"SHORT-HORNED" BUGS
(HOMOPTERA: AUCHENORRHYNCHA)

K.G.A. Hamilton

CONCLUSIONS

The MCE is an ecozone of great complexity, both regionally and at varying elevation. By far the greatest diversity of “short-horned” bugs is found in the southern parts that properly belong to the Great Basin or “Western Interior Basin and Ranges” fauna. Elsewhere, considerable uniformity of fauna is deduced although the Caribou district has pockets of both mountain and valley species that probably represent Hypsithermal disjuncts.

The rich fauna of the MCE is probably well buffered against effects of climate change. Great elevational differences within short distances ensure that faunas can adjust to changing conditions easily by relatively minor changes in distribution patterns. The reverse is true of effects of habitat changes caused by human activities. The highly fragmented nature of the habitats and the large number of disjunct populations makes local extirpation a very real possibility. The fauna of valley bottoms is particularly at risk, being both speciose, competing unsuccessfully with many imported species, and under strong pressures from human land use. This is especially true of the Okanagan which is experiencing rapidly expanding industrial and housing demands combined with the majority of accidental importation of exotic species in the MCE. Thus, natural habitats are being ousted by a combination of excavation and concrete, plus European flora and fauna, while native stands are becoming degraded by invasive species and overgrazing. Such a process is already under way; only our ignorance of presettlement conditions prevents a detailed analysis of extirpated or endangered species in the MCE.