Tree-Grass Interactions in Savannas

Annual Reviews - Tập 28 Số 1 - Trang 517-544 - 1997
Robert J. Scholes1, Steve Archer2
1Division of Water, Environment and Forest Science and Technology, CSIR, PO Box 395, Pretoria 0001, South Africa;
2Department of Rangeland Ecology and Management, Texas A&M University, College Station, Texas 77843-2126, USA;

Tóm tắt

Savannas occur where trees and grasses interact to create a biome that is neither grassland nor forest. Woody and gramineous plants interact by many mechanisms, some negative (competition) and some positive (facilitation). The strength and sign of the interaction varies in both time and space, allowing a rich array of possible outcomes but no universal predictive model. Simple models of coexistence of trees and grasses, based on separation in rooting depth, are theoretically and experimentally inadequate. Explanation of the widely observed increase in tree biomass following introduction of commercial ranching into savannas requires inclusion of interactions among browsers, grazers, and fires, and their effects on tree recruitment. Prediction of the consequences of manipulating tree biomass through clearing further requires an understanding of how trees modify light, water, and nutrient environments of grasses. Understanding the nature of coexistence between trees and grass, which under other circumstances are mutually exclusive or unequal partners, yields theoretical insights and has practical implications.

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Tài liệu tham khảo

10.2307/2845381

10.2307/3545695

10.1016/S0140-1963(05)80085-0

Anderson RC, 1997, Savanna, Barren and Rock Outcrop Plant Communities of North America.

10.2307/3899008

10.2307/4003039

10.1086/284996

Archer S. 1994.Woody plant encroachment into southwestern grasslands and savannas: rates, patterns and proximate causes.InEcological Implications of Livestock Herbivory in the West, ed. M Vavra, W Laycock, R Pieper, pp. 13–68. Denver: Soc. Range Manage.

Archer S, 1995, Trop. Grassl., 29, 218

10.1080/11956860.1995.11682272

Archer S. 1996.Assessing and interpreting grass-woody plant dynamics.InThe Ecology and Management of Grazing Systems, ed. J Hodgson, A Illius, pp. 101–34. Wallingford, UK: CAB Int.

10.1007/BF01091640

10.2307/1942463

10.2307/1550499

10.2307/3235759

10.1038/383577a0

10.1139/x90-208

10.2136/sssaj1980.03615995004400010023x

10.2136/sssaj1978.03615995004200050031x

10.2307/4002824

10.1111/j.1365-2028.1984.tb00701.x

10.2307/2845380

10.2307/1939416

10.2307/4002725

10.2307/2403708

10.2307/1312205

10.2307/2404278

10.1007/BF00705265

10.2307/1941892

10.2307/3544672

10.1016/0378-1127(88)90054-0

10.2307/2845378

10.2307/3899114

10.2307/1937544

Bourliere F, ed. 1983.Tropical Savannas. Amsterdam: Elsevier. 730 pp.

10.2307/3897682

10.1016/0378-1127(93)90101-R

10.1038/336464a0

10.2307/3565966

Burgess TL. 1995.Desert grassland, mixed shrub savanna, shrub steppe, or semidesert scrub? The dilemma of coexisting growth forms.InThe Desert Grasslands, ed. MP McClaran, TR Van Devender, pp. 31–67. Tucson: Univ. Ariz. Press

10.2307/2845383

10.2307/3897324

10.1007/BF00378231

10.1038/327615a0

10.1007/BF02912621

10.1071/AR9890699

10.1007/BF00704827

10.2307/1310177

Cole MM, 1986, The Savannas: Biogeography and Geobotany.

10.1007/BF00317208

10.2307/2845587

10.1007/BF00317442

10.2307/1940607

10.2307/1940606

10.2307/5037

10.2307/4002794

10.2307/3899086

Escudero A, 1985, Oecol. Plant., 6, 73

10.1007/BF00627735

10.2307/4002959

10.2307/4003706

Fulbright JE, 1987, Wildl. Soc. Bull., 15, 560

Gadgill M, Meher-Homji VM. 1985.Land use and productive potential of Indian savannas.InEcology and Management of the World's Savannas, ed. JC Tothill, JJ Mott, pp. 107–13. Canberra: Aust. Acad. Sci.

10.2307/1933601

Gardener GJ, McIvor JG, Williams J. 1990.Dry tropical rangelands: solving one problem and creating another.InAustralian Ecosystems: 200 Years of Utilization, Degradation and Reconstruction, ed. DA Saunders, AJM Hopkins, RA How, pp. 279–86. Geraldton, West. Aust.: Ecol. Soc. Aust.

10.1017/S0266467400003254

10.1111/j.1469-185X.1977.tb01347.x

Gutierrez JR, 1979, Oecol. Plant., 14, 151

Hara M, 1987, Vegetatio, 71, 67, 10.1007/BF00044819

10.2307/1940611

10.2307/2404376

Harris DR, 1980, Human Ecology in Savanna Environments.

10.1007/BF00044689

10.1006/jare.1995.0057

10.2307/3899690

10.1016/S0140-1963(18)31334-X

10.2307/2261290

Hoffman MT, 1990, S Afr. J. Sci., 86, 462

10.1017/S0266467400000997

10.1007/978-3-642-68786-0

10.1146/annurev.es.22.110191.002401

10.1017/S0266467400006623

10.1016/0167-8809(90)90126-X

10.1007/BF00333714

10.2307/3896260

10.2307/1939317

10.1007/BF02344747

Johnson RW, Tothill JC. 1985.Definition and broad geographic outline of savanna lands.InEcology and Management of the World's Savannas, ed. JC Tothill, JJ Mott, pp. 1–13. Canberra, ACT: Aust. Acad. Sci.

10.2307/2261261

10.2307/2259112

10.2307/1941257

10.2307/3898853

10.2307/2259780

10.2307/2426272

10.1007/BF00328579

10.2307/2426206

10.1007/BF00158553

10.2307/1937186

10.2307/2444008

10.2307/2261665

10.2307/4002276

10.2307/3545315

10.2136/sssaj1991.03615995005500020037x

McClaran MP, 1989, Madroño, 36, 141

McPherson G, 1997, Ecology and Management of North American Savannas., 10.1353/book.109739

10.1016/0378-1127(92)90089-R

10.2307/3236134

McPherson GR, 1991, Gt. Basin Nat., 51, 316

10.1016/0378-1127(87)90042-9

10.2307/2425767

10.2307/2845379

Merz RW, 1956, J. For., 54, 774

10.2307/1312298

10.2307/2261014

10.2307/4002976

10.1007/BF00010549

10.2307/3236217

10.1016/0022-1694(90)90197-6

Noble JC, 1997, The delicate and noxious scrub: CSIRO research into native tree and shrub proliferation in the semi-arid woodlands of Eastern Australia.

10.1007/BF00329083

10.1080/10220119.1995.9647864

10.1086/297048

Palaez DV, 1994, Oecologia, 81, 501

10.2307/2425189

10.1111/j.1365-2028.1983.tb00311.x

10.2307/2260224

10.2307/3899002

10.1071/BT9730235

Pressland AJ, 1975, Aust. J. Bot., 23, 965

10.2307/2401358

10.2307/2269349

10.1016/S0022-4618(16)30158-9

10.1007/BF00378959

10.2307/1939963

San José JJ, 1991, Acta Oecol., 12, 237

10.2307/2388296

10.4159/harvard.9780674418554

10.2307/1938649

10.2307/4002530

10.2307/3236173

10.1111/j.1442-9993.1990.tb01527.x

10.5962/bhl.title.8099

Schlesinger WH, 1996, Ecology, 72, 364, 10.2307/2265615

10.1126/science.247.4946.1043

10.2307/4002665

10.2307/2845371

Scholes RJ, Hall DO. 1996.The carbon budget of tropical savannas, woodlands, and grasslands.InModelling Terrestrial Ecosystems, ed. A Breymeyer, D Hall, J Melillo, G Agren, pp. 69–100. Chichester: Wiley

10.1017/CBO9780511565472

Scifres CJ. 1980.Brush Management: Principles and Practices for Texas and the Southwest. College Station, TX: Texas A&M Univ. Press

10.2307/3899387

10.2307/3898637

10.1017/S0266467400008713

Sinclair ARE. 1979.Dynamics of the Serengeti ecosystem.InSerengeti: Dynamics of an Ecosystem, ed. ARE Sinclair, M Norton-Griffiths, pp. 1–30. Chicago: Univ. Chicago Press

10.1139/z85-147

10.2307/2404383

10.1007/BF00045650

10.2307/3235754

10.2307/2260231

10.2307/2388488

10.1007/978-3-642-78969-4

10.1007/BF00036131

Stewart OC. 1955.Fire as the first great force employed by man.InMan's Role in Changing the Face of the Earth, ed. WL Thomas, pp. 115–33. Chicago, IL: Univ. Chicago Press

Strang RM, 1969, Com. For. Rev., 48, 26

10.2307/2403668

10.1080/02566702.1987.9648078

10.1126/science.249.4972.1017

10.1016/0378-1127(91)90212-E

10.1080/02566702.1992.9648301

10.2307/3899611

10.2307/3896877

10.2136/sssaj1973.03615995003700010033x

10.2307/3897722

10.2136/sssaj1986.03615995005000020044x

10.2136/sssaj1986.03615995005000020044x

10.2307/2260204

10.1111/j.1442-9993.1990.tb01017.x

Tothill JC, Mott JJ, eds. 1985.Ecology and Management of the World's Savannas. Canberra: Aust. Acad. Sci. 384pp.

10.2307/2257252

10.1080/00725560.1980.9648907

10.1080/00725560.1980.9648907

10.2307/3899473

10.1007/BF00036129

10.2307/3235758

10.1016/0378-1127(86)90009-5

10.2307/1942601

Walker BH, 1987, Determinants of Tropical Savannas.

Walker BH. 1987.A general model of savanna structure and function.InDeterminants of Savannas, ed. BH Walker, pp. 1–12. Paris: IUBS

10.2307/2259679

10.1007/978-3-642-68786-0_26

10.1071/AR9720405

10.1111/j.1442-9993.1986.tb01384.x

Walter H, 1971, Ecology of Tropical and Subtropical Vegetation.

10.2307/3897253

10.1890/0012-9658(1997)078[0751:SMROVS]2.0.CO;2

10.2307/3235707

Werner PA, 1991, Savanna Ecology and Management: Australian Perspectives and Intercontinental Comparisons.

10.2307/1937666

10.1038/241104a0

Westoby M, 1979, Israel J. Bot., 28, 169

10.2307/3899492

10.2307/2258392

10.2307/2258290

10.2307/2259222

10.2307/3897252

10.1016/0304-3800(85)90054-7

10.2307/2260630

10.1017/S0043174500059075

Young MD, 1993, The World's Savannas: Economic Driving Forces, Ecological Constraints and Policy Options for Sustainable Land Use.

10.2307/1932049