Abstract
Juniperus woodlands are widely distributed in western North America. Few studies of seedling emergence, long-term survival, growth or mortality of the dominant Juniperus spp. in these woodlands have been carried out. Consequently, regeneration dynamics in these woodlands are poorly understood. Juniperus ashei is the dominant woody plant in the majority of woodland and savanna communities of the Edwards Plateau region in central Texas. We examined the emergence, mortality and growth of various spatial and temporal cohorts of J. ashei seedlings over an eight or nine-year period. Greatest emergence was found during the cool, mostly winter months and under the canopy of mature J. ashei trees. Emergence was significantly inversely related to temperature and significantly linearly related to rainfall, but only if the monthly rainfall and emergence were offset by one to four months. Greatest survival occurred below the J. ashei canopy, but greatest growth was at the canopy edge. Emerging seedlings were not from the current year’s seed crop, but from one or more previous year’s seed crops. Greatest mortality occurred mostly during the summer months and in the grassland habitat. There was a significant inverse logarithmic or exponential relationship between mean monthly temperature and mean monthly mortality. A large number of J. ashei seedlings or immature plants with reduced growth were found beneath the canopy of mature trees. These plants seem to serve as a seedling bank, providing the source of recruitment into the population should the overstory trees be removed. Survival of the two canopy cohorts with known emergence dates declined with time (negative exponential function) and was 1.0–3.4% after eight or nine years depending on the cohort. The pre-existing cohort seemed to have constant mortality (and presumably replacement), with about 8% of the population dying each year. Higher growth rates for seedlings were found at the edge of the established woodland canopy, which suggests that conditions in the edge habitat or possibly in canopy gaps are best for growth beyond the seedling stage.
Similar content being viewed by others
References
Ahmed M., Shaukat S. S. and Buzdar A. H. 1990. Population structure and dynamics of Juniperus excelsa in Balouchistan, Pakistan. Journal of Vegetation Science 1: 271–276.
Allison P. O. 1995. Survival analysis using SAS system: a practical guide. SAS Institute, Cary, North Carolina, USA.
Allen C. D. and Breshears D. D. 1998. Drought-induced shift of a forest-woodland ecotone: rapid landscape response to climate variation. Proceedings of the National Academy of Science USA 95: 14839–14842.
Anderson L. J., Brumbaugh S. M. and Jackson R. B. 2001. Water and tree-understory interactions: a natural experiment in a savanna with oak wilt. Ecology 82: 33–39.
Archer S., Schimel D. S. and Holland E. A. 1995. Mechanisms of shrubland expansion: land use, climate or CO2? Climate Change 29: 91–99.
Bahre C. J. 1991. A legacy of change: historic human impact on vegetation of the Arizona Borderlands. University of Arizona Press, Tucson, Arizona, USA.
Bray W. L. 1904. The timber of the Edwards Plateau of Texas: Its relation to climate, water supply, and soil. United States Department of Agriculture, Bureau of Forestry Bulletin No.47.
Breshears D.D., Rich P.M., Barnes F.J. and Campbell K. 1997. Overstory-imposed heterogeneity in solar radiation and soil moisture in a semiarid woodland. Ecological Applications 7: 1201–1215.
Breshears D.D., Nyhan J.W., Heil C.E. and Wilcox B.P. 1998. Effects of woody plants on microclimate in a semiarid woodland: soil temperature and evaporation in canopy and intercanopy patches. International Journal of Plant Science 159: 1010–1017.
Briggs J.M., Knapp A.K. and Brock B.L. 2002. Expansion of woody plants in tallgrass prairie: a fifteen-year study of fire and fire-grazing interactions. American Midland Naturalist 147: 287–294.
Burkhardt J.W. and Tisdale E.W. 1976. Causes of juniper invasion in Southwestern Idaho. Ecology 57: 472–484.
Bush J.K. and Van Auken O.W. 1995. Woody plant growth related to planting time and clipping of a C4 grass. Ecology 76: 1603–1609.
Cadenasso M.L., Pickett S.T.A. and Morin P.J. 2002. Experimental test of the role of mammalian herbivores on old field succession: community structure and seedling survival. Journal of the Torrey Botanical Society 129: 228–237.
Chapin F.S. III, Sala O.E., Burke I.C., Grime J.P., Hooper D.U., Lauernroth W.K., Lombard A., Mooney H.A., Mosier A.R., Naeem S., Pacala S.W., Roy J., Steffen W.L. and Tilman D. 1998. Ecosystem consequences of changing biodiversity. Bio-Science 48: 45–52.
Chavez-Ramirez F. and Slack R.D. 1994. Effects of avian foraging and post-foraging behavior on seed dispersal patterns of Ashe juniper. Oikos 71: 40–46.
Diamond D.D., Rowel G.A. and Keddy-Hector D.P. 1995. Conservation of ashe juniper (Juniperus ashei Buchholz) woodlands of the central Texas Hill Country. Natural Areas Journal 15: 189–197.
Dobson A.P., Bradshaw A.D. and Baker A.J.M. 1997. Hopes for the future: restoration ecology and conservation biology. Science 277: 515–522.
Eddleman L.E. 1987. Establishment and stand development of western juniper in central Oregon. In: Everett R.L. (ed.), Proceedings of the Pinyon-Juniper Conference. United States Forest Service General Technical Report INT-215, Ogden, Utah, pp. 255–259.
Fenner M. 1985. Seed ecology. Chapman and Hall, New York, USA.
Gardner A.S. and Fisher M. 1994. How the forest lost its trees: just so storytelling about Juniperus excelsa in Arabia. Journal of Arid Environments 26: 299–301.
Harper J.L. 1977. Population biology of plants. Academic Press, New York, USA.
Holthuijzen A.M.A., Shank T.L. and Fraser J.D. 1987. Dispersal of eastern red cedar (Juniperus virginiana) into pastures: an overview. Canadian Journal of Botany 65: 1092–1095.
Hora B. 1981. The Oxford encyclopedia of trees of the world. Oxford University Press, New York, USA.
Howard L.F. and Lee T.D. 2002. Upland old-field succession in southeastern new Hampshire. Journal of the Torrey Botanical Society 129: 60–76.
Jackson J.T. and Van Auken O.W. 1997. Seedling survival, growth and mortality of Juniperus ashei (Cupressacae) in the Edwards Plateau Region of central Texas. Texas Journal of Science 49: 267–278.
Jones R.H., Sharitz R.S., Dixon P.M., Segal D.S. and Schneider R.L. 1994. Woody plant regeneration in four floodplain forests. Ecological Monographs 64: 345–367.
Johnsen T.N. 1962. One-seed juniper invasion of Northern Arizona grasslands. Ecological Monographs 32: 187–207.
Joy D.A. and Young D.R. 2002. Promotion of mid-successional seedling recruitment and establishment by Juniperus virginiana in a coastal environment. Plant Ecology 160: 125–135.
Little E.L. 1971. Atlas of United States trees, volume 1, conifers and important hardwoods. United States Department of Agriculture, Miscellaneous Publication 1146.
Mack R.N. 1986. Alien plant invasion into the intermountain west: a case history. In: Mooney H.A. and Drake J.A. (eds), Ecology of biological invasions of North America and Hawaii. Springer-Verlag, New York, USA, pp. 191–213.
Marks P.L. and Gardescu S. 1998. A case study of sugar maple (Acer saccharum) as a forest seedling bank species. Journal of the Torrey Botanical Society 125: 287–296.
McKinley D.C. and Van Auken O.W. 2004. Influence of interacting factors on the growth and mortality of Juniperus ashei seedlings. International Journal of Plant Science (in press).
McPherson G.R. 1997. Ecology and management of North American savannas. The University of Arizona Press, Tucson, Arizona, USA.
McPherson G.R., Wright H.A. and Wester D.B. 1988. Patterns of shrub invasion in semiarid Texas grasslands. American Midland Naturalist 120: 391–397.
Miller R.F. and Wigand P.E. 1994. Holocene changes in semiarid pinyon-juniper woodlands: response to climate, fire, and human activities in the Great Basin. BioScience 44: 465–474.
National Oceanic and Atmospheric Administration. 1999. National Climatic Data Center, Asheville, North Carolina, USA.
Norris M.D., Blair J.M., Johnson L.C. and McKane R.B. 2001. Assessing changes in biomass, productivity, and C and N stores following Juniperus virginiana forest expansion into tallgrass prairie. Canadian Journal of Forest Research 31: 1940–1946.
Orwig D.A. and Abrams M.D. 1997. Variation in radial growth responses to drought among species, site and canopy strata. Trees 11: 474–484.
Oswald B.P. and Neuenschwander L.F. 1995. Mortality of western larch seedlings in relation to seedbed characteristics at the dry end of its ecological range. Bulletin of the Torrey Botanical Club 122: 101–108.
Owens M.K. and Schliesing T.G. 1995. Invasive potential of ashe juniper after mechanical disturbance. Journal of Range Management 48: 503–507.
Pimm S.L., Russell G.J., Gittleman J.L. and Brooks T.M. 1995. The future of biodiversity. Science 269: 347–350.
Phillips P.L. and Barnes P.W. 2003. Spatial asymmetry in tree-shrub clusters in a subtropical savanna. American Midland Naturalist 149: 59–70.
SAS Institute. 1989. SAS user’s guide. SAS Institute, Cary, North Carolina, USA.
Schmidt T.L. and Stubbendieck J. 1993. Factors influencing eastern redcedar seedling survival on rangeland. Journal of Range Management 46: 448–451.
Smeins F.E. and Merrill L.B. 1988. Long term change in a semiarid grassland. In: Amos B.B. and Gehlbach F.R. (eds), Edward’s Plateau vegetation: plant ecological studies in central Texas. Baylor University Press, Waco, Texas, pp. 101–114.
Smeins F.E. and Fuhlendorf S.D. 2001. Biology and ecology of Ashe (blueberry) juniper. In: Taylor C.A. (ed.), Juniper Symposium, 2001 Proceedings. Texas Agriculture Experiment Station, College Station, Texas, pp. 23–37.
Steel R.G.D. and Torrie J.H. 1980. Principles and procedures of statistics: a biometric approach. McGraw-Hill, New York, USA.
Streng D.R., Glitzenstein J.S. and Harcombe P.A. 1989. Woody seedling dynamics in an east Texas floodplain forest. Ecological Monographs 59: 177–204.
Terletzky P.A. and Van Auken O.W. 1996. Comparison of cedar glades and associated woodlands of the southern Edwards Plateau. Texas Journal of Science 48: 55–67.
Turner R.M., Alcorn S.M., Olin G. and Booth J.A. 1966. The influence of shade, soil, and water on saguaro seedling establishment. Botanical Gazette 127: 95–102.
Van Auken O.W. 1988. Woody vegetation of the southeastern escarpment and Plateau. In: Amos B.B. and Gehlbach F.R. (eds), Edward’s Plateau vegetation: plant ecological studies in central Texas. Baylor University Press, Waco, Texas, USA, pp. 43–55.
Van Auken O.W. 1993. Size distribution patterns and potential population change of some dominant woody species of the Edwards Plateau region of Texas. Texas Journal of Science 45: 199–210.
Van Auken O.W. 2000a. Shrub invasions of North American semiarid grasslands. Annual Review of Ecology and Systematics 31: 197–215.
Van Auken O.W. 2000b. Characteristics of intercanopy bare patches in Juniperus woodlands of the southern Edwards Plateau, Texas. Southwestern Naturalist 45: 95–110.
Van Auken O.W., Ford A.L. and Allen J.L. 1981. An ecological comparison of upland deciduous and evergreen forests of central Texas. American Journal of Botany 68: 1249–1256.
Van Auken O.W. and Bush J.K. 1997. Growth of Prosopis glandulosa in response to changes in aboveground and belowground interference. Ecology 78: 1222–1229.
Wayne R. and Van Auken O.W. 2002. Spatial and temporal patterns of xylem water potential in Juniperus ashei seedlings. Southwestern Naturalist 47: 153–161.
West N.E. 1984. Successional patterns and productivity potentials of pinyon-juniper ecosystems. In: National research council/National academy of sciences, Developing strategies for range management. Westview Press, Boulder, Colorado, USA, pp. 1301–1332.
Yu Z.C. 2003. Late Quaternary dynamics of tundra and forest vegetation in the southern Niagara Escarpment, Canada. New Phytologist 157: 365–390.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Van Auken, O.W., Jackson, J.T. & Jurena, P.N. Survival and growth of Juniperus seedlings in Juniperus woodlands. Plant Ecol 175, 245–257 (2005). https://doi.org/10.1007/s11258-005-0022-z
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11258-005-0022-z