Native Bees Along Elevation Gradients as Bioindicators of Climate Change Scott Daniels 1, Dave Smith 2, Neil Cobb 3 1. Cesar Chavez High School, Laveen, Arizona; 2. U.S. Fish and Wildlife Service; 3. Merriam-Powell Center for Environmental Research, Northern Arizona University Results Acknowledgements We would like to thank Jacob Higgins for his patience and assistance with the statistical analysis. Discussion Figure 1. a. Desert b. Pinyon-juniper c. Mixed Conifer Abstract Methods A total of 144 of the samples collected contained bees and 1484 bees were collected. There were 88 different species of bees. Differences in species abundance were significant among the three sites ( F=12.431, p<.0001). The desert habitat had the greatest abundance and was dominated by two species (Diadasia ochracea and Melissodes sp.), representing 63% of the desert abundance (table 1). Species richness was highest at both the pinyon-juniper and the mixed conifer sites with 42 species collected. However, species richness was not significantly different among the three different life zones (F=.055, p=.946) (table1). Diversity and evenness were highest at the mixed-confer site (E=0.810) and lowest in the desert (E=0.550) (table 1). Biodiversity and abundance of native bees were established for three different life zones along an elevation gradient. These three life zones (figure 2) consisted of high desert (1556 m), pinyon-juniper (2020 m), and mixed conifer (2620 m). Thirty pollinator traps were placed at each of the three sites. Traps were left for one week. Specimens were identified to the lowest taxonomic level possible. One-Way ANOVA in SPSS statistics 17.0 was used to test for differences in species richness and abundance between the three sites. To determine diversity, the Shannon- Wiener index value was calculated for each. Table 1. Species Abundance, richness, and diversity Introduction In this study, we examined species abundance, richness, and diversity at three life zones along an elevation gradient of the San Francisco Peaks north of Flagstaff, Arizona. Three colors of pollinator traps were placed at each of three life zones: high desert, pinyon-juniper, and mixed conifer (figure 1). We found no significant differences in species richness between the three sites. However, abundance in the desert was significantly different from the pinyon-juniper and mixed conifer sites. Species diversity increased with an increase in elevation. The broader goal of this project was to develop monitoring program plans using pollinators as bioindicators of global change. This includes land use change impacts as well as climate change. It is well understood that climate change affects plant and animal biodiversity. Changes in climate can disrupt the phenology of both plants and animals and these changes could lead to plant–pollinator interaction mismatches and therefore changes in ecological communities (Root et. al 2005). We can understand how species may change with global warming in the future by examining their distribution along elevation gradients in the present. As a dominant pollinator, bees play a major role in maintaining plant communities. Although there seems to be evidence that pollinator populations are declining around the world, the status of most wild pollinators in North America is not known (Committee on the Status of Pollinators in North America 2007). With both climate change and native pollinator decline being such significant issues, it is crucial we improve our understanding of the role of native bees as pollinators. This study is part of a larger project which will collect baseline information on native pollinators in five different life zones. These baseline data will be used to assist in future monitoring of the effects of climate change along an elevation gradient. This study investigated differences in species abundance, richness, and diversity of native bees in three of those life zones. Literature Cited Cesar Chavez High School a.b. c. Committee on the Status of Pollinators in North America, National Research Council Status of Pollinators in North America. The National Academies Press. Washington, D.C. pp , Hannah, L., T. Lovejoy, and S.H. Schneider Biodiversity and climate change in context. In: Climate Change and Biodiversity (T.E. Lovejoy and L Hannah, editors), Yale University Press, New Haven, pp Root, T.L., and L. Hughes Present and future phenological changes in wild plants and animals. In: Climate Change and Biodiversity (T.E. Lovejoy and L Hannah, editors), Yale University Press, New Haven, pp Wilson, J.S., T. Griswold, and O.J. Messinger Sampling bee communities (Hymenoptera: Apiformes) in a desert landscape: Are pan traps sufficient? J. Kans. Entomol. Soc. 81(3): Life ZoneSpecies Abundance Species Richness Shannon- Wiener Diversity Index Desert Pinyon- juniper Mixed Conifer Figure 2. Sampling sites: Great Basin Desert, Pinyon-juniper, and Mixed- Conifer. Bee abundance was significantly higher in the high desert than at the other two sites. However, this higher abundance could be the result of a sampling bias. Bees in the desert may be more attracted to the pollinator cups because few flowers are present. In one previous study, capture rates in pollinator traps were lowest when flowering plant richness was highest (Wilson et al. 2008). Although there was no significant difference in species richness between the three sites, the three communities did show differences in species diversity. Species diversity increased with elevation. This increase was expected because plant diversity along the San Francisco Peaks is highest at the mixed conifer site and lowest in the desert. 22 species, including all those in the genus Bombus, were found only at the mixed conifer site. Such species would most likely be impacted by global warming. Nine species were found throughout the elevation gradient (e.g. Diadasia diminuta, Mellisodes spp.) and therefore might be least impacted by global change. Life Zones Percentage of Species Overlap Desert/ Pinyon-juniper24% Pinyon-juniper / Mixed Conifer17% Desert/ Mixed Conifer10% Table 2. Species overlap between life zones Figure 3. Percentage of species unique to one life zone. Nine species (10.2%) were collected at all three sites. 44 of the 88 species were collected at only one site. 7 species were found only in the desert, 15 species were found only in the pinyon- juniper, and 22 species were found only in the mixed conifer (figure 3).