scholarly journals Contrasting Hydraulic Efficiency and Photosynthesis Strategy in Differential Successional Stages of a Subtropical Forest in a Karst Region

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2604
Author(s):  
Guilin Wu ◽  
Dexiang Chen ◽  
Zhang Zhou
Keyword(s):  
Drought Tolerance ◽  
Wood Density ◽  
Photosynthetic Rate ◽  
Species Abundance ◽  
Negative Relationship ◽  
Resource Acquisition ◽  
Karst Region ◽  
Turgor Loss Point ◽  
Successional Stages ◽  
Early Succession

Understanding the successional process from a disturbed forest to a mature forest is essential for species recovery and conservation initiatives. The resource acquisition and drought tolerance of plants can be instructive to predictions of species abundance and distribution for different forests. However, they have not been adequately tested at different successional stages in karst regions. Here, we selected seven dominant species in an early-succession forest and 17 species in a late-succession forest in a karst region of southwestern China. Resource acquisition-related traits such as hydraulic conductivity and photosynthetic rate, and drought tolerance-related traits, including turgor loss point and wood density, were measured. We found that species in the early-succession forest had a higher hydraulic conductance and photosynthetic rate than those in the late-succession forest, while leaf water potential at turgor loss point and wood density showed nonsignificant differences between the two forests. In addition, we observed a significant negative relationship between photosynthetic rate and drought tolerance in the early-succession forest, which was not identified in late-succession forests. Our study indicates that resource acquisition rather than drought tolerance was the key factor explaining plant distributions in forests at different successional stages in karst regions. We also suggest that the resource acquisition and drought tolerance trade-off hypothesis is not always supported for karst region species. Our study could inform about the design of species replacements in successional forests and provide forest management and restoration guidelines for karst regions.

Quantification of biogeomorphic interactions between small-scale sediment transport and primary vegetation succession on proglacial slopes of the Gepatschferner, Austria

2021 ◽  
Author(s):  
Stefan Haselberger ◽  
Lisa-Maria Ohler ◽  
Jan-Christoph Otto ◽  
Robert R. Junker ◽  
Thomas Glade ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Sediment Yield ◽  
Plant Cover ◽  
Species Abundance ◽  
Small Scale ◽  
Vegetation Composition ◽  
Mechanical Erosion ◽  
Successional Stages ◽  
Three Stages ◽  
Specific Sediment Yield

<p>Proglacial slopes provide suitable conditions to observe the co-development of abiotic and biotic systems. The frequency and magnitude of geomorphic processes and composition of plants govern this interplay, which is described in the biogeormorphic feedback window for glacier forelands. The study sets out to quantify small-scale sediment transport via mechanical erosion plots along a plant cover gradient and to investigate the multidirectional interactions between abiotic and biotic processes. We aim to generate quantitative data to test the biogeomorphic feedback window.</p><p>Small-scale biogeomorphic interactions were investigated on 30 test plots of 2 x 3 m size on proglacial slopes of the Gepatschferner (Kaunertal) in the Austrian Alps during snow-free summer months over three consecutive years. The experimental plots were established on slopes along a plant cover gradient. A detailed vegetation survey was carried out to capture biotic conditions and specific sediment yield was measured at each plot. Species abundance and composition at each site, as well as plant functional types reflected successional stages.</p><p>We observed a strong decline in geomorphic activity on plots with above 30% plant cover. Mean monthly rates of specific sediment yield decreased from 111 g m<sup>-2 </sup>to 37 g m<sup>-2</sup>. Non-metric multidimensional scaling showed distinct vegetation composition for the three stages of biogeomorphic succession. Quantified process rates and observed vegetation composition support the concept of biogeomorphic feedback windows. The findings help to narrow down a stage during succession where the importance of biotic processes start to dominate.</p>

scholarly journals Use of Time-of-Flight Ultrasound to Measure Wave Speed in Poplar Seedlings

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 682 ◽  
Author(s):  
Fenglu Liu ◽  
Pengfei Xu ◽  
Houjiang Zhang ◽  
Cheng Guan ◽  
Dan Feng ◽  
...  
Keyword(s):  
Ultrasonic Velocity ◽  
Wood Density ◽  
Microfibril Angle ◽  
Negative Relationship ◽  
Acoustic Resonance ◽  
Ultrasonic Speed ◽  
Root Collar Diameter ◽  
Collar Diameter ◽  
Root Collar ◽  
Poplar Seedlings

In this study, 145 poplar (Populus × euramericana cv.’74/76’) seedlings, a common plantation tree species in China, were selected and their ultrasonic velocities were measured at four timepoints during the first growth year. After that, 60 poplar seedlings were randomly selected and cut down to determine their acoustic velocity, using the acoustic resonance method. The effects of influencing factors such as wood green density, microfibril angle, growth days, and root-collar diameter on acoustic speed in seedlings and the relationship between ultrasonic speed and acoustic resonance speed were investigated and analyzed in this work. The number of specimens used for investigating growth days and root-collar diameter was 145 in both cases, while 60 and two specimens were used for investigating wood density and the microfibril angle, respectively. The results of this study showed that the ultrasonic speed of poplar seedlings significantly and linearly increased with growth days, within 209 growing days. The ultrasonic velocity of poplar seedlings has a high and positive correlation with growth days, and the correlation was 0.99. However, no significant relationship was found between the ultrasonic velocity and root-collar diameter of poplar seedlings. Furthermore, a low and negative relationship was found between wood density and ultrasonic speed (R2 = 0.26). However, ultrasonic velocity significantly decreased with increasing microfibril angle (MFA) in two seedlings, and thus MFA may have an impact on ultrasonic speed in poplar seedlings. In addition, ultrasonic velocity was found to have a strong correlation with acoustic resonance velocity (R2 = 0.81) and a good correlation, R2 = 0.75, was also found between the dynamic moduli of elasticity from ultrasonic and acoustic resonance tests. The results of this study indicate that the ultrasonic technique can possibly be used to measure the ultrasound speed of young seedlings, and thus early screen seedlings for their stiffness properties in the future.

Carbohydrate accumulation and turgor maintenance in seedling shoots and roots of two boreal conifers subjected to water stress

1991 ◽  
Vol 69 (11) ◽  
pp. 2522-2528 ◽  
Author(s):  
R. S. Koppenaal ◽  
T. J. Tschaplinski ◽  
S. J. Colombo
Keyword(s):  
Water Stress ◽  
Drought Tolerance ◽  
Osmotic Adjustment ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
White Spruce ◽  
Jack Pine ◽  
Organic Solutes ◽  
Carbohydrate Accumulation ◽  
Turgor Loss Point

Water potential components and organic solutes were examined in shoots and roots of potted jack pine (Pinus banksiana Lamb.) and white spruce (Picea glauca (Moench) Voss) seedlings after exposure to 7 days of water stress. The osmotic potential at the turgor loss point (ψπTLP) decreased in shoots and roots of water-stressed seedlings of both species, resulting in the maintenance of positive turgor at lower xylem water potentials (ψX) compared with nonstressed seedlings. Following water stress, ψπTLP of shoots and roots declined by 0.28 MPa and 0.14 MPa, respectively, in jack pine, and 0.19 MPa and 0.28 MPa, respectively, in white spruce. The osmotic potential at saturation (ψπ100) was significantly lower after water stress only in jack pine roots. Active osmotic adjustment during water stress was confirmed by higher concentrations of organic solutes in white spruce shoots (1.4 × increase relative to nonstressed plants) and roots (1.7 ×) and in the roots (2.2 ×) but not the shoots of jack pine. Carbohydrates, particularly fructose and glucose, were the primary organic solutes accumulating in both species. Tissue elasticity was greater in the roots than the shoots of both jack pine and white spruce regardless of treatment. Consequently, the relative water content at the turgor loss point was 22% and 18% lower in the roots than in the shoots of jack pine and white spruce, respectively. Osmotic adjustment in the roots and shoots of these two boreal conifers suggests that preconditioning planting stock by exposure to water stress may increase carbohydrate concentrations and enhance seedling drought tolerance. Key words: carbohydrate accumulation, drought tolerance, organic solutes, osmotic adjustment, Picea glauca, Pinus banksiana, water potential components.

Water source segregation along successional stages in a degraded karst region of subtropical China

2018 ◽  
Vol 29 (5) ◽  
pp. 933-942 ◽  
Author(s):  
Yun‐peng Nie ◽  
Hong‐song Chen ◽  
Ya‐li Ding ◽  
Ke‐lin Wang
Keyword(s):  
Water Source ◽  
Karst Region ◽  
Subtropical China ◽  
Successional Stages ◽  
Source Segregation

scholarly journals REGENERAÇÃO NATURAL DE FLORESTA ESTACIONAL SEMIDECIDUAL EM DIFERENTES ESTÁGIOS SUCESSIONAIS (ZONA DA MATA, MG, BRASIL)

FLORESTA ◽  
2013 ◽  
Vol 44 (1) ◽  
pp. 111 ◽  
Author(s):  
Sustanis Horn Kunz ◽  
Sebastião Venâncio Martins
Keyword(s):  
Natural Regeneration ◽  
Species Abundance ◽  
Detrended Correspondence Analysis ◽  
Floristic Composition ◽  
Importance Value ◽  
Successional Stage ◽  
Semideciduous Forest ◽  
Regeneration Stage ◽  
Successional Stages ◽  
Seasonal Semideciduous Forest

O objetivo deste estudo foi avaliar a estrutura e a composição florística da regeneração natural de trechos de Floresta Estacional Semidecidual em diferentes estágios sucessionais. Para a estrutura fitossociológica, foram demarcadas sistematicamente 10 parcelas de 5 x 10 m em trecho de floresta em estágio médio de regeneração (FEM), floresta em estágio avançado de regeneração (FEA) e pastagem abandonada (PAS), sendo amostrados os indivíduos com altura ≥ 50 cme diâmetro à altura do solo ≤ 5 cm. Foi realizada análise de correspondência retificada e análise de espécies indicadoras de cada trecho. Na estrutura da regeneração natural da FEM e da pastagem, houve destaque de apenas uma espécie (Psychotria sessilis e Vernonia polyanthes, respectivamente) quanto ao Valor de Importância (VI), devido principalmente à alta densidade. Já na FEA não foi observada forte dominância por uma espécie. As três áreas apresentaram-se distintas quanto à abundância e composição de espécies, sugerindo que a matriz florestal é composta por um mosaico sucessional. Além disso, cada trecho ainda mantém espécies indicadoras características, de acordo com o estágio sucessional em que se encontram, razão pela qual ações de manejo e enriquecimento poderiam ser adotadas para acelerar o processo de sucessão.Palavras-chave: Composição florística; conservação; estrutura; sucessão secundária. AbstractNatural regeneration of seasonal semideciduous forest in different successional stages (Zona da Mata, MG, Brazil). The objective of this study was to evaluate the floristic structure and composition of the natural regeneration of stretches from Seasonal Semideciduous Forest in different successional stages. Ten plots, 5 x 10 meters in size, were systematically delimited for phytosociological structure in patches of forest which were in intermediate regeneration stage (FEM), advanced regeneration stage (FEA) and abandoned pasture (PAS).We sampled the individuals with ≥ 50 cm in height and diameter at ground height ≤ 5 cm. We performed Detrended Correspondence Analysis and analysis of indicative species of each forest section. In the natural regeneration structure of FEM and pasture it was featured only one species (Psychotria sessilis and Vernonia polyanthes, respectively) in the Importance Value (IV), mainly due to high density. In relation to the FEA there was no strong dominance by one species. The three sections showed distinct species abundance and composition, which suggests that the forest matrix comprises a successional mosaic. Furthermore, each stretch still maintains indicative characteristic species, according to the successional stage they are in. Because of this, management and enrichment actions could be performed to accelerate the succession process.Keywords: Floristic composition; conservation; structure; secondary succession.

Comparative hydraulic architecture of tropical tree species representing a range of successional stages and wood density

Oecologia ◽  
2011 ◽  
Vol 167 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Katherine A. McCulloh ◽  
Frederick C. Meinzer ◽  
John S. Sperry ◽  
Barbara Lachenbruch ◽  
Steven L. Voelker ◽  
...  
Keyword(s):  
Wood Density ◽  
Tree Species ◽  
Tropical Tree ◽  
Hydraulic Architecture ◽  
Tropical Tree Species ◽  
Successional Stages

scholarly journals Drought tolerance as predicted by leaf water potential at turgor loss point varies strongly across species within an Amazonian forest

2015 ◽  
Vol 29 (10) ◽  
pp. 1268-1277 ◽  
Author(s):  
Isabelle Maréchaux ◽  
Megan K. Bartlett ◽  
Lawren Sack ◽  
Christopher Baraloto ◽  
Julien Engel ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Amazonian Forest ◽  
Turgor Loss Point

scholarly journals Overwhelming presence of non-food vegetation undermines the reliability of NDVI as a surrogate of forage abundance for a large herbivore in a tropical forest habitat

2018 ◽  
Author(s):  
Hansraj Gautam ◽  
Evangeline Arulmalar ◽  
Mihir R Kulkami ◽  
TNC Vidya
Keyword(s):  
Tropical Forest ◽  
Vegetation Index ◽  
Species Abundance ◽  
Negative Relationship ◽  
Ground Level ◽  
Food Abundance ◽  
Total Abundance ◽  
Large Herbivore ◽  
Forage Availability ◽  
Food Species

AbstractThe use of remotely-sensed vegetation indices has increased in wildlife studies but field-based support for their utility as a measure of forage availability largely comes from open-canopy habitats. In this paper, we assessed whether the popular vegetation index, NDVI, actually represents forage availability for Asian elephants in a southern Indian tropical forest. We found that the number of food species was a small percentage of all plant species, and the abundance of food species compared to total species abundance varied across different vegetation categories. NDVI was not a good measure of food abundance in any vegetation category partly because of a) small to moderate proportional abundances of food species relative to the total abundance of all species in that category (herb and shrub categories), b) abundant overstorey vegetation resulting in low correlations between NDVI and food abundance despite a high proportional abundance of food species and a concordance between total abundance and food species abundance (graminoid category), and c) the relevant variables measured and important as food at the ground level (count and GBH) not being related to primary productivity (trees and recruits). NDVI had a negative relationship with the total abundance of graminoids, which represent a bulk of elephant and other herbivore diet, because of the presence of other vegetation types and canopy cover that positively explained NDVI. We also found that spatially interpolated total graminoid abundance modelled from field data outperformed NDVI in predicting total graminoid abundance, although interpolation models of food graminoid species abundance were not satisfactory. Our results reject the utility of NDVI as a surrogate of elephant forage abundance in tropical forests with multistorey vegetation, a finding that has implications for studies of other herbivores in such habitats.

Spatial and Temporal Distribution of Photosynthesis and Transpiration by Single Leaves in a Rainforest Tree, Argyrodendron peralatum

1988 ◽  
Vol 15 (2) ◽  
pp. 317 ◽  
Author(s):  
D Doley ◽  
GL Unwin ◽  
DJ Yates
Keyword(s):  
Water Supply ◽  
Photosynthetic Rate ◽  
Temporal Distribution ◽  
Spatial And Temporal Distribution ◽  
Leaf Surfaces ◽  
Successional Stages

The light environments and rates of photosynthesis by leaves of Argyrodendron peralatum (F. M. Bailey) I.H. Boas were examined at eight positions within a natural rainforest canopy. Daily integrals of irradiance at leaf surfaces expressed as a percentage of that reaching a horizontal sensor in the open decreased from about 50% in the uppermost leaves to about 20% at a point 2 m below the top of the crown and to 10-15% in the lower crown and understory. Leaves in the upper crown had maximum instantaneous rates of apparent photosynthesis of 11.5 �mol CO2 m-2 s-1, whilst leaves in the lower crown of the same tree, and in understory saplings had maximum photosynthesis rates of 8.2 �mol m-2 s-1. These rates were not significantly different, and are within the range observed in a number of rainforest species characteristic of later successional stages. Under conditions of adequate water supply, photosynthetic rate was light-saturated by 500 �mol quanta m-2 s-1, irrespective of level in the canopy.

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