TY - JOUR
T1 - Interactions between plant size and canopy openness influence vital rates and life-history tradeoffs in two neotropical understory herbs
AU - Westerband, Andrea C.
AU - Horvitz, Carol C.
N1 - Funding Information:
The authors thank R. McElderry for useful comments regarding statistical analyses. Funding was provided by a generous grant from the Vaughn Jordan Foundation, the University of Miami's Department of Biology and Center for Latin American Studies, and by the Organization for Tropical Studies.
Publisher Copyright:
© 2015 Botanical Society of America
PY - 2015/8
Y1 - 2015/8
N2 - • Premise of the study: For tropical forest understory plants, the ability to grow, survive, and reproduce is limited by the availability of light. The extent to which reproduction incurs a survival or growth cost may change with light availability, plant size, and adaptation to shade, and may vary among similar species. • Methods: We estimated size-specific rates of growth, survival, and reproduction (vital rates), for two neotropical understory herbs (order Zingiberales) in a premontane tropical rainforest in Costa Rica. During three annual censuses we monitored 1278 plants, measuring leaf area, number of inflorescences, and canopy openness. We fit regression models of all vital rates and evaluated them over a range of light levels. The best fitting models were selected using Akaike's Information Criterion. • Key results: All vital rates were significantly influenced by size in both species, but not always by light. Increasing light resulted in higher growth and a higher probability of reproduction in both species, but lower survival in one species. Both species grew at small sizes but shrank at larger sizes. The size at which shrinkage began differed among species and light environments. Vital rates of large individuals were more sensitive to changes in light than small individuals. • Conclusions: Increasing light does not always positively influence vital rates; the extent to which light affects vital rates depends on plant size. Differences among species in their abilities to thrive under different light conditions and thus occupy distinct niches may contribute to the maintenance of species diversity.
AB - • Premise of the study: For tropical forest understory plants, the ability to grow, survive, and reproduce is limited by the availability of light. The extent to which reproduction incurs a survival or growth cost may change with light availability, plant size, and adaptation to shade, and may vary among similar species. • Methods: We estimated size-specific rates of growth, survival, and reproduction (vital rates), for two neotropical understory herbs (order Zingiberales) in a premontane tropical rainforest in Costa Rica. During three annual censuses we monitored 1278 plants, measuring leaf area, number of inflorescences, and canopy openness. We fit regression models of all vital rates and evaluated them over a range of light levels. The best fitting models were selected using Akaike's Information Criterion. • Key results: All vital rates were significantly influenced by size in both species, but not always by light. Increasing light resulted in higher growth and a higher probability of reproduction in both species, but lower survival in one species. Both species grew at small sizes but shrank at larger sizes. The size at which shrinkage began differed among species and light environments. Vital rates of large individuals were more sensitive to changes in light than small individuals. • Conclusions: Increasing light does not always positively influence vital rates; the extent to which light affects vital rates depends on plant size. Differences among species in their abilities to thrive under different light conditions and thus occupy distinct niches may contribute to the maintenance of species diversity.
KW - Calathea
KW - Heliconia
KW - canopy openness
KW - life history tradeoffs
KW - shade tolerance
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U2 - 10.3732/ajb.1500041
DO - 10.3732/ajb.1500041
M3 - Article
C2 - 26290552
AN - SCOPUS:84973425917
VL - 102
SP - 1290
EP - 1299
JO - American Journal of Botany
JF - American Journal of Botany
SN - 0002-9122
IS - 8
ER -