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1. Variations in Amazon forest productivity correlated with foliar nutrients and modelled rates of photosynthetic carbon supply.

Author

Mercado, Lina M., Patiño, Sandra, Domingues, Tomas F., Fyllas, Nikolaos M., Weedon, Graham P., Sitch, Stephen, Quesada, Carlos Alberto, Phillips, Oliver L., Aragão, Luiz E. O. C., Malhi, Yadvinder, Dolman, A. J., Restrepo.-Coupe, Natalia, Saleska, Scott R., Baker, Timothy R., Almeida, Samuel, Higuchi, Niro, and Lloyd, Jon

Abstract

The rate of above-ground woody biomass production, WP, in some western Amazon forests exceeds those in the east by a factor of 2 or more. Underlying causes may include climate, soil nutrient limitations and species composition. In this modelling paper, we explore the implications of allowing key nutrients such as N and P to constrain the photosynthesis of Amazon forests, and also we examine the relationship between modelled rates of photosynthesis and the observed gradients in WP. We use a model with current understanding of the underpinning biochemical processes as affected by nutrient availability to assess: (i) the degree to which observed spatial variations in foliar [N] and [P] across Amazonia affect stand-level photosynthesis; and (ii) how these variations in forest photosynthetic carbon acquisition relate to the observed geographical patterns of stem growth across the Amazon Basin. We find nutrient availability to exert a strong effect on photosynthetic carbon gain across the Basin and to be a likely important contributor to the observed gradient in WP. Phosphorus emerges as more important than nitrogen in accounting for the observed variations in productivity. Implications of these findings are discussed in the context of future tropical forests under a changing climate. [ABSTRACT FROM AUTHOR]

Published
2011
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2. Evolutionary heritage influences Amazon tree ecology

Author

Coelho de Souza, Fernanda, Dexter, Kyle G., Phillips, Oliver L., Brienen, Roel J.W., Chave, Jerome, Galbraith, David R., Lopez Gonzalez, Gabriela, Monteagudo Mendoza, Abel, Pennington, R. Toby, Poorter, Lourens, Alexiades, Miguel, Álvarez-Dávila, Esteban, Andrade, Ana, Aragão, Luis E.O.C., Araujo-Murakami, Alejandro, Arets, Eric J.M.M., Aymard C, Gerardo A., Baraloto, Christopher, Barroso, Jorcely G., Bonal, Damien, Boot, Rene G.A., Camargo, José L.C., Comiskey, James A., Valverde, Fernando Cornejo, de Camargo, Plínio B., Di Fiore, Anthony, Elias, Fernando, Erwin, Terry L., Feldpausch, Ted R., Ferreira, Leandro, Fyllas, Nikolaos M., Gloor, Emanuel, Herault, Bruno, Herrera, Rafael, Higuchi, Niro, Honorio Coronado, Eurídice N., Killeen, Timothy J., Laurance, William F., Laurance, Susan, Lloyd, Jon, Lovejoy, Thomas E., Malhi, Yadvinder, Maracahipes, Leandro, Marimon, Beatriz S., Marimon-Junior, Ben H., Mendoza, Casimiro, Morandi, Paulo, Neill, David A., Vargas, Percy Núñez, Oliveira, Edmar A., Lenza, Eddie, Palacios, Walter A., Peñuela-Mora, Maria C., Pipoly, John J., Pitman, Nigel C.A., Prieto, Adriana, Quesada, Carlos A., Ramirez-Angulo, Hirma, Rudas, Agustin, Ruokolainen, Kalle, Salomão, Rafael P., Silveira, Marcos, Stropp, Juliana, ter Steege, Hans, Thomas-Caesar, Raquel, van der Hout, Peter, van der Heijden, Geertje M.F., van der Meer, Peter J., Vasquez, Rodolfo V., Vieira, Simone A., Vilanova, Emilio, Vos, Vincent A., Wang, Ophelia, Young, Kenneth R., Zagt, Roderick J., Baker, Timothy R., Coelho de Souza, Fernanda, Dexter, Kyle G., Phillips, Oliver L., Brienen, Roel J.W., Chave, Jerome, Galbraith, David R., Lopez Gonzalez, Gabriela, Monteagudo Mendoza, Abel, Pennington, R. Toby, Poorter, Lourens, Alexiades, Miguel, Álvarez-Dávila, Esteban, Andrade, Ana, Aragão, Luis E.O.C., Araujo-Murakami, Alejandro, Arets, Eric J.M.M., Aymard C, Gerardo A., Baraloto, Christopher, Barroso, Jorcely G., Bonal, Damien, Boot, Rene G.A., Camargo, José L.C., Comiskey, James A., Valverde, Fernando Cornejo, de Camargo, Plínio B., Di Fiore, Anthony, Elias, Fernando, Erwin, Terry L., Feldpausch, Ted R., Ferreira, Leandro, Fyllas, Nikolaos M., Gloor, Emanuel, Herault, Bruno, Herrera, Rafael, Higuchi, Niro, Honorio Coronado, Eurídice N., Killeen, Timothy J., Laurance, William F., Laurance, Susan, Lloyd, Jon, Lovejoy, Thomas E., Malhi, Yadvinder, Maracahipes, Leandro, Marimon, Beatriz S., Marimon-Junior, Ben H., Mendoza, Casimiro, Morandi, Paulo, Neill, David A., Vargas, Percy Núñez, Oliveira, Edmar A., Lenza, Eddie, Palacios, Walter A., Peñuela-Mora, Maria C., Pipoly, John J., Pitman, Nigel C.A., Prieto, Adriana, Quesada, Carlos A., Ramirez-Angulo, Hirma, Rudas, Agustin, Ruokolainen, Kalle, Salomão, Rafael P., Silveira, Marcos, Stropp, Juliana, ter Steege, Hans, Thomas-Caesar, Raquel, van der Hout, Peter, van der Heijden, Geertje M.F., van der Meer, Peter J., Vasquez, Rodolfo V., Vieira, Simone A., Vilanova, Emilio, Vos, Vincent A., Wang, Ophelia, Young, Kenneth R., Zagt, Roderick J., and Baker, Timothy R.

Abstract

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change.

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3. Evolutionary heritage influences Amazon tree ecology

Author

Coelho de Souza, Fernanda, Dexter, Kyle G., Phillips, Oliver L., Brienen, Roel J.W., Chave, Jerome, Galbraith, David R., Lopez Gonzalez, Gabriela, Monteagudo Mendoza, Abel, Pennington, R. Toby, Poorter, Lourens, Alexiades, Miguel, Álvarez-Dávila, Esteban, Andrade, Ana, Aragão, Luis E.O.C., Araujo-Murakami, Alejandro, Arets, Eric J.M.M., Aymard C, Gerardo A., Baraloto, Christopher, Barroso, Jorcely G., Bonal, Damien, Boot, Rene G.A., Camargo, José L.C., Comiskey, James A., Valverde, Fernando Cornejo, de Camargo, Plínio B., Di Fiore, Anthony, Elias, Fernando, Erwin, Terry L., Feldpausch, Ted R., Ferreira, Leandro, Fyllas, Nikolaos M., Gloor, Emanuel, Herault, Bruno, Herrera, Rafael, Higuchi, Niro, Honorio Coronado, Eurídice N., Killeen, Timothy J., Laurance, William F., Laurance, Susan, Lloyd, Jon, Lovejoy, Thomas E., Malhi, Yadvinder, Maracahipes, Leandro, Marimon, Beatriz S., Marimon-Junior, Ben H., Mendoza, Casimiro, Morandi, Paulo, Neill, David A., Vargas, Percy Núñez, Oliveira, Edmar A., Lenza, Eddie, Palacios, Walter A., Peñuela-Mora, Maria C., Pipoly, John J., Pitman, Nigel C.A., Prieto, Adriana, Quesada, Carlos A., Ramirez-Angulo, Hirma, Rudas, Agustin, Ruokolainen, Kalle, Salomão, Rafael P., Silveira, Marcos, Stropp, Juliana, ter Steege, Hans, Thomas-Caesar, Raquel, van der Hout, Peter, van der Heijden, Geertje M.F., van der Meer, Peter J., Vasquez, Rodolfo V., Vieira, Simone A., Vilanova, Emilio, Vos, Vincent A., Wang, Ophelia, Young, Kenneth R., Zagt, Roderick J., Baker, Timothy R., Coelho de Souza, Fernanda, Dexter, Kyle G., Phillips, Oliver L., Brienen, Roel J.W., Chave, Jerome, Galbraith, David R., Lopez Gonzalez, Gabriela, Monteagudo Mendoza, Abel, Pennington, R. Toby, Poorter, Lourens, Alexiades, Miguel, Álvarez-Dávila, Esteban, Andrade, Ana, Aragão, Luis E.O.C., Araujo-Murakami, Alejandro, Arets, Eric J.M.M., Aymard C, Gerardo A., Baraloto, Christopher, Barroso, Jorcely G., Bonal, Damien, Boot, Rene G.A., Camargo, José L.C., Comiskey, James A., Valverde, Fernando Cornejo, de Camargo, Plínio B., Di Fiore, Anthony, Elias, Fernando, Erwin, Terry L., Feldpausch, Ted R., Ferreira, Leandro, Fyllas, Nikolaos M., Gloor, Emanuel, Herault, Bruno, Herrera, Rafael, Higuchi, Niro, Honorio Coronado, Eurídice N., Killeen, Timothy J., Laurance, William F., Laurance, Susan, Lloyd, Jon, Lovejoy, Thomas E., Malhi, Yadvinder, Maracahipes, Leandro, Marimon, Beatriz S., Marimon-Junior, Ben H., Mendoza, Casimiro, Morandi, Paulo, Neill, David A., Vargas, Percy Núñez, Oliveira, Edmar A., Lenza, Eddie, Palacios, Walter A., Peñuela-Mora, Maria C., Pipoly, John J., Pitman, Nigel C.A., Prieto, Adriana, Quesada, Carlos A., Ramirez-Angulo, Hirma, Rudas, Agustin, Ruokolainen, Kalle, Salomão, Rafael P., Silveira, Marcos, Stropp, Juliana, ter Steege, Hans, Thomas-Caesar, Raquel, van der Hout, Peter, van der Heijden, Geertje M.F., van der Meer, Peter J., Vasquez, Rodolfo V., Vieira, Simone A., Vilanova, Emilio, Vos, Vincent A., Wang, Ophelia, Young, Kenneth R., Zagt, Roderick J., and Baker, Timothy R.

Abstract

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change.

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4. Evolutionary heritage influences Amazon tree ecology

Author

Coelho de Souza, Fernanda, Dexter, Kyle G., Phillips, Oliver L., Brienen, Roel J.W., Chave, Jerome, Galbraith, David R., Lopez Gonzalez, Gabriela, Monteagudo Mendoza, Abel, Pennington, R. Toby, Poorter, Lourens, Alexiades, Miguel, Álvarez-Dávila, Esteban, Andrade, Ana, Aragão, Luis E.O.C., Araujo-Murakami, Alejandro, Arets, Eric J.M.M., Aymard C, Gerardo A., Baraloto, Christopher, Barroso, Jorcely G., Bonal, Damien, Boot, Rene G.A., Camargo, José L.C., Comiskey, James A., Valverde, Fernando Cornejo, de Camargo, Plínio B., Di Fiore, Anthony, Elias, Fernando, Erwin, Terry L., Feldpausch, Ted R., Ferreira, Leandro, Fyllas, Nikolaos M., Gloor, Emanuel, Herault, Bruno, Herrera, Rafael, Higuchi, Niro, Honorio Coronado, Eurídice N., Killeen, Timothy J., Laurance, William F., Laurance, Susan, Lloyd, Jon, Lovejoy, Thomas E., Malhi, Yadvinder, Maracahipes, Leandro, Marimon, Beatriz S., Marimon-Junior, Ben H., Mendoza, Casimiro, Morandi, Paulo, Neill, David A., Vargas, Percy Núñez, Oliveira, Edmar A., Lenza, Eddie, Palacios, Walter A., Peñuela-Mora, Maria C., Pipoly, John J., Pitman, Nigel C.A., Prieto, Adriana, Quesada, Carlos A., Ramirez-Angulo, Hirma, Rudas, Agustin, Ruokolainen, Kalle, Salomão, Rafael P., Silveira, Marcos, Stropp, Juliana, ter Steege, Hans, Thomas-Caesar, Raquel, van der Hout, Peter, van der Heijden, Geertje M.F., van der Meer, Peter J., Vasquez, Rodolfo V., Vieira, Simone A., Vilanova, Emilio, Vos, Vincent A., Wang, Ophelia, Young, Kenneth R., Zagt, Roderick J., Baker, Timothy R., Coelho de Souza, Fernanda, Dexter, Kyle G., Phillips, Oliver L., Brienen, Roel J.W., Chave, Jerome, Galbraith, David R., Lopez Gonzalez, Gabriela, Monteagudo Mendoza, Abel, Pennington, R. Toby, Poorter, Lourens, Alexiades, Miguel, Álvarez-Dávila, Esteban, Andrade, Ana, Aragão, Luis E.O.C., Araujo-Murakami, Alejandro, Arets, Eric J.M.M., Aymard C, Gerardo A., Baraloto, Christopher, Barroso, Jorcely G., Bonal, Damien, Boot, Rene G.A., Camargo, José L.C., Comiskey, James A., Valverde, Fernando Cornejo, de Camargo, Plínio B., Di Fiore, Anthony, Elias, Fernando, Erwin, Terry L., Feldpausch, Ted R., Ferreira, Leandro, Fyllas, Nikolaos M., Gloor, Emanuel, Herault, Bruno, Herrera, Rafael, Higuchi, Niro, Honorio Coronado, Eurídice N., Killeen, Timothy J., Laurance, William F., Laurance, Susan, Lloyd, Jon, Lovejoy, Thomas E., Malhi, Yadvinder, Maracahipes, Leandro, Marimon, Beatriz S., Marimon-Junior, Ben H., Mendoza, Casimiro, Morandi, Paulo, Neill, David A., Vargas, Percy Núñez, Oliveira, Edmar A., Lenza, Eddie, Palacios, Walter A., Peñuela-Mora, Maria C., Pipoly, John J., Pitman, Nigel C.A., Prieto, Adriana, Quesada, Carlos A., Ramirez-Angulo, Hirma, Rudas, Agustin, Ruokolainen, Kalle, Salomão, Rafael P., Silveira, Marcos, Stropp, Juliana, ter Steege, Hans, Thomas-Caesar, Raquel, van der Hout, Peter, van der Heijden, Geertje M.F., van der Meer, Peter J., Vasquez, Rodolfo V., Vieira, Simone A., Vilanova, Emilio, Vos, Vincent A., Wang, Ophelia, Young, Kenneth R., Zagt, Roderick J., and Baker, Timothy R.

Abstract

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change.

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5. Evolutionary heritage influences Amazon tree ecology

Author

Coelho de Souza, Fernanda, Dexter, Kyle G., Phillips, Oliver L., Brienen, Roel J.W., Chave, Jerome, Galbraith, David R., Lopez Gonzalez, Gabriela, Monteagudo Mendoza, Abel, Pennington, R. Toby, Poorter, Lourens, Alexiades, Miguel, Álvarez-Dávila, Esteban, Andrade, Ana, Aragão, Luis E.O.C., Araujo-Murakami, Alejandro, Arets, Eric J.M.M., Aymard C, Gerardo A., Baraloto, Christopher, Barroso, Jorcely G., Bonal, Damien, Boot, Rene G.A., Camargo, José L.C., Comiskey, James A., Valverde, Fernando Cornejo, de Camargo, Plínio B., Di Fiore, Anthony, Elias, Fernando, Erwin, Terry L., Feldpausch, Ted R., Ferreira, Leandro, Fyllas, Nikolaos M., Gloor, Emanuel, Herault, Bruno, Herrera, Rafael, Higuchi, Niro, Honorio Coronado, Eurídice N., Killeen, Timothy J., Laurance, William F., Laurance, Susan, Lloyd, Jon, Lovejoy, Thomas E., Malhi, Yadvinder, Maracahipes, Leandro, Marimon, Beatriz S., Marimon-Junior, Ben H., Mendoza, Casimiro, Morandi, Paulo, Neill, David A., Vargas, Percy Núñez, Oliveira, Edmar A., Lenza, Eddie, Palacios, Walter A., Peñuela-Mora, Maria C., Pipoly, John J., Pitman, Nigel C.A., Prieto, Adriana, Quesada, Carlos A., Ramirez-Angulo, Hirma, Rudas, Agustin, Ruokolainen, Kalle, Salomão, Rafael P., Silveira, Marcos, Stropp, Juliana, ter Steege, Hans, Thomas-Caesar, Raquel, van der Hout, Peter, van der Heijden, Geertje M.F., van der Meer, Peter J., Vasquez, Rodolfo V., Vieira, Simone A., Vilanova, Emilio, Vos, Vincent A., Wang, Ophelia, Young, Kenneth R., Zagt, Roderick J., Baker, Timothy R., Coelho de Souza, Fernanda, Dexter, Kyle G., Phillips, Oliver L., Brienen, Roel J.W., Chave, Jerome, Galbraith, David R., Lopez Gonzalez, Gabriela, Monteagudo Mendoza, Abel, Pennington, R. Toby, Poorter, Lourens, Alexiades, Miguel, Álvarez-Dávila, Esteban, Andrade, Ana, Aragão, Luis E.O.C., Araujo-Murakami, Alejandro, Arets, Eric J.M.M., Aymard C, Gerardo A., Baraloto, Christopher, Barroso, Jorcely G., Bonal, Damien, Boot, Rene G.A., Camargo, José L.C., Comiskey, James A., Valverde, Fernando Cornejo, de Camargo, Plínio B., Di Fiore, Anthony, Elias, Fernando, Erwin, Terry L., Feldpausch, Ted R., Ferreira, Leandro, Fyllas, Nikolaos M., Gloor, Emanuel, Herault, Bruno, Herrera, Rafael, Higuchi, Niro, Honorio Coronado, Eurídice N., Killeen, Timothy J., Laurance, William F., Laurance, Susan, Lloyd, Jon, Lovejoy, Thomas E., Malhi, Yadvinder, Maracahipes, Leandro, Marimon, Beatriz S., Marimon-Junior, Ben H., Mendoza, Casimiro, Morandi, Paulo, Neill, David A., Vargas, Percy Núñez, Oliveira, Edmar A., Lenza, Eddie, Palacios, Walter A., Peñuela-Mora, Maria C., Pipoly, John J., Pitman, Nigel C.A., Prieto, Adriana, Quesada, Carlos A., Ramirez-Angulo, Hirma, Rudas, Agustin, Ruokolainen, Kalle, Salomão, Rafael P., Silveira, Marcos, Stropp, Juliana, ter Steege, Hans, Thomas-Caesar, Raquel, van der Hout, Peter, van der Heijden, Geertje M.F., van der Meer, Peter J., Vasquez, Rodolfo V., Vieira, Simone A., Vilanova, Emilio, Vos, Vincent A., Wang, Ophelia, Young, Kenneth R., Zagt, Roderick J., and Baker, Timothy R.

Abstract

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change.

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6. Exploring the West African forest island phenomenon: scientific insights gained, successes achieved and capacities strengthened.

Author

Logah V, Azeez JO, Compaore H, Mesele SA, Ocansey CM, Bougma AB, Tetteh EN, Veenendaal E, and Lloyd J

Abstract

Anthropogenic activities around local villages in mesic savanna landscapes of West Africa have resulted in soil improvement and forest establishment outside their climatic zones. Such unique 'forest islands' have been reported to provide ecosystem services including biodiversity conservation. However, the science underpinning their formations is limitedly studied. In 2015 and with funding support from the Royal Society-DFID (now FCDO), we set out to investigate the biogeochemistry of the forest islands in comparison with adjacent natural savanna and farmlands across 11 locations in Burkina Faso, Ghana and Nigeria. Our results showed that the forest islands do not differ significantly from the adjoining ecosystems in soil mineralogy implying that their formation was anthropogenically driven. We observed greater soil organic carbon and nutrient distributions in the forest islands, which also had more stable macro (>500 μm) and meso-aggregates (500-250 μm) than the adjoining agricultural lands. We found that soil micro-aggregate (250-53 μm) stability was climate (precipitation) driven in the West African ecosystems while meso- and macro-aggregate stability was land-use driven. In one of the unique forest islands we studied in the Mole National Park of Ghana, we found its mineral-associated organic carbon over 40% greater than the adjoining natural savanna with potential implications for the achievement of the global initiative of the '4p1000' in West Africa. We conclude that the North-South-South research collaboration has established clearly, the science underlying the age-long West African forest island phenomenon and has, among many successes, led to capacity building of young scientists driving cutting-edge research in climate change adaptation and food systems transformation in the sub-region., Competing Interests: We declare we have no competing interests., (© 2024 The Author(s).)

Published
2024
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7. Above-ground biomass and structure of 260 African tropical forests.

Author

Lewis SL, Sonké B, Sunderland T, Begne SK, Lopez-Gonzalez G, van der Heijden GM, Phillips OL, Affum-Baffoe K, Baker TR, Banin L, Bastin JF, Beeckman H, Boeckx P, Bogaert J, De Cannière C, Chezeaux E, Clark CJ, Collins M, Djagbletey G, Djuikouo MN, Droissart V, Doucet JL, Ewango CE, Fauset S, Feldpausch TR, Foli EG, Gillet JF, Hamilton AC, Harris DJ, Hart TB, de Haulleville T, Hladik A, Hufkens K, Huygens D, Jeanmart P, Jeffery KJ, Kearsley E, Leal ME, Lloyd J, Lovett JC, Makana JR, Malhi Y, Marshall AR, Ojo L, Peh KS, Pickavance G, Poulsen JR, Reitsma JM, Sheil D, Simo M, Steppe K, Taedoumg HE, Talbot J, Taplin JR, Taylor D, Thomas SC, Toirambe B, Verbeeck H, Vleminckx J, White LJ, Willcock S, Woell H, and Zemagho L

Subjects
Africa, Biomass, Carbon Cycle, Climate Change, Conservation of Natural Resources, Models, Biological, Soil, Trees anatomy & histology, Trees growth & development, Trees metabolism, Tropical Climate
Abstract

We report above-ground biomass (AGB), basal area, stem density and wood mass density estimates from 260 sample plots (mean size: 1.2 ha) in intact closed-canopy tropical forests across 12 African countries. Mean AGB is 395.7 Mg dry mass ha⁻¹ (95% CI: 14.3), substantially higher than Amazonian values, with the Congo Basin and contiguous forest region attaining AGB values (429 Mg ha⁻¹) similar to those of Bornean forests, and significantly greater than East or West African forests. AGB therefore appears generally higher in palaeo- compared with neotropical forests. However, mean stem density is low (426 ± 11 stems ha⁻¹ greater than or equal to 100 mm diameter) compared with both Amazonian and Bornean forests (cf. approx. 600) and is the signature structural feature of African tropical forests. While spatial autocorrelation complicates analyses, AGB shows a positive relationship with rainfall in the driest nine months of the year, and an opposite association with the wettest three months of the year; a negative relationship with temperature; positive relationship with clay-rich soils; and negative relationships with C : N ratio (suggesting a positive soil phosphorus-AGB relationship), and soil fertility computed as the sum of base cations. The results indicate that AGB is mediated by both climate and soils, and suggest that the AGB of African closed-canopy tropical forests may be particularly sensitive to future precipitation and temperature changes.

Published
2013
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8. Effects of rising temperatures and [CO2] on the physiology of tropical forest trees.

Author

Lloyd J and Farquhar GD

Subjects
Greenhouse Effect, Tropical Climate, Carbon Dioxide, Temperature, Trees physiology
Abstract

Using a mixture of observations and climate model outputs and a simple parametrization of leaf-level photosynthesis incorporating known temperature sensitivities, we find no evidence for tropical forests currently existing "dangerously close" to their optimum temperature range. Our model suggests that although reductions in photosynthetic rate at leaf temperatures (TL) above 30 degrees C may occur, these are almost entirely accountable for in terms of reductions in stomatal conductance in response to higher leaf-to-air vapour pressure deficits D. This is as opposed to direct effects of TL on photosynthetic metabolism. We also find that increases in photosynthetic rates associated with increases in ambient [CO2] over forthcoming decades should more than offset any decline in photosynthetic productivity due to higher D or TL or increased autotrophic respiration rates as a consequence of higher tissue temperatures. We also find little direct evidence that tropical forests should not be able to respond to increases in [CO2] and argue that the magnitude and pattern of increases in forest dynamics across Amazonia observed over the last few decades are consistent with a [CO2]-induced stimulation of tree growth.

Published
2008
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