scholarly journals Dynamics of Abies Nephrolepis Seedlings in Relation to Environmental Factors in Seorak Mountain, South Korea

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 702
Author(s):  
Kim ◽  
Lim ◽  
Yun
Keyword(s):  
Species Richness ◽  
Environmental Factors ◽  
Abiotic Factors ◽  
Negative Relationship ◽  
Basal Area ◽  
Ecosystem Dynamics ◽  
Environmental Drivers ◽  
Canopy Openness ◽  
Seedling Density ◽  
Rock Exposure

We present novel evidence of environmental drivers of seedling density in Abies nephrolepis, an alpine and subalpine tree species. Continuous monitoring of natural conditions is required to understand forest ecosystem dynamics. We investigated Abies nephrolepis seedling dynamics in relation to biotic and abiotic factors. The survey, which included the measurement of trees and seedlings, was carried out from March to October in 2016 and 2018. Monitoring sites in the coniferous forests of Seorak Mountain were divided into 27 quadrats. We analyzed relationships using simple and multiple linear regression. The majority of Abies nephrolepis individuals had a diameter at breast height less than l0 cm, and the number of seedlings increased over the study period. This reflects survival and growth due to successive annual mast seeding events. Aspect direction (R2 = 0.201, p < 0.05), rock exposure (R2 = 0.364, p < 0.001), canopy openness (R2 = 0.322, p < 0.05), herbaceous cover (R2 = 0.268, p < 0.01), and basal area (R2 = 0.199, p < 0.05) show significant linear relationships with seedling density. Seedling density was positively related to rock exposure, canopy openness, and species richness, and there was a negative relationship between herbaceous cover and basal area (p < 0.0001). The relative importance of predictor variables was as follows: Rock exposure (40.3%), canopy openness (30.2%), basal area (13.9%), herbaceous cover (11.5%), and species richness (4.1%). Seedling density was most strongly influenced by the presence of large rocks, which provide shelter from harsh winds and a substrate for moss. We conclude that appropriate canopy openness creates a synergistic relationship. We found a positive association between the Abies nephrolepis seedling density in subalpine forests and certain physical environmental factors. Therefore, environmental gradients about the roles of rocks and canopies apply, even in this habitat.

Biotic and abiotic drivers of dipterocarp seedling survival following mast fruiting in Malaysian Borneo

2014 ◽  
Vol 31 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Chiaki Oshima ◽  
Yuji Tokumoto ◽  
Michiko Nakagawa
Keyword(s):  
Survival Data ◽  
Species Coexistence ◽  
Seedling Survival ◽  
Abiotic Factors ◽  
Canopy Openness ◽  
Relative Importance ◽  
Tropical Rain Forests ◽  
Seedling Density ◽  
Mast Fruiting ◽  
General Flowering

Abstract:South-East Asian tropical rain forests experience sporadic, but profuse, seed production after general flowering, leading to the synchronous emergence of various seedlings and subsequent seedling dynamics, which play a crucial role in determining species distribution and coexistence. We examined the relative importance of both biotic (initial height, conspecific seedling density) and abiotic (canopy openness, per cent sand, soil water content) drivers using survival data for 1842 seedlings of 12 dipterocarp species for 1.5 y following mast fruiting in an old-growth Bornean tropical rain forest. More than 30% of all dipterocarp seedlings survived 1.5 y after mast fruiting. When all species were analysed together, we found that initial seedling height, canopy openness and conspecific seedling density affected dipterocarp seedling survival. Negative density dependence indicated that predators were not satiated, but dipterocarp seedlings rather suffered from host-specific natural enemies or intraspecific competition. Species-level analyses of seven dipterocarp species showed large variation in response to biotic and abiotic factors. These results suggest that interspecific differences in the relative importance of biotic and abiotic effects on seedling survival might contribute to species coexistence.

scholarly journals The predominant role of soil in determining species composition of fern communities in subtropical coastal forest ecosystems

2019 ◽  
Vol 14 (4) ◽  
pp. 559-575
Author(s):  
Amanda Angélica Carmes ◽  
Michele de Sá Dechoum ◽  
Pedro Fiaschi
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Atlantic Forest ◽  
Vegetation Structure ◽  
Environmental Variables ◽  
Abiotic Factors ◽  
Canopy Openness ◽  
Vegetation Types ◽  
Edaphic Conditions ◽  
Fern Species

Ferns are an important component in the understorey of tropical forests and their distribution is influenced by several biotic and abiotic factors. At a regional scale, soil characteristics and canopy openness play an important role in fern species composition and richness, as well as in the abundance of individuals. Our objective was to compare the influence of edaphic conditions and vegetation structure on the abundance and distribution of fern communities in Atlantic forest and restinga forest. Our hypotheses were that fern species richness and diversity are higher in Atlantic forest than in restinga due to limiting conditions in this habitat and the composition of fern species in Atlantic forest differs from restinga, especially due to differences in edaphic conditions. A principal coordinates analysis was applied to ordinate sampling units in relation to the environmental variables and a permutational multivariate analysis of variance was used to test that environmental variables did not differ between the two vegetation types. Species richness was compared using rarefaction curves. The influence of abiotic variables in species composition and abundance was verified using canonical correspondence analysis. No differences were observed in species richness, diversity or dominance between vegetation types, although abundance was higher in restinga. Fern communities respond to edaphic conditions and vegetation structure variations between vegetation types, the soil playing a major role. A greater variety of habitats resulting from differences in soil drainage in restinga facilitates the co-existence of species with different ecological tolerance, increasing local diversity and compensating for limiting conditions in restinga.

scholarly journals Disentangling structural patterns of natural forest fragments in a savanna matrix in the eastern Brazilian Amazon

2017 ◽  
Vol 47 (2) ◽  
pp. 111-122
Author(s):  
Iêda Leão do AMARAL ◽  
William Ernest MAGNUSSON ◽  
Francisca Dionízia de Almeida MATOS ◽  
Ana Luisa K. ALBERNAZ ◽  
Yuri Oliveira FEITOSA ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Density ◽  
Fragment Size ◽  
Negative Relationship ◽  
Basal Area ◽  
Average Diameter ◽  
Diameter Distribution ◽  
Forest Fragments ◽  
Continuous Forest ◽  
Individual Trees

ABSTRACT Natural fragments are an important source of richness for the management and conservation of a local flora. The objective of this study was to evaluate the effect of fragmentation on the structure and composition of the plant communities of forest fragments (FF) in Alter do Chão, eastern Brazilian Amazonia. The study sample consisted of 25 FF and nine continuous forest (CF) sites. We compared plant density and species richness between site categories by t-tests, analyzed the differences in composition by cluster analysis, and assessed the effect of fragment size and distance to CF on the basal area and diameter of FF assemblages by linear regression. Individual trees and shrubs with DBH ≥1.27 cm were measured in 2x250 m plots. 17,078 individuals were recorded - 75.32% in FF and 24.68% in CF, comprising 475 species, 216 genera and 64 families. Myrtaceae and Fabaceae were the most abundant families in both FF and CF. Average species richness in FF and CF was statistically different. The 20 species with the highest importance values were similar in FF and CF. The average plant diameter was similar in FF and CF, suggesting that both are "mature" forests composed of thin individuals. Average diameter and total basal area showed a negative relationship with distance to CF and fragment area, respectively. Similarity analysis revealed two groups, one composed exclusively of portions of fragmented forest. Fragments and continuous forest differed in species composition, but were similar in structure. Diameter distribution in fragments was similar to that of primary forests.

scholarly journals Plant communities and their environmental drivers on an arid mountain, Gebel Elba, Egypt

2020 ◽  
Vol 1 ◽  
pp. 21-36 ◽  
Author(s):  
Maged M. Abutaha ◽  
Ahmed A. El-Khouly ◽  
Norbert Jürgens ◽  
Jens Oldeland
Keyword(s):  
Species Richness ◽  
Environmental Factors ◽  
Soil Quality ◽  
Vegetation Structure ◽  
Biological Diversity ◽  
Vegetation Type ◽  
Elevational Gradient ◽  
Environmental Drivers ◽  
Mountain Range ◽  
Perennial Vegetation

Aims: Gebel Elba is an arid mountain range supporting biological diversity that is incomparable to any other region of Egypt. This mountain has a vegetation structure and floristic community similar to the highlands of East Africa and the southwestern Arabian Peninsula. We aimed to provide the first classification of the vegetation units on Gebel Elba and identify the environmental factors controlling their distribution. Study area: Wadi Yahmib and its tributaries, which drain the north-western slopes of Gebel Elba, south-eastern Egypt. Methods: On the basis of 169 relevés, we used TWINSPAN to classify the perennial vegetation. We calculated separate GAMs for the deciduous and evergreen species to describe the patterns for each leaf strategy type with elevation. We used CCA to quantify the relationship between the perennial vegetation and the studied environmental factors. To estimate diversity and our sampling strategy, we used rarefaction curves for species richness. Results: We identified seven communities along the elevational gradient of Wadi Yahmib and its tributaries. We found that each community was restricted to a confined habitat depending on its drought resistance ability. Deciduous Vachellia woodland was the main vegetation type on Gebel Elba, while evergreen Olea woodland appeared in small fragments at higher elevations. We analysed the distribution patterns of deciduous and evergreen trees along the elevational gradient. We found a turnover at 500 m, indicating a potential ecotone between the Vachellia and Olea woodlands that was occupied by a Ficus community. CCA revealed the importance of altitude and soil quality in determining the vegetation structure of Gebel Elba. The species richness increased with elevation as a result of reduced stress and increased water availability at the upper wadis. Conclusions: This study identified seven vegetation units in the study area and showed the importance of orographic precipitation, soil quality and the complex topography in determining the habitats. Taxonomic reference: Boulos (2009); names updated according to POWO (2019). Abbreviations: CCA = Canonical Correspondence Analysis; GAM = Generalized Additive Model; TWINSPANTWINSPAN = Two Way Indicator Species Analysis.

scholarly journals A Combination of Biotic and Abiotic Factors and Diversity Determine Productivity in Natural Deciduous Forests

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1450
Author(s):  
Mahmoud Bayat ◽  
Pete Bettinger ◽  
Sahar Heidari ◽  
Seyedeh Kosar Hamidi ◽  
Abolfazl Jaafari
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Species Richness ◽  
Species Diversity ◽  
Tree Species ◽  
Abiotic Factors ◽  
Basal Area ◽  
Forest Productivity ◽  
Tree Species Diversity ◽  
Artificial Neural

The relative importance of different biotic and abiotic variables for estimating forest productivity remains unclear for many forest ecosystems around the world, and it is hypothesized that forest productivity could also be estimated by local biodiversity factors. Using a large dataset from 258 forest monitoring permanent sample plots distributed across uneven-aged and mixed forests in northern Iran, we tested the relationship between tree species diversity and forest productivity and examined whether several factors (solar radiation, topographic wetness index, wind velocity, seasonal air temperature, basal area, tree density, basal area in largest trees) had an effect on productivity. In our study, productivity was defined as the mean annual increment of the stem volume of a forest stand in m3 ha−1 year−1. Plot estimates of tree volume growth were based on averaged plot measurements of volume increment over a 9-year growing period. We investigated relationships between productivity and tree species diversity using parametric models and two artificial neural network models, namely the multilayer perceptron (MLP) and radial basis function networks. The artificial neural network (ANN) of the MLP type had good ability in prediction and estimation of productivity in our forests. With respect to species richness, Model 4, which had 10 inputs, 6 hidden layers and 1 output, had the highest R2 (0.94) and the lowest RMSE (0.75) and was selected as the best species richness predictor model. With respect to forest productivity, MLP Model 2 with 10 inputs, 12 hidden layers and 1 output had R2 and RMSE of 0.34 and 0.42, respectively, representing the best model. Both of these used a logistic function. According to a sensitivity analysis, diversity had significant and positive effects on productivity in species-rich broadleaved forests (approximately 31%), and the effects of biotic and abiotic factors were also important (29% and 40%, respectively). The artificial neural network based on the MLP was found to be superior for modeling productivity–diversity relationships.

scholarly journals How Does Radial Growth of Water-Stressed Populations of European Beech (Fagus sylvatica L.) Trees Vary under Multiple Drought Events?

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 129
Author(s):  
Tamalika Chakraborty ◽  
Albert Reif ◽  
Andreas Matzarakis ◽  
Somidh Saha
Keyword(s):  
Soil Water ◽  
Fagus Sylvatica ◽  
Tree Growth ◽  
Radial Growth ◽  
Basal Area ◽  
European Beech ◽  
Canopy Openness ◽  
Fagus Sylvatica L ◽  
The Impact ◽  
Neighborhood Competition

European beech (Fagus sylvatica L.) trees are becoming vulnerable to drought, with a warming climate. Existing studies disagree on how radial growth varies in European beech in response to droughts. We aimed to find the impact of multiple droughts on beech trees’ annual radial growth at their ecological drought limit created by soil water availability in the forest. Besides, we quantified the influence of competition and canopy openness on the mean basal area growth of beech trees. We carried out this study in five near-natural temperate forests in three localities of Germany and Switzerland. We quantified available soil water storage capacity (AWC) in plots laid in the transition zone from oak to beech dominated forests. The plots were classified as ‘dry’ (AWC < 60 mL) and ‘less-dry’ (AWC > 60 mL). We performed dendroecological analyses starting from 1951 in continuous and discontinuous series to study the influence of climatic drought (i.e., precipitation-potential evapotranspiration) on the radial growth of beech trees in dry and less-dry plots. We used observed values for this analysis and did not use interpolated values from interpolated historical records in this study. We selected six drought events to study the resistance, recovery, and resilience of beech trees to drought at a discontinuous level. The radial growth was significantly higher in less-dry plots than dry plots. The increase in drought had reduced tree growth. Frequent climatic drought events resulted in more significant correlations, hence, increased the dependency of tree growth on AWC. We showed that the recovery and resilience to climatic drought were higher in trees in less-dry plots than dry plots, but it was the opposite for resistance. The resistance, recovery, and resilience of the trees were heterogeneous between the events of drought. Mean growth of beech trees (basal area increment) were negatively impacted by neighborhood competition and positively influenced by canopy openness. We emphasized that beech trees growing on soil with low AWC are at higher risk of growth decline. We concluded that changes in soil water conditions even at the microsite level could influence beech trees’ growth in their drought limit under the changing climate. Along with drought, neighborhood competition and lack of light can also reduce beech trees’ growth. This study will enrich the state of knowledge about the ongoing debate on the vulnerability of beech trees to drought in Europe.

scholarly journals Temperature and Prey Species Richness Drive the Broad-Scale Distribution of a Generalist Predator

Diversity ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 169
Author(s):  
Danai-Eleni Michailidou ◽  
Maria Lazarina ◽  
Stefanos P. Sgardelis
Keyword(s):  
Species Richness ◽  
Species Distribution ◽  
Prey Species ◽  
Abiotic Factors ◽  
Biodiversity Loss ◽  
Generalist Predator ◽  
Distributional Patterns ◽  
The Future ◽  
Grass Snake ◽  
Broad Scale

The ongoing climate change and the unprecedented rate of biodiversity loss render the need to accurately project future species distributional patterns more critical than ever. Mounting evidence suggests that not only abiotic factors, but also biotic interactions drive broad-scale distributional patterns. Here, we explored the effect of predator-prey interaction on the predator distribution, using as target species the widespread and generalist grass snake (Natrix natrix). We used ensemble Species Distribution Modeling (SDM) to build a model only with abiotic variables (abiotic model) and a biotic one including prey species richness. Then we projected the future grass snake distribution using a modest emission scenario assuming an unhindered and no dispersal scenario. The two models performed equally well, with temperature and prey species richness emerging as the top drivers of species distribution in the abiotic and biotic models, respectively. In the future, a severe range contraction is anticipated in the case of no dispersal, a likely possibility as reptiles are poor dispersers. If the species can disperse freely, an improbable scenario due to habitat loss and fragmentation, it will lose part of its contemporary distribution, but it will expand northwards.

scholarly journals Seasonal biological carryover dominates northern vegetation growth

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xu Lian ◽  
Shilong Piao ◽  
Anping Chen ◽  
Kai Wang ◽  
Xiangyi Li ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Growing Season ◽  
Ecosystem Dynamics ◽  
Environmental Drivers ◽  
Subsequent Growth ◽  
Ecosystem Models ◽  
Carryover Effect ◽  
Vegetation Growth ◽  
Sequestration Potential ◽  
Future Warming

AbstractThe state of ecosystems is influenced strongly by their past, and describing this carryover effect is important to accurately forecast their future behaviors. However, the strength and persistence of this carryover effect on ecosystem dynamics in comparison to that of simultaneous environmental drivers are still poorly understood. Here, we show that vegetation growth carryover (VGC), defined as the effect of present states of vegetation on subsequent growth, exerts strong positive impacts on seasonal vegetation growth over the Northern Hemisphere. In particular, this VGC of early growing-season vegetation growth is even stronger than past and co-occurring climate on determining peak-to-late season vegetation growth, and is the primary contributor to the recently observed annual greening trend. The effect of seasonal VGC persists into the subsequent year but not further. Current process-based ecosystem models greatly underestimate the VGC effect, and may therefore underestimate the CO2 sequestration potential of northern vegetation under future warming.

scholarly journals Quantifying Understory Complexity in Unmanaged Forests Using TLS and Identifying Some of Its Major Drivers

2021 ◽  
Vol 13 (8) ◽  
pp. 1513
Author(s):  
Dominik Seidel ◽  
Peter Annighöfer ◽  
Christian Ammer ◽  
Martin Ehbrecht ◽  
Katharina Willim ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Structural Equation Models ◽  
Light Availability ◽  
Structural Complexity ◽  
Basal Area ◽  
Ecosystem Functions ◽  
Canopy Openness ◽  
Seasonal Precipitation ◽  
Wide Range ◽  
Precipitation And Temperature

The structural complexity of the understory layer of forests or shrub layer vegetation in open shrublands affects many ecosystem functions and services provided by these ecosystems. We investigated how the basal area of the overstory layer, annual and seasonal precipitation, annual mean temperature, as well as light availability affect the structural complexity of the understory layer along a gradient from closed forests to open shrubland with only scattered trees. Using terrestrial laser scanning data and the understory complexity index (UCI), we measured the structural complexity of sites across a wide range of precipitation and temperature, also covering a gradient in light availability and basal area. We found significant relationships between the UCI and tree basal area as well as canopy openness. Structural equation models (SEMs) confirmed significant direct effects of seasonal precipitation on the UCI without mediation through basal area or canopy openness. However, annual precipitation and temperature effects on the UCI are mediated through canopy openness and basal area, respectively. Understory complexity is, despite clear dependencies on the available light and overall stand density, significantly and directly driven by climatic parameters, particularly the amount of precipitation during the driest month.

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