DRAGONFLIES (ODONATA) OF THE NORTHWEST TERRITORIES STATUS RANKING AND PRELIMINARY ATLAS PAUL M. CATLING University of Ottawa 2003 TABLE OF CONTENTS Abstract ....................................................................3 Acknowledgements ...........................................................3 Methods ....................................................................3 The database .................................................................4 History .....................................................................5 Rejected taxa ................................................................5 Possible additions ............................................................5 Additional field inventory ......................................................7 Collection an Inventory of dragonflies .............................................8 Literature Cited .............................................................10 Appendix Table 1 - checklist ...................................................13 Appendix Table 2 - Atlas and ranking notes .......................................15 2 ABSTRACT: occurrences was provided by Dr. Rex Thirty-five species of Odonata are given Kenner, Dr. Donna Giberson, Dr. Nick status ranks in the Northwest Territories Donnelly and Dr. Robert Cannings (some based on number of occurrences and details provided below). General distributional area within the territory. Nine information on contacts and locations of species are ranked as S2, may be at risk, collections provided by Dr. Cannings was including Aeshna subarctica, Lestes very useful. congener, Nehalennia irene, Ophiogomphus colubrinus, Somatochlora albicincta, METHODS Somatochlora forcipata, Somatochlora franklini, Somatochlora sahlbergii and The dragonflies (ORDER - ODONATA) in Somatochlora septentrionalis. Many of these the broad and frequently used sense include are widespread and on the edge of their the suborder ANISOPTERA, the dragonflies range in the Northwest Territories. The most and the suborder ZYGOPTERA, the restricted species overall in North America damselflies. Both of these suborders are is the Paleaectic - East Beringian covered here. Somatochlora sahlbergi. Ophiogomphus colubrinus appears rare and local in the The general status ranking for dragonflies of western part of its range. Nineteen species NWT is part of an existing plan for are ranked as S3, sensitive and 7 are ranked additional groups to be covered in the report as S4, secure. The ranking is based on a on general status due in 2005 (Carrière and database of 1040 records each defined as Lange 2002). unique combination of date, location and Ranks are generally assigned using the collector. Rejected taxa and possible procedures manual and using three additions are outlined. Regions requiring categories of information: size, trend and further survey are noted. Information on threat in tables (Carrière and Lange 2002, collecting and inventory is provided. pp. 6-14) and applying guidelines (Carrière Distribution maps for the species in the and Lange 2002, pp. 16-17). The size Northwest Territories are included. information includes population size, number of occurrences, and distribution, this latter being a percentage of the territory ACKNOWLEDGEMENTS occupied. The trend information includes a consideration of trends in both population Help with many aspects of this work was and distribution. Threat includes both threat provided by both Dr. Suzanne Carrière, to population and threat to habitat. Species Ecosystem Management Biologist, Wildlife are assigned a rank corresponding to the and Fisheries, Dept. of Resources, Wildlife most serious risk category of any indicator. and Economic Development , Government of the Northwest Territories and Dr. Lisa In the case of dragonflies there is currently Twolan, Scientific Project Officer, General no specific information on threat, trend and Status of Species in Canada, Canadian population size. Nevertheless specimens in Wildlife Service , Ottawa. Information on several institutional collections have been 3 databased and they provide a means of evaluating number of occurrences and distribution. Using the process (Carrière and Lange 2002), a rank of “S2" indicating “may be at risk” was assigned to species with less than 5 occurrences. A rank of S3 denoting “sensitive” was assigned to either species with 6-20 occurrences, and/or species restricted to less than 10% of the surface of the continental Northwest Territories. Species with more than 21 occurrences and/or occurring in more than 10% of the land area were given a rank of S4 denoting “secure.” Using the database table of 1040 distinct accumulated by Odonata expert Professor (species, locaton, date, observer) records in E.M. Walker when he was working on the ARVIEW-GIS, maps were produced dragonflies of Canada at the Royal Ontario showing occurrences. Approximate Museum (ROM). These were published by distribution areas were then calculated by Walker (Walker 1943, 1947 and 1951), but enclosing occurrences in a poygon for which have not been examined by the author. The area was automatically calculated. This area literature reports were included in the was then expressed as a percentage of the database. There are also specimens in the continental Northwest Territories land Royal British Columbia Museum (RBCM) surface. and a database including 180 reports was provided by Dr. Robert A. Cannings who has examined and verified some of the THE DATABASE mateial, but none of it was seen by the author. A few smaller databases were also In order to provide the basis for a book on accumulated. These provided useful records, the dragonflies of the Northwest Territories, none of which have been verified by the a database of specimens in collections was author. These include 105 records in a completed. It provided a basis for ranking. database at the Spencer Entomological The source of the database is three major Museum (SEM) at the University of British collections which contain a substantial Columbia supplied by Dr. Rex Kenner and number of specimens from the Northwest Ms. Karen Needham, several records Territories. These are the Canadian National supplied by Dr. Nick Donnelly of Collection of Agriculture and Agr-Food Binghamton, New York, and 13 records Canada in Ottawa (CNC) which has the from Dr. Donna Giberson with voucher largest number of specimens from the specimens at University of Prince Edward Northwest Territories. This collection was Island. In summation more than half of the examined and databased by the author. A database includes material at CNC examined large number of specimens were by the author. The rest has been examined 4 and verified by two other acknowledged elsewhere. Odonata experts leaving less than 5% lacking expert verification. A few records in this 5% were dubious and were rejected (see RANKING RESULTS below for an explanation). Thirty-five species of Odonata were assigned status ranks in the Northwest HISTORY Territories based on number of occurrences and distributional area within the territory The earliest publication that gathered (Appendices 1 and 2). Nine species are together the widely scattered Odonata ranked as S2, may be at risk, including records for northern Canada was that of Aeshna subarctica, Lestes congener, Walker (1943) entitled “the subarctic Nehalennia irene, Ophiogomphus Odonata of North America.” Although dates colubrinus, Somatochlora albicincta, were given they did not include the year. Somatochlora forcipata, Somatochlora There are a number of very early reports of franklini, Somatochlora sahlbergii and Odonata from the Northwest Territories. Somatochlora septentrionalis. Many of these Coenagrion resolutum and Somatochlora are widespread and on the edge of their franklini were reported from Fort Resolution range in the Northwest Territories. The most in 1875 by Selys, the former based on a restricted species overall in North America specimen in the Selys collection in Brussels is the Paleaectic - East Beringian (Walker 1925). Fort Resolution is the type Somatochlora sahlbergi. Ophiogomphus locality for both of these species. In 1871 colubrinus appears rare and local in the Selys reported Somatcochlora western part of its range. Nineteen species septentrionalis from Fort Simpson and are ranked as S3, sensitive and 7 are ranked Somatochlora hudsonica from Fort as S4, secure. Resolution. In his North American synopsis published in 1875, Hagen reported Aeshna eremita, Aeshna juncea, Cordulia shurtleffi, REJECTED TAXA Somatochlora franklini, Somatochlora forcipata and Leucorrhinia hudsonica from Leucorrhinia glacialis is listed from Niven Fort Resolution. Lake near Yellowknife in the Royal British Columbia Museum database. The specimen Most of the material from the Northwest was collected by C. Shank on 2 July 1997. Territories in collections was obtained The specimen was not available for during the fisheries surveys of Great Slave verification and is rejected as a probable Lake and during the Northern Insect Survey, misidentification. both of which occurred in the middle 20th century. The major collector was J. R. Enallagma exsulans is listed from Inuvik, Vockeroth, Research Scientist with Northwest Territories, in the Royal British Agriculture and Agri-Food Canada. A Columbia Museum database. The specimen detailed history of the survey of Odonata of was collected on 18 Aug. 1985 by S. the Northwest Territories will appear Laycock. It is rejected as a probable 5 misidentification A. eremita. They differ from