The pitcher of the carnivorous plant Sarracenia purpurea L. contains an entrapped body of liquid within which its prey is digested. Free calcium in the pitcher is derived from either the pitcher walls or from prey falling into the pitcher; in the absence of exogenous (prey-derived) calcium it will depend on the active and passive calcium regulatory properties of the pitcher walls and may to some extent therefore mimic calcium in the apoplast of plant cells. Using a calcium-specific electrode, the free calcium concentration of the pitchers of Sarracenia plants was investigated and the effect of adding a variety of concentrations of calcium in water determined. The mean pitcher free calcium concentration in vivo was 2.3 × 10−5 M±2.5 × 10−5 M; when pitchers were washed and filled with water containing lower calcium concentrations, the concentration in the pitcher water rose to 1−5 × 10−5 M. When higher calcium concentrations (up to 1 × 10−4 M) were added, the pitcher calcium concentration declined to 1−7 × 10−5 M. Concentrations of calcium above 1 × 10−4 M were also reduced, but to a lesser extent. Metabolic inhibition of active ion transport, while inhibiting pitcher acidification, did not inhibit regulation of pitcher free calcium, suggested that it occurs as a result of calcium exchange sites in the pitcher walls. The data are discussed in relation to the physiology of Sarracenia pitchers and to the usefulness of the pitcher as a model for free calcium in the higher plant apoplast.

Carnivorous plant

10.1093/oxfordjournals.aob.a088295

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Citations (5)

Tropical ant community responses to experimental soil warming

Biology Letters (2022)

Jelena Bujan Andrew T. Nottingham Esther Velasquez Patrick Meir Michael Kaspari

Climate change is one of the primary agents of the global decline in insect abundance. Because of their narrow thermal ranges, tropical ectotherms are predicted to be most threatened by global warming, yet tests of this prediction are often confounded by other anthropogenic disturbances. We used a tropical forest soil warming experiment to directly test the effect of temperature increase on litter-dwelling ants. Two years of continuous warming led to a change in ant community between warming and control plots. Specifically, six ant genera were recorded only on warming plots, and one genus only on control plots. Wasmannia auropuctata, a species often invasive elsewhere but native to this forest, was more abundant in warmed plots. Ant recruitment at baits was best predicted by soil surface temperature and ant heat tolerance. These results suggest that heat tolerance is useful for predicting changes in daily foraging activity, which is directly tied to colony fitness. We show that a 2-year increase in temperature (of 2-4°C) can have a profound effect on the most abundant insects, potentially favouring species with invasive traits and moderate heat tolerances.

Ectotherm

Plant litter

10.1098/rsbl.2021.0518

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Citations (11)

Direct evidence for phosphorus limitation on Amazon forest productivity

Nature (2022)

Hellen Fernanda Viana Cunha Kelly M. Andersen Laynara F. Lugli Flávia Delgado Santana Izabela Aleixo

10.1038/s41586-022-05085-2

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Citations (133)

Multiple phosphorus acquisition strategies adopted by fine roots in low-fertility soils in Central Amazonia

Plant and Soil (2019)

Laynara F. Lugli Kelly M. Andersen Luiz E. O. C. Aragão Amanda L. Cordeiro Hellen Fernanda Viana Cunha

Ancient Amazon soils are characterised by low concentrations of soil phosphorus (P). Therefore, it is hypothesised that plants may invest a substantial proportion of their resources belowground to adjust their P-uptake strategies, including root morphological, physiological (phosphatase enzyme activities) and biotic (arbuscular mycorrhizal (AM) associations) adaptations. Since these strategies are energy demanding, we hypothesise that trade-offs between morphological traits and root phosphatase exudation and symbiotic associations would occur. Specifically, we expected that plants which invest in finer roots, and therefore have greater ability to explore large soil volumes, would have a high investment in physiological adaptations such as enhanced phosphatase production. In contrast, we expected that plants with predominantly thicker roots would invest more in symbiotic associations, in which carbon is traded for P acquired from AM fungal communities. We collected absorptive roots (<2 mm diameter) from a lowland Central Amazon forest near Manaus, Brazil. We measured fine root diameter, specific root length (SRL), specific root area (SRA), root tissue density (RTD), root phosphatase activity (APase) and arbuscular mycorrhizal (AM) fungi colonisation. Root morphological traits were related to APase activity, with higher APase activity in roots with higher SRL and SRA but lower RTD. However, the degree of AM colonisation was not related to any measured root morphological trait. Fine absorptive roots likely benefit from having low RTD, high SRL, SRA and APase exudation to acquire P efficiently. However, because AM colonisation was not related to root morphology, we suggest that investment in multiple P-uptake strategies is required for maintaining productivity in Central Amazon forests.

Colonisation

Plant Physiology

Phosphorus deficiency

Root system

10.1007/s11104-019-03963-9

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Citations (96)

Understanding the relationships between ecosystem services and poverty alleviation: A conceptual framework

Ecosystem Services (2013)

Janet Fisher Geneviève Patenaude Kalpana Giri Kristina H. Lewis Patrick Meir

As interest grows in the contribution of ecosystem services to poverty alleviation, we present a new conceptual framework, synthesizing insights from existing frameworks in social–ecological systems science and international development. People have differentiated abilities to benefit from ecosystem services, and the framework places emphasis on access to services, which may constrain the poorest more than aggregate availability. Distinctions are also made between categories of ecosystem service in their contribution to wellbeing, provisioning services and cash being comparatively easy to control. The framework gives analytical space for understanding the contribution of payments for ecosystem services to wellbeing, as distinct from direct ecosystem services. It also highlights the consumption of ecosystem services by external actors, through land appropriation or agricultural commodities. Important conceptual distinctions are made between poverty reduction and prevention, and between human response options of adaptation and mitigation in response to environmental change. The framework has applications as a thinking tool, laying out important relationships such that an analyst could identify and understand these in a particular situation. Most immediately, this has research applications, as a basis for multidisciplinary, policy-relevant research, but there are also applications to support practitioners in pursuing joint policy objectives of environmental sustainability and poverty alleviation.

Provisioning

Conceptual framework

Millennium Ecosystem Assessment

10.1016/j.ecoser.2013.08.002

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Citations (240)

The regional variation of aboveground live biomass in old‐growth Amazonian forests

Global Change Biology (2006)

Yadvinder Malhi Daniel Wood Timothy R. Baker Jim A. Wright Oliver L. Phillips

Abstract The biomass of tropical forests plays an important role in the global carbon cycle, both as a dynamic reservoir of carbon, and as a source of carbon dioxide to the atmosphere in areas undergoing deforestation. However, the absolute magnitude and environmental determinants of tropical forest biomass are still poorly understood. Here, we present a new synthesis and interpolation of the basal area and aboveground live biomass of old‐growth lowland tropical forests across South America, based on data from 227 forest plots, many previously unpublished. Forest biomass was analyzed in terms of two uncorrelated factors: basal area and mean wood density. Basal area is strongly affected by local landscape factors, but is relatively invariant at regional scale in moist tropical forests, and declines significantly at the dry periphery of the forest zone. Mean wood density is inversely correlated with forest dynamics, being lower in the dynamic forests of western Amazonia and high in the slow‐growing forests of eastern Amazonia. The combination of these two factors results in biomass being highest in the moderately seasonal, slow growing forests of central Amazonia and the Guyanas (up to 350 Mg dry weight ha −1 ) and declining to 200–250 Mg dry weight ha −1 at the western, southern and eastern margins. Overall, we estimate the total aboveground live biomass of intact Amazonian rainforests (area 5.76 × 10 6 km 2 in 2000) to be 93±23 Pg C, taking into account lianas and small trees. Including dead biomass and belowground biomass would increase this value by approximately 10% and 21%, respectively, but the spatial variation of these additional terms still needs to be quantified.

Basal area

Deforestation

Liana

Carbon sink

Old-growth forest

10.1111/j.1365-2486.2006.01120.x

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Citations (661)

Microbes follow Humboldt: temperature drives plant and soil microbial diversity patterns from the Amazon to the Andes

Ecology (2018)

Andrew T. Nottingham Noah Fierer Benjamin L. Turner Jeanette Whitaker Nick Ostle

Abstract More than 200 years ago, Alexander von Humboldt reported that tropical plant species richness decreased with increasing elevation and decreasing temperature. Surprisingly, coordinated patterns in plant, bacterial, and fungal diversity on tropical mountains have not yet been observed, despite the central role of soil microorganisms in terrestrial biogeochemistry and ecology. We studied an Andean transect traversing 3.5 km in elevation to test whether the species diversity and composition of tropical forest plants, soil bacteria, and fungi follow similar biogeographical patterns with shared environmental drivers. We found coordinated changes with elevation in all three groups: species richness declined as elevation increased, and the compositional dissimilarity among communities increased with increased separation in elevation, although changes in plant diversity were larger than in bacteria and fungi. Temperature was the dominant driver of these diversity gradients, with weak influences of edaphic properties, including soil pH . The gradients in microbial diversity were strongly correlated with the activities of enzymes involved in organic matter cycling, and were accompanied by a transition in microbial traits towards slower‐growing, oligotrophic taxa at higher elevations. We provide the first evidence of coordinated temperature‐driven patterns in the diversity and distribution of three major biotic groups in tropical ecosystems: soil bacteria, fungi, and plants. These findings suggest that interrelated and fundamental patterns of plant and microbial communities with shared environmental drivers occur across landscape scales. These patterns are revealed where soil pH is relatively constant, and have implications for tropical forest communities under future climate change.

Edaphic

Biogeochemistry

10.1002/ecy.2482

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Citations (244)

ENSO Drives interannual variation of forest woody growth across the tropics

Philosophical Transactions of the Royal Society B Biological Sciences (2018)

Sami W. Rifai Cécile A. J. Girardin Érika Berenguer Jhon del Águila Pasquel Cecilia A. L. Dahlsjö

Meteorological extreme events such as El Niño events are expected to affect tropical forest net primary production (NPP) and woody growth, but there has been no large-scale empirical validation of this expectation. We collected a large high–temporal resolution dataset (for 1–13 years depending upon location) of more than 172 000 stem growth measurements using dendrometer bands from across 14 regions spanning Amazonia, Africa and Borneo in order to test how much month-to-month variation in stand-level woody growth of adult tree stems (NPP stem ) can be explained by seasonal variation and interannual meteorological anomalies. A key finding is that woody growth responds differently to meteorological variation between tropical forests with a dry season (where monthly rainfall is less than 100 mm), and aseasonal wet forests lacking a consistent dry season. In seasonal tropical forests, a high degree of variation in woody growth can be predicted from seasonal variation in temperature, vapour pressure deficit, in addition to anomalies of soil water deficit and shortwave radiation. The variation of aseasonal wet forest woody growth is best predicted by the anomalies of vapour pressure deficit, water deficit and shortwave radiation. In total, we predict the total live woody production of the global tropical forest biome to be 2.16 Pg C yr −1 , with an interannual range 1.96–2.26 Pg C yr −1 between 1996–2016, and with the sharpest declines during the strong El Niño events of 1997/8 and 2015/6. There is high geographical variation in hotspots of El Niño–associated impacts, with weak impacts in Africa, and strongly negative impacts in parts of Southeast Asia and extensive regions across central and eastern Amazonia. Overall, there is high correlation ( r = −0.75) between the annual anomaly of tropical forest woody growth and the annual mean of the El Niño 3.4 index, driven mainly by strong correlations with anomalies of soil water deficit, vapour pressure deficit and shortwave radiation. This article is part of the discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

Biome

Seasonality

Dry season

10.1098/rstb.2017.0410

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Citations (65)