Thursday, February 7, 2013

The (Ancient) Earthworms of British Columbia

Providing information on the presence and distribution of the faunal groups found in British Columbia is quite a challenge. It requires a cooperative effort with experts who specialize in each faunal group, including groups that most of us might overlook and that are difficult to identify.  This is particularly true of earthworms, a group that requires dissection for proper identification of species.  Fortunately, with the help of earthworm expert John Reynolds, who has provided direction, key literature and maps, we have been able to provide information on the earthworms of British Columbia on E-Fauna BC.

Thanks to John, we now know that twenty-four taxa of earthworms are documented for the province (Marshall and Fender 2007). We also know that most species present in BC (and across Canada) are European introductions and are widespread throughout the southern part of the province (earthworms are limited in their northern distributions).  Only four species are native--the 'ancient' earthworms of British Columbia (Marshall and Fender 1998).  These are species that survived glaciation in unglaciated 'refugias', and today small populations persist only on Vancouver Island (excluding the southeastern part of the island) and in the Queen Charlottes.  These are Bimastos lawrenceae, Arctiostrotus perrieri, Arctiostrotus vancouverensis and Toutellus oregonensis (Reynolds 2009 pers. comm., McKey-Fender et al. 1994). Arctiostrotus vancouverensis is the most widespread of our four native species (Marshall and Fender 1998) and Bimastos lawrenceae appears to be endemic, "known only from a limited area on the west part of Vancouver Island" (Marshall and Fender 2007).
 
 With John's help, we have been able to provide a checklist of the earthworms of British Columbia, an introduction to earthworms (biology), and an introduction to the earthworms of BC. We also provide atlas pages for our BC species with text/species descriptions adapted from his book on the earthworms of Ontario (with permission of the Royal Ontario Museum).  We have also been able to add photos for many species, thanks to the Earthworm Research Group at the University of Lancashire. Their photos illustrate many of the European introductions.

References:

 Reynolds, John W. 1977. The Earthworms (Lumbricidae and Sparganophilidae) of Ontario, Royal Ontario Museum. 

Marshall, Valin G. and William M. Fender. 1998. Native Earthworms of British Columbia forests. Northwest Science 72. Special Issue 2. Pages 101-102.

Marshall, Valin G. and William M. Fender. 2007. Native and Introduced Earthworms (Oligochaeta) of British Columbia, Canada. Megadrilogica 11 (4): 29-52. 

McKey-Fender, Dorothy, William M. Fender and Valin G. Marshall. 1994. North American earthworms native to Vancouver Island and the Olympic Peninsula. Canadian Journal of Zoology 72: 1325-1339.

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