Two species of Ephedra: E. trifurca and E. torreyana inhabit shrub and grassland habitats in the northern Chihuahuan Desert. E. torreyana is limited to black grama grasslands where grasses are taller than the shrub. E. torreyana is heavily browsed by vertebrates and E. trifurca is browsed during some years. We established an experiment with cylindrical exclosures that excluded rabbits and rodents, rabbits but accessible to rodents, for comparison with E. torreyana plants available to all herbivores. Plants accessible to all vertebrate herbivores were significantly smaller with shorter stem lengths than plants in exclosures. We concluded that E. torreyana in black grama grassland are largely hidden from vertebrate herbivores and that intense herbivory reflects the degraded state of the study site which makes the E. torreyana evergreen shrubs apparent to vertebrates.
References
[1]
Hollander, J.L., Vander Wall, S.B. and Baguley, J.G. (2010) Evolution of Seed Dispersal in North American Ephedra. Evolutionary Ecology, 24, 333-345. https://doi.org/10.1007/s10682-009-9309-1
[2]
Loera, I., Sosa, V. and Ickert-Bond, S.M. (2012) Diversification in North America Arid Lands: Niche Conservatism, Divergence and Expansion of Habitat Explain Speciation in the Genus Ephedra. Molecular Phylogenetics and Evolution, 65, 437-450. https://doi.org/10.1016/j.ympev.2012.06.025
[3]
Whitford, W.G. (2002) Ecology of Desert Systems. Academic Press, London.
[4]
Killgore, A., Jackson, E. and Whitford, W.G. (2009) Fire in Chihuahuan Desert Grassland: Short-Term Effects on Vegetation, Small Mammal Populations, and Faunal Pedoturbation. Journal of Arid Environments, 73, 1029-1034. https://doi.org/10.1016/j.jaridenv.2009.04.016
[5]
Buffington, L.C. and Herbel, C.H. (1965) Vegetational Changes on a Semidesert Grassland Range from 1858-1963. Ecological Monographs, 35, 139-164. https://doi.org/10.2307/1948415
[6]
Kerley, G.I.H., Whitford, W.G. and Kay, F.R. (1997) Mechanisms for the Keystone Status of Kangaroo rats: Graminivory Rather Than Granivory? Oecologia, 111, 422-428. https://doi.org/10.1007/s004420050254
[7]
Chebouat, E., Gherraf, N., Dadamoussa, B., Chirite, A. and Zellagui, A. (2016) Chemical Composition of the Drichloromethane Extract of Ephedra alata Leaves and Flowers. Der Pharmacia Lettre, 8, 19-13.
[8]
Long, C., Kakiuchi, N., Zhong, G. and Mikage, M. (2005) Survey on Resources of Ephedra Plants in Xinjiang. Biological and Pharmaceutical Bulletin, 28, 285-288. https://doi.org/10.1248/bpb.28.285
Mikage, M., Hong, H. and Cai, X. (2008) Studies of Ephedra Plants in Asia. Part 5. The Herbivory Damage to Ephedra Plants by Livestock. Journal of Traditional Medicines, 23, 108-111.
[11]
Puig, S., Videla, F., Cona, M.I. and Monge, S.A. (2007) Diet of the Brown Hare (Lepus europaeus) and Food Availability in Northern Patagonia (Mendoza, Argentina). Mammalian Biology, 72, 240-250. https://doi.org/10.1016/j.mambio.2006.08.006
[12]
Liu, W., Xu, W., Yang, W., Xu, F. and Qiao, H. (2012) Food Habits of the Great Gerbil (Rhombomysopimus) in the Southern Gubantunggut Desert, Xinjiang, China. Pakistan Journal of Zoology, 44, 931-936.
[13]
Boecklen, W.J. and Hoffman, M.T. (1993) Sex-Biased Herbivory in Ephedra trifurca: The Importance of Sex-by-Environment Interactions. Oecologia, 96, 49-55. https://doi.org/10.1007/BF00318030
[14]
Wooten Jr., R.C. and Crawford, C.S. (1975) Food, Ingestion Rates, and Assimilation in the Desert Millipede Orthorporusornatus (Girard) (Diplopoda). Oecologia, 20, 231-236. https://doi.org/10.1007/BF00347475
