scholarly journals Characteristics and factors influencing the natural regeneration of Larix principis-rupprechtii seedlings in northern China

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12327
Author(s):  
Weiwen Zhao ◽  
Wenjun Liang ◽  
Youzhi Han ◽  
Xi Wei
Keyword(s):  
Spatial Distribution ◽  
Natural Regeneration ◽  
Pair Correlation ◽  
Principal Component ◽  
Northern China ◽  
Point Pattern Analysis ◽  
Point Pattern ◽  
Adult Trees ◽  
Herb Diversity ◽  
Univariate Distribution

Larix principis-rupprechtii is an important and widely distributed species in the mountains of northern China. However, it has inefficient natural regeneration in many stands and difficulty recruiting seedlings and saplings. In this study, we selected six plots with improved naturally-regenerated L. principis-rupprechtii seedlings. A point pattern analysis (pair-correlation function) was applied to identify the spatial distribution pattern and correlation between adult trees and regenerated seedlings mapped through X/Y coordinates. Several possible influencing factors of L. principis-rupprechtii seedlings’ natural regeneration were also investigated. The results showed that the spatial distribution patterns of Larix principis-rupprechtii seedlings were concentrated 0–5 m around adult trees when considering the main univariate distribution type of regeneration. There was a positive correlation at a scale of 1.5–4 m between seedlings and adult trees according to bivariate analyses. When the scale was increased, these relationships were no longer significant. Generally, adult trees raised regenerated L. principis-rupprechtii seedlings at a scale of 1.5–4 m. Principal component analysis showed that the understory herb diversity and litter layer had a negative correlation with the number of regenerated seedlings. There was also a weak relationship between regenerated numbers and canopy density. This study demonstrated that the main factors promoting natural regeneration were litter thickness, herb diversity, and the distance between adult trees and regenerated seedlings. Additionally, these findings will provide a basis for the late-stage and practical management of natural regeneration in northern China’s mountain ranges.

Potential contact statistics for measuring scale-dependent spatial pattern and association: an example of northern cod (Gadus morhua) and capelin (Mallotus villosus)

2000 ◽  
Vol 57 (7) ◽  
pp. 1355-1368 ◽  
Author(s):  
Richard L O'Driscoll ◽  
David C Schneider ◽  
George A Rose ◽  
George R Lilly
Keyword(s):  
Spatial Distribution ◽  
Spatial Pattern ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Simulated Data ◽  
Point Pattern Analysis ◽  
Point Pattern ◽  
Mallotus Villosus ◽  
Capelin Mallotus Villosus ◽  
Potential Contact

Analysis of simulated data showed that potential contact statistics could be used to describe spatial pattern in sample density data. Potential contact is a new method, analogous to Ripley's K function for mapped point pattern analysis. Potential contact can be used to describe spatial pattern and association over a range of scales without grouping data and is robust against the presence of zeros. The statistical output is ecologically interpretable, as a measure of the degree of contact between individuals. This new technique was applied to examine changes in the spatial distribution of Atlantic cod (Gadus morhua) off Newfoundland, Canada, from 1985 to 1994, a period that encompassed a collapse of the cod stock. Sample data from bottom-trawl surveys indicated that cod were aggregated in patches with dimensions of 100-250 km. During the period of cod decline in the 1990s, spatial structure changed in three ways: the number of patches decreased, patch size shrank, and contact with conspecifics at small (10-20 km) scales fell. Cod were broadly associated with capelin (Mallotus villosus), a major prey species. Spatial distribution of capelin changed over the same time period as changes in cod distribution, and there was no evidence that contact between cod and capelin decreased.

scholarly journals Analyzing the Spatial Distribution of Drumlins: A Two-Phase Mosaic Approach

1984 ◽  
Vol 30 (106) ◽  
pp. 302-307
Author(s):  
B. N. Boots ◽  
R. K. Burns
Keyword(s):  
Spatial Distribution ◽  
Pattern Analysis ◽  
Point Pattern Analysis ◽  
Point Pattern ◽  
Statistical Bias ◽  
Two Phase ◽  
Alternative Approach ◽  
Mosaic Approach ◽  
The Individual

AbstractResearchers have analyzed various properties of drumlins within individual drumlin fields in order to provide evidence to help in identifying the processes involved in drumlin formation. One property which has been examined is the spatial distribution of drumlins within a field. Traditionally, in such endeavours the individual drumlins have been represented as points and their distribution examined using techniques of point-pattern analysis. We suggest that not only is such a representation inappropriate at this scale, it also introduces statistical bias which makes the results of such analyses questionable. Consequently, we propose an alternative approach which involves representing individual drumlins as areal phenomena and considering their pattern as a two-phase mosaic. The advantages of such an approach are discussed and it is illustrated by applying it to two different drumlin fields.

scholarly journals Spatial distribution of inselbergs in Igbajo district of Western Nigeria

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Matthew Afolabi ◽  
Olayinka Ogunkoya
Keyword(s):  
Spatial Distribution ◽  
Point Pattern Analysis ◽  
Point Pattern ◽  
P Value ◽  
Distribution Analysis ◽  
Nearest Neighbour ◽  
Test Statistic ◽  
Drainage Pattern ◽  
River Drainage ◽  
Significant Difference

Inselbergs’ spatial distribution is the primary focus of this study carried out in Igbajo District of Western Nigeria. Additionally, a common hypothesis that spatial distribution of inselbergs is informed by the differing modes of evolution of the landforms was also examined. Inselbergs are defined as points on the topographic sheet and satellite terrain elevation data and are thereafter subjected to point pattern analysis. Two point pattern analyses: Poisson Probability Distribution (PPD) and Nearest Neighbour Analysis (NNA) are employed to determine the pattern of inselberg distribution over space. Additional analysis focused on the relationship between regional river drainage and inselbergs’ spatial distribution. Findings from the study confirmed that inselberg form a clustered distribution. The PPD results suggest that the observed distribution of inselbergs has a statistically significant difference from the expected pattern generated by the random process (c2 test statistic = 49.82 >  =12.59 (α= 0.05) and 16.81 (α= 0.01). Similarly, the NNA with a R < 1 (Nearest Neighbour Ratio, R = 0.92) and p-value = -2.52, also indicated a clustered distribution. Analysis of river drainage pattern similarly revealed a cluster of high rising landforms situated in the centre of the regional watershed. It is concluded that inselberg distribution in the study area is clustered although the observed pattern does not necessarily validate or invalidate the alternative evolutionary theories.

scholarly journals Spatial distribution patterns of plague hosts: point pattern analysis of the burrows of great gerbils in Kazakhstan

2015 ◽  
Vol 42 (7) ◽  
pp. 1281-1292 ◽  
Author(s):  
Liesbeth I. Wilschut ◽  
Anne Laudisoit ◽  
Nelika K. Hughes ◽  
Elisabeth A. Addink ◽  
Steven M. de Jong ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Pattern Analysis ◽  
Distribution Patterns ◽  
Point Pattern Analysis ◽  
Point Pattern ◽  
Spatial Distribution Patterns

scholarly journals Analyzing the Spatial Distribution of Drumlins: A Two-Phase Mosaic Approach

1984 ◽  
Vol 30 (106) ◽  
pp. 302-307 ◽  
Author(s):  
B. N. Boots ◽  
R. K. Burns
Keyword(s):  
Spatial Distribution ◽  
Pattern Analysis ◽  
Point Pattern Analysis ◽  
Point Pattern ◽  
Statistical Bias ◽  
Two Phase ◽  
Alternative Approach ◽  
Mosaic Approach ◽  
The Individual

AbstractResearchers have analyzed various properties of drumlins within individual drumlin fields in order to provide evidence to help in identifying the processes involved in drumlin formation. One property which has been examined is the spatial distribution of drumlins within a field. Traditionally, in such endeavours the individual drumlins have been represented as points and their distribution examined using techniques of point-pattern analysis. We suggest that not only is such a representation inappropriate at this scale, it also introduces statistical bias which makes the results of such analyses questionable. Consequently, we propose an alternative approach which involves representing individual drumlins as areal phenomena and considering their pattern as a two-phase mosaic. The advantages of such an approach are discussed and it is illustrated by applying it to two different drumlin fields.

scholarly journals Proliferation of household waste irregular dumpsites in Niger Delta region (Nigeria): unsustainable public health monitoring and future restitution

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Donatus A. Okpara ◽  
Marianna Kharlamova ◽  
Vladimir Grachev
Keyword(s):  
Spatial Distribution ◽  
Negative Impact ◽  
Point Pattern Analysis ◽  
Household Waste ◽  
Point Pattern ◽  
Governmental Agencies ◽  
Public Health Monitoring ◽  
Niger Delta Region ◽  
Waste Dumps ◽  
Disease Occurrence

AbstractInadequate collection and improper disposal of municipal waste have a direct negative impact on cities. Disease occurrence in Obio-Akpor (Port Harcourt metropolis, Nigeria) was suspected and linked to the proliferation of dumpsites and proximity to residential households. Evidence showed frequent incidence of diseases outbreak coupled with the topographic coastal nature and the morphological propelling dynamics of sediments transport in the area assisting the situation. The main objective of this study was to assess how the spatial distribution of irregular dumpsites is linked to the disease occurrence (cholera, diarrhoea and malaria) in the community. The data used for the study was obtained through questionnaires administrated at the hospitals, use of GPS for locating disease incidences and waste dumps, interviews and observations. Point pattern analysis using the G-function and the K-function was employed in analyzing the spatial distribution of dumpsites and disease incidences. Correlation tests were performed to test for the relationship between disease incidences and presence of dumpsites. The results showed that there was a significant relationship (p < 0.05) between disease incidences and presence of dumpsites. It was also observed that diseases could occur in areas where dumpsites were not present as cholera and diarrhoea are contagious but malaria is not, though it spreads. The study will be beneficial to governmental agencies, waste managers, institutions, environmentalists, health, social workers and future researchers.

scholarly journals Spatial point pattern analysis of prehospital naloxone administrations

2017 ◽  
Author(s):  
Christopher Ryan
Keyword(s):  
United States ◽  
Monte Carlo Simulation ◽  
Spatial Distribution ◽  
Pattern Analysis ◽  
Spatial Clustering ◽  
The United States ◽  
Point Pattern Analysis ◽  
Point Pattern ◽  
Opioid Overdose ◽  
Spatial Point

AbstractObjectivesThe increasing problem in the United States with opioid dependence and overdose, often fatal, is well-recognized. As naloxone has only one clinical use—the treatment of opioid overdose—its administration by EMS personnel can serve as a surveillance indicator for opioid overdose. This study uses specific locations of EMS calls, and methods of point pattern analysis, to detect overall spatial clustering among EMS naloxone administrations compared to EMS calls in general.Study DesignA cross-sectional study of incident locations of EMS responses in a three-county EMS region in the United States.MethodsRepeated random samples from the spatial distribution of all EMS calls were used, in a Monte Carlo simulation, to represent the background inhomogeneity of the population. Observed F, G, and inhomogeneous K and L functions from the spatial distribution of naloxone-involved calls were compared to their null sampling distributions obtained from the Monte Carlo simulation.ResultsCases of naloxone administration demonstrated spatial clustering in the range of 0 to 5000 meters, and particularly around 2500 meters, beyond what could be attributable to the spatial heterogeneity of all EMS calls.ConclusionsEfforts to understand the fundamental nature of opioid overdose as a spatial point process could yield innovative public health interventions to control the epidemic.

scholarly journals Spatial distribution of four sympatric owl species in Carpathian montane forests

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Karol Šotnár ◽  
Ján Obuch ◽  
Samuel Pačenovský ◽  
Benjamín Jarčuška
Keyword(s):  
Spatial Distribution ◽  
Tree Species ◽  
Species Coexistence ◽  
Spatial Arrangement ◽  
Point Pattern Analysis ◽  
Stand Age ◽  
Point Pattern ◽  
Montane Forests ◽  
Aegolius Funereus ◽  
Coexistence Mechanisms

AbstractKnowledge about spatial distribution of owl species is important for inferring species coexistence mechanisms. In the present study, we explore spatial patterns of distribution and habitat selection of four owl species – Eurasian pygmy owl (Glaucidium passerinum), boreal owl (Aegolius funereus), tawny owl (Strix aluco) and Ural owl (Strix uralensis) – ranging in body mass from 50 g to 1300 g, with sympatric occurrence in temperate continuous montane forests in the Veľká Fatra Mts., Western Carpathians, central Slovakia. Locations of hooting owl males were surveyed between 2009–2015 in an area of 317 km2. Spatial point pattern analysis was used for analysis of owl distribution. Random patterns of owls’ spatial arrangement dominate at both intra‐ and interspecific levels within the studied area. Only intraspecific distribution of pygmy owls and interspecific distribution of Ural owls toward tawny owls exhibited positive associations. This discrepancy with other studies can be explained in terms of pygmy owls’ preference for high‐quality nest sites and/or spatial clustering in their prey distribution, and due to aggressive behaviour of dominant Ural owls toward subdominant tawny owls, respectively. Moreover, we found considerable overlap in habitat preferences between owl species, considering stand age, stand height, tree species richness, distance to open area, elevation, slope, percentage of coniferous tree species and position on hillslope, although pygmy owls were not registered in pure broadleaved stands, Ural owls were not registered in pure coniferous stands, and boreal and Ural owls were more common on slope summits and shoulders than tawny and pygmy owls. The observed patterns of spatial arrangement might suggest developed coexistence mechanisms in these owl species; differences between studies may indicate complex interactions between intra‐ and interspecific associations and habitat quality and quantity, food availability and owl species involved in those interactions on a landscape scale.

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