@article {1575,
	title = {Temporally persistent patterns of incidence and abundance in a pollinator guild at annual and decadal scales: the bees of Larrea tridentata},
	journal = {Biological Journal of the Linnean Society, London},
	volume = {85},
	year = {2005},
	month = {2005///},
	pages = {319 - 329},
	abstract = {A recent alternative model to conventional coevolution, the geographic mosaic theory of coevolution, posits that reciprocal selection is episodic and local, rather than persistent and spatially extensive. However, little empirical evidence addresses this model{\textquoteright}s tenets, in particular the temporal stability of local plant-pollinator interactions. We evaluated this tenet using the richly diverse guild of bees at creosote bush (Larrea tridentata), a generalist plant that hosts many specialist bees. We systematically resampled over 2-5 years at 11 sites across the south-western USA. Incidence and abundance also were compared for survey sites sampled 20 2 years earlier. Average Morisita-Horn faunal similarities of local bee guilds was 87\% for sequential years and 36\% after 20 years. Similarities in taxonomic composition of resampled local bee guilds could be statistically represented as a random assemblage drawn from the regional source pool of 54-68 bee species that could be expected at Larrea, weighted by regional abundance. At every site, only the minority of abundant bee species was typically persistent in local guilds, even after > 20 years. Most bee species in the Larrea guild were chronically uncommon, geographically sporadic and temporally unpredictable, attributes that render them numerically inconsequential as pollinators in their local guild. Persistence among abundant bee species in local pollinator assemblages satisfies one condition by which reciprocal selection could act locally. The well-being of these more abundant core species, and not bee diversity per se, may better characterize the health of such plant-pollinator associations.},
	keywords = {Apoidea, COMMUNITIES, ECOLOGY-HISTORICAL, GUILD, LARREA, POLLINATOR, VARIATION},
	author = {Cane, J. H. and Minckley,R. and Kervin,L. and Roulston,T.}
}
@article {1579,
	title = {Complex responses within a desert bee guild (Hymenoptera: Apiformes) to urban habitat fragmentation},
	journal = {Ecological Applications},
	volume = {16},
	year = {2006},
	month = {2006///submitted},
	pages = {632 - 644},
	abstract = {Urbanization within the Tucson basin of Arizona during the past 50+ years has fragmented the original desert scrub into patches of different sizes and ages. These remnant patches, like the surrounding desert, are dominated by Larrea tridentata (creosote bush), a long-lived, evergreen shrub whose flowers are visited by more than 120 native bee species across its range. Twenty-one of these bee species restrict their pollen foraging to L. tridentata. To evaluate the response of this native bee fauna to fragmentation, we compared species incidence and abundance patterns for the bee guild visiting Larrea at 59 habitat fragments of known size (0.002-5 ha) and age (up to 70 years), and in adjacent desert. The 62 bee species caught during this study responded to fragmentation heterogeneously and not in direct relation to their abundance or incidence in undisturbed desert. Only a few species found in continuous desert outside the city were entirely absent from urban fragments. Species of ground-nesting Larrea specialists were under-represented in smaller fragments and less abundant in the smaller and older fragments. In contrast, cavity-nesting bees (including one Larrea specialist) were over-represented in the habitat fragments, probably due to enhanced nesting opportunities available in the urban matrix. Small-bodied bee species were no more likely than larger-bodied species to be absent from the smaller fragments. The introduced European honeybee, Apis mellifera, was a minor faunal element at >90\% of the fragments and exerted little if any influence on the response patterns of native bee species to fragmentation. Overall, native bee response to urban habitat fragmentation was best predicted by ecological traits associated with nesting and dietary breadth. The consequences for the floral host and its pollination interactions are not intuitive but await investigation.},
	keywords = {Apoidea, BEE SIZE, CONSERVATION, FRAGMENTATION, GUILD, HABITAT, INCOMPLETE, LARREA, OLIGOLECTY},
	author = {Cane, J. H. and Minckley,R. and Roulston,T. and Kervin,L.J. and Williams,N.M.}
}
