Will Canadian Policies Protect British Columbia's Endangered Pairs of Sympatric Sticklebacks?

Abstract

Limnetic‐benthic sympatric species pairs of threespine stickleback (Gasterosteus spp.) are unique to lakes of southwestern British Columbia. One pair has gone extinct and the remaining three pairs are listed as endangered. The biodiversity conservation policies that could potentially protect these species are examined. The plight of the stickleback pairs serves as a test of the sufficiency of Canada's constellation of biodiversity conservation policies. This article finds that until very recently not even the combination of national and provincial policies offered unequivocal protection for these species. A new national Species at Risk Act now offers more promise. Nevertheless, a more fundamental issue remains. A misconception concerning the value of biodiversity may be impeding the formulation of adequate policies and plans for biodiversity conservation in general, both in Canada and worldwide.

Extinction of a weakly armoured threespine stickleback (Gasterosteus aculeatus) population in Prator Lake, Alaska

“…For example, introduction of brown bullheads (Ameiurus nebulosus) in the early 1990s in Hadley Lake, British Columbia, led to the extinction of a unique threespine stickleback species pair (Hatfield 2001). Three other species pairs in British Columbian lakes have been identified as highly endangered (Wood 2003), and the bullhead has been implicated as a major threat in these cases as well. Kynard (1979) attributed the drastic decline of the stickleback population in Wapato Lake, Washington, to the introduction of the pumpkinseed sunfish (Lepomis gibbosus).…”

Information needs for assessing critical habitat of freshwater fish

“…Increases in turbidity, loss of differential productivity between benthic and limnetic habitats that maintains a size differential between reproductive individuals of different species, and loss of nest site segregation have all been implicated as potential factors contributing to breakdown of reproductive isolation (presently an area of active research). For instance, increased turbidity might impair detection of nuptial colours and cause increased hybridization independent of effects on population limitation (Seehausen et al 1997;Boughman 2001;Wood 2003). In this scenario, introduction of an alien species is the ultimate driver of hybridization, but impacts are largely mediated through habitat change.…”