H
WILDLIFE IN BRITIS COLUMBIAAT RISK
Rare Dragonflies of British Columbia
British Columbia is home to species of dragonflies; of these are considered rare or potentially at risk.
Ministry of Sustainable Resource Management Ministry of Water, Land and Air Protection support the most species. The aquatic thorax (damselflies) or by the top of larvae are predacious and are armed the head (dragonflies) with the with an enormous hinged labium claspers at the tip of his abdomen. The (sort of a lower lip), which is used female loops the end of her abdomen ven though dragonflies are predomi- as an extendible grasping tool for up to the base of the male’s abdomen, nantly a tropical group, and even capturing prey. Larvae are voracious, where the sperm is stored and trans- though they are one of the smaller eating small aquatic insects, crus- ferred. The Odonata are the only insects Einsect orders, British Columbia is taceans and even fish. Larvae can be that mate in this “wheel position.” home to 87 species, roughly 40 percent of divided into three categories accord- The female lays the eggs once they the Canadian total. Twenty-three species ing to their feeding strategy: climbers are fertilized. All damselflies and some are considered rare or potentially at risk stalk through vegetation; sprawlers dragonflies (mainly the darners in the and have been placed on the provincial ambush prey while sitting on bottom family Aeshnidae) have a knifelike Red and Blue lists. In this brochure we sediments or debris; and burrowers egg-laying structure, called an ovipos- look at the nine Red-listed species. wait under cover itor, at the tip of the abdomen. They The Odonata of sand and mud. lay their eggs in plant tissue of various Introducing dragonflies After 10 to 15 sorts. In many species, the male often he insect order Odonata and their moults, the full- retains his hold on the female while (Greek for “toothed jaws”) ancestors are grown larva crawls she lays her eggs, guarding her from contains the groups of insects out of the water other males who may attempt to mate Tknown as the dragonflies and some of the up a plant stalk or with her. Some female damselflies damselflies; however, we also use most ancient some other sup- actually crawl below the water surface the name “dragonflies” to refer to port. The skin on to escape the attentions of males, the whole order. The Odonata is a of insects – its back splits open remaining there for over an hour to small order of about 5000 named fossil records and the adult lay their eggs. They can take a film of species and 23 families worldwide. dragonfly squeezes air down with them, trapped in the The Odonata and their ancestors go back more out. The newly- hairs on their body. Species lacking are some of the most ancient of than emerged dragonfly ovipositors usually just dip the tip of insects. Fossil records go back to pumps blood into the abdomen into the water and wash more than 300 million years ago, million years. its wing veins and off the eggs,which then sink to the bottom. predating dinosaurs by more than the wings expand. For many of the damselflies and 100 million years and birds by some 150 Gradually the body hardens, and some dragonflies in million. Dragonflies have many primi- after an hour or so the dragonfly The most the province, the tive features, but also possess many can fly. It leaves behind the life cycle takes about specializations that reflect their aerial empty larval skin, or exuvia. serious stress a year. Spreadwing and predatory lifestyle. The order is Adults are aerial, visually ori- on dragonfly damselflies (Lestes) divided into two suborders in British ented predators: they are large, and some meadow- Columbia: the damselflies or Zygoptera strong-flying insects with huge populations hawks (Sypetrum) (“joined wings”) and the true dragonflies eyes, strong mandibles and spiny has been the overwinter as eggs, or Anisoptera (“unequal wings”). Dam- legs. They prey on a wide range hatch in the spring selflies are slimmer, usually smaller and of flying insects, which are usu- elimination and emerge as ad- fly more slowly than dragonflies. At rest, ally captured in flight. Adults are or alteration ults in the summer. their equal-sized wings are usually held often colourfully patterned and Others overwinter together above the body. Dragonflies are exhibit a wide variety of behav- of their as larvae and em- robust and often fast-flying. Their hind- iours. Mature males patrol the freshwater erge the following wings are broader than their forewings breeding habitats, aggressively spring or summer, and, when perched, they hold their searching for mates and may, habitats. and some, under wings out away from the body. like birds, defend a territory certain conditions, Dragonflies live in and around against other males. will overwinter two years. The larval most types of fresh water. Ponds and When a male is ready to mate, he stages can last four or five years for marshes rich in aquatic vegetation grasps a female by the front of the the larger dragonflies, such as darners (Aeshna) or emeralds (Somatochlora), many of which live in cold mountain or northern waters where summers are short. In British Columbia, adult drag- onflies live for about one to two months. The larva of the Olive Clubtail burrows in the sand and silt of rivers and lakes in the warmest valleys Where do they live of the southern interior. in British Columbia? wetlands in the province – 175 000 populations are vulnerable and this ifferent dragonfly species have differ- hectares flooded in the Peace River damselfly has almost certainly been ent habitat requirements. Some system, 91 000 ha in the Nechako extirpated from some developed tolerate only a narrow range of con- system and 102 000 ha in the Colum- springs, such as those at Radium. Dditions, whereas others live in a wide bia system. These reservoirs have Many species breeding in small, range of ecosystems. Some key habitat eliminated populations of almost all often temporary ponds or spring-fed types in British Columbia that have dragonfly species on the provincial streams in grasslands and dry forest distinctive dragonfly faunas are: large, list. Dams not only inundate wetlands, have been adversely affected by cattle warm lakes; small lakes and ponds with lakes and streams upstream, but also that trample and pollute these habitats. floating vegetation; alkaline (saline) completely alter the natural flow The Vivid Dancer is especially vulner- lakes; cattail and bulrush marshes; sedge regime downstream. Since Montana’s able to these effects, since outside of marshes; warm creeks and rivers (e.g., Libby Dam eliminated the spring hot springs it is known from only a those that drain lakes); small springs and freshet of the Kootenay River through handful of tiny, spring-fed streams in seeps; temporary ponds; bog and fen the Creston Valley, the large marshes Interior rangelands, all of which are ponds; and shallow sedge-moss fens. that remain along the river are potentially affected by the activities of (Bogs are acidic peatlands low in nutri- now artificially maintained in a series cattle or horses. ents and dominated by sphagnum moss- of dyked impoundments. These are Logging and associated road build- es. Fens are richer, less acidic peatlands drained periodically and their dragon- ing can result in streams with less dominated by sedges, grasses and non- fly communities are undoubtedly stable flows, warmer water tempera- sphagnum mosses.) different from those that existed tures and higher silt loads, all of which before the dam was built. negatively affect dragonfly larvae. Why are dragonflies at risk? Hundreds of smaller, high-elevation Logging has also likely affected the com- he most serious stress on dragonfly dams built to supply water to lowland munity structure in peatlands, marshes populations has been the elimination communities have flooded peatlands, and lakes, especially at higher elevations. or alteration of their freshwater ponds, shallow lakes and slow streams. Fish are major predators of dragonfly Thabitats. Most destructive has been They have eliminated the drag- larvae, so the energetic the draining and filling of marshes. onflies of these diverse ecosys- Detailed programs to release sport Many of the richest marshes and ponds tems, replacing them with a few fish into a large number are associated with flat floodplains, and of the more common, ubiqui- and of lakes in British Col- these wetlands are often sacrificed to tous species characteristic of focussed umbia (many originally road and railway construction, commer- montane lakeshores. fish-free) must have had a cial and residential development and Many natural lakeshores inventories significant effect on both intensive agriculture. For example, only have been destroyed, mostly for of species the abundance of Odon- about 15 percent of Okanagan Valley housing and swimming beach- ata and the composition wetlands remain and most of those left es, reducing the habitat avail- and their of the communities in have been significantly altered by water able for many lake dwelling habitats these lakes. The poisoning flow changes. The channelling and dyk- dragonflies, particularly in the of aquatic communities ing of the Okanagan River for most of its warm southern valleys. are urgently to preparelakes for sport length between Penticton and Osoyoos Humans almost always needed. fish introductions in past Lake has eliminated much habitat for a modify hot springs. In British years also likely had a sig- number of Red- and Blue-listed species. Columbia, the Vivid Dancer, Argia nificant impact on dragonfly populations. Large hydroelectric and flood-control vivida, is largely restricted to the out- The aquatic communities of many dams have destroyed many lowland let streams of hot springs. The small systems that historically contained fish have also been altered by the many other localities in the region. purposeful or accidental introduc- Adults fly with a dancing, butterfly-like tion of non-native fish species. Some flight and perform striking courtship of these species not only eat many displays. Females lay eggs in floating dragonfly larvae, but also alter the mats of vegetation. The stiff, elongate habitat structure. For example, carp larvae cling to aquatic plants, roots and were introduced into the mainstem woody debris. lakes of the Okanagan in 1917 and subsequently destroyed or reduced Vivid Dancer Dennis Paulson photo much of the native aquatic vegetation. Argia vivida Climate change will drastically The Vivid Dancer is a large, bright blue represents part of a larger population affect present Odonata distributions damselfly of the mountains of western stretching eastward, but the species is as lowland water bodies dry and North America. In southern British otherwise unknown in Canada west of water generally becomes scarcer. A Columbia it is associated with warm or Saskatchewan; surveys in the interven- significant component of the dragonfly hot springs from Meager Creek in the ing territory have failed to find it. It is fauna of the province lives in grass- southern Coast Range east to the Rocky adept at colonizing new habitats such as land ponds and marshes and small Mountains. Because of the large number cattle ponds and flooded gravel pits, lakes in the lowlands, many of which of hot springs in the Kootenays, the and has spread significantly northwest- will probably disappear in any drying bulk of the province’s population lives ward in North America in recent years. trend. The extensive dragonfly popu- lations in montane and northern Plains Forktail peatlands will have similar problems. Ischnura damula The Plains Forktail is a small dam- Red-listed dragonflies selfly of the Great Plains, the American in British Columbia Southwest and the eastern slope of the River Jewelwing Rocky Mountains. Males are blue, Calopteryx aequabilis green and black. However, it is known The jewelwings are the largest and most from only a single locality in British George Doerksen photo, Royal BC Museum spectacular damselflies in Canada. The Columbia – Liard River Hot Springs in River Jewelwing is British Columbia’s there. Adults perch frequently on stones the far northeast. Perhaps it was more only representative of the family. It has or on the ground near the water, and widespread in the northern part of its a metallic green body with blue reflec- the females, when laying eggs in under- range seven or eight thousand years ago tions, broad wings darkened at the tips, water vegetation, often submerge for when the climate was warmer, but with and long, black legs with impressive long periods. The larvae live in the spines. The River Jewelwing is mostly streams and pools draining the springs. found in eastern North America, but Humans almost always develop, divert there are a few western populations. or otherwise modify hot springs, and It is known only from one site in the the Vivid Dancer’s small populations province: Christina Creek at the outlet are threatened by these habitat changes. of Christina Lake. Because this species requires warm, slow-moving streams, Familiar Bluet it probably will not be found in Enallagma civile The Familiar Bluet is a wide-ranging North American damselfly found from southern Canada south to South America and the Caribbean. In British Columbia, however, it is apparently exceedingly rare, known only from Bridge Lake in the southern Cariboo region. Logically, this record probably Netta Smith photo George Doerksen photo, Royal BC Museum climatic cooling its populations have sandy or muddy edged rivers or lake- several sites in the central Rockies and shrunk in the region, today holding out shores in hot, dry areas, where the larvae on the Nechako Plateau. In the Rockies, only at this one thermal spring. burrow in the substrate. Adults fly out the Forcipate Emerald breeds in shal- over the water and land along the shore low, spring-fed streamlets, often only Grappletail or, more commonly, on trees and Octogomphus specularis shrubs near the water. Its worst enemy The Grappletail is a yellow and black is the modification of riverbanks dragonfly that ranges from the extreme and beaches. The channelling of the south coast of British Columbia south Okanagan River in the 1950s probably seriously reduced its numbers.
Quebec Emerald Somatochlora brevicincta For years since its discovery in the Blair Nikula photo 1950s, the Quebec Emerald was only 20 to 30 centimetres wide, trickling known from remote fens in central through subalpine hillside fens, or in Quebec. In the 1990s, dragonfly surveys tiny pools associated with flowing found it in scattered localities in eastern groundwater in such situations. George Doerksen photo, Royal BC Museum to Baja California. The almost all-black Kennedy’s Emerald abdomen, the broad pale stripe along Somatochlora kennedyi the middle of the top of the thorax Better known in eastern Canada and the and the strikingly broad, spiny tip to northeastern United States than in the the male’s abdomen all make this an West,Kennedy’s Emerald is uncommon unusual western gomphid dragonfly. throughout its range. Most western col- In British Columbia it lives only along lections are from the Yukon, but there is streams flowing swiftly out of warm a single record from the Fort Nelson Sid Dunkle photo lakes nestled in the hills bordering the lower Fraser Valley. The larvae live Canada and Maine, and in 2000 it was among stones and boulders in creek discovered unexpectedly far to the west riffles and pools. Adults perch on stones in British Columbia. It flies in small along the stream or on tree branches numbers around mossy, slightly acidic away from water. pools in a handful of localities from the Cariboo and Rocky Mountains near Olive Clubtail McBride, north to the Nechako Plateau Stylurus olivaceus and Omineca Mountains. Probably it A dragonfly of western valleys and is a rare inhabitant of mossy fens right plateaus in North America, the Olive across the southern boreal forest of Clubtail is known in British Columbia North America. only from the Thompson-Okanagan Robert A. Cannings photo and Boundary regions. It lives along Forcipate Emerald area in northeastern British Columbia. Somatochlora forcipata In the West, this is a species that prefers The Forcipate Emerald is mostly known to breed in shallow, moss-bottomed as an uncommon dweller of spring-fed pools in sedge-dominated fens. streams in the forests of eastern Canada and northeastern United States. How- What can we do? ever, it also lives in the Rocky Mountains irst, we must discover more about of Alberta and British Columbia. First our rare dragonflies – where exactly discovered in British Columbia in Yoho they are and what sort of habitats Dennis Paulson photo National Park in 1998, it is known from Fthey need. Detailed and focussed inventories of species and their habitats are urgently needed. It is critical to study the exact habitat requirements of each species and then to protect, conserve and, where possible, increase the number of suitable habitats. The habitat requirements of some dragon- flies are narrow and these are obviously the species that are most at risk. Other species are wide-ranging in their needs and will survive in many habitats. Dragonfly conservation means habitat conservation. Rob Cannings standing at a small spring-fed The important collections of speci- Here one of the last remnants of the once extensive streamlet near Ross Lake, Yoho National Park, Penticton Marsh is being filled. breeding habitat of the rare Forcipate Emerald. mens in museums, such as the Royal Steve Cannings photo Syd Cannings photo British Columbia Museum and the Spencer Entomological Museum at the organizations to learn more about the plans and regulations that preserve, University of British Columbia, have natural world in our neighbourhoods. rather than destroy, natural diversity. been examined and their information We can encourage all levels of govern- And we can maintain and create recorded in databases. In conjunction ment to protect aquatic ecosystems on natural habitats on our own prop- with museums, the British Columbia public land. We can get involved in erty and encourage others to do the Conservation Data Centre keeps track public processes to develop land use same. of this information in the same way it manages data on rare vertebrates, plants and ecosystems. , : Education is vital. Dragonfly con- BC Conservation Data Centre servation will not be supported if no Ministry of Sustainable Resource Management one appreciates these insects. Thank- PO Box 9993, Stn. Prov. Govt. fully, more and more naturalists are Victoria, British Columbia, V8W 9R7 becoming excited about studying [email protected] dragonflies because of their colourful http://srmwww.gov.bc.ca/cdc beauty and fascinating behaviour. New information and publications will , encourage this. , : But even before all the information Naturescape British Columbia is available, we must act quickly to PO Box 9354, Stn. Prov. Govt. protect the natural communities that Victoria, British Columbia, V8W 9M1 still remain home for dragonflies. http://www.hctf.ca/nature.htm Small ponds, marshes, springs and streams in British Columbia’s southern valleys sustain some of the rarest of our species. These habitats are among the first to disappear in the expansion of housing, industrial and agricultural developments. Even sensitive aquatic habitats in remote areas can be drasti- cally affected by industrial activity. The Habitat Conservation Trust Fund Suitable sites are disappearing faster than new ones are being formed and, --- , until that trend is reversed, there is . , continuing cause for concern. What can we do as individuals? We can get involved with local naturalist Printed in British Columbia on recycled paper with vegetable inks.