scholarly journals Leaf Elemental Concentrations, Stoichiometry, and Resorption in Guam’s Coastal Karst Forests

Diversity ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 545
Author(s):  
Thomas E. Marler
Keyword(s):  
Ecosystem Function ◽  
Tree Species ◽  
Leaf Traits ◽  
Resorption Efficiency ◽  
Carbon And Nitrogen ◽  
Karst Forest ◽  
Elemental Concentrations ◽  
Coastal Karst ◽  
Interspecific Diversity ◽  
Dry Combustion

Greater knowledge concerning the interspecific diversity of the plant leaf ionome is required to effectively understand the spatiotemporal dynamics of biogeochemistry, but Micronesia has been ignored in this literature. The objectives of this study were to quantify the leaf ionome, resorption efficiency, and stoichiometry of leaves from 25 plant species representing Guam’s coastal karst forests. Carbon and nitrogen were quantified by dry combustion, and other minerals and metals were quantified by spectrometry. Nitrogen and calcium concentrations in Guam’s green leaves exceeded the published global means, but manganese and copper concentrations were less than the global means. The remainder of the elements were within the expected ranges. Nutrient resorption rates exhibited a decreasing order of potassium > phosphorus > nitrogen > zinc > copper. The term “accretion efficiency” is introduced to describe the accumulation of an element throughout leaf aging and senescence, and calcium and iron exhibited substantial accretion efficiency in this study. Stoichiometry relations indicated that Guam’s karst forest is most limited by phosphorus and then secondarily limited by nitrogen, although several individual taxa exhibited co-limitation by potassium. Five of the species are officially listed on extinction threat lists. Of these, the Malvaceae tree Heriteria longipetiolata exhibited leaf traits depicting the most recalcitrant litter characteristics, and the Fabaceae tree Serianthes nelsonii exhibited leaf traits depicting the most labile litter characteristics. The contributions of these two tree species to spatiotemporal diversity in biogeochemistry appear to be profound, indicating species recovery efforts are of paramount importance for maintaining ecosystem function and soil heterotroph biodiversity in northern Guam.

scholarly journals Leaf Nutrient Relations of Cycads in a Common Garden

2021 ◽  
Vol 14 ◽  
pp. 194008292110365
Author(s):  
Thomas E. Marler ◽  
Anders J. Lindström
Keyword(s):  
Common Garden ◽  
Nutrient Content ◽  
Leaf Traits ◽  
Botanical Garden ◽  
Active Management ◽  
Nitrogen And Phosphorus ◽  
Representative Species ◽  
Nutrient Relations ◽  
Homogeneous Environment ◽  
Dry Combustion

Background and Aims Research required to clarify leaf nutrient relations of cycad species has been inadequate. Common garden studies are useful for determining the influence of genetics on leaf traits because of the homogeneous environment among experimental units. To date, there have been no common garden studies which included all ten genera of cycads. The full phylogenetic breadth has, therefore, not been included in this important area of study. Methods We examined macronutrient and micronutrient content of leaves from one representative species from each of the ten cycad genera at Nong Nooch Tropical Botanical Garden in Thailand. Nitrogen content was determined by dry combustion, and the remaining nutrients were quantified by spectrometry. Results The least variable elements were nitrogen and phosphorus, and the most variable elements were boron and sodium. Nutrient content based on leaflet area was more variable than based on leaflet mass, reflecting species differences in specific leaf area. There were no universal macronutrient or micronutrient signals indicating clear phylogenetic distinctions. Implications for Conservation: Active management of threatened cycad taxa requires research to develop the knowledge to enable evidence-based decisions. This common garden study inclusive of all 10 cycad genera creates a foundation to determine leaf nutrient sufficiency ranges to inform management decisions.

scholarly journals Environmental change impacts on the C- and N-cycle of European forests: a model comparison study

2013 ◽  
Vol 10 (3) ◽  
pp. 1751-1773 ◽  
Author(s):  
D. R. Cameron ◽  
M. Van Oijen ◽  
C. Werner ◽  
K. Butterbach-Bahl ◽  
R. Grote ◽  
...  
Keyword(s):  
Carbon Sequestration ◽  
Central Europe ◽  
Tree Species ◽  
Carbon Sink ◽  
N2o Emission ◽  
Forest Growth ◽  
N2o Emissions ◽  
European Forests ◽  
Considerable Uncertainty ◽  
Carbon And Nitrogen

Abstract. Forests are important components of the greenhouse gas balance of Europe. There is considerable uncertainty about how predicted changes to climate and nitrogen deposition will perturb the carbon and nitrogen cycles of European forests and thereby alter forest growth, carbon sequestration and N2O emission. The present study aimed to quantify the carbon and nitrogen balance, including the exchange of greenhouse gases, of European forests over the period 2010–2030, with a particular emphasis on the spatial variability of change. The analysis was carried out for two tree species: European beech and Scots pine. For this purpose, four different dynamic models were used: BASFOR, DailyDayCent, INTEGRATOR and Landscape-DNDC. These models span a range from semi-empirical to complex mechanistic. Comparison of these models allowed assessment of the extent to which model predictions depended on differences in model inputs and structure. We found a European average carbon sink of 0.160 ± 0.020 kgC m−2 yr−1 (pine) and 0.138 ± 0.062 kgC m−2 yr−1 (beech) and N2O source of 0.285 ± 0.125 kgN ha−1 yr−1 (pine) and 0.575 ± 0.105 kgN ha−1 yr−1 (beech). The European average greenhouse gas potential of the carbon sink was 18 (pine) and 8 (beech) times that of the N2O source. Carbon sequestration was larger in the trees than in the soil. Carbon sequestration and forest growth were largest in central Europe and lowest in northern Sweden and Finland, N. Poland and S. Spain. No single driver was found to dominate change across Europe. Forests were found to be most sensitive to change in environmental drivers where the drivers were limiting growth, where changes were particularly large or where changes acted in concert. The models disagreed as to which environmental changes were most significant for the geographical variation in forest growth and as to which tree species showed the largest rate of carbon sequestration. Pine and beech forests were found to have differing sensitivities to environmental change, in particular the response to changes in nitrogen and precipitation, with beech forest more vulnerable to drought. There was considerable uncertainty about the geographical location of N2O emissions. Two of the models BASFOR and LandscapeDNDC had largest emissions in central Europe where nitrogen deposition and soil nitrogen were largest, whereas the two other models identified different regions with large N2O emission. N2O emissions were found to be larger from beech than pine forests and were found to be particularly sensitive to forest growth.

scholarly journals Leaf traits and gas exchange in saplings of native tree species in the Central Amazon

2010 ◽  
Vol 67 (6) ◽  
pp. 624-632 ◽  
Author(s):  
Keila Rego Mendes ◽  
Ricardo Antonio Marenco
Keyword(s):  
Gas Exchange ◽  
Nitrogen Content ◽  
Leaf Area ◽  
Tree Species ◽  
Leaf Traits ◽  
Leaf Nitrogen ◽  
Dry Season ◽  
Leaf Thickness ◽  
Rainfall Regime ◽  
Leaf Nitrogen Content

Global climate models predict changes on the length of the dry season in the Amazon which may affect tree physiology. The aims of this work were to determine the effect of the rainfall regime and fraction of sky visible (FSV) at the forest understory on leaf traits and gas exchange of ten rainforest tree species in the Central Amazon, Brazil. We also examined the relationship between specific leaf area (SLA), leaf thickness (LT), and leaf nitrogen content on photosynthetic parameters. Data were collected in January (rainy season) and August (dry season) of 2008. A diurnal pattern was observed for light saturated photosynthesis (Amax) and stomatal conductance (g s), and irrespective of species, Amax was lower in the dry season. However, no effect of the rainfall regime was observed on g s nor on the photosynthetic capacity (Apot, measured at saturating [CO2]). Apot and leaf thickness increased with FSV, the converse was true for the FSV-SLA relationship. Also, a positive relationship was observed between Apot per unit leaf area and leaf nitrogen content, and between Apot per unit mass and SLA. Although the rainfall regime only slightly affects soil moisture, photosynthetic traits seem to be responsive to rainfall-related environmental factors, which eventually lead to an effect on Amax. Finally, we report that little variation in FSV seems to affect leaf physiology (Apot) and leaf anatomy (leaf thickness).

scholarly journals Stem trait spectra underpin multiple functions of temperate gymnosperm and angiosperm tree species

2021 ◽  
Author(s):  
Shanshan Yang ◽  
Frank J. Sterck ◽  
Ute Sass-Klaassen ◽  
J. Hans C. Cornelissen ◽  
Richard S.P. van Logtestijn ◽  
...  
Keyword(s):  
Tree Species ◽  
Leaf Traits ◽  
Fast Growth ◽  
Growth Strategy ◽  
Trade Off ◽  
Plant Strategy ◽  
Leaf Habit ◽  
Angiosperm Species ◽  
Central Paradigm ◽  
Diffuse Porous

Abstract A central paradigm in comparative ecology is that species sort out along a global economic strategy spectrum, ranging from slow to fast growth. Many studies evaluated plant strategy spectra for leaf traits, b u t few studies evaluated stem strategy spectra using a comprehensive set of anatomical, chemical and morphological traits, addressing key stem functions of different stem compartments (inner wood, outer wood and bark). This study evaluates how stem traits vary in the wood and bark of temperate tree species, and whether a slow-fast growth strategy spectrum exists and what traits make up this plant strategy spectrum. For 14 temperate gymnosperm and angiosperm species, 20 traits belonging to six key stem functions were measured for three stem compartments. Both across and within gymnosperms and angiosperms, a slow-fast stem strategy spectrum is found. Gymnosperms have slow traits and showed converging stem strategies because of their uniform tracheids. Angiosperms have fast traits and showed diverging stem strategies because of a wider array of tissues (vessels, parenchyma and fibers) and vessel size and arrangements (ring-porous versus diffuse porous). Gymnosperms showed a main trade-off between hydraulic efficiency and safety, and angiosperms showed a main trade-off between ‘slow’ diffuse porous species and ‘fast’ ring porous species. The slow traits of gymnosperms allow for a high hydraulic safety, an evergreen leaf habit and steady but slow growth makes them successful in unproductive habitats whereas the fast traits of angiosperms allow for high conductivity, a deciduous leaf habit and fast growth which makes them successful in productive habitats.

scholarly journals Leaf trait variation and field spectroscopy of generalist tree species on contrasting soil types

2016 ◽  
Author(s):  
Matheus Henrique Nunes ◽  
Matthew P. Davey ◽  
David Anthony Coomes
Keyword(s):  
Soil Type ◽  
Tree Species ◽  
Leaf Traits ◽  
Partial Least Square ◽  
Soil Types ◽  
Species Variation ◽  
Trait Variation ◽  
Field Spectroscopy ◽  
Specific Variation ◽  
Foliar Traits

Abstract. Understanding the causes of variation in plant functional traits is a central issue in ecology, particularly in the context of global change. Analyses of the drivers of traits variation based on thousands of tree species are starting to unravel patterns of variation at the global scale, but these studies tend to focus on interspecific variation, and the contribution of intraspecific changes remains less well understood. Hyperspectroscopy is a recently developed technology for estimating the traits of fresh leaves. Few studies have evaluated its potential for assessing inter- and intra-specific trait variability in community ecology. Working with 24 leaf traits for European tree species on contrasting soil types, found growing on deep alluvial soils and nearby shallow chalk soils, we ask: (i) What contribution do soil type and species identity make to trait variation? (ii) When traits are clustered into three functional groups (light capture and growth, leaf structure and defence, as well as rock-derived nutrients), are some groups more affected by soil than others? (iii) What traits can be estimated precisely using field spectroscopy? (iv) Can leaf spectra be used to detect inter-soil as well as inter-specific variation in traits? The contribution of species and soil-type effects to variation in traits were evaluated using statistical analyses. Foliar traits were predicted from spectral reflectance using partial least square regression, and so inter- and intra-specific variation. Most leaf traits varied greatly among species. The effects of soil type were generally weak by comparison. Macronutrient concentrations were greater on alluvial than chalk soils while micronutrient concentration showed the opposite trend. However, structural traits, as well as most pigments and phenolic concentrations varied little with soil type. Field spectroscopy provided accurate estimates of species-level trait values, but was less effective at detecting subtle variation of rock-derived nutrients between soil types. Field spectroscopy was a powerful technique for estimating cross-species variation in foliar traits and Si predictions using spectroscopy appear to be promising. However, it was unable to detect subtle within-species variation of traits associated with soil type.

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