scholarly journals Analysing Amazonian forest productivity using a new individual and trait-based model (TFS v.1)

2014 ◽  
Vol 7 (4) ◽  
pp. 1251-1269 ◽  
Author(s):  
N. M. Fyllas ◽  
E. Gloor ◽  
L. M. Mercado ◽  
S. Sitch ◽  
C. A. Quesada ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Functional Traits ◽  
Amazon Basin ◽  
Census Data ◽  
Soil Nutrient ◽  
Forest Growth ◽  
High Rate ◽  
Mean Annual Precipitation ◽  
Water Fluxes ◽  
Amazonian Forest

Abstract. Repeated long-term censuses have revealed large-scale spatial patterns in Amazon basin forest structure and dynamism, with some forests in the west of the basin having up to a twice as high rate of aboveground biomass production and tree recruitment as forests in the east. Possible causes for this variation could be the climatic and edaphic gradients across the basin and/or the spatial distribution of tree species composition. To help understand causes of this variation a new individual-based model of tropical forest growth, designed to take full advantage of the forest census data available from the Amazonian Forest Inventory Network (RAINFOR), has been developed. The model allows for within-stand variations in tree size distribution and key functional traits and between-stand differences in climate and soil physical and chemical properties. It runs at the stand level with four functional traits – leaf dry mass per area (Ma), leaf nitrogen (NL) and phosphorus (PL) content and wood density (DW) varying from tree to tree – in a way that replicates the observed continua found within each stand. We first applied the model to validate canopy-level water fluxes at three eddy covariance flux measurement sites. For all three sites the canopy-level water fluxes were adequately simulated. We then applied the model at seven plots, where intensive measurements of carbon allocation are available. Tree-by-tree multi-annual growth rates generally agreed well with observations for small trees, but with deviations identified for larger trees. At the stand level, simulations at 40 plots were used to explore the influence of climate and soil nutrient availability on the gross (ΠG) and net (ΠN) primary production rates as well as the carbon use efficiency (CU). Simulated ΠG, ΠN and CU were not associated with temperature. On the other hand, all three measures of stand level productivity were positively related to both mean annual precipitation and soil nutrient status. Sensitivity studies showed a clear importance of an accurate parameterisation of within- and between-stand trait variability on the fidelity of model predictions. For example, when functional tree diversity was not included in the model (i.e. with just a single plant functional type with mean basin-wide trait values) the predictive ability of the model was reduced. This was also the case when basin-wide (as opposed to site-specific) trait distributions were applied within each stand. We conclude that models of tropical forest carbon, energy and water cycling should strive to accurately represent observed variations in functionally important traits across the range of relevant scales.

scholarly journals Analysing Amazonian forest productivity using a new individual and trait-based model (TFS v.1)

2014 ◽  
Vol 7 (1) ◽  
pp. 1413-1452 ◽  
Author(s):  
N. M. Fyllas ◽  
E. Gloor ◽  
L. M. Mercado ◽  
S. Sitch ◽  
C. A. Quesada ◽  
...  
Keyword(s):  
Soil Fertility ◽  
Functional Traits ◽  
Large Scale ◽  
Amazon Basin ◽  
Census Data ◽  
Forest Growth ◽  
High Rate ◽  
Water Fluxes ◽  
Amazonian Forest ◽  
Large Trees

Abstract. Repeated long-term censuses have revealed large-scale spatial patterns in Amazon Basin forest structure and dynamism, with some forests in the west of the Basin having up to a twice as high rate of aboveground biomass production and tree recruitment as forests in the east. Possible causes for this variation could be the climatic and edaphic gradients across the Basin and/or the spatial distribution of tree species composition. To help understand causes of this variation a new individual-based model of tropical forest growth designed to take full advantage of the forest census data available from the Amazonian Forest Inventory Network (RAINFOR) has been developed. The model incorporates variations in tree size distribution, functional traits and soil physical properties and runs at the stand level with four functional traits, leaf dry mass per area (Ma), leaf nitrogen (NL) and phosphorus (PL) content and wood density (DW) used to represent a continuum of plant strategies found in tropical forests. We first applied the model to validate canopy-level water fluxes at three Amazon eddy flux sites. For all three sites the canopy-level water fluxes were adequately simulated. We then applied the model at seven plots, where intensive measurements of carbon allocation are available. Tree-by-tree multi-annual growth rates generally agreed well with observations for small trees, but with deviations identified for large trees. At the stand-level, simulations at 40 plots were used to explore the influence of climate and soil fertility on the gross (ΠG) and net (ΠN) primary production rates as well as the carbon use efficiency (CU). Simulated ΠG, ΠN and CU were not associated with temperature. However all three measures of stand level productivity were positively related to annual precipitation and soil fertility.

Spatial Patterns and Drivers of Soil Chemical Properties in a Typical Hickory Plantation

2021 ◽  
Author(s):  
Mengjiao Sun ◽  
Enqing Hou ◽  
Jiasen Wu ◽  
Jianqin Huang ◽  
Xingzhao Huang
Keyword(s):  
Random Forest ◽  
Soil Nutrients ◽  
Spatial Patterns ◽  
Abiotic Factors ◽  
Soil Nutrient ◽  
Parent Material ◽  
Mean Annual Precipitation ◽  
Nutrient Concentrations ◽  
Available Phosphorus ◽  
Mean Annual Temperature

Abstract Background: Soil nutrients play critical roles in regulating and improving the sustainable development of economic forests. Consequently, an elucidation of the spatial patterns and drivers of soil nutrients in these forests is fundamental to their management. For this study, we collected 314 composite soils at a 0-30 cm depth from a typical hickory plantation in Lin 'an, Zhejiang Province, China. We determined the concentrations of macronutrients (i.e., soil organic carbon, hydrolyzed nitrogen, available phosphorus, and available potassium) and micronutrients (i.e., iron, manganese, zinc, and copper.) of the soils. We employed random forest analysis to quantify the relative importance of soil-forming factors to predict the soil nutrient concentrations, which could then be extrapolated to the entire hickory region. Results: Random forest models explained 61%–88% of the variations in soil nutrient concentrations. The mean annual temperature and mean annual precipitation were the most important predictor of soil macronutrient and micronutrient concentrations. Moreover, parent material was another key predictor of soil available phosphorus and micronutrient concentrations. Mapping results demonstrated the importance of climate in controlling the spatial distribution of soil nutrient concentrations at finer scales, as well as the effect of parent material, topography, stand structure, and management measures of hickory plantations. Conclusions: Our study highlights the biotic factors, abiotic factors, and management factors control over soil macronutrient and micronutrient concentrations, which have significant implications for the sustainability of soil nutrients in forest plantations.

Flesh flies (Diptera: Sarcophagidae) from a white-sand habitat in the Brazilian Amazon, with the description of four new species

Zootaxa ◽  
2018 ◽  
Vol 4504 (3) ◽  
pp. 401
Author(s):  
FERNANDO DA SILVA CARVALHO-FILHO ◽  
INOCÊNCIO DE SOUSA GORAYEB ◽  
JÉSSICA MARIA MENEZES SOARES ◽  
MATHEUS TAVARES DE SOUZA
Keyword(s):  
New Species ◽  
Tropical Forest ◽  
Amazon Basin ◽  
Vegetation Type ◽  
Brazilian Amazon ◽  
Insect Fauna ◽  
Flesh Fly ◽  
Small Areas ◽  
White Sand ◽  
Flesh Flies

The white-sand enclaves in the Amazon Basin are small areas scattered through the tropical forest, with sandy and nutrient-poor soils and an unusual vegetation type. The insect fauna of this ecosystem is poorly known, especially in the eastern Amazon. The flesh fly fauna of an area of open herbaceous white-sand vegetation known as “Campo Redondo” in the municipality of Cametá, state of Pará, was surveyed, resulting in the discovery of 43 species in 11 genera representing the subfamilies Sarcophaginae and Miltogramminae. Four new species are described: Dexosarcophaga (Dexosarcophaga) campina sp. nov., Helicobia cametaensis sp. nov., Helicobia domquixote sp. nov., and Metopia fofo sp. nov. Lepidodexia (Lepidodexia) grisea Lopes and Lepidodexia (Notochaeta) setifrons (Lopes) are newly recorded from Brazil. Dexosarcophaga (Bezzisca) ampullula (Engel), D. (Dexosarcophaga) transita Townsend and Titanogrypa (Cucullomyia) larvicida (Lopes) are newly recorded from the Brazilian Amazon. 

scholarly journals Improved understanding of drought controls on seasonal variation in Mediterranean forest canopy CO<sub>2</sub> and water fluxes through combined in situ measurements and ecosystem modelling

2009 ◽  
Vol 6 (8) ◽  
pp. 1423-1444 ◽  
Author(s):  
T. Keenan ◽  
R. García ◽  
A. D. Friend ◽  
S. Zaehle ◽  
C. Gracia ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Forest Canopy ◽  
Moisture Stress ◽  
Mediterranean Ecosystems ◽  
Forest Growth ◽  
Water Fluxes ◽  
Soil Moisture Stress ◽  
Dynamic Global Vegetation Model ◽  
Forest Growth Model

Abstract. Water stress is a defining characteristic of Mediterranean ecosystems, and is likely to become more severe in the coming decades. Simulation models are key tools for making predictions, but our current understanding of how soil moisture controls ecosystem functioning is not sufficient to adequately constrain parameterisations. Canopy-scale flux data from four forest ecosystems with Mediterranean-type climates were used in order to analyse the physiological controls on carbon and water flues through the year. Significant non-stomatal limitations on photosynthesis were detected, along with lesser changes in the conductance-assimilation relationship. New model parameterisations were derived and implemented in two contrasting modelling approaches. The effectiveness of two models, one a dynamic global vegetation model ("ORCHIDEE"), and the other a forest growth model particularly developed for Mediterranean simulations ("GOTILWA+"), was assessed and modelled canopy responses to seasonal changes in soil moisture were analysed in comparison with in situ flux measurements. In contrast to commonly held assumptions, we find that changing the ratio of conductance to assimilation under natural, seasonally-developing, soil moisture stress is not sufficient to reproduce forest canopy CO2 and water fluxes. However, accurate predictions of both CO2 and water fluxes under all soil moisture levels encountered in the field are obtained if photosynthetic capacity is assumed to vary with soil moisture. This new parameterisation has important consequences for simulated responses of carbon and water fluxes to seasonal soil moisture stress, and should greatly improve our ability to anticipate future impacts of climate changes on the functioning of ecosystems in Mediterranean-type climates.

scholarly journals Quantitative estimates of deciduousness in woody species from a seasonally dry tropical forest are related to leaf functional traits and the timing of leaf flush

2021 ◽  
Author(s):  
Souparna Chakrabarty ◽  
Sheetal Sharma ◽  
Shatarupa Ganguly ◽  
Asmi Jezeera ◽  
Neha Mohanbabu ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Functional Traits ◽  
Woody Species ◽  
Leaf Phenology ◽  
Deciduous Species ◽  
Seasonally Dry Tropical Forest ◽  
Leaf Functional Traits ◽  
Dry Tropical Forest ◽  
Seasonally Dry ◽  
Quantitative Estimates

AbstractLeaf phenology based classification of woody species into discrete evergreen and deciduous categories is widely used in ecology, but these categories hide important variation in leaf phenological behaviour. Few studies have examined the continuous nature of deciduousness and our understanding of variation in quantitative estimates of leaf shedding behaviour and the causes and consequences of this is limited. In this study we monitored leaf phenology in 75 woody species from a seasonally dry tropical forest to quantify three quantitative measures of deciduousness, namely: maximum canopy loss, duration of deciduousness, and average canopy loss. Based on proposed drought tolerance and drought avoidance strategies of evergreen and deciduous species, respectively, we tested whether the quantitative measures of deciduousness were related to leaf functional traits. Additionally, to understand the functional consequences of variation in deciduousness we examined relationships with the timing of leaf flushing and senescing. We found wide and continuous variation in quantitative measures of deciduousness in these coexisting species. Variation in deciduousness was related to leaf function traits, and the timing of leaf flushing. Along a continuous axis ranging from evergreen to deciduous species, increasing deciduousness was associated with more acquisitive leaf functional traits, with lower leaf mass per area and leaf dry matter content, and greater leaf nitrogen content. These results indicate that the continuous nature of deciduousness is an important component of resource acquisition strategies in woody species from seasonally dry forests.

scholarly journals Habitat fragmentation narrows the distribution of avian functional traits associated with seed dispersal in tropical forest

2018 ◽  
Vol 16 (2) ◽  
pp. 90-96 ◽  
Author(s):  
Alex A.A. Bovo ◽  
Katia M.P.M.B. Ferraz ◽  
Marcelo Magioli ◽  
Eduardo R. Alexandrino ◽  
Érica Hasui ◽  
...  
Keyword(s):  
Habitat Fragmentation ◽  
Seed Dispersal ◽  
Tropical Forest ◽  
Functional Traits

scholarly journals The Piedra Chamana fossil woods and leaves: a record of the vegetation and palaeoenvironment of the Neotropics during the late middle Eocene

2020 ◽  
Vol 125 (7) ◽  
pp. 1077-1089
Author(s):  
Deborah W Woodcock ◽  
Herbert W Meyer
Keyword(s):  
Water Stress ◽  
Tropical Forest ◽  
Middle Eocene ◽  
Vessel Diameter ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Lowland Tropical Forest ◽  
Modern Analogue ◽  
Vessel Elements ◽  
Analytical Approaches

Abstract Background and Aims The Piedra Chamana fossil forest in northern Peru is an assemblage of angiosperm woods and leaves preserved in volcaniclastic rocks dated to 39 Mya (late Middle Eocene). We analysed the anatomical and morphological features of the fossils to reconstruct the palaeoenvironment during this time of global warmth, taking advantage of the co-occurrence of woods and leaves to compare different proxies and analytical approaches. Methods Wood characters analysed include vessel-related functional traits, traits linked to Baileyan trends, and quantitative features such as vessel diameter and density. Diameter-distribution and diameter and position plots are used to represent vessel diameter and arrangement. Leaf margin and area analysis provides additional climate estimates. Key Results The fossil woods show many similarities with modern tropical-forest woods and tropical fossil-wood assemblages; closest correspondence within the Neotropics is to semi-deciduous lowland tropical forest with moderate precipitation (~1000–1200 mm). Features unusual for the modern South American tropics are mainly vessel-related characters (semi-ring porosity, grouped vessels, helical vessel thickenings, short vessel elements) linked to water stress or seasonal water availability. Leaf analysis indicates mean annual temperature of 31 °C (n = 19, 100 % entire-margined) and mean annual precipitation of 1290 mm (n = 22, predominantly microphylls and notophylls). Conclusions The palaeovegetation was clearly lowland tropical forest with a dry aspect, but anomalous aspects of the wood anatomy are consistent with the high temperatures indicated by the leaves and are probably explained by differences in seasonality and water stress compared to the present-day Neotropics. A close modern analogue may be in very seasonal regions of Asia. Pronounced monsoonal (summer-rain) conditions may relate to a location (palaeolatitude of 13°S) outside the near-equatorial tropics.

Early responses of elevated nutrient input on above-ground net primary production of a lower-montane tropical forest in Uganda

2020 ◽  
Author(s):  
Raphael Manu ◽  
Marife D. Corre ◽  
Edzo Veldkamp ◽  
Oliver van Straaten
Keyword(s):  
Primary Production ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Net Primary Production ◽  
Forest Growth ◽  
Nutrient Addition ◽  
Litter Production ◽  
N Addition ◽  
Litter Fall ◽  
Montane Tropical Forest

&lt;p&gt;Nutrient availability in tropical forest ecosystems plays a critical role in sustaining forest growth and productivity. Observational evidence for nutrient limitations on net primary productivity (NPP) in the tropics is rare yet crucial for predicting the impacts of human-induced changes on tropical forests, particularly for underrepresented tropical regions in Africa. In an ecosystem-scale nutrient manipulation experiment, we assessed the response of different components of above-ground net primary production (ANPP) to nutrient addition of nitrogen (N), phosphorus (P), potassium (K) and all possible combinations (NP, NK, PK, and NPK) at rates of 125 kg N ha&lt;sup&gt;-1&lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;, 50 kg P ha&lt;sup&gt;-1&lt;/sup&gt; yr&lt;sup&gt;-1&lt;/sup&gt; and 50 kg K ha&lt;sup&gt;-1&lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;We established 32 (8 treatments &amp;#215; 4 replicates) experimental plots of 40 &amp;#215; 40 m&lt;sup&gt;2&lt;/sup&gt; each and measured stem growth of over 15,000 trees with diameter at breast height (dbh) &amp;#8805; 1 cm as well as litter production and above-ground woody biomass production (AWBP), of a lower-montane tropical forest (1100 m a.s.l.) in northwestern Uganda.&lt;/p&gt;&lt;p&gt;After 18 months of nutrient addition, we found that different aspects of ANPP, including litter production and AWBP are controlled by multiple soil nutrients. Specifically, we measured higher total fine-litter production in the N (13.6 &amp;#177; 1.4 Mg ha&lt;sup&gt;-1 &lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;) and K (13.3 &amp;#177; 1.8 Mg ha&lt;sup&gt;-1 &lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;) addition plots than the control (11.1 &amp;#177; 0.6 Mg ha&lt;sup&gt;-1 &lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;) plots. Both reproductive litter (flowers and fruits; 10% of total fine-litter fall) and leaf litter (62% of total fine-litter fall) significantly increased with K addition. In general, fine-litter production in our plots is higher than what has been reported so far for lower-montane tropical forests. Increased AWBP is associated with N addition plots. The response of trees to nutrient addition however, varied with tree sizes. Trees with dbh between 10 &amp;#8211; 30 cm increased significantly in AWBP under PK addition. There was no effect of nutrient addition associated with either smaller (1 &amp;#8211; 10 cm dbh) or larger trees (dbh &gt; 30 cm). The medium-sized trees which may have experienced resource competition but have now transitioned into the canopy layer (exposed to sunlight) are able to use additional nutrient for active growth. In contrast, bigger trees may allocate extra nutrient for reproduction and leaf-vitality, while smaller trees remain shaded, co-limited by sunlight and therefore unable to utilize increased available nutrients for stem diameter growth. ANPP increased by 39% with N addition and marginally by 23% with K additions relative to the control. In conclusion, our experiment provides evidence of N and potentially K limitation of ANPP in this lower-montane tropical forest, and highlights that, in a highly diverse ecosystem different components of ANPP may be regulated by multiple nutrients.&amp;#160;&lt;/p&gt;

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