Huxel, G. R. 1999.Rapid displacement of native species by invasive species: effects of hybridization. Biological Conservation 89:143-152.
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Abstract: The introduction of non-native populations can lead to the competitive exclusion (displacement) of native populations. This has been hypothesized to be further exacerbated by the potential of hybridization, which can dilute or genetically assimilate the native genotype leaving no "pure" natives. With relatively moderate to high rates of immigration, the loss of native species can be rapid with or without hybridization. Using single-locus, two allele models, I find that species replacement can occur very rapidly and the time to displacement decreases rapidly with increasing immigration and selection differential. Immigration and selection act in two different ways: increasing immigration results in displacement by overwhelming the native; whereas increasing the selection differential in favor of the invader leads to displacement via genetic assimilation. The implications of these results are the need for more empirical studies on the immigration patterns of invasive species and their potential for interbreeding with natives.

The effect of the Argentine ant on the threatened valley elderberry longhorn beetle.
Huxel, G. R.,  2000.  Biological Invasions 2:81-84.
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Abstract:  Many extinctions have followed the introduction of exotic predatory species, yet this is still a rarely (if ever) reported phenomenon for insect species.  Here, I present intriguing evidence of an endangered insect under risk of increased extinction due to an invasive predator.  The Argentine ant (Linepithema humile) has been spreading throughout California, especially in riparian woodland habitat along permanent streams, posing a serious risk to the threatened valley elderberry longhorn beetle (hereafter VELB; Desmocerus californicus dimorphus).  Recent surveys have found that in location along Putah Creek the VELB was present in sites where L. humile has not yet colonized, but not present in sites where L. humile is present, with the exception of two sites recently colonized by L. humile.  Along the American River there was no significant relationship between the two species.  However, the coexistence of L. humile and native ant species suggests that L. humile has only recently invaded the riparian woodlands along the American River.  These findings indicate that L. humile is currently impacting the VELB along Putah Creek and will soon be an important factor along the American River given continued rapid spread along permanent streams in California's Central Valley.  The local extirpation of VELB from these two critical drainages represents a critical obstacle for the persistence of this threated species.