THE DRAGONFLIES AND DAMSELFLIES OF NEBRASKA

Nebraska had been very poorly surveyed prior to 2005 and 63 counties had fewer than 10 records. By 2017 the number of county records had nearly quadrupled, to over 3000 records, the average county total had increased from 9 to 33 and all counties had at least 21 records. An effort was made to collect data more or less uniformly from all 93 Nebraska counties. The areas with intense corn and soybean farming, eastern and southcentral areas, are low in diversity (2130 species per county), the southeast and western half of the state are higher (31-40 species) and the northwestern and northern Sandhill counties are the richest with more than 50 species per county. The present state list of 109 species represents 12 additions since 1998. Eleven 3 Odonates of Nebraska 2019 additional species have been reported from the state, but are considered invalid or have been re-identified. This paper presents a short history of odonate study in Nebraska and an analysis of the data for the 109 species recorded in Nebraska to date. These species are primarily Eastern (37) or species common in the east but transcontinental in distribution (40). The Midwestern species (11) and Western species (17) account for only 16% of the county records. At the Iowa/Nebraska border and more markedly at the Nebraska/Wyoming border, there is an obvious drop-off in eastern species. Eastern species are common to the middle of the state and then drop off gradually to the Wyoming border and very sharply in Wyoming. Transcontinental species (28) going north of Nebraska show a marked Midwestern gap with some species present in western Iowa and western Nebraska with no records in between. The much smaller number of Transcontinental Southern species (12) include 7 of the 10 commonest species in the state. They show no Midwestern gap but drop off precipitously at the Wyoming border. The 17 western species drop off quickly east of the Panhandle at about the 101st parallel.