Most ecological hypotheses about species coexistence hinge on species differences, but quantifyin... more Most ecological hypotheses about species coexistence hinge on species differences, but quantifying trait differences across species in diverse communities is often unfeasible. We examined the variation of demographic traits using a global tropical forest data set covering 4500 species in 10 large-scale tree inventories. With a hierarchical Bayesian approach, we quantified the distribution of mortality and growth rates of all tree species at each site. This allowed us to test the prediction that demographic differences facilitate species richness, as suggested by the theory that a tradeoff between high growth and high survival allows species to coexist. Contrary to the prediction, the most diverse forests had the least demographic variation. Although demographic differences may foster coexistence, they do not explain any of the 16-fold variation in tree species richness observed across the tropics.
... KYLE E. HARMS Department of Biological Sciences Louisiana State University Baton Rouge, LA 70... more ... KYLE E. HARMS Department of Biological Sciences Louisiana State University Baton Rouge, LA 70803 ... gender-biased function of a floral trait is often unapparent because secondary sexual traits and primary sexual organs of both genders co-occur within most bisexual flowers. ...
ABSTRACT We conducted monthly measurements of extractable soil nutrients, including N, P, base ca... more ABSTRACT We conducted monthly measurements of extractable soil nutrients, including N, P, base cations, and micronutrients, as well as the potential toxin Al, in a long-term fertilization experiment in lowland tropical rain forest in the Republic of Panama. Our prediction was that the response of individual nutrients to seasonal climate and fertilizer addition would vary depending on the nature of their biogeochemical cycles. We detected significant seasonal variation in soil pH and all nutrients measured, although only extractable K concentrations were greater in the early wet season, while extractable phosphate varied little in plots that did not receive P addition. A decade of N addition increased soil nitrate, had no effect on extractable ammonium, and decreased soil pH (similar to 0.8 units in plots receiving only N). The decline in pH caused a corresponding decline in extractable base cations (Ca and K) and increased extractable Al, highlighting an important but poorly understood consequence of long-term atmospheric N deposition onto tropical forests. A decade of P addition increased extractable phosphate by 50-fold, indicating that chronic fertilizer addition has overcome the high phosphate sorption capacity of the soil. Potassium addition without N increased extractable soil K by 91%, but only by 25% when K was added in combination with N, suggesting that the previously reported N x K interactive effect on trunk growth rates could be a true response to N addition. Extractable Cu and Zn were increased twofold by micronutrient fertilizer addition, were reduced in the dry season, but were not affected by N addition (i.e., soil acidification). We conclude that the response of extractable nutrients to seasonal climate and fertilizer addition varies among nutrients, and suggest that greater attention be paid to the biological implications of acidification in response to long-term atmospheric N deposition onto strongly-weathered tropical forest soils.
... ACKNOWLEDGEMENTS Nataly Hidalgo, Patricia Alvarez-Loayza, ChristinaGeorgiou and Cecilia Carra... more ... ACKNOWLEDGEMENTS Nataly Hidalgo, Patricia Alvarez-Loayza, ChristinaGeorgiou and Cecilia Carrasco helped to set up the watering system and measured multitudes of seedlings and saplings. We thank Nigel Pitman ...
... in tropical trees and lianas KYLE E. HARMS* and JAMES W. DALLINGf * Department of Ecology and... more ... in tropical trees and lianas KYLE E. HARMS* and JAMES W. DALLINGf * Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544, USA f SmithsonianTropical Research Institute, Apartado 2072, Balboa, Republica de Panama ...
... for frugivorous bats (Stenodermatinae) in the Peruvian Amazon Adriana Bravo ∗,1 , Kyle E. Har... more ... for frugivorous bats (Stenodermatinae) in the Peruvian Amazon Adriana Bravo ∗,1 , Kyle E. Harms ∗, and Louise H. Emmons ∗ Department of Biological Sciences, Louisiana State University,Baton Rouge, LA 70803, USA ... 2002, Klaus et al. 1998, Mokhtar et al. 1990). ...
Most ecological hypotheses about species coexistence hinge on species differences, but quantifyin... more Most ecological hypotheses about species coexistence hinge on species differences, but quantifying trait differences across species in diverse communities is often unfeasible. We examined the variation of demographic traits using a global tropical forest data set covering 4500 species in 10 large-scale tree inventories. With a hierarchical Bayesian approach, we quantified the distribution of mortality and growth rates of all tree species at each site. This allowed us to test the prediction that demographic differences facilitate species richness, as suggested by the theory that a tradeoff between high growth and high survival allows species to coexist. Contrary to the prediction, the most diverse forests had the least demographic variation. Although demographic differences may foster coexistence, they do not explain any of the 16-fold variation in tree species richness observed across the tropics.
... KYLE E. HARMS Department of Biological Sciences Louisiana State University Baton Rouge, LA 70... more ... KYLE E. HARMS Department of Biological Sciences Louisiana State University Baton Rouge, LA 70803 ... gender-biased function of a floral trait is often unapparent because secondary sexual traits and primary sexual organs of both genders co-occur within most bisexual flowers. ...
ABSTRACT We conducted monthly measurements of extractable soil nutrients, including N, P, base ca... more ABSTRACT We conducted monthly measurements of extractable soil nutrients, including N, P, base cations, and micronutrients, as well as the potential toxin Al, in a long-term fertilization experiment in lowland tropical rain forest in the Republic of Panama. Our prediction was that the response of individual nutrients to seasonal climate and fertilizer addition would vary depending on the nature of their biogeochemical cycles. We detected significant seasonal variation in soil pH and all nutrients measured, although only extractable K concentrations were greater in the early wet season, while extractable phosphate varied little in plots that did not receive P addition. A decade of N addition increased soil nitrate, had no effect on extractable ammonium, and decreased soil pH (similar to 0.8 units in plots receiving only N). The decline in pH caused a corresponding decline in extractable base cations (Ca and K) and increased extractable Al, highlighting an important but poorly understood consequence of long-term atmospheric N deposition onto tropical forests. A decade of P addition increased extractable phosphate by 50-fold, indicating that chronic fertilizer addition has overcome the high phosphate sorption capacity of the soil. Potassium addition without N increased extractable soil K by 91%, but only by 25% when K was added in combination with N, suggesting that the previously reported N x K interactive effect on trunk growth rates could be a true response to N addition. Extractable Cu and Zn were increased twofold by micronutrient fertilizer addition, were reduced in the dry season, but were not affected by N addition (i.e., soil acidification). We conclude that the response of extractable nutrients to seasonal climate and fertilizer addition varies among nutrients, and suggest that greater attention be paid to the biological implications of acidification in response to long-term atmospheric N deposition onto strongly-weathered tropical forest soils.
... ACKNOWLEDGEMENTS Nataly Hidalgo, Patricia Alvarez-Loayza, ChristinaGeorgiou and Cecilia Carra... more ... ACKNOWLEDGEMENTS Nataly Hidalgo, Patricia Alvarez-Loayza, ChristinaGeorgiou and Cecilia Carrasco helped to set up the watering system and measured multitudes of seedlings and saplings. We thank Nigel Pitman ...
... in tropical trees and lianas KYLE E. HARMS* and JAMES W. DALLINGf * Department of Ecology and... more ... in tropical trees and lianas KYLE E. HARMS* and JAMES W. DALLINGf * Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544, USA f SmithsonianTropical Research Institute, Apartado 2072, Balboa, Republica de Panama ...
... for frugivorous bats (Stenodermatinae) in the Peruvian Amazon Adriana Bravo ∗,1 , Kyle E. Har... more ... for frugivorous bats (Stenodermatinae) in the Peruvian Amazon Adriana Bravo ∗,1 , Kyle E. Harms ∗, and Louise H. Emmons ∗ Department of Biological Sciences, Louisiana State University,Baton Rouge, LA 70803, USA ... 2002, Klaus et al. 1998, Mokhtar et al. 1990). ...
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