The effects of water availability on root growth and morphology in an Amazon rainforest

Metcalfe, Daniel B.; Meir, Patrick; Aragão, Luiz E. O. C.; Costa, Antonio; Braga, Anna Rafaela Cavalcante; Gonçalves, P. H. L.; Silva, João de Athaydes; Almeida, Samuel; Dawson, Lorna; Malhi, Yadvinder; Williams, Mathew

doi:10.1007/s11104-008-9670-9

Cited by 156 publications

(187 citation statements)

References 60 publications

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“…The greater SRL during the dry season supports the hypothesis presented by Metcalfe et al (2008) that the plants respond to drought by increasing SRL. This strategy is an advantage for plants that increase their water and nutrient absorption potential.…”

Section: Discussionsupporting

confidence: 85%

“…Variation in root production associated with rainfall seasonality was also observed in other studies in tropical forests (Kavanagh and Kellman 1992;Visalakshi 1994;Sundarapandian and Swamy 1996;Cavelier et al 1999;Metcalfe et al 2008;Lima et al 2010), but there was greater fine-root production in the wet compared to the dry season in these studies.…”

Section: Fine-root Morphologysupporting

confidence: 82%

“…Differences between sites may be a reflection of the quantity of organic matter in the soil, since it was greater in the 18-year-old site preserved and probably the soil moisture better during the dry season. Data for SRL that give an idea of root morphology are needed to determine how root systems vary among ecosystems and respond to environmental changes (Metcalfe et al 2008).…”

Section: Discussionmentioning

confidence: 99%

“…We averaged the five samples per plot, resulting in n = 4 for each site and sampling date. Specific root length (SRL) (Jackson et al 1997;Metcalfe et al 2008) was calculated by dividing live root length by live root biomass and represented an index of fine root morphology.…”

Section: Measuring Fine-root Productionmentioning

confidence: 99%

“…Several environmental factors affect fine root production (Hendrick and Pregitzer 1996;Silver et al 2005), such as seasonality (Cavelier et al 1999;Yavitt and Wright 2001;Lima et al 2010) Metcalfe et al 2008). Floristic composition (Visalakshi 1994), forest successional stage and soil-use history (Castellanos et al 2001;Cavelier et al 1996;Jaramillo et al 2003) have also been reported as sources of variation for fine-root production.The objective of this study was to assess the fine root production dynamics in two tropical forest regrowth sites with distinct ages.…”

Section: Introductionmentioning

confidence: 99%

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Fine-root production in two secondary forest sites with distinct ages in Eastern Amazon

2012

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The objective of this work was to assess the fine-root (≤ 2 mm diameter) production dynamics of two forest regrowths at different ages. Fine-root production was monitored by the ingrowth core method in one 18-year-old site (2 ha) and one 10-year-old site (0.5 ha), both localized in the Apeú region, Northern Pará State, Brazil. The sites were abandoned after successive shifting cultivation, beginning in 1940. Monthly production of live fine-root was similar between sites and was influenced by rainfall seasonality, with higher production during the dry season than the wet season for mass and length. However, mortality in terms of mass was higher in the 10-year-old site than in the 18-year-old site. The seasonality influenced mortality only in the 18-year old site following the pattern observed for live fine-root. The influence seasonal on mortality in terms of length was different between sites, with higher mortality during the wet season in the 10-year-old site and higher mortality during the dry season in the 18-year-old site. Specific root length was higher during the wet season and at the 10-year-old site. Fine-root production was not influenced by the chronosequence of the sites studied, probably fine-root production may have already stabilized in the sites or it depended more on climate and soil conditions. The production of fine-roots mass and length were indicators that generally showed the same pattern. Keywords: drought, root biomass, seasonality, succession, tropical forest Produção de raízes finas em dois sítios de floresta secundária com diferentes idades na Amazônia Orientalresumo O objetivo deste trabalho foi avaliar a dinâmica de produção de raízes finas (diâmetro ≤ 2 mm) em duas áreas de floresta secundária com diferentes idades. A produção de raízes finas foi monitorada utilizando a técnica de ingrowth core em um sítio com 18 anos de idade (2 ha) e um outro sítio com 10 anos de idade (0,5 ha), localizados na região de Apeú, nordeste do Estado do Pará. Os sítios foram abandonados depois de sucessivos ciclos agrícolas, iniciados em 1940. A produção mensal de raízes vivas foi semelhante entre os sítios e influenciada pela sazonalidade pluviométrica, com maior produção durante a estação seca para massa e comprimento. No entanto, a mortalidade, em termos de massa, foi maior no sítio de 10 anos. A sazonalidade influenciou a mortalidade somente no sítio de 18 anos, seguindo o padrão observado para as raízes vivas. A influência sazonal sobre a mortalidade em termos de comprimento foi diferente entre os sítios, com maior mortalidade durante a estação chuvosa no sítio de 10 anos e maior mortalidade durante a estação seca no sítio de 18 anos. O comprimento radicular específico foi maior durante a estação chuvosa e influenciado pelos sítios, sendo maior no sítio de 10 anos. A produção de raízes finas não foi influenciada pela cronossequência dos sítios estudados, provavelmente porque a produção de raízes finas pode ter estabilizado nos sítios ou depende mais das condições de clima e solo. A produção,...

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Section: Discussionsupporting

confidence: 85%

Section: Fine-root Morphologysupporting

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Section: Measuring Fine-root Productionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Fine-root production in two secondary forest sites with distinct ages in Eastern Amazon

2012

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Montane forest root growth and soil organic layer depth as potential factors stabilizing Cenozoic global change

Doughty

Taylor

Malhi

et al. 2014

Geophysical Research Letters

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Tree roots and their symbiotic fungal partners are believed to play a major role in regulating long-term global climate, but feedbacks between global temperature and biotic weathering have not yet been explored in detail. In situ field data from a 3000 m altitudinal transect in Peru show fine root growth decreases and organic layer depth increases with the cooler temperatures that prevail at increased altitude. We hypothesize that this observation suggests a negative feedback: as global temperatures rise, the soil organic layer will shrink, and more roots will grow in the mineral layer, thereby accelerating weathering and reducing atmospheric CO 2 . We examine this mechanism with a process-based biological weathering model and demonstrate that this negative feedback could have contributed to moderating long-term global Cenozoic climate during major Cenozoic CO 2 changes linked to volcanic degassing and tectonic uplift events.

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Seasonal trends of Amazonian rainforest phenology, net primary productivity, and carbon allocation

Girardin

Malhi

Doughty

et al. 2016

Global Biogeochemical Cycles

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The seasonality of solar irradiance and precipitation may regulate seasonal variations in tropical forests carbon cycling. Controversy remains over their importance as drivers of seasonal dynamics of net primary productivity in tropical forests. We use ground data from nine lowland Amazonian forest plots collected over 3 years to quantify the monthly primary productivity (NPP) of leaves, reproductive material, woody material, and fine roots over an annual cycle. We distinguish between forests that do not experience substantial seasonal moisture stress (“humid sites”) and forests that experience a stronger dry season (“dry sites”). We find that forests from both precipitation regimes maximize leaf NPP over the drier season, with a peak in production in August at both humid (mean 0.39 ± 0.03 Mg C ha−1 month−1 in July, n = 4) and dry sites (mean 0.49 ± 0.03 Mg C ha−1 month−1 in September, n = 8). We identify two distinct seasonal carbon allocation patterns (the allocation of NPP to a specific organ such as wood leaves or fine roots divided by total NPP). The forests monitored in the present study show evidence of either (i) constant allocation to roots and a seasonal trade‐off between leaf and woody material or (ii) constant allocation to wood and a seasonal trade‐off between roots and leaves. Finally, we find strong evidence of synchronized flowering at the end of the dry season in both precipitation regimes. Flower production reaches a maximum of 0.047 ± 0.013 and 0.031 ± 0.004 Mg C ha−1 month−1 in November, in humid and dry sites, respectively. Fruitfall production was staggered throughout the year, probably reflecting the high variation in varying times to development and loss of fruit among species.

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The effects of water availability on root growth and morphology in an Amazon rainforest

Cited by 156 publications

References 60 publications

Fine-root production in two secondary forest sites with distinct ages in Eastern Amazon

Fine-root production in two secondary forest sites with distinct ages in Eastern Amazon

Montane forest root growth and soil organic layer depth as potential factors stabilizing Cenozoic global change

Seasonal trends of Amazonian rainforest phenology, net primary productivity, and carbon allocation

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