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Endemism in Wyoming plant and insect herbivore communities during the early Eocene hothouse

  • Ellen D. Currano (a1), Esther R. S. Pinheiro (a2), Robert Buchwaldt (a3), William C. Clyde (a4) and Ian M. Miller (a5)...


The warm, equable, and ice-free early Eocene Epoch permits investigation of ecosystem function and macro-ecological patterns during a very different climate regime than exists today. It also provides insight into what the future may entail, as anthropogenic CO2 release drives Earth toward a comparable hothouse condition. Studying plant–insect herbivore food webs during hothouse intervals is warranted, because these account for the majority of nonmicrobial terrestrial biodiversity. Here, we report new plant and insect herbivore damage census data from two floodplain sites in the Wind River Basin of central Wyoming, one in the Aycross Formation (50–48.25 Ma) at the basin edge (WRE) and the second in the Wind River Formation in the interior of the basin (WRI). The WRI site is in stratigraphic proximity to a volcanic ash that is newly dated to 52.416 ± 0.016/0.028/0.063 (2σ). We compare the Wind River Basin assemblages to published data from a 52.65 Ma floodplain flora in the neighboring Bighorn (BH) Basin and find that only 5.6% of plant taxa occur at all three sites and approximately 10% occur in both basins. The dissimilar floras support distinct suites of insect herbivores, as recorded by leaf damage. The relatively low-diversity BH flora has the highest diversity of insect damage, contrary to hypotheses that insect herbivore diversity tracks floral diversity. The distinctiveness of the WRE flora is likely due to its younger age and cooler reconstructed paleotemperature, but these factors are nearly identical for the WRI and BH floras. Site-specific microenvironmental factors that cannot be measured easily in deep time may account for these differences. Alternatively, the Owl Creek Mountains between the two basins may have provided a formidable barrier to the thermophilic organisms that inhabited the basin interiors, supporting Janzen's hypothesis that mountain passes appear higher in tropical environments.



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Abels, H. A., Clyde, W. C., Gingerich, P. D., Hilgen, F. J., Fricke, H. C., Bowen, G. J., and Lourens, L. J.. 2012. Terrestrial carbon isotope excursions and biotic change during Palaeogene hyperthermals. Nature Geoscience 5:326329.
Adams, J. M., Ahn, S., Ainuddin, N., and Lee, M. L.. 2011. A further test of a palaeoecological thermometer: tropical rainforests have more herbivore damage diversity than temperate forests. Review of Palaeobotany and Palynology 164:6066.
Archibald, S. B., Greenwood, D. R., and Mathewes, R. W.. 2013. Seasonality, montane beta diversity, and Eocene insects: testing Janzen's dispersal hypothesis in an equable world. Palaeogeography, Palaeoclimatology, Palaeoecology 371:18.
Arnone, J. A., and Gordon, J. C.. 1990. Effect of nodulation, nitrogen fixation and CO2 enrichment on the physiology, growth and dry mass allocation of seedlings of Alnus rubra Bong. New Phytologist 116:5566.
Bernays, E. A., and Chapman, R. F.. 1994. Host-plant selection by phytophagous insects. Chapman and Hall, London.
Bijl, P. K., Schouten, S., Sluijs, A., Reichart, G.-J., Zachos, J. C., and Brinkhuis, H.. 2009. Early Palaeogene temperature evolution of the southwest Pacific Ocean. Nature 461:776779.
Bröse, U. 2003. Bottom-up control of carabid beetle communities in early successional wetlands: mediated by vegetation structure or plant diversity? Oecologia 135:407413.
Burnham, R. J., Wing, S. L., and Parker, G. G.. 1992. The reflection of deciduous forest communities in leaf litter—implications for autochthonous litter assemblages from the fossil record. Paleobiology 18:3049.
Caballero, R., and Huber, M.. 2013. State-dependent climate sensitivity in past warm climates and its implications for future climate projections. Proceedings of the National Academy of Sciences USA 110:1416214167.
Calosi, P., Bilton, D. T., Spicer, J. I., Votier, S. C., and Atfield, A.. 2010. What determines a species’ geographical range? Thermal biology and latitudinal range size relationships in European diving beetles (Coleoptera: Dytiscidae). Journal of Animal Ecology 79:194204.
Coley, P. D., and Barone, J. A.. 1996. Herbivory and plant defenses in tropical forests. Annual Review of Ecology and Systematics 27:305335.
Currano, E. D. 2009. Patchiness and long-term change in early Eocene insect feeding damage. Paleobiology 35:484498.
Currano, E. D., Labandeira, C. C., and Wilf, P.. 2010. Fossil insect folivory tracks paleotemperature for six million years. Ecological Monographs 80:547567.
Currano, E. D., Laker, R., Flynn, A. G., Fogt, K. K., Stradtman, H., and Wing, S. L.. 2016. Consequences of elevated temperature and pCO2 on insect folivory at the ecosystem level: perspectives from the fossil record. Ecology and Evolution 6:43184331.
Davies-Vollum, K. S., and Wing, S. L.. 1998. Sedimentological, taphonomic, and climatic aspects of Eocene swamp deposits (Willwood Formation, Bighorn Basin, Wyoming). Palaios 13:2840.
De Araújo, W. S., Vieira, M. C., Lewinsohn, T. M., and Almeida-Neto, M.. 2015. Contrasting effects of land use intensity and exotic host plants on the specialization of interactions in plant-herbivore networks. PLoS ONE 10: e0115606.
Dickinson, W. R., Klute, M. A., Hayes, M. J., Janecke, S. U., Lundin, E. R., McKittrick, M. A., and Olivares, M. D.. 1988. Paleogeographic and paleotectonic setting of the Laramide sedimentary basins in the central Rocky Mountain region. Geological Society of America Bulletin 100:10231039.
Diefendorf, A. F., Freeman, K. H., Wing, S. L., Currano, E. D., and Mueller, K. E.. 2015. Paleogene plants fractionated carbon isotopes similar to modern plants. Earth and Planetary Science Letters 429:3344.
Doyle, J. A. 2007. Systematic value and evolution of leaf architecture across the angiosperms in light of molecular phylogenetic analyses. Courier Forschungs-Institut Senckenberg 258:2137.
Dyer, L. A., Singer, M. S., Lill, J. T., Stireman, J. O., Gentry, G. L., Marquis, R. J., Ricklefs, R. E., Greeney, H. F., Wagner, D. L., Morais, H. C., Diniz, I. R., Kursar, T. A., and Coley, P. D.. 2007. Host specificity of Lepidoptera in tropical and temperate forests. Nature 448:696700.
Eberle, J. J., and Greenwood, D. R.. 2012. Life at the top of the greenhouse Eocene world—a review of the Eocene flora and vertebrate fauna from Canada's High Arctic. Geological Society of America Bulletin 124:323.
Ellis, B., Daly, D. C., Hickey, L. J., Johnson, K. R., Mitchell, J. D., Wilf, P., and Wing, S. L.. 2009. Manual of leaf architecture. Cornell University Press, Ithaca, N.Y.
Ellis, B., and Johnson, K. R.. 2013. Comparison of leaf samples from mapped tropical and temperate forests: implications for interpretations of the diversity of fossil assemblages. Palaios 28:163177.
Engemann, K., Sandel, B., Enquist, B. J., Jorgensen, P. M., Kraft, N., Marcuse-Kubitza, A., McGill, B., Morueta-Holme, N., Peet, R. K., Violle, C., Wiser, S., and Svenning, J. C.. 2016. Patterns and drivers of plant functional group dominance across the Western Hemisphere: a macroecological re-assessment based on a massive botanical dataset. Botanical Journal of the Linnean Society 180:141160.
Erwin, T. L. 1982. Tropical forests: their richness in Coleoptera and other arthropod species. Coleopteris Bulletin 36:7475.
Fan, M., DeCelles, P. G., Gehrels, G. E., Dettman, D. L., Quade, J., and Peyton, S. L.. 2011. Sedimentology, detrital zircon geochronology, and stable isotope geochemistry of the lower Eocene strata in the Wind River Basin, central Wyoming. Geological Society of America Bulletin 123:979996.
Fan, M. J., and Carrapa, B.. 2014. Late Cretaceous–early Eocene Laramide uplift, exhumation, and basin subsidence in Wyoming: crustal responses to flat slab subduction. Tectonics 33:509529.
Feeny, P. 1976. Plant apparency and chemical defense. Pp. 140 in Wallace, J. W. and Mansell, R. L., eds. Biochemical interaction between plants and insects. Plenum, New York.
Gaston, K. J. 2000. Global patterns in biodiversity. Nature 405:220227.
Ghalambor, C. K., Huey, R. B., Martin, P. R., Tewksbury, J. J., and Wang, G.. 2006. Are mountain passes higher in the tropics? Janzen's hypothesis revisited. Integrative and Comparative Biology 46:517.
Gradstein, F. M., Ogg, J. G., Orr, G., and Smith, A. G., eds. 2012. The geologic time scale 2012. Elsevier, Oxford.
Grubb, P. J., Jackson, R. V., Barberis, I. M., Bee, J. N., Coomes, D. A., Dominy, N. J., de la Fuente, M. A. S., Lucas, P. W., Metcalfe, D. J., Svenning, J.-C., Turner, I. M., and Vargas, O.. 2008. Monocot leaves are eaten less than dicot leaves in tropical lowland rainforests: correlations with leaf toughness and leaf presentation. Annals of Botany 101:13791389.
Gunkel, S., and Wappler, T.. 2015. Plant-insect interactions in the upper Oligocene of Enspel (Westerwald, Germany), including an extended mathematical framework for rarefaction. Palaeobiodiversity and Palaeoenvironments 95:5575.
Hawkins, B. A., and Porter, E. E.. 2003. Does herbivore diversity depend on plant diversity? The case of the California butterflies. American Naturalist 161:4049.
Heck, K. L., van Belle, G., and Simberloff, D.. 1975. Explicit calculation of the rarefaction diversity measurement and the determination of sufficient sample size. Ecology 56:14591461.
Heller, P. L., and Liu, L.. 2016. Dynamic topography and vertical motion of the US Rocky Mountain region prior to and during the Laramide orogeny. Geological Society of America Bulletin 128:973988.
Hickey, L. J., and Wolfe, J. A.. 1975. The bases of angiosperm phylogeny: vegetative morphology. Annals of the Missouri Botanical Garden 62:538589.
Hillebrand, H. 2004. On the generality of the latitudinal diversity gradient. American Naturalist 163:192211.
Huber, M., and Caballero, R.. 2011. The early Eocene equable climate problem revisited. Climate of the Past 7:603633.
Jankowski, J. E., Ciecka, A. L., Meyer, N. Y., and Rabenold, K. N.. 2009. Beta diversity along environmental gradients: implications of habitat specialization in tropical montane landscapes. Journal of Animal Ecology 78:315327.
Janzen, D. H. 1967. Why mountain passes are higher in tropics. American Naturalist 101:233249.
Keefer, W. R. 1965. Stratigraphy and geologic history of the uppermost Cretaceous, Paleocene, and lower Eocene Rocks in the Wind River Basin, Wyoming. U.S. Geological Survey Professional Paper 495-A:A1A77.
Knops, J. M., Tilman, D., Haddad, N. M., Naeem, S., Mitchell, C. E., Haarstad, J., Ritchie, M. E., Howe, K. M., Reich, P. B., and Siemann, E.. 1999. Effects of plant species richness on invasion dynamics, disease outbreaks, insect abundances and diversity. Ecology Letters 2:286293.
Kraus, M. J., and Aslan, A.. 1993. Eocene hydromorphic paleosols: significance for interpreting ancient floodplain processes. Journal of Sedimentary Petrology 63:453463.
Labandeira, C. C., Johnson, K. R., and Wilf, P.. 2002. Impact of the terminal Cretaceous event on plant-insect associations. Proceedings of the National Academy of Sciences USA 99:20612066.
Labandeira, C. C., Wilf, P., Johnson, K. R., and Marsh, F.. 2007. Guide to insect (and other) damage types on compressed plant fossils, Version 3.0. Smithsonian Institution, Washington, D.C.
Lande, R. 1996. Statistics and partitioning of species diversity, and similarity among multiple communities. Oikos 76:513.
Lewinsohn, T. M., and Roslin, T.. 2008. Four ways towards tropical herbivore megadiversity. Ecology Letters 11:398416.
Lewinsohn, T. M., Novotny, V., and Basset, Y.. 2005. Insects on plants: diversity of herbivore assemblages revisited. Annual Review of Ecology, Evolution, and Systematics 36:597620.
Loptson, C. A., Lunt, D. J., and Francis, J. E.. 2014. Investigating vegetation-climate feedbacks during the early Eocene. Climate of the Past 10:419436.
Lynch, R. L., Chen, H., Brandt, L. A., and Mazzotti, F. J.. 2009. Old World climbing fern (Lygodium microphyllum) invasion in hurricane caused treefalls. Natural Areas Journal 29:210215.
MacGinitie, H. D., Leopold, E. B., and Rohrer, W. L.. 1974. An early middle Eocene flora from the Yellowstone-Absaroka volcanic province, northwestern Wind River Basin, Wyoming. University of California Publications in Geological Sciences 108:1103.
Malone, D. H., Craddock, J. P., Garber, K. L., and Trela, J.. 2017. Detrital zircon geochronology of the Aycross Formation (Eocene) near Togwotee Pass, western Wind River Basin, Wyoming. Mountain Geologist 54:6985.
Novotny, V., Drozd, P., Miller, S. E., Kulfan, M., Janda, M., Basset, Y., and Weiblen, G. D.. 2006. Why are there so many species of herbivorous insects in tropical rainforests? Science 313:11151118.
Novotny, V., Miller, S. E., Baje, L., Balagawi, S., Basset, Y., Cizek, L., Craft, K. J., Dem, F., Drew, R. A. I., Hulcr, J., Leps, J., Lewis, O. T., Pokon, R., Stewart, A. J. A., Samuelson, G. A., and Weiblen, G. D.. 2010. Guild-specific patterns of species richness and host specialization in plant-herbivore food webs from a tropical forest. Journal of Animal Ecology 79:11931203.
Nyman, T. 2010. To speciate, or not to speciate? Resource heterogeneity, the subjectivity of similarity, and the macroevolutionary consequences of niche-width shifts in plant-feeding insects. Biological Reviews 85:393411.
Pärtel, M., Bennett, J. A., and Zobel, M.. 2016. Macroecology of biodiversity: disentangling local and regional effects. New Phytologist 211:404410.
Patzkowsky, M. E., and Holland, S. M.. 2007. Diversity partitioning of a Late Ordovician marine biotic invasion: controls on diversity in regional ecosystems. Paleobiology 33:295309.
Payros, A., Ortiz, S., Millán, I., Arostegi, J., Orue-Etxebarria, X., and Apellaniz, E.. 2015. Early Eocene climatic optimum: environmental impact on the North Iberian continental margin. Geological Society of America Bulletin 127:16321644.
Pennings, S. C., and Silliman, B. R.. 2005. Linking biogeography and community ecology: Latitudinal variation in plant-herbivore interaction strength. Ecology 86:23102319.
Quispel, A. 1954. Symbiotic nitrogen-fixation in non-leguminous plants. I. Preliminary experiments on the root-nodule symbiosis of Alnus glutinosa. Acta Botanica Neerlandica 3:495511.
Rasmann, S., and Agrawal, A. A.. 2009. Plant defense against herbivory: progress in identifying synergism, redundancy, and antagonism between resistance traits. Current Opinion in Plant Biology 12:473478.
Royer, D. L., Sack, L., Wilf, P., Lusk, C. H., Jordan, G. J., Niinemets, U., Wright, I. J., Westoby, M., Cariglino, B., Coley, P. D., Cutter, A. D., Johnson, K. R., Labandeira, C. C., Moles, A. T., Palmer, M. B., and Valladares, F.. 2007. Fossil leaf economics quantified: calibration, Eocene case study, and implications. Paleobiology 33:574589.
Seeland, D. A. 1978. Eocene fluvial drainage patterns and their implications for uranium and hydrocarbon exploration in the Wind River Basin, Wyoming. U.S. Geological Society Bulletin 1446:121.
Siemann, E., Tilman, D., and Haarstad, J.. 1996. Insect species diversity, abundance and body size relationships. Nature 380:704706.
Smith, M. E., Singer, B. S., and Carroll, A. R.. 2004. Discussion: 40Ar/39Ar geochronology of the Eocene Green River Formation, Wyoming. Geological Society of America Bulletin 116:253256.
Smith, M. E., Carroll, A. R., and Singer, B. S.. 2008. Synoptic reconstruction of a major ancient lake system: Eocene Green River Formation, western United States. Geological Society of America Bulletin 120:5484.
Sokal, R. R. and Rohlf, F. J.. 1995. Biometry, 3rd ed. Freeman, New York.
Torres, V. 1985. Stratigraphy of the Eocene Willwood, Aycross, and Wapiti Formations along the North Fork of the Shoshone River, north-central Wyoming. Contributions to Geology, University of Wyoming 23:8397.
Volin, J. C., Parent, J. R., and Dreiss, L. M.. 2013. Functional basis for geographical variation in growth among invasive plants. Pp. 2943 in Jose, S., Singh, H. P., Batish, D. R., and Kohli, R. K., eds. Invasive plant ecology. CRC Press, Boca Raton, Fla.
Wilf, P., and Labandeira, C. C.. 1999. Response of plant-insect associations to Paleocene–Eocene warming. Science 284:21532156.
Wilf, P., Wing, S. L., Greenwood, D. R., and Greenwood, C. L.. 1998. Using fossil leaves as paleoprecipitation indicators: an Eocene example. Geology 26:203206.
Wilf, P., Labandeira, C. C., Johnson, K. R., Coley, P. D., and Cutter, A. D.. 2001. Insect herbivory, plant defense, and early Cenozoic climate change. Proceedings of the National Academy of Sciences USA 98:62216226.
Willig, M. R., Kaufman, D. M., and Stevens, R. D.. 2003. Latitudinal gradients of biodiversity: pattern, process, scale, and synthesis. Annual Review of Ecology, Evolution, and Systematics 34:273309.
Wing, S. L. 1981. A study of paleoecology and paleobotany in the Willwood Formation (early Eocene, Wyoming). Unpublished Ph.D. dissertation. Yale University, New Haven, Conn.
Wing, S. L., and Currano, E. D.. 2013. The response of plants to a global greenhouse event 56 million years ago. American Journal of Botany 100:12341524.
Wing, S. L., and Greenwood, D. R.. 1993. Fossils and fossil climate: the case for equable continental interiors in the Eocene. Philosophical Transactions of the Royal Society of London B 341:243252.
Wing, S. L., Alroy, J., and Hickey, L. J.. 1995. Plant and mammal diversity in the Paleocene to early Eocene of the Bighorn basin. Palaeogeography, Palaeoclimatology, Palaeoecology 115:117155.
Wing, S. L., Bao, H., and Koch, P. L.. 2000. An early Eocene cool period? Evidence for continental cooling during the warmest part of the Cenozoic. Pp. 197237 in Huber, B. T., MacLeod, K. G., and Wing, S. L., eds. Warm climates in earth history. Oxford University Press, Cambridge.
Winterfeld, G. F., and Conard, J. B.. 1983. Laramide tectonics and deposition, Washakie Range and northwestern Wind River basin, Wyoming. Pp. 137148 in Lowell, J. D., ed. Rocky Mountain foreland basins and uplifts. Rocky Mountain Association of Geologists, Denver.
Woodburne, M. O., Gunnell, G. F., and Stucky, R. K.. 2009. Climate directly influences Eocene mammal faunal dynamics in North America. Proceedings of the National Academy of Sciences USA 106:1339913403.
Wright, M. G., and Samways, M. J.. 1998. Insect species richness tracking plant species richness in a diverse flora: gall-insects in the Cape Floristic Region, South Africa. Oecologia 115:427433.


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