|
COPYRIGHT 2006 Wilson Ornithological Society
Two recent studies based on mitochondrial gene sequence (Benedict et al. 2003, Oyler-McCance et al. 2005) and nuclear microsatellite markers (Oyler-McCance et al. 2005) revealed a genetically distinct population of Greater Sage-Grouse (Centrocercus urophasianus) on the Nevada/California border (Lyon, Nevada/Mono, California). Those studies indicated that the Lyon/Mono Greater SageGrouse population is more genetically distinct from other Greater Sage-Grouse populations than is the newly described (Young et al. 2000) Gunnison Sage-Grouse (C. minimus) species. Several factors, including the apparent genetic and geographic isolation of Lyon/ Mono sage-grouse from other populations, the degradation and loss of sagebrush (Artemisia spp.) habitat, and an overall population decline, have made this a population of interest from both evolutionary and conservation perspectives.
Morphological (Hupp and Braun 1991) and behavioral studies (Young et al. 1994) of Gunnison Sage-Grouse provided evidence that sexual selection bad driven speciation in the isolated populations of sage-grouse in southwestern Colorado and southeastern Utah. The use of both mitochondrial (Kahn et al. 1999) and nuclear markers (Oyler-McCance et al. 1999) supported the morphological and behavioral data and led to species designation for the Gunnison Sage-Grouse (American Ornithologists' Union 2000, Young et al. 2000). A similar approach would determine whether the genetic distinctiveness of the Lyon/Mono population has been manifested morphologically and/or behaviorally as it has in Gunnison Sage-Grouse. If so, it could potentially lead to a taxonomic reclassification.
Male mating success and mate-choice cues (Gibson and Bradbury 1985), territoriality (Gibson and Bradbury 1987), components of female choice (Gibson et al. 1991), and male strutting behavior (Young et al. 1994) have been studied previously in the Mono sage-grouse population. However, with the exception of Young et al. (1994), there have been no comparative studies among populations. Young et al. (1994) compared secondary sexual characteristics from male strut displays among three populations--one Gunnison Sage-Grouse population (Gunnison Basin, Colorado) and two Greater Sage-Grouse populations (Mono, California, and Jackson, Colorado). The structure of the Gunnison male strut display was strikingly different from that of the other two populations. However, the comparison of the similarly structured strut display between males from Mono and Jackson indicated statistically significant differences in most of the acoustic measures.
In light of the genetic distinctiveness of Lyon/Mono sage-grouse and the behavioral results of Young et al. (1994), we undertook a further examination of male strut display behavior. We compared the Lyon/Mono population with two proximal populations of Greater Sage-Grouse (Fig. 1). We tested the hypothesis that the Lyon/Mono population's behavior is measurably different from that of other Greater Sage-Grouse populations and may, in fact, be considered a separate taxon given the genetic differences. Alternatively, although the Lyon/Mono population appears genetically isolated, behaviorally it may not be significantly different from other Greater Sage-Grouse populations, indicating that...
Read the full article for free courtesy of your local library.
|
Bookmark this article
Print this article
Link to this article
Email this article
Digg It!
Add to del.icio.us
RSS
