메뉴 건너뛰기




Volumn 16, Issue 2, 2006, Pages 479-489

Nitrogen spatial heterogeneity influences diversity following restoration in a ponderosa pine forest, Montana

Author keywords

Diversity; Douglas fir; Lubrecht Experimental Forest; Nitrogen; Ponderosa pine; Restoration treatments; Richness; Western Montana, USA

Indexed keywords

NITRATE; NITROGEN; QUATERNARY AMMONIUM DERIVATIVE;

EID: 33646132517     PISSN: 10510761     EISSN: 10510761     Source Type: Journal    
DOI: 10.1890/1051-0761(2006)016[0479:NSHIDF]2.0.CO;2     Document Type: Article
Times cited : (59)

References (69)
  • 1
    • 0030617593 scopus 로고    scopus 로고
    • Climate, leaf litter chemistry and leaf litter decomposition in terrestrial ecosystems: A triangular relationship
    • Aerts, R. 1997. Climate, leaf litter chemistry and leaf litter decomposition in terrestrial ecosystems: a triangular relationship. Oikos 79:439-449.
    • (1997) Oikos , vol.79 , pp. 439-449
    • Aerts, R.1
  • 2
    • 0032941679 scopus 로고    scopus 로고
    • Interspecific competition in natural plant communities: Mechanisms, tradeoffs, and plant-soil feedbacks
    • Aerts, R. 1999. Interspecific competition in natural plant communities: mechanisms, tradeoffs, and plant-soil feedbacks. Journal of Experimental Botany 50:29-37.
    • (1999) Journal of Experimental Botany , vol.50 , pp. 29-37
    • Aerts, R.1
  • 3
    • 20544438786 scopus 로고
    • Application of selective logging to a ponderosa pine operation in western Montana
    • University of Montana, Missoula, Montana, USA
    • Anderson, I. V. 1933. Application of selective logging to a ponderosa pine operation in western Montana. University of Montana Bulletin Number 339. University of Montana, Missoula, Montana, USA.
    • (1933) University of Montana Bulletin Number 339
    • Anderson, I.V.1
  • 4
    • 0000554164 scopus 로고
    • Forest fire history in the northern Rockies
    • Arno, S. F. 1980. Forest fire history in the northern Rockies. Journal of Forestry 78:460-465.
    • (1980) Journal of Forestry , vol.78 , pp. 460-465
    • Arno, S.F.1
  • 7
    • 2942532129 scopus 로고    scopus 로고
    • Plant community response to resource availability and heterogeneity during restoration
    • Baer, S. G., J. M. Blair, S. L. Collins, and A. K. Knapp. 2004. Plant community response to resource availability and heterogeneity during restoration. Oecologia 139:617-629.
    • (2004) Oecologia , vol.139 , pp. 617-629
    • Baer, S.G.1    Blair, J.M.2    Collins, S.L.3    Knapp, A.K.4
  • 8
    • 0032698941 scopus 로고    scopus 로고
    • Leaf construction cost, nutrient concentration, and net CO2 assimilation of native and invasive species in Hawaii
    • Baruch, Z., and G. Goldstein. 1999. Leaf construction cost, nutrient concentration, and net CO2 assimilation of native and invasive species in Hawaii. Oecologia 121:183-192.
    • (1999) Oecologia , vol.121 , pp. 183-192
    • Baruch, Z.1    Goldstein, G.2
  • 9
    • 0020458152 scopus 로고
    • Reconstruction of a presettlement giant sequioa-mixed conifer forest community using the aggregation approach
    • Bonnicksen, T. M., and E. C. Stone. 1982. Reconstruction of a presettlement giant sequioa-mixed conifer forest community using the aggregation approach. Ecology 63:1134-1148.
    • (1982) Ecology , vol.63 , pp. 1134-1148
    • Bonnicksen, T.M.1    Stone, E.C.2
  • 10
    • 84974940794 scopus 로고
    • Nitrogen fixation associated with bryophytes colonizing burnt sites in southern Tasmania, Australia
    • Brassell, H. M., S. K. Davies, and J. P. Mattay. 1986. Nitrogen fixation associated with bryophytes colonizing burnt sites in southern Tasmania, Australia. Journal of Bryology 13:139-149.
    • (1986) Journal of Bryology , vol.13 , pp. 139-149
    • Brassell, H.M.1    Davies, S.K.2    Mattay, J.P.3
  • 12
    • 0031920230 scopus 로고    scopus 로고
    • The in.uence of geomorphological heterogeneity on biodiversity. I. A patch-scale perspective
    • Burnett, M. R., P. V. August, J. H. Brown, and K. T. Killingbeck. 1997. The in.uence of geomorphological heterogeneity on biodiversity. I. A patch-scale perspective. Conservation Biology 12:363-370.
    • (1997) Conservation Biology , vol.12 , pp. 363-370
    • Burnett, M.R.1    August, P.V.2    Brown, J.H.3    Killingbeck, K.T.4
  • 13
    • 0001940576 scopus 로고    scopus 로고
    • Seed longevity of 41 weed species buried 17 years in eastern and western Nebraska
    • Burnside, O. C., R. G. Wilson, S. Weisberg, and K. G. Hubbard. 1996. Seed longevity of 41 weed species buried 17 years in eastern and western Nebraska. Weed Science 44:74-86.
    • (1996) Weed Science , vol.44 , pp. 74-86
    • Burnside, O.C.1    Wilson, R.G.2    Weisberg, S.3    Hubbard, K.G.4
  • 14
    • 0021620234 scopus 로고
    • The effects of a prescribed burn in southwestern ponderosa pine on organic matter and nutrients in woody debris and forest floor
    • Covington, W. W., and S. S. Sackett. 1984. The effects of a prescribed burn in southwestern ponderosa pine on organic matter and nutrients in woody debris and forest floor. Forest Science 30:183-192.
    • (1984) Forest Science , vol.30 , pp. 183-192
    • Covington, W.W.1    Sackett, S.S.2
  • 16
    • 0027089432 scopus 로고
    • Soil mineral nitrogen changes following prescribed burning in ponderosa pine
    • Covington, W. W., and S. S. Sackett. 1992. Soil mineral nitrogen changes following prescribed burning in ponderosa pine. Forest Ecology and Management 54:175-191.
    • (1992) Forest Ecology and Management , vol.54 , pp. 175-191
    • Covington, W.W.1    Sackett, S.S.2
  • 17
    • 0034314219 scopus 로고    scopus 로고
    • Effects of selection harvest and prescribed fire on the soil nitrogen status of ponderosa pine forests
    • DeLuca, T. H., and K. L. Zouhar. 2000. Effects of selection harvest and prescribed fire on the soil nitrogen status of ponderosa pine forests. Forest Ecology and Management 138:263-271.
    • (2000) Forest Ecology and Management , vol.138 , pp. 263-271
    • DeLuca, T.H.1    Zouhar, K.L.2
  • 20
    • 20544471360 scopus 로고    scopus 로고
    • Stand structure in response to selection cutting and burning
    • H. Smith and S. F. Arno, editors General Technical Report RMRS-23. USDA Forest Service, Rocky Mountain Research Station, Fort Collins, Colorado, USA
    • Fiedler, C. E. 1999. Stand structure in response to selection cutting and burning. In H. Smith and S. F. Arno, editors. Eighty-eight years of change in a managed ponderosa pine forest. General Technical Report RMRS-23. USDA Forest Service, Rocky Mountain Research Station, Fort Collins, Colorado, USA.
    • (1999) Eighty-eight Years of Change in a Managed Ponderosa Pine Forest
    • Fiedler, C.E.1
  • 21
    • 0000788527 scopus 로고    scopus 로고
    • Restoration treatments promote growth and reduce mortality of old-growth ponderosa pine (Montana)
    • Fiedler, C. E. 2000. Restoration treatments promote growth and reduce mortality of old-growth ponderosa pine (Montana). Ecological Restoration 18:117-119.
    • (2000) Ecological Restoration , vol.18 , pp. 117-119
    • Fiedler, C.E.1
  • 22
    • 19544362525 scopus 로고    scopus 로고
    • Fire hazard and potential treatment effectiveness: A statewide assessment in Montana
    • Fiedler, C. E., C. E. Keegan, T. A. Morgan, and C. W. Woodall. 2003. Fire hazard and potential treatment effectiveness: a statewide assessment in Montana. Journal of Forestry 101:7.
    • (2003) Journal of Forestry , vol.101 , pp. 7
    • Fiedler, C.E.1    Keegan, C.E.2    Morgan, T.A.3    Woodall, C.W.4
  • 23
    • 0020411957 scopus 로고
    • Influence of soil heterogeneity on the coexistence of grassland species
    • Fitter, A. H. 1982. Influence of soil heterogeneity on the coexistence of grassland species. Journal of Ecology 70:139-148.
    • (1982) Journal of Ecology , vol.70 , pp. 139-148
    • Fitter, A.H.1
  • 24
    • 0030613978 scopus 로고    scopus 로고
    • Determining reference conditions for ecosystem management of southwestern ponderosa pine forests
    • Fulé , P. Z., W. W. Covington, and M. M. Moore. 1997. Determining reference conditions for ecosystem management of southwestern ponderosa pine forests. Ecological Applications 7:895-908.
    • (1997) Ecological Applications , vol.7 , pp. 895-908
    • Fulé, P.Z.1    Covington, W.W.2    Moore, M.M.3
  • 25
    • 0001761666 scopus 로고
    • On the relationship between species and area
    • Gleason, H. A. 1922. On the relationship between species and area. Ecology 3:158-162.
    • (1922) Ecology , vol.3 , pp. 158-162
    • Gleason, H.A.1
  • 26
    • 36949060119 scopus 로고
    • Competitive exclusion in herbaceous vegetation
    • Grime, J. P. 1973. Competitive exclusion in herbaceous vegetation. Nature 242:344-347.
    • (1973) Nature , vol.242 , pp. 344-347
    • Grime, J.P.1
  • 27
    • 0020457264 scopus 로고
    • Colonizing abilities of "biennial" plant species in relation to ground cover: Implication for their distributions in a successional sere
    • Gross, K. L., and P. A. Werner. 1982. Colonizing abilities of "biennial" plant species in relation to ground cover: implication for their distributions in a successional sere. Ecology 63:921-931.
    • (1982) Ecology , vol.63 , pp. 921-931
    • Gross, K.L.1    Werner, P.A.2
  • 28
    • 20544455920 scopus 로고    scopus 로고
    • Restoration management in a Montana ponderosa pine forest: Effects on soil physical, chemical, and biological properties
    • Gundale, M. J., T. H. DeLuca, C. E. Fiedler, P. W. Ramsey, M. G. Harrington, and J. E. Gannon. 2005. Restoration management in a Montana ponderosa pine forest: effects on soil physical, chemical, and biological properties. Forest Ecology and Management 213:25-38.
    • (2005) Forest Ecology and Management , vol.213 , pp. 25-38
    • Gundale, M.J.1    DeLuca, T.H.2    Fiedler, C.E.3    Ramsey, P.W.4    Harrington, M.G.5    Gannon, J.E.6
  • 29
    • 34248971890 scopus 로고
    • The competitive exclusion principle
    • Hardin, G. 1960. The competitive exclusion principle. Science 131:1292-1297.
    • (1960) Science , vol.131 , pp. 1292-1297
    • Hardin, G.1
  • 31
    • 0028978308 scopus 로고
    • Convergence and divergence of old-field vegetation after 11 yr of nitrogen addition
    • Inouye, R. S., and D. Tilman. 1995. Convergence and divergence of old-field vegetation after 11 yr of nitrogen addition. Ecology 76:1872-1887.
    • (1995) Ecology , vol.76 , pp. 1872-1887
    • Inouye, R.S.1    Tilman, D.2
  • 32
    • 0031766497 scopus 로고    scopus 로고
    • Ecological restoration alters nitrogen transformations in a ponderosa pine-bunchgrass ecosystem
    • Kaye, J. P., and S. C. Hart. 1998. Ecological restoration alters nitrogen transformations in a ponderosa pine-bunchgrass ecosystem. Ecological Applications 8::1052-1060.
    • (1998) Ecological Applications , vol.8 , pp. 1052-1060
    • Kaye, J.P.1    Hart, S.C.2
  • 33
    • 24944533365 scopus 로고
    • Nonmetric multidimensional scaling: A numerical method
    • Kruskal, J. B. 1964. Nonmetric multidimensional scaling: a numerical method. Psychometrika 29:115-129.
    • (1964) Psychometrika , vol.29 , pp. 115-129
    • Kruskal, J.B.1
  • 34
    • 77956829221 scopus 로고
    • Inherent variation in growth rate between higher plants: A search for physiological causes and ecological consequences
    • Lambers, H., and H. Poorter. 1992. Inherent variation in growth rate between higher plants: a search for physiological causes and ecological consequences. Advances in Ecological Research 23:188-261.
    • (1992) Advances in Ecological Research , vol.23 , pp. 188-261
    • Lambers, H.1    Poorter, H.2
  • 35
    • 0000273547 scopus 로고
    • The limiting similarity, convergence, and divergence of coexisting species
    • MacArthur, R. H., and R. Levins. 1967. The limiting similarity, convergence, and divergence of coexisting species. American Naturalist 101:377-385.
    • (1967) American Naturalist , vol.101 , pp. 377-385
    • MacArthur, R.H.1    Levins, R.2
  • 37
    • 8844250201 scopus 로고    scopus 로고
    • Forest structure and organic matter analysis along a fire chronosequence in the low elevation forests of western Montana
    • MacKenzie, D. M., T. H. DeLuca, and A. Sala. 2004. Forest structure and organic matter analysis along a fire chronosequence in the low elevation forests of western Montana. Forest Ecology and Management 203:331-343.
    • (2004) Forest Ecology and Management , vol.203 , pp. 331-343
    • MacKenzie, D.M.1    DeLuca, T.H.2    Sala, A.3
  • 38
    • 0006148094 scopus 로고
    • The role of nutrition in the health of inland western forests
    • Mandzak, J.M., and J. A. Moore. 1994. The role of nutrition in the health of inland western forests. Journal of Sustainable Forestry 2:191-210.
    • (1994) Journal of Sustainable Forestry , vol.2 , pp. 191-210
    • Mandzak, J.M.1    Moore, J.A.2
  • 42
    • 31444452147 scopus 로고    scopus 로고
    • Restoration treatment effects on the understory of ponderosa pine/Douglas-fir forests in western Montana, USA
    • In press
    • Metlen, K. L., and C. E. Fiedler. In press. Restoration treatment effects on the understory of ponderosa pine/Douglas-fir forests in western Montana, USA. Forest Ecology and Management.
    • Forest Ecology and Management
    • Metlen, K.L.1    Fiedler, C.E.2
  • 44
    • 0030616920 scopus 로고    scopus 로고
    • Shortand long-term effects of prescribed underburning on nitrogen availability in ponderosa pine stands in central Oregon
    • Monleon, V. J., K. Cromack, and J. D. Landsberg. 1997. Shortand long-term effects of prescribed underburning on nitrogen availability in ponderosa pine stands in central Oregon. Canadian Journal of Forest Research 27:369-378.
    • (1997) Canadian Journal of Forest Research , vol.27 , pp. 369-378
    • Monleon, V.J.1    Cromack, K.2    Landsberg, J.D.3
  • 45
    • 0032700231 scopus 로고    scopus 로고
    • Reference conditions and ecological restoration: A southwestern ponderosa pine perspective
    • Moore, M. M., W. W. Covington, and P. Z. Fulé. 1999. Reference conditions and ecological restoration: a southwestern ponderosa pine perspective. Ecological Applications 9:1266-1277.
    • (1999) Ecological Applications , vol.9 , pp. 1266-1277
    • Moore, M.M.1    Covington, W.W.2    Fulé, P.Z.3
  • 46
    • 0031945213 scopus 로고    scopus 로고
    • The influence of geomorphological heterogeneity on biodiversity II. A landscape perspective
    • Nichols, W. F., K. T. Killingbeck, and P. V. August. 1998. The influence of geomorphological heterogeneity on biodiversity II. A landscape perspective. Conservation Biology 12:371-379.
    • (1998) Conservation Biology , vol.12 , pp. 371-379
    • Nichols, W.F.1    Killingbeck, K.T.2    August, P.V.3
  • 47
    • 0003880702 scopus 로고
    • Miscellaneous Publication Number 44. Montana Forest and Conservation Experiment Station, Missoula, Montana, USA
    • Nimlos, T. J. 1986. Soils of Lubrecht Experimental Forest. Miscellaneous Publication Number 44. Montana Forest and Conservation Experiment Station, Missoula, Montana, USA.
    • (1986) Soils of Lubrecht Experimental Forest
    • Nimlos, T.J.1
  • 48
    • 0036989904 scopus 로고    scopus 로고
    • Are invaders disturbance limited? Conservation of mountain grasslands in central Argentina
    • Petryna, L., M. Mooraj, C. O. Nunes, J. J. Cantero, and M. Zobel. 2002. Are invaders disturbance limited? Conservation of mountain grasslands in central Argentina. Applied Vegetation Science 5:195-202.
    • (2002) Applied Vegetation Science , vol.5 , pp. 195-202
    • Petryna, L.1    Mooraj, M.2    Nunes, C.O.3    Cantero, J.J.4    Zobel, M.5
  • 49
    • 0002891016 scopus 로고
    • Latitudinal gradients in species diversity: A review of concepts
    • Pianka, E. R. 1966. Latitudinal gradients in species diversity: a review of concepts. American Naturalist 100:33-46.
    • (1966) American Naturalist , vol.100 , pp. 33-46
    • Pianka, E.R.1
  • 50
    • 0036013693 scopus 로고    scopus 로고
    • Effect of thinning and prescribed burning on crown fire severity in ponderosa pine forests
    • Pollet, J., and P. N. Omi. 2002. Effect of thinning and prescribed burning on crown fire severity in ponderosa pine forests. International Journal of Wildland Fire 11:1-10.
    • (2002) International Journal of Wildland Fire , vol.11 , pp. 1-10
    • Pollet, J.1    Omi, P.N.2
  • 51
    • 0001847329 scopus 로고
    • Modification of the soil environment by vegetation fires, with particular reference to nitrogen transformations: A review
    • Raison, R. J. 1979. Modification of the soil environment by vegetation fires, with particular reference to nitrogen transformations: a review. Plant and Soil 51:73-108.
    • (1979) Plant and Soil , vol.51 , pp. 73-108
    • Raison, R.J.1
  • 53
    • 0031284533 scopus 로고    scopus 로고
    • Soil heterogeneity and plant competition in an annual grassland
    • Reynolds, H. L., B. A. Hungate, F. S. Chapin, and C. M. D'Antonio. 1997. Soil heterogeneity and plant competition in an annual grassland. Ecology 78:2076-2090.
    • (1997) Ecology , vol.78 , pp. 2076-2090
    • Reynolds, H.L.1    Hungate, B.A.2    Chapin, F.S.3    D'Antonio, C.M.4
  • 54
    • 0000432060 scopus 로고
    • Environmental heterogeneity and plant species diversity
    • Ricklefs, R. E. 1977. Environmental heterogeneity and plant species diversity. American Naturalist 111::376-381.
    • (1977) American Naturalist , vol.111 , pp. 376-381
    • Ricklefs, R.E.1
  • 55
    • 0026442962 scopus 로고
    • Competition for resources between understory and overstory ponderosa pine
    • Riegel, G. M., R. F. Miller, and W. C. Krueger. 1992. Competition for resources between understory and overstory ponderosa pine. Ecological Applications 2:71-85.
    • (1992) Ecological Applications , vol.2 , pp. 71-85
    • Riegel, G.M.1    Miller, R.F.2    Krueger, W.C.3
  • 56
    • 0000640962 scopus 로고
    • The effects of aboveground and belowground competition on understory species composition in a Pinus ponderosa forest
    • Riegel, G. M., R. F. Miller, and W. C. Krueger. 1995. The effects of aboveground and belowground competition on understory species composition in a Pinus ponderosa forest. Forest Science 41:864-889.
    • (1995) Forest Science , vol.41 , pp. 864-889
    • Riegel, G.M.1    Miller, R.F.2    Krueger, W.C.3
  • 57
    • 0027706703 scopus 로고
    • How are diversity and productivity related?
    • R. E. Ricklefs and D. Schluter, editors University of Chicago Press, Chicago, Illinois, USA
    • Rozenzweig, M. L., and Z. Abramsky. 1993. How are diversity and productivity related? Pages 52-65 in R. E. Ricklefs and D. Schluter, editors. Species diversity in ecological communities. University of Chicago Press, Chicago, Illinois, USA.
    • (1993) Species Diversity in Ecological Communities , pp. 52-65
    • Rozenzweig, M.L.1    Abramsky, Z.2
  • 58
    • 0034969080 scopus 로고    scopus 로고
    • Physiological and morphological traits of exotic, invasive exotic, and native plant species in tallgrass prairie
    • Smith, M. D., and A. K. Knapp. 2001. Physiological and morphological traits of exotic, invasive exotic, and native plant species in tallgrass prairie. International Journal of Plant Science 162:785-792.
    • (2001) International Journal of Plant Science , vol.162 , pp. 785-792
    • Smith, M.D.1    Knapp, A.K.2
  • 60
    • 0031661837 scopus 로고    scopus 로고
    • Habitat patchiness affects decomposition and faunal diversity: A microcosm experiment on forest floor
    • Sulkava, P., and V. Huhta. 1998. Habitat patchiness affects decomposition and faunal diversity: a microcosm experiment on forest floor. Oecologia 116:390-396.
    • (1998) Oecologia , vol.116 , pp. 390-396
    • Sulkava, P.1    Huhta, V.2
  • 62
    • 0021562720 scopus 로고
    • Plant dominance along an experimental nutrient gradient
    • Tilman, D. 1984. Plant dominance along an experimental nutrient gradient. Ecology 65:1445-1453.
    • (1984) Ecology , vol.65 , pp. 1445-1453
    • Tilman, D.1
  • 63
    • 0027704788 scopus 로고
    • The maintenance of species richness in plant communities
    • R. E. Ricklefs and D. Schluter, editors. University of Chicago Press, Chicago, Ilinois, USA
    • Tilman, D., and S. Pacala. 1993. The maintenance of species richness in plant communities. Pages 13-25 in R. E. Ricklefs and D. Schluter, editors. Species diversity in ecological communities. University of Chicago Press, Chicago, Ilinois, USA.
    • (1993) Species Diversity in Ecological Communities , pp. 13-25
    • Tilman, D.1    Pacala, S.2
  • 64
    • 0026312019 scopus 로고
    • Nitrogen limitation on land and in the sea: How can it occur?
    • Vitousek, P. M., and R. W. Howarth. 1991. Nitrogen limitation on land and in the sea: How can it occur? Biogeochemistry 13:87-115.
    • (1991) Biogeochemistry , vol.13 , pp. 87-115
    • Vitousek, P.M.1    Howarth, R.W.2
  • 65
    • 0030617453 scopus 로고    scopus 로고
    • Microtopographic heterogeneity and floristic diversity in experimental wetland communities
    • Vivian-Smith, G. 1997. Microtopographic heterogeneity and floristic diversity in experimental wetland communities. Ecology 85:71-82.
    • (1997) Ecology , vol.85 , pp. 71-82
    • Vivian-Smith, G.1
  • 66
    • 0000594195 scopus 로고
    • Evolution and measurement of species diversity
    • Whittaker, R. H. 1972. Evolution and measurement of species diversity. Taxon 21:213-251.
    • (1972) Taxon , vol.21 , pp. 213-251
    • Whittaker, R.H.1
  • 67
    • 0023470136 scopus 로고
    • Automated method for determining nitrate and nitrite in water and soil extracts
    • Willis, R. B., and C. E. Gentry. 1987. Automated method for determining nitrate and nitrite in water and soil extracts. Communications in Soil Science and Plant Analysis 18:625-636.
    • (1987) Communications in Soil Science and Plant Analysis , vol.18 , pp. 625-636
    • Willis, R.B.1    Gentry, C.E.2
  • 68
    • 0001390770 scopus 로고
    • Elimination of interferences in the colorimetric analysis of ammonium in water and soil extracts
    • Willis, R. B., G. J. Schwab, and C. E. Gentry. 1993. Elimination of interferences in the colorimetric analysis of ammonium in water and soil extracts. Communications in Soil Science and Plant Analysis 24:1009-1019.
    • (1993) Communications in Soil Science and Plant Analysis , vol.24 , pp. 1009-1019
    • Willis, R.B.1    Schwab, G.J.2    Gentry, C.E.3
  • 69
    • 0004252445 scopus 로고    scopus 로고
    • Prentice Hall, Upper Saddle River, New Jersey, USA
    • Zar, J. H. 1999. Biostatistical analysis. Prentice Hall, Upper Saddle River, New Jersey, USA.
    • (1999) Biostatistical Analysis
    • Zar, J.H.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.