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Spatial patterns on the sagebrush steppe/Western juniper ecotone

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Abstract

Analysis of the spatial patterns of woody plants is important to better understand the ecological processes that govern the worldwide expansion of woody plants across semi-arid ecosystems. Second-order characteristics of a marked spatial point pattern of western juniper (Juniperus occidentalis subsp. occidentalis) were analyzed using Ripley’s K-functions and the pair-correlation function g. The marked point process of crown diameters was produced via two-dimensional wavelet analysis of a fine scale aerial photograph at the woodland-steppe ecotone in the Reynolds Creek watershed in the Owyhee Mountains, southwestern Idaho.

Colonization of J. occidentalis stems from mature juniper trees growing in rocky, fire resistant areas. Although these areas introduce components of natural heterogeneity within the landscape, the selected study area is situated within a single soil type, and we modeled the expansion of juniper plants into previously juniper-free sagebrush steppe as a homogeneous point process with constant intensity.

Through this research we have identified two statistically significant spatial scales characteristic of J. occidentalis on the woodland/steppe ecotone: (1) We observed inhibition between J. occidentalis plants at distances  <15 m, resulting in a regular pattern, rather than clumped or random. This short-distance inhibition can be attributed to competition for water and other resources. Recruitment of young J. occidentalis occurs significantly more often in a direction away from older plants, maximizing the utilization of water and light resources, and perpetuating the spread of the species into previously juniper-free shrub-steppe. (2) J. occidentalis on the ecotone exhibits significant clustering within a 30–60 m radius. Bivariate point pattern analyses provide evidence that, within a distance of 50–70 m, there is a spatial dependence in tree size such that medium trees are more likely than small trees to be close to large trees. We attribute these phenomena to the fact that juniper seeds are commonly dispersed by berry-eating birds with small territories (0.3–1 ha). Beyond a distance of 50–70 m, juniper plants are randomly distributed, suggesting that additional long-range seed dispersal processes are at work. We further acknowledge the importance of including a reference to spatial scale when formulating hypotheses in statistical analysis of spatio-temporal point patterns.

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References

  • Addison PS (2002) The illustrated wavelet transform handbook, Institute of Physics Publishing. The Institute of Physics, London, UK

    Book  Google Scholar 

  • Asner GP, Archer S, Hughes RF, Ansley RJ and Wessman CA (2003) Net change in regional woody vegetation cover and carbon storage in Texas Drylands, 1937–1999. Glob Change Biol 9:316–335

    Article  Google Scholar 

  • Baddeley A, Turner R (2005) Spatstat: an R package for analyzing spatial point patterns. J Statis Software 12:1–42

    Google Scholar 

  • Burkhardt JW, Tisdale EW (1976) Cause of juniper invasion in Southeastern Idaho. Ecology 57:472–484

    Article  Google Scholar 

  • Carothers SW, Balda RP, Haldeman JR (1973) Habitat selection and density of breeding birds of a coniferous forest in the White Mountains, Arizona. Pages 22–36 In: Carothers SW, Haldeman JR, Balda RP (eds) Breeding birds of the San Francisco Mountain area and the White Mountains, Arizona. Mus. North. Ariz. Tech. Ser. 12. 54pp

  • Chambers JC, Vander-Wall SB, Schupp EW (1999) Seed and seedling ecology of pinyon and juniper species in the pygmy woodlands of western North America. Bot Rev 65:1–38

    Google Scholar 

  • Clark JS, Fastie C, Hurtt G, Jackson ST, Johnson C, King G, Lewis M, Lynch J, Pacala S, Prentice C, Schupp EW, Webb III T, Wyckoff P (1998) Dispersal theory offers solutions to Reid’s paradox of rapid plant migration. BioScience 48:13–24

    Article  Google Scholar 

  • Couteron P, Kokou K (1997) Woody vegetation spatial patterns in a semi-arid savanna of Burkina Faso, West Aftica. Plant Ecol 132:211–227

    Article  Google Scholar 

  • Cressie NAC (1991) Statistics for spatial data. John Wiley, Chichester, UK

    Google Scholar 

  • Diggle PJ (2003) Statistical analysis of spatial point patterns, 2nd edn. Oxford University Press, New York

    Google Scholar 

  • Fule’ PZ, Covington WW (1998) Spatial patterns of Mexican pine-oak forests under different recent fire regimes. Plant Ecol 134:197–209

    Article  Google Scholar 

  • Hudak AT, Wessman CA (1998) Textural analysis of historical aerial photography to characterize woody plant encroachment in South African savanna. Remote Sensing Environ 66:317–330

    Article  Google Scholar 

  • Isaaks EH, Srivastava RM (1989) An introduction to applied geostatistics. Oxford University Press Inc., New York, New York

    Google Scholar 

  • Jameson DA (1970) Degradation and accumulation of inhibitory substances from Juniperus osteosperma (Torr.) Little. Plant Soil 33:213–224

    Article  CAS  Google Scholar 

  • Josaitis RM (1991) The effects of western juniper occupancy on changes in soil characteristics in relation to shrub and grass establishment. Masters Thesis, University of Idaho, Moscow, Idaho, USA

  • Lederer RJ (1977) Winter territoriality and foraging behavior of the townsend’s soiliataire. Am Midl Nat 97(1):101–109

    Article  Google Scholar 

  • Maser C and Gashwiler JS (1977) Interrelationships of wildlife and western juniper. In: Proceedings of the western juniper ecology and management workshop in Bend Oregon pp. 37–82, In: Martin RE, Dealy JE, Caraher DL (eds) USDA Forest Service Portland Oregon GTR PNW-74

  • MATLAB® (2004) Matlab and Simulink, Version 7.0.0.27 (R14). The MathWorks, http://www.mathworks.com/products/matlab/

  • Miller RF, Rose JA (1995) Historic expansion of juniperus occidentalis in southeastern Oregon. Great Basin Nat 55:37–45

    Google Scholar 

  • Miller RF, Bates JD, Svejcar TJ, Pierson FB, Eddleman LE (2005) Biology, Ecology, and Management of Western Juniper. Technical Bulletin 152, June 2005, Oregon State University, Agricultural Experiment Station

  • Park A (2003) Spatial segregation of pines and oaks under different fire regimes in the Sierra Madre Occidental. Plant Ecol 169:1–20

    Article  Google Scholar 

  • Poddar S, Lederer RJ (1982) Juniper berries as and exclusive winter forage for townsend’s soilitaires. Am Midl Nat 108(1):34–40

    Article  Google Scholar 

  • R Development Core Team (2004) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-00-3,http://www.R-project.org

  • Ribeiro Jr. PJ, Diggle PJ (2001) geoR: a package for geostatistical analysis. R-NEWS Vol 1, No 2. ISSN 1609-3631. Available for download at: http://www.cran.r-project.org/doc/Rnews

  • Ripley BD (1981) Spatial statistics. Wiley, New York, USA

    Book  Google Scholar 

  • Ripley BD (1988) Statistical inference for spatial processes. Cambridge University Press

  • Roth A (2004) Fire patterns within a successional gradient of a sagebrush steppe/juniper woodland. Masters Thesis, University of Idaho, Moscow, Idaho, USA

  • Salomonson MG, Balda RP (1977) Winter territoriality of townsend’s solitaires (Myadestes townsendi) in a pinyon-juniper-ponderosa pine ecotone. Condor 79:148–161

    Article  Google Scholar 

  • Schofield CJ, Bucher EH (1986) Industrial contributions to desertification in South America. Trends Ecol Evol 1:78–80

    Article  Google Scholar 

  • Schupp EW, Gomez JM, Jimenez JE, Fuentes M (1997) Dispersal of Juniperus occidentalis (western juniper) seeds by frugivorous mammals on Juniper Mountain, southeastern Oregon. Great Basin Nat 57:74–78

    Google Scholar 

  • Schurr FM, Bossdorf O, Milton SJ, Schumacher J (2004) Spatial pattern formation in semi-arid shrublands: a priori predicted versus observed pattern characteristics. Plant Ecol 173:271–282

    Article  Google Scholar 

  • Seligman N, Henkin Z (2002) Persistence in Sarcopoterium spinosum dwarf-shrub communities. Plant Ecol 164:95–107

    Article  Google Scholar 

  • Stoyan D, Penttinen A (2000) Recent applications of point process methods in forestry statistics. Stat Sci 15(1):61–78

    Article  Google Scholar 

  • Stoyan D, Stoyan H (1994) Fractals, random shapes and point fields: methods of geometrical statistics. Wiley, Chichester, UK

    Google Scholar 

  • Strand EK, Vierling LA, Smith AMS, Bunting SC, Hann DB, Gessler PE (2005). Wavelet estimation of plant spatial patterns in multi-temporal aerial photography, Eos transactions, American Geophysical Union, 86, 52, Fall Meeting, San Francisco, CA, December 5–9, 2005, Supplemental, B43B-0287

  • Strand EK, Smith AMS, Bunting SC, Vierling LA, Hann DB, Gessler PE (2006). Wavelet Estimation of plant spatial patterns in multi-temporal aerial photography, Int J Remote Sens, 27(9–10):2049–2054

    Google Scholar 

  • Tausch RJ, West NE (1988) Differential establishment of pinyon and juniper following fire. Am Midl Nat 119(1):174–184

    Article  Google Scholar 

  • Van Auken OW (2000) Shrub invasions of North American semiarid grasslands. Annu Rev Ecol Syst 31:197–215

    Article  Google Scholar 

  • Van Auken OW, Jackson JT, Jurena PN (2004) Survival and growth of Juniperus seedlings in Juniperus woodlands. Plant Ecol 175:245–257

    Article  Google Scholar 

  • Walker J, Gillison AN (1982) Australian savannas. In: Huntley BJ, Walker BH (eds) Ecology of tropical savannas. Springer Verlag, New York, pp 5–24

    Google Scholar 

  • Whiteman G, Brown JR (1998) Assessment of a method for mapping woody plant density in a grassland matrix. J Arid Environ 38:269–282

    Article  Google Scholar 

  • Wiegand T, Moloney KA (2004) Rings, circles, and null-models for point pattern analysis in ecology. Oikos 104:209–229

    Article  Google Scholar 

  • Young H (1956) Territorial activities of the American Robin (Turdus migratorius). Ibis 98:448–452

    Google Scholar 

Download references

Acknowledgements

We thank two anonymous reviewers for their insightful comments that have contributed to the contents and quality of this manuscript.

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Authors and Affiliations

  1. Department of Rangeland Ecology and Management, University of Idaho, Moscow, ID, 83844, USA

    Eva K. Strand & Stephen C. Bunting

  2. Department of Mathematics and Statistics, University of Melbourne, VIC, 3010, Melbourne, Australia

    Andrew P. Robinson

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  1. Eva K. Strand
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  2. Andrew P. Robinson
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  3. Stephen C. Bunting
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Correspondence to Eva K. Strand.

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Strand, E.K., Robinson, A.P. & Bunting, S.C. Spatial patterns on the sagebrush steppe/Western juniper ecotone. Plant Ecol 190, 159–173 (2007). https://doi.org/10.1007/s11258-006-9198-0

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  • DOI: https://doi.org/10.1007/s11258-006-9198-0

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