Seedling functional types in a lowland rain forest in Mexico.

Seedling morphology of 210 species (173 trees and 37 lianas) was studied from a community perspective to identify major patterns of seedling functional types in a Mexican rain forest. Five types of seedlings were distinguished: cryptocotylar with reserve storage or absorption cotyledons (epigeal [CER] and hypogeal [CHR]), phanerocotylar epigeal, either with photosynthetic cotyledons (PEF) or with reserve storage or absorption cotyledons (PER), and phanerocotylar hypogeal with reserve cotyledons (PHR). The most common seedling type was PEF (49.5%), followed by CHR (31.4%), PER (9.5%), PHR (7.2%), and CER (2.4%). Excepting the CER type, seedling type frequencies did not differ between trees and lianas. The PEF seedlings had the lightest seeds, whereas CHR seedlings had the heaviest ones. Pioneer trees showed lighter seeds than persistent trees or lianas in species with PEF but not in species with PER. Pioneer trees (38 species) showed three seedling types and the most common was PEF (82%). Persistent trees (135 species) showed the five seedling types but PEF (43%) and CHR (37%) were the most frequent. Seedling type frequencies differed among dispersal syndrome groups. The animal dispersal syndrome was significantly more frequent in species with CHR. Our results show an evolutionary convergence of seedling types at the community level worldwide and the existence of a phylogenetic inertia in the evolution of initial seedling morphology. A comparison among eight tropical communities indicated on average that PEF is the most frequent type and CER the least common, although the relative frequency of each seedling type differs among communities, particularly between Neotropical and Paleotropical sites.

[1]  Elizabeth A. Kellogg,et al.  Plant Systematics: A Phylogenetic Approach , 2000 .

[2]  D. Soltis,et al.  Angiosperm phylogeny inferred from multiple genes as a tool for comparative biology , 1999, Nature.

[3]  M. Martínez‐Ramos,et al.  SEED MASS, SEEDLING EMERGENCE, AND ENVIRONMENTAL FACTORS IN SEVEN RAIN FOREST PSYCHOTRIA (RUBIACEAE) , 1999 .

[4]  F. Bazzaz,et al.  ASYMPTOTIC HEIGHT AS A PREDICTOR OF PHOTOSYNTHETIC CHARACTERISTICS IN MALAYSIAN RAIN FOREST TREES , 1999 .

[5]  B. M. Johri,et al.  Flowering Plants: Taxonomy and Phylogeny , 1998 .

[6]  M. Martínez‐Ramos,et al.  Tree life history patterns and forest dynamics: a conceptual model for the study of plant demography in patchy environments , 1997 .

[7]  E. Soriano,et al.  Historia natural de los Tuxtlas , 1997 .

[8]  M. Westoby,et al.  Seedling longevity under deep shade in relation to seed size , 1996 .

[9]  Adaptation and inertia in the Australian tropical lowland rain-forest flora: Contradictory trends in intergeneric and intrageneric comparisons of seed size in relation to light demand , 1996 .

[10]  G. Ibarra-Manríquez,et al.  Estación de Biología Tropical "Los Thxtlas", Veracruz, México: Lista florística comentada (Mimosaceae a Verbenaceae) , 1996 .

[11]  D. Metcalfe,et al.  Seed mass and light requirements for regeneration in Southeast Asian rain forest , 1995 .

[12]  M. Westoby,et al.  Correlates of seed size variation: A comparison among five temperate floras , 1995 .

[13]  M. Westoby,et al.  The role of large seed size in shaded conditions: experimental evidence , 1994 .

[14]  O. Phillips,et al.  Increasing Turnover Through Time in Tropical Forests , 1994, Science.

[15]  Michael J. Crawley,et al.  GLIM for Ecologists , 1994 .

[16]  A. Ellison,et al.  SEED AND SEEDLING ECOLOGY OF NEOTROPICAL MELASTOMATACEAE , 1993 .

[17]  Miguel Franco,et al.  comparative plant demography - relative importance of life-cycle components to the finite rate of increase in woody and herbaceous perennials , 1993 .

[18]  E. Álvarez-Buylla,et al.  Demography and allometry of Cecropia obtusifolia, a neotropical pioneer tree - an evaluation of the climax-pioneer paradigm for tropical rain forests , 1992 .

[19]  K. Kitajima.  Relationship between photosynthesis and thickness of cotyledons for tropical tree species , 1992 .

[20]  D. Clark,et al.  The Impact of Physical Damage on Canopy Tree Regeneration in Tropical Rain Forest , 1991 .

[21]  E. Hegarty,et al.  Distribution and abundance of vines in forest communities , 1991 .

[22]  E. Álvarez-Buylla,et al.  Tree Demography and Gap Dynamics in a Tropical Rain Forest , 1989 .

[23]  A. Gentry,et al.  Changes in Plant Community Diversity and Floristic Composition on Environmental and Geographical Gradients , 1988 .

[24]  Sophie Miquel.  Morphologie fonctionnelle de plantules d'espèces forestières du Gabon , 1987 .

[25]  Susan A. Foster,et al.  The relationship between seed size and establishment conditions in tropical woody plants , 1985 .

[26]  F. Putz.  The natural history of lianas on Barro Colorado Island, Panama , 1984 .

[27]  D. Clark,et al.  Spacing Dynamics of a Tropical Rain Forest Tree: Evaluation of the Janzen-Connell Model , 1984, The American Naturalist.

[28]  C. Augspurger.  Light requirements of neotropical tree seedlings: a comparative study of growth and survival , 1984 .

[29]  N. Garwood.  Seed Germination in a Seasonal Tropical Forest in Panama: A Community Study , 1983 .

[30]  Henry Howe,et al.  Ecology of Seed Dispersal , 1982 .

[31]  E. Vogel.  Seedlings of dicotyledons : structure, development, types : descriptions of 150 woody Malesian taxa , 1980 .

[32]  M. Angevine,et al.  Seed Germination Syndromes in Higher Plants , 1979 .

[33]  J. Harper.  Population Biology of Plants , 1979 .

[34]  James A. Duke,et al.  On Tropical Tree Seedlings I. Seeds, Seedlings, Systems, and Systematics , 1969 .

[35]  J. Duke.  Keys for the Identification of Seedlings of Some Prominent Woody Species in Eight Forest Types in Puerto Rico , 1965 .