Traits and gradients influence the canopy position of small-statured rain forest trees

2012 ◽  
Vol 60 (8) ◽  
pp. 735
Author(s):  
Robert M. Kooyman
Keyword(s):  
Species Composition ◽  
Wood Density ◽  
Environmental Gradients ◽  
Soil Depth ◽  
Canopy Height ◽  
Maximum Height ◽  
Canopy Position ◽  
Species Trait ◽  
Topographic Positions ◽  
Abiotic Gradients

Plant height determines a species’ position in the canopy and regulates access to light. Shifts in trait values for assemblages (plots) arrayed along abiotic gradients can reflect changes in species composition, and shifts in species trait values. Multivariate analysis was used to quantify the relationship of assemblage-level floristic composition to environmental gradients. Species trait values for maximum height, leaf area, seed size and wood density were quantified for woody species in the assemblage samples, and partitioned into within- and among-assemblage components to enable trait correlations to be identified, including in relation to abiotic gradients. Assemblages in upslope topographic positions had lower height, smaller leaves and higher wood density. Across the assemblages, shifts in species composition, decreasing canopy height and the position of smaller trees in the canopy were all linked to decreasing soil depth in upslope topographic positions. Regardless of stand height, the canopy position of most main canopy dominants remained largely unchanged in response to shifts in environmental gradients. In contrast, shorter-stature tree species retained height along the gradient and subsequently shifted from the subcanopy to the canopy as soil depth and site (plot) canopy height decreased. Within a community, height and position in the canopy can shift under differing environmental conditions.

scholarly journals Effects of Land Use, Soil Depth and Topography on Soil Physicochemical Properties along the Toposequence at the Wadla Delanta Massif, Northcentral Highlands of Ethiopia

2016 ◽  
Vol 5 (2) ◽  
pp. 57 ◽  
Author(s):  
Nahusenay Abate ◽  
Kibebew Kibret
Keyword(s):  
Land Use ◽  
Physicochemical Properties ◽  
Soil Depth ◽  
Bottom Layer ◽  
Exchange Capacity ◽  
Available Phosphorus ◽  
Soil Physicochemical Properties ◽  
Cultivated Land ◽  
Topographic Positions ◽  
Effects Of Land Use

The study was conducted to investigate the effects of land use, depth and topography on soil physicochemical properties at the Wadla Delanta Massif, northcentral Ethiopia. Four land uses (natural forest, shrub, grazing and cultivated land), three soil depths (0-20, 20-40, 40-60 cm) and three topographic positions (upper, middle and lower) in three replications were considered for this study. A total of 108 composite samples were collected for laboratory analysis. The results show that particle size distribution was affected by the main effects of land use and soil depth; bulk and particle densities, total porosity, organic matter and total nitrogen contents, C:N ratio and available phosphorus were significantly affected by the interaction of land use by soil depth only, whereas, soil pH, electrical conductivity, exchangeable bases, cation exchange capacity, percent base saturation and extractable micronutrients were affected by the interaction effects of the three factors. Highest clay and bulk density were recorded at the bottom layer of the cultivated land soils, while the utmost porosity, organic matter and nitrogen contents, and available phosphorus were recorded at the surface layers of the natural forest land soils. Highest pH was at the bottom layer of the cultivated land at the three topographic positions. Highest exchangeable bases and cation exchange capacity were observed in the bottom layers of soils under the four land use types at the lower topographic position, whilst extractable micronutrients were recorded at the surface layers of the forest land soils at the upper topographic position. In general, most of the measured soil properties were measured better in forest than in other land use soils and the lower topographic positions than the upper and middle ones. Interaction of land use with topography showed negative effects especially on cultivated and grazing land soils in all topographic positions. Therefore, integrated soil fertility management and soil conservation measures are required in all topographic positions to maintain soil physicochemical properties.

scholarly journals Testing for consistency in the impacts of a burrowing ecosystem engineer on soil and vegetation characteristics across biomes

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
M. A. Louw ◽  
N. S. Haussmann ◽  
P. C. le Roux
Keyword(s):  
Species Composition ◽  
Ecosystem Engineer ◽  
Environmental Gradients ◽  
Plant Cover ◽  
Ecosystem Engineers ◽  
Conservation Strategies ◽  
Annual Rainfall ◽  
Mesic Grassland ◽  
Vegetation Characteristics ◽  
Semi Arid

AbstractThe impacts of ecosystem engineers may be expected to vary along environmental gradients. Due to some resources being more limited in arid than in mesic environments, disturbances created by burrowing mammals are expected to have a greater ameliorating effect in arid environments, with larger differences in microhabitat conditions expected between burrows and undisturbed areas. The aim of this study was to test if the impacts of a medium-sized burrowing mammal, the aardvark, on soil properties (soil temperature, moisture and compaction) and vegetation characteristics (plant cover, species richness and species composition) are consistent across three biomes that differ strongly in annual rainfall. Burrowing affected soil and vegetation attributes, but the direction and magnitude of these biogeomorphological impacts were not consistent across the different biomes. For example, plant species composition was altered by burrowing in the arid scrubland and in the mesic grassland, but not in the semi-arid savannah. Contrary to expectations, the difference in the impacts of burrowing between biomes were not related to rainfall, with burrowing having strong, albeit different, impacts in both the arid scrubland and the mesic grassland, but weaker effects in the semi-arid savannah. It appears, therefore, that the impacts of these biogeomorphic agents may be site-specific and that it may be difficult to predict variation in their biotic and abiotic effects across environmental gradients. As a result, forecasting the impacts of ecosystem engineers under different conditions remains a challenge to management, restoration and conservation strategies related to these types of species.

Crown structural properties, wood density, and liana load: influence on growth and mortality in subtropical forests

2021 ◽  
Vol 51 (1) ◽  
pp. 111-121
Author(s):  
Sabrina A. Rodríguez ◽  
Piedad M. Cristiano ◽  
Oscar A. Lezcano ◽  
Teresa M. Suirezs ◽  
M. Virginia E. Díaz Villa ◽  
...  
Keyword(s):  
Structural Properties ◽  
Wood Density ◽  
Community Level ◽  
Individual Level ◽  
Explanatory Variables ◽  
Canopy Tree ◽  
Canopy Position ◽  
The Individual ◽  
Demographic Patterns ◽  
Architectural Traits

Wood density (WD) and other wood mechanical and structural properties may have a strong functional relationship with demographic patterns and allometry of trees. We analyzed the influence of WD, structural properties, architectural traits, and community-level attributes on growth rates (GRs) and mortality modes of canopy tree species in a subtropical forest of Argentina. Stem WD and the WD, strength, stiffness, toughness, and hardness of branches were measured in 10 canopy species. Architectural traits and liana load were also determined. Strength and hardness of branches were linearly correlated to branch WD, and GRs were linearly correlated to stem WD across species. At the individual level, trees with greater hardness and toughness in branches died mostly uprooted, and trees with greater branch stiffness and susceptibility to colonization by lianas were mostly broken. At the community level, the suppressed trees died mostly broken. The dominant trees with high local tree density died mostly broken, whereas more isolated trees died mostly uprooted. Mortality modes were determined not only by mechanical properties, but also by community properties such as liana load, crown canopy position, and number of neighboring trees. Other biophysical traits besides WD are important explanatory variables when dry wood is used to describe functional characteristics of trees.

scholarly journals Environmental and ecological factors mediate taxonomic composition and body size of polyplacophoran assemblages along the Peruvian Province

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Christian M. Ibáñez ◽  
Melany Waldisperg ◽  
Felipe I. Torres ◽  
Sergio A. Carrasco ◽  
Javier Sellanes ◽  
...  
Keyword(s):  
Body Size ◽  
Species Composition ◽  
Size Structure ◽  
Environmental Gradients ◽  
Ecological Factors ◽  
Taxonomic Composition ◽  
Latitudinal Gradients ◽  
Size Segregation ◽  
Biogeographic Patterns ◽  
Diversity Gradient

Abstract Intertidal communities’ composition and diversity usually exhibit strong changes in relation to environmental gradients at different biogeographical scales. This study represents the first comprehensive diversity and composition description of polyplacophoran assemblages along the Peruvian Province (SE Pacific, 12°S–39°S), as a model system for ecological latitudinal gradients. A total of 4,775 chitons from 21 species were collected on twelve localities along the Peruvian Province. This sampling allowed us to quantitatively estimate the relative abundance of the species in this assemblage, and to test whether chitons conform to elementary predictions of major biogeographic patterns such as a latitudinal diversity gradient. We found that the species composition supported the division of the province into three ecoregional faunal groups (i.e. Humboldtian, Central Chile, and Araucanian). Though chiton diversity did not follow a clear latitudinal gradient, changes in species composition were dominated by smaller scale variability in salinity and temperature. Body size significantly differed by ecoregions and species, indicating latitudinal size-structure assamblages. In some localities body size ratios differed from a random assemblage, evidencing competition at local scale. Changes in composition between ecoregions influence body size structure, and their overlapping produce vertical size segregation, suggesting that competition coupled with environmental conditions structure these assemblages.

scholarly journals Pecan Kernel Phenolics Content and Antioxidant Capacity Are Enhanced by Mechanical Pruning and Higher Fruit Position in the Tree Canopy

2020 ◽  
Vol 145 (3) ◽  
pp. 193-202
Author(s):  
Yi Gong ◽  
Ronald B. Pegg ◽  
Adrian L. Kerrihard ◽  
Brad E. Lewis ◽  
Richard J. Heerema
Keyword(s):  
High Performance ◽  
Light Exposure ◽  
Antioxidant Properties ◽  
Reversed Phase ◽  
Tree Canopy ◽  
Canopy Height ◽  
Canopy Position ◽  
Phenolics Content ◽  
Bound Phenolics

Pecan (Carya illinoinensis) is a tree nut native to North America. Although inhibited light exposure (most specifically as a result of overlapping tree canopies) has been shown to impair yield, the effect of this factor on nut antioxidant properties remains unknown. This study investigated effects of mechanical pruning and canopy height position of fruit on pecan kernel antioxidant contents and capacity. Beginning in 2006, trees in a ‘Western’ pecan orchard in New Mexico were subjected to three mechanical pruning frequency treatments (annual, biennial, and triennial) paralleling conventional practices, while other trees were maintained as unpruned controls. During the 2012 to 2014 seasons, pecans were sampled at fruit maturity from three canopy height zones (“low,” “middle,” and “high,” corresponding to 1.5 to 3.0 m, 3.0 to 4.5 m, and 4.5 to 6.0 m above the orchard floor). In vitro phenolics contents and antioxidant capacities of the nutmeats were evaluated by total phenolics content (TPC) and oxygen radical absorbance capacity (H-ORACFL), respectively. Soluble ester- and glycoside-bound phenolics were quantified by reversed-phase high-performance liquid chromatography (HPLC). For both TPC and H-ORACFL, results determined pruned samples had significantly higher values than unpruned samples (P < 0.001 for both comparisons), and that samples of “high” canopy height were significantly greater than those of “middle” height, which were in turn greater than those of “low” height (P < 0.001 for all comparisons). HPLC findings showed that in all three phenolic fractions (free, esterified, and glycoside-bound phenolics), nuts acquired from pruned trees had substantially greater concentrations of ellagic acid and its derivatives. Our findings indicate mechanical pruning of pecan trees and higher tree canopy position of fruit increase nut antioxidant properties.

scholarly journals Relative importance of region, seasonality and weed management practices effects on the functional structure of weed communities in French vineyards

2021 ◽  
Author(s):  
Marie-Charlotte Bopp ◽  
Elena Kazakou ◽  
Aurelie Metay ◽  
Guillaume Fried
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Environmental Gradients ◽  
Cropping Systems ◽  
Seed Mass ◽  
Soil Disturbance ◽  
Lateral Spread ◽  
Maximum Height ◽  
Weed Communities ◽  
Mechanical Disturbance

Winegrowers have diversified their weed management practices over the last two decades changing the structure and the composition of weed communities. Complementary to taxonomic studies, trait-based approaches are promising ways for a better understanding of weed communities responses to environmental and agronomic filters. In the present study, the impacts of climate, soil characteristics, seasons and weed management practices (chemical weeding, tillage and mowing) were assessed on weed communities from 46 plots in three French wine-growing regions (Champagne, Languedoc and Rhone valley). These agro-environmental gradients structuring weed communities according to their combinations of traits were highlighted using multivariate analysis (RLQ). The impacts of these filters on Community Weighted Means (CWM) and Community Weighted Variance (CWV) of weed communities were analysed using mixed and null modelling. Our results showed that spatio-temporal and weed management practices variables explained from 13% to 48% of the total variance of CWM (specific leaf area, maximum height, seed mass, flowering onset and duration and lateral spread). Region, seasonality and management practices explained 53%, 28% and 19% of CWM marginal variance, respectively. Weed management impacted CWM and CWV through two main gradients: (i) a soil disturbance gradient with high mechanical disturbance of soil in tilled plots and low mechanical disturbance in chemically weeded plots and (ii) a vegetation cover gradient with high vegetation abundance in mowed plots compared to more bare soils in tilled and chemically weeded plots. In Languedoc, chemical weeding filtered weed communities with ruderal strategy trait values (low seed mass, small-stature) while mowed communities were more competitive (higher seed mass, higher stature and lower SLA). In Languedoc and Champagne, tillage favoured communities with high seed mass that increases the viability of buried seeds and high lateral spread values associated to the ability to resprout after tillage. This study demonstrated that trait-based approaches can be successfully applied to perennial cropping systems such as vineyards, in order to understand community assembly to better guide weed management practices.

scholarly journals Grassland communities of Stol mountain (eastern Serbia ): Vegetation and environment al relationships

2013 ◽  
Vol 65 (1) ◽  
pp. 211-227 ◽  
Author(s):  
Svetlana Acic ◽  
U. Silc ◽  
S. Vrbnicanin ◽  
Svjetlana Cupac ◽  
G. Topisirovic ◽  
...  
Keyword(s):  
Species Composition ◽  
Environmental Gradient ◽  
Environmental Gradients ◽  
Detrended Correspondence Analysis ◽  
Ecological Indicator ◽  
Vegetation Types ◽  
Indicator Values ◽  
Grassland Vegetation ◽  
Data Set ◽  
Grassland Communities

The systematic survey of grassland communities was performed on Mt. Stol (eastern Serbia). The main aims of the research were to: (1) determine grassland vegetation types of the researched area; (2) correlate the impacts of the soil and environmental conditions on the occurrence of certain plant communities, and (3) comment on the conservational value of the grasslands in the researched area. The data set included 60 phytosociological relev?s of grasslands recorded between 2001 and 2004. The main environmental gradients of species composition were analyzed by Detrended Correspondence Analysis (DCA). For the ecological interpretation of ordination axes, ecological indicator values were used. Three associations were distinguished: Danthonietum calycinae, Asperulo-Agrostietum vulgaris and Ranunculo bulbosi- Arrhenatheretum elatioris belonging to two alliances and two classes: Chrysopogono-Danthonion - Festuco-Brometea and Arrhenatherion - Molinio-Arrhenatheretea. The results of the DCA support our assumption that the main environmental gradient in the species composition of the grasslands is related to nutrients and moisture. The conservational value of grasslands in the researched area is discussed.

Functional relationships between soil fungi and environment in alpine tundra

1979 ◽  
Vol 57 (15) ◽  
pp. 1642-1659 ◽  
Author(s):  
J. Bissett ◽  
D. Parkinson
Keyword(s):  
Low Temperature ◽  
Species Composition ◽  
Dominant Species ◽  
Soil Fungi ◽  
Soil Depth ◽  
Limiting Factor ◽  
Adverse Conditions ◽  
Functional Relationships ◽  
Conflicting Demands ◽  
Grassland Site

Temperature, moisture, available potassium, and soil pH were the most important abiotic variables influencing the distribution and community composition of soil fungi from three diverse alpine habitats. The major differences in species composition occurred among the sites. An ordination contrasting the sites, based on the species composition of the mycoflora, was correlated with a gradient contrasting temperature and moisture with potassium. The observed differences in species composition among the sites were concluded to have resulted from conflicting demands on the species for efficiency and adaptability. Relatively few species were isolated from the more exposed summit ridge site (2840 m). and these were probably genetically diverse species capable of adapting to environmental extremes. Alternatively, dominant species may be specialists adapted to limiting dimensions that are widely distributed in the environment. Dominant species at the drought-prone grassland site (1900 m) appeared adapted to low moisture, and those of the alpine meadow site (2530 m) to low temperature.Seasonal changes in mycoflora composition were related to changes in the moisture and temperature status of the soils, with low temperature limiting in the spring and low moisture in the fall. Chrysosporium pannorum and Penieillium janthinellum were adapted to combined low temperature and moisture. Cylindroearpon didymuin, Glioeladium deliquescens, Fusarium merismoides. Penicillium steckii, and Cylindrocarpon destructans occurred only in soils with a relatively high temperature–moisture status. Changes in mycoflora composition with soil depth were attributed to an environmental gradient combining temperature, moisture, and K without contrasts. Sterile fungi, apparently adapted to the adverse conditions of low temperature. moisture, and K. were dominant in the lower horizons at all three sites. Soil K appeared to be a limiting factor for many species restricted to the surface horizons, including the frequently isolated species Fusarium acuminatum. Penicillium janthinellum. Penicillium simplicissimum. Penicillium steckii. Phoma eupyrena. and Trichoderma liamatum.

Photoprotective carotenoids and antioxidants are more affected by canopy position than by nitrogen supply in 21-year-old Pinus radiata

2008 ◽  
Vol 35 (6) ◽  
pp. 470 ◽  
Author(s):  
Sabine Posch ◽  
Charles R. Warren ◽  
Mark A. Adams ◽  
Helmut Guttenberger
Keyword(s):  
Pinus Radiata ◽  
Light Harvesting ◽  
Co2 Assimilation ◽  
Canopy Height ◽  
Effective Quantum Yield ◽  
N Supply ◽  
Net Co2 Assimilation ◽  
Canopy Position ◽  
Quantum Yield Of Psii ◽  
Β Carotene

Photoprotection, light harvesting and light utilisation were investigated as a function of variation in N supply and canopy position in 21-year-old Pinus radiata D. Don. Chlorophyll fluorescence, gas exchange and photoprotective compounds were measured on lower, middle and upper canopy needles in trees receiving N fertiliser and in control trees not receiving N fertiliser. Irrespective of canopy height, additional N increased the light-harvesting capacity through greater contents of chlorophyll, neoxanthin and lutein, but did not affect light-utilisation processes, such as effective quantum yield of PSII or rates of net CO2 assimilation. Additional N fertiliser did not affect the concentrations of the measured photoprotective carotenoids (violaxanthin, antheraxanthin, zeaxanthin, α-carotene and β-carotene) or antioxidants (ascorbic acid, glutathione and α-tocopherol); however, carotenoids and antioxidants were strongly affected by canopy height and increased in concentration with increasing canopy height. The present study found that pools of photoprotective carotenoids and antioxidants were not driven by imbalances in light-harvesting and light-utilisation processes, but rather by gradients in light.

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