is con­ cluded that G. fraternus has declined substantially in Lake Erie and is possi­ bly extirpated from the lake. Th decline app ars to have occurred between 1950 and 1960, and thus approximates the mid-1950s decline of burrowing mayflies in Lake Erie, which has been associated with warm weather oxygen depletion and pollution. Although it may never be possible to precisely deter­ mine the cause of th decline of G. fraternus, i is likely that a number offac­ tors are involved including climatic warming, pollution, changes to the shore­ line, other effects of shoreline development, and introduced species. A widespread dragonfly, the midland clubtail (Gomphus fraternus frater­ nus Say) occurs from southern Quebec to Manitoba, s uth to Texas and Vir­ ginia. In Ontario it occurs in four general regions: (1) the Carolinian zone north of Lake Erie and eastern Lake Ontario, (2) the Lake Simcoe/Georgian Bay area, (3) the Ottawa valley, and (4) in northwestern Ontario in the Lake of the Woods area (Walker 1941, 1958; Catting and Brownell 2000). The ma­ jority of the Ontario records are from the Carolinian region and within th s region almost half of the records are for the Lake Erie shoreline (Walker 1941). In 1941 Walker noted that G. fraternus was "abundant in Lake Erie", and he cited Point Pelee, Rondeau Park, Fisher's Glen, St. Williams, Long Point, Turkey Point, and Norfolk. In 1958 Walker indic ted that in Canada G. fraternus was "abundant along the shore of Lake Erie, where it is sometimes found in vast numbers." Referring to the shoreline of the inner bay of Long Point, south of St. Williams, he noted that on 22 Ju e 1934, he was "amazed to see the multitudes of of both sexes settling everywhere" along the beach and he reported seeing many pairs in copula. He also noted th t along the shore the "exuviae were lying in tens of thousands". While compiling infor­ mation for an assessment of dragonfly diversity in the Mixedwood Plains eco­ zone (Catling t al.1998), it was noticed that h re were remarkably few, if 12326 Scrivens Drive, RR#3, Metcalfe, Ontario, KOA2PQ Canada. 1 Catling: Decline of Gomphus Fraternus Fraternus (Odonata: Gomphidae Published by ValpoScholar, 2001 2 THE GREAT LAKES ENTOMOLOGIST Vol. 34, No.1
File Format	PDF HTM / HTML
Alternate Webpage(s)	https://scholar.valpo.edu/cgi/viewcontent.cgi?article=2027&context=tgle
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article