135Davidsonia 15:4 A Hard Life (25 Years Later):

It has been 25 years since renowned ecologist and botanist Arthur Kruckeberg first introduced, within the pages of Davidsonia, the ultramafic (serpentine) soil habitats of British Columbia. In what was likely the first article of its kind on BC serpentines, Kruckeberg described the harsh reali-ties of ultramafic soils faced by plant life. These included an adverse chemi-cal and physical soil environment, and the myriad forms of botanical re-sponse to this “serpentine effect ” (ecotypic differentiation, speciation, exclu-sion, indifference, heavy metal hyper-accumulation, etc.) that give rise to a host of unique ecologies. He also outlined his and other workers ’ botanical and ecological observations from various BC ultramafic sites and compared them to the well-known ultramafic sites of Oregon and California thereby placing them in a western North American ultramafic context. Kruckeberg’s major observation was that of a diminishing and “less spec-tacular ” response by plant life to ultramafic soil habitats with latitude in western North America. In his 1992 paper, he described this pattern as potentially relating to increasing precipitation (since drought is likely a key component of the serpentine effect), the presence of non-ultramafic glacial till (which could potentially mute the influence of ultramafic bedrock), and the relatively short time available for speciation since glacial retreat about 12,000 years ago. He also noted that many of the plant species occurring on BC ultramafic sites tend to be drawn from the drier habitats of neighbour-ing regions, not just from the adjacent matrix of vegetation over “normal” soils. In the past 25 years much work has taken place internationally on ultramafic soil habitats. Inspired by the pioneering work of Kruckeberg and others, an entire sub-discipline of plant ecology has arisen to understand the unique-ness of ultramafic soil habitats. Four international conferences have take