scholarly journals Spatial Pattern and Competitive Relationships of Moso Bamboo in a Native Subtropical Rainforest Community

Forests ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 774 ◽  
Author(s):  
Haonan Zhang ◽  
Jianhui Xue
Keyword(s):  
Spatial Pattern ◽  
Correlation Functions ◽  
Large Scale ◽  
Pair Correlation ◽  
Moso Bamboo ◽  
Guizhou Province ◽  
Forest Community ◽  
Native Forest ◽  
Mature Trees ◽  
Native Forests

Bamboo has invaded native forests worldwide, and its aggressive spread by rhizomes facilitates patch expansion and the eventual replacement of adjacent forests. However, fine-scale studies of the spatial pattern and competitive relationships of bamboo in native forests are still lacking. We obtained data from nine plots in a native south subtropical rainforest in Guizhou Province, northwest China. Pair-correlation functions indicated that competition caused by bamboo expansion has not led to large-scale regular spatial distributions in bamboo forest and negative density-related dependence mechanisms regulating the spatial pattern of the native forest community. Marked correlation functions indicated small bamboo in clusters form colony patches that grow around the larger mature trees, resulting in patch expansion in the native forest community. Mark variogram functions identified significant positive spatial autocorrelation of moso bamboo caused by interactions with similar-sized trees within colony patches. This study showed that moso bamboo has colonized and expanded within the native forest community. Compared to the native forest species, the strategy of patch expansion and equal tree sizes in colony patches of moso bamboo could prevent regular distribution trend and size-asymmetric competition between nearby bamboo for the asymmetric and limited sources (i.e., light) in the forest, enhancing the persistence of moso bamboo in the native forest in our study stand located in a south subtropical rainforest in a river valley.

scholarly journals Assesment of soil erosion by 137Cs technique in native forests in Londrina City, Parana, Brazil

2007 ◽  
Vol 50 (6) ◽  
pp. 1051-1060 ◽  
Author(s):  
Avacir Casanova Andrello ◽  
Carlos Roberto Appoloni ◽  
Virgílio Franco do Nascimento Filho
Keyword(s):  
Soil Erosion ◽  
Soil Loss ◽  
Balance Model ◽  
Native Forest ◽  
Mass Balance Model ◽  
Erosion Process ◽  
137Cs Inventory ◽  
Native Forests ◽  
137Cs Distribution ◽  
137Cs Technique

The aim of this work was to assess the soil erosion process in native forest by the 137Cs methodology. The mass balance model was applied to assess the rates of soil loss in three native forests around of Londrina city, Paraná, Brazil. 137Cs distribution depth was of exponential type for the three forests and 137Cs inventory was 241 Bq m-2 for Mata 1, 338 Bq m-2 for Mata 2 and 325 Bq m-2 for Mata UEL. The soil loss value calculated for three native forests was: 6,684 kg ha-1 yr-1 for Mata 1, 1,788 kg ha-1 yr-1 for Mata 2 and 4,524 kg ha-1 yr-1 for Mata UEL.

scholarly journals Distinguishing step relaxation mechanisms via pair correlation functions

2004 ◽  
Vol 70 (23) ◽  
Author(s):  
D. B. Dougherty ◽  
I. Lyubinetsky ◽  
T. L. Einstein ◽  
E. D. Williams
Keyword(s):  
Correlation Functions ◽  
Pair Correlation ◽  
Pair Correlation Functions

scholarly journals An assessment of the population status of the threatened medicinal plant Illicium griffithii Hook.f. & Thomson in West Kameng District of Arunachal Pradesh, India

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Tashi Dorjee Bapu ◽  
Gibji Nimasow
Keyword(s):  
Medicinal Plant ◽  
Large Scale ◽  
Arunachal Pradesh ◽  
Mature Trees ◽  
Regeneration Rate ◽  
Dead Trees ◽  
Threatened Medicinal Plant ◽  
The Family ◽  
Proper Training ◽  
Large Scale Cultivation

Illicium griffithii Hook.f. & Thomson, a medicinal plant of the family Schisandraceae, is an Endangered species listed by the IUCN.  A decline in population of this plant due to climate change as well as increasing human influences on the natural resources has been a matter of great concern among the researchers.  In order to estimate the existing population of this plant, a field-based study employing linear transect method was conducted in four phases, May–June 2017, May–June 2018, April–May 2019, October–November 2019 covering an area of 700km² (approx.) in West Kameng District of Arunachal Pradesh that lies within the Himalayan biodiversity hotspot.  The study recorded 3,044 live individuals of I. griffithii including 1,372 seedlings, 1,358 saplings, and only 314 mature trees.  Additionally, 126 dead trees were also recorded.  The study confirmed that the plant has a good regeneration rate but with a poor survival rate of saplings.  Besides, large-scale collection of its fruits for trade and anthropogenic disturbances in the study area appears to be the major threat to its existing population.  Therefore, proper training of the local people on large-scale cultivation of this plant together with awareness towards judicious harvesting of fruits from the wild may be the significant approach to conservation. 

scholarly journals Differentiating amyloid beta spread in autosomal dominant and sporadic Alzheimer's disease

2021 ◽  
Author(s):  
Elizabeth Levitis ◽  
Jacob W Vogel ◽  
Thomas Funck ◽  
Vladimir Halchinski ◽  
Serge Gauthier ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Spatial Pattern ◽  
Amyloid Beta ◽  
Large Scale ◽  
Autosomal Dominant ◽  
Model Performance ◽  
Sporadic Alzheimer’S Disease ◽  
Individual Level ◽  
Data Driven Approach

Amyloid-beta (Aβ) deposition is one of the hallmark pathologies in both sporadic Alzheimer's disease (sAD) and autosomal dominant Alzheimer's disease (ADAD), the latter of which is caused by mutations in genes involved in Aβ processing. Despite Aβ deposition being a centerpiece to both sAD and ADAD, some differences between these AD subtypes have been observed with respect to the spatial pattern of Aβ. Previous work has shown that the spatial pattern of Aβ in individuals spanning the sAD spectrum can be reproduced with high accuracy using an epidemic spreading model (ESM), which simulates the diffusion of Aβ across neuronal connections and is constrained by individual rates of Aβ production and clearance. However, it has not been investigated whether Aβ deposition in the rarer ADAD can be modeled in the same way, and if so, how congruent the spreading patterns of Aβ across sAD and ADAD are. We leverage the ESM as a data-driven approach to probe individual-level variation in the spreading patterns of Aβ across three different large-scale imaging datasets (2 SAD, 1 ADAD). We applied the ESM separately to the Alzheimer's Disease Neuroimaging initiative (N=737), the Open Access Series of Imaging Studies (N=510), and the Dominantly Inherited Alzheimer's Network (N=249), the latter two of which were processed using an identical pipeline. We assessed inter- and intra-individual model performance in each dataset separately, and further identified the most likely epicenter of Aβ spread for each individual. Using epicenters defined in previous work in sAD, the ESM provided moderate prediction of the regional pattern of Aβ deposition across all three datasets. We further find that, while the most likely epicenter for most Aβ-positive subjects overlaps with the default mode network, 13% of ADAD individuals were best characterized by a striatal origin of Aβ spread. These subjects were also distinguished by being younger than ADAD subjects with a DMN Aβ origin, despite having a similar estimated age of symptom onset. Together, our results suggest that most ADAD patients express Aβ spreading patters similar to those of sAD, but that there may be a subset of ADAD patients with a separate, striatal phenotype.

scholarly journals Optimizing smartphone-based canopy hemispherical photography

2021 ◽  
Author(s):  
Gastón Mauro Díaz
Keyword(s):  
Large Scale ◽  
Forest Canopy ◽  
Accuracy Assessment ◽  
Low Cost ◽  
R Package ◽  
Coefficient Of Determination ◽  
Native Forest ◽  
Hemispherical Photography ◽  
Area Index ◽  
Plant Area Index

1) Hemispherical photography (HP) is a long-standing tool for forest canopy characterization. Currently, there are low-cost fisheye lenses to convert smartphones into high-portable HP equipment; however, they cannot be used whenever since HP is sensitive to illumination conditions. To obtain sound results outside diffuse light conditions, a deep-learning-based system needs to be developed. A ready-to-use alternative is the multiscale color-based binarization algorithm, but it can provide moderate-quality results only for open forests. To overcome this limitation, I propose coupling it with the model-based local thresholding algorithm. I call this coupling the MBCB approach. 2) Methods presented here are part of the R package CAnopy IMage ANalysis (caiman), which I am developing. The accuracy assessment of the new MBCB approach was done with data from a pine plantation and a broadleaf native forest. 3) The coefficient of determination (R^2) was greater than 0.7, and the root mean square error (RMSE) lower than 20 %, both for plant area index calculation. 4) Results suggest that the new MBCB approach allows the calculation of unbiased canopy metrics from smartphone-based HP acquired in sunlight conditions, even for closed canopies. This facilitates large-scale and opportunistic sampling with hemispherical photography.

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