Reconciling plant strategy theories of Grime and Tilman

Summary 1 The theories of Grime and Tilman are ambitious attempts to unify disparate theories regarding the construction of plants, their interaction with the environment and the assembly of communities. After over two decades of parallel research, their ideas have not been reconciled, hindering progress in understanding the functioning of ecosystems. 2 Grime’s theories do not adequately incorporate the importance of non-heterogeneous supplies of nutrients and how these supplies are partitioned over long time scales, are inconsistent regarding the importance of disturbance in nutrient-limited habitats and need to reconsider the carbon economy of shade-tolerant plants. 3 Failure to account for differences between aquatic and terrestrial systems in how resource supplies are partitioned led Tilman to develop a shifting set of theories that have become reduced in mechanistic detail over time. The most recent highlighted the reduction of nutrient concentrations in soil solution, although it can no longer be derived from any viable mechanistic model. The slow diffusion of nutrients in soils means that the reduction of average soil solution nutrient concentrations cannot explain competitive exclusion. 4 Although neither theory, nor a union of the two, adequately characterizes the dynamics of terrestrial plant assemblages, the complementarity in their assumptions serve as an important foundation for future theory and research. 5 Reconciling the approaches of Grime and Tilman leads to six scenarios for competition for nutrients and light, with the outcome of each depending on the ability of plants to preempt supplies. Under uniform supplies, pulses or patches, light competition requires leaf area dominance, while nutrient competition requires root length dominance. There are still important basic questions regarding the nature of nutrient supplies that will need to be answered, but recent research brings us closer to a unified set of theories on resource competition.

[1]  R. Peters,et al.  A Test of the Tilman Model of Plant Strategies: Relative Growth Rate and Biomass Partitioning , 1990, The American Naturalist.

[2]  D. Goldberg,et al.  Root competition can cause a decline in diversity with increased productivity , 2003 .

[3]  F. S. Chapin,et al.  Relationship between the structure of root systems and resource use for 11 North American grassland plants , 2003, Plant Ecology.

[4]  W. Stanley Harpole,et al.  Mechanisms responsible for the positive diversity–productivity relationship in Minnesota grasslands , 2004 .

[5]  J. P. Grime,et al.  AN INVESTIGATION OF LEAF PALATABILITY USING THE SNAIL CEPAEA NEMORALIS L. , 1968 .

[6]  D. Tilman,et al.  Species effects on nitrogen cycling: a test with perennial grasses , 1990, Oecologia.

[7]  D. Tilman,et al.  Convergence and divergence of old-field vegetation after 11 yr of nitrogen addition , 1995 .

[8]  Jessica Gurevitch,et al.  EMPIRICAL APPROACHES TO QUANTIFYING INTERACTION INTENSITY: COMPETITION AND FACILITATION ALONG PRODUCTIVITY GRADIENTS , 1999 .

[9]  D. Tilman.  Nitrogen-Limited Growth in Plants from Different Successional Stages , 1986 .

[10]  Bill Shipley,et al.  The Seduction by Mechanism: A Reply to Tilman , 1991, The American Naturalist.

[11]  Jacob Weiner,et al.  Mechanisms determining the degree of size asymmetry in competition among plants , 1998, Oecologia.

[12]  J. Grace.  On the relationship between plant traits and competitive ability. , 1990 .

[13]  D. Tilman,et al.  DYNAMICS OF NITROGEN COMPETITION BETWEEN SUCCESSIONAL GRASSES , 1991 .

[14]  M. Austin,et al.  Competition between Australian native and introduced grasses along a nutrient gradient , 2003 .

[15]  J. Grace,et al.  Mechanisms of plant competition for nutrients: the elements of a predictive theory of competition. , 1990 .

[16]  P. Reich,et al.  Leaf-level light compensation points in shade-tolerant woody seedlings. , 2005, The New phytologist.

[17]  D. Tilman.  The Resource-Ratio Hypothesis of Plant Succession , 1985, The American Naturalist.

[18]  James B. Grace,et al.  On the Measurement of Plant Competition Intensity , 1995 .

[19]  J. Cahill,et al.  Antagonistic interactions between competition and insect herbivory on plant growth , 2004 .

[20]  J. P. Grime,et al.  AN ANALYSIS OF COMPETITIVE ABILITY IN THREE PERENNIAL GRASSES , 1976 .

[21]  DAVID TITMAN,et al.  Ecological Competition Between Algae: Experimental Confirmation of Resource-Based Competition Theory , 1976, Science.

[22]  D. Tilman,et al.  Influence of Nitrogen Loading and Species Composition on the Carbon Balance of Grasslands , 1996, Science.

[23]  Steward T. A. Pickett,et al.  Forest Reorganization: A Case Study in an Old‐Growth Forest Catastrophic Blowdown , 1995 .

[24]  J. Battles,et al.  RESPONSES OF EARLY SUCCESSIONAL NORTHERN HARDWOOD FORESTS TO CHANGES IN NUTRIENT AVAILABILITY , 1998 .

[25]  W. Bowman,et al.  Species effects on resource supply rates: do they influence competitive interactions? , 2004, Plant Ecology.

[26]  J. P. Grime,et al.  The effects of trophic structure and soil fertility on the assembly of plant communities: a microcosm experiment , 2000 .

[27]  J. P. Grime.  FACTORS DETERMINING THE OCCURRENCE OF CALCIFUGE SPECIES ON SHALLOW SOILS OVER CALCAREOUS SUBSTRATA , 1963 .

[28]  J. P. Grime,et al.  Evidence for the Existence of Three Primary Strategies in Plants and Its Relevance to Ecological and Evolutionary Theory , 1977, The American Naturalist.

[29]  D. Coomes,et al.  IMPACTS OF ROOT COMPETITION IN FORESTS AND WOODLANDS: A THEORETICAL FRAMEWORK AND REVIEW OF EXPERIMENTS , 2000 .

[30]  D. Tilman.  Relative Growth Rates and Plant Allocation Patterns , 1991, The American Naturalist.

[31]  C. Prentice.  Plants in changing environments: Linking physiological, population and community ecology , 1997 .

[32]  F. Berendse,et al.  Competition and Nitrogen Loss from Plants in Grassland Ecosystems , 1992 .

[33]  P. Reich,et al.  Low-light carbon balance and shade tolerance in the seedlings of woody plants: Do winter deciduous and broad-leaved evergreen species differ? , 1999 .

[34]  J. P. Grime,et al.  Plant Strategies, Vegetation Processes, and Ecosystem Properties , 2006 .

[35]  J. Monod,et al.  Technique, Theory and Applications of Continuous Culture. , 1950 .

[36]  D. Tilman.  Plant Strategies and the Dynamics and Structure of Plant Communities. (MPB-26), Volume 26 , 1988 .

[37]  C. Welden,et al.  The Intensity of Competition Versus its Importance: An Overlooked Distinction and Some Implications , 1986, The Quarterly Review of Biology.

[38]  The Schism between Theory and Ardent Empiricism: A Reply to Shipley and Peters , 1991, The American Naturalist.

[39]  K. Thompson.  The resource ratio hypothesis and the meaning of competition , 1987 .

[40]  P. B. Tinker,et al.  Solute Movement in the Rhizosphere , 2000 .

[41]  D. Tilman,et al.  Growth of old field herbs on a nitrogen gradient , 1989 .

[42]  David Tilman,et al.  Allocation and the transient dynamics of succession on poor soils. , 1990 .

[43]  K. Kirkman,et al.  Plant strategies and trait trade‐offs influence trends in competitive ability along gradients of soil fertility and disturbance , 2005 .

[44]  A. Hodge,et al.  Are microorganisms more effective than plants at competing for nitrogen? , 2000, Trends in plant science.

[45]  J. P. Grime,et al.  Seedling resistance to herbivory as a predictor of relative abundance in a synthesised prairie community , 2003 .

[46]  D. Tilman,et al.  Plant allocation, growth rate and successional status , 1994 .

[47]  D. Goldberg.  Competitive ability: Definitions, contingency and correlated traits , 1996 .

[48]  J. Fargione,et al.  Supply pre-emption, not concentration reduction, is the mechanism of competition for nutrients. , 2005, The New phytologist.

[49]  J. P. Grime,et al.  Plant Strategies and Vegetation Processes. , 1980 .

[50]  H. Poorter,et al.  INTERSPECIFIC VARIATION IN RELATIVE GROWTH RATE : ON ECOLOGICAL CAUSES AND PHYSIOLOGICAL CONSEQUENCES , 2003 .

[51]  J. E. Weaver,et al.  EXTENT AND LONGEVITY OF THE SEMINAL ROOTS OF CERTAIN GRASSES. , 1945, Plant physiology.

[52]  J. Schimel,et al.  NITROGEN MINERALIZATION: CHALLENGES OF A CHANGING PARADIGM , 2004 .

[53]  D. Tilman.  Resource Competition between Plankton Algae: An Experimental and Theoretical Approach , 1977 .

[54]  J. P. Grime.  Shade Tolerance in Flowering Plants , 1965, Nature.

[55]  David Tilman,et al.  Secondary Succession and the Pattern of Plant Dominance Along Experimental Nitrogen Gradients , 1987 .

[56]  C. Lusk.  Leaf area accumulation helps juvenile evergreen trees tolerate shade in a temperate rainforest , 2002, Oecologia.

[57]  F. Putz,et al.  Mechanisms of arrested succession in shrublands: root and shoot competition between shrubs and tree seedlings , 1992 .

[58]  J. E. Weaver.  Prairie Plants and Their Environment: A Fifty-year Study in the Midwest , 1968 .

[59]  David Tilman,et al.  Competition Among Grasses Along a Nitrogen Gradient: Initial Conditions and Mechanisms of Competition , 1993 .

[60]  Christopher J. Lortie,et al.  The importance of importance , 2005 .

[61]  D. Tilman.  On the meaning of competition and the mechanisms of competitive superiority , 1987 .

[62]  D. Clarkson.  Calcium Uptake by Calcicole and Calcifuge Species in the Genus Agrostis L. , 1965 .

[63]  Paul A. Keddy,et al.  Effects of low and high nutrients on the competitive hierarchy of 26 shoreline plants , 2000 .

[64]  P. J. Smethurst,et al.  SIMULATING NUTRIENT UPTAKE BY SINGLE OR COMPETING AND CONTRASTING ROOT SYSTEMS , 1993 .

[65]  Katherine J. Willis,et al.  The Evolution of Plants , 2002 .

[66]  J. Lovett-Doust,et al.  Plant strategies, vegetation processes, and ecosystem properties , 2002 .

[67]  P. Reich,et al.  [Letters to nature] , 1975, Nature.

[68]  D. A. Bella,et al.  A Theoretical Approach to Interspecific Competition in Phytoplankton Communities , 1973, The American Naturalist.

[69]  P. Reich,et al.  The Evolution of Plant Functional Variation: Traits, Spectra, and Strategies , 2003, International Journal of Plant Sciences.

[70]  Alastair Fitter,et al.  Why plants bother: root proliferation results in increased nitrogen capture from an organic patch when two grasses compete , 1999 .

[71]  Jacques Monod,et al.  LA TECHNIQUE DE CULTURE CONTINUE THÉORIE ET APPLICATIONS , 1978 .

[72]  David Tilman,et al.  Resources: A Graphical-Mechanistic Approach to Competition and Predation , 1980, The American Naturalist.

[73]  D. Tilman.  Resource competition and community structure. , 1983, Monographs in population biology.

[74]  Xavier Raynaud,et al.  SOIL CHARACTERISTICS PLAY A KEY ROLE IN MODELING NUTRIENT COMPETITION IN PLANT COMMUNITIES , 2004 .

[75]  J. E. Weaver,et al.  LENGTH OF LIFE OF ROOTS OF TEN SPECIES OF PERENNIAL RANGE AND PASTURE GRASSES. , 1946, Plant physiology.

[76]  E. Aschehoug,et al.  Invasive plants versus their new and old neighbors: a mechanism for exotic invasion. , 2000, Science.

[77]  P. Reich,et al.  Functional traits, productivity and effects on nitrogen cycling of 33 grassland species , 2002 .

[78]  J. P. Grime,et al.  Competitive Exclusion in Herbaceous Vegetation , 1973, Nature.

[79]  R. Aerts.  Interspecific competition in natural plant communities: mechanisms, trade-offs and plant-soil feedbacks , 1999 .